serial: max310x: fix indentation

Fix indentation and add line after do/while() block.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-18-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: reformat and improve comments

Add comments about I2C slave address structure, and reformat to
improve readability.

Also reformat some comments according to kernel coding style.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-17-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: replace bare use of 'unsigned' with 'unsigned int' (checkpatch)

Fixes the following checkpatch warnings:

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

With this change, the affected functions now match the prototypes in
struct gpio_chip.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-16-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use common power function for all variants

Simplify driver by defining a common function to handle the power
control of all variants.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-15-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use common detect function for all variants

Simplify driver by defining a common function to handle the detection
of all variants.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-14-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: replace hardcoded masks with preferred GENMASK()

GENMASK() is preferred when defining bitmasks.

Of all the masks changed, only MAX310x_REV_MASK is actually used.

No functional change.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-13-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use dev_err_probe() instead of dev_err()

Replace dev_err() with dev_err_probe().

This helps in simplifing code and standardizing the error output.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-12-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: add explicit return for some switch default cases

Allows to simplify code by removing the break statement in the default
switch/case in some functions.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-11-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: simplify probe() and remove() error handling

Simplify error handling and only call uart_remove_one_port() if line bit
is set, instead of having to manually set s->p[i].port.dev to NULL.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-10-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use separate regmap name for each port

Use a separate regmap name for each port so they can each have their own
debugfs entry, allowing to access each port registers independently.

For example, a four channels/ports device like the MAX14830 will have four
entries in its regmap debugfs:

$ find /sys/kernel/debug/regmap -type d | grep spi0.0
/sys/kernel/debug/regmap/spi0.0-port0
/sys/kernel/debug/regmap/spi0.0-port1
/sys/kernel/debug/regmap/spi0.0-port2
/sys/kernel/debug/regmap/spi0.0-port3

Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://lore.kernel.org/all/77f101f1-897d-4e6d-a8fd-27b818caf768@cesnet.cz/
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-9-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: add macro for max number of ports

Add macro to hold the maximum number of UART ports per IC/device.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Tested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://lore.kernel.org/all/ddbc67dd-f8a3-4a6a-954a-bee49260ecab@cesnet.cz/
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-8-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: remove holes in struct max310x_devtype

Running pahole shows that there are some holes within the
max310x_devtype structure.

Remove holes and optimize alignment by reorganizing structure members.

This can also lead to data structure size reduction for some CPUs.

On 64-bit CPU (arm64):
Before:
/* size: 40, cachelines: 1, members: 6 */
/* sum members: 34, holes: 2, sum holes: 6 */
/* last cacheline: 40 bytes */
After:
/* size: 40, cachelines: 1, members: 6 */
/* padding: 6 */
/* last cacheline: 40 bytes */

On 32-bit CPU (i386):
Before:
/* size: 32, cachelines: 1, members: 6 */
/* sum members: 26, holes: 2, sum holes: 6 */
/* last cacheline: 32 bytes */
After:
/* size: 24, cachelines: 1, members: 8 */
/* padding: 2 */
/* last cacheline: 24 bytes */

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-7-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: fix syntax error in IRQ error message

Replace g with q.

Helpful when grepping thru source code or logs for
"request" keyword.

Fixes: f65444187a66 ("serial: New serial driver MAX310X")
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-6-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use spi_get_device_match_data()

Use preferred spi_get_device_match_data() instead of
device_get_match_data() and spi_get_device_id() to get the driver match
data.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use i2c_get_match_data()

Use preferred i2c_get_match_data() instead of device_get_match_data()
to get the driver match data.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-4-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: add I2C device table for instantiation from userspace

This allows to instantiate a max14830 I2C device from userspace.

Helpful when testing driver with i2c-stub.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: fix NULL pointer dereference in I2C instantiation

When trying to instantiate a max14830 device from userspace:

echo max14830 0x60 > /sys/bus/i2c/devices/i2c-2/new_device

we get the following error:

Unable to handle kernel NULL pointer dereference at virtual address...
...
Call trace:
max310x_i2c_probe+0x48/0x170 [max310x]
i2c_device_probe+0x150/0x2a0
...

Add check for validity of devtype to prevent the error, and abort probe
with a meaningful error message.

Fixes: 2e1f2d9a9bdb ("serial: max310x: implement I2C support")
Cc: stable@vger.kernel.org
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240118152213.2644269-2-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: prevent infinite while() loop in port startup

If there is a problem after resetting a port, the do/while() loop that
checks the default value of DIVLSB register may run forever and spam the
I2C bus.

Add a delay before each read of DIVLSB, and a maximum number of tries to
prevent that situation from happening.

Also fail probe if port reset is unsuccessful.

Fixes: 10d8b34a4217 ("serial: max310x: Driver rework")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240116213001.3691629-5-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: fail probe if clock crystal is unstable

A stable clock is really required in order to use this UART, so log an
error message and bail out if the chip reports that the clock is not
stable.

Fixes: 4cf9a888fd3c ("serial: max310x: Check the clock readiness")
Cc: stable@vger.kernel.org
Suggested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://www.spinics.net/lists/linux-serial/msg35773.html
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240116213001.3691629-4-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: improve crystal stable clock detection

Some people are seeing a warning similar to this when using a crystal:

max310x 11-006c: clock is not stable yet

The datasheet doesn't mention the maximum time to wait for the clock to be
stable when using a crystal, and it seems that the 10ms delay in the driver
is not always sufficient.

Jan Kundrát reported that it took three tries (each separated by 10ms) to
get a stable clock.

Modify behavior to check stable clock ready bit multiple times (20), and
waiting 10ms between each try.

Note: the first draft of the driver originally used a 50ms delay, without
checking the clock stable bit.
Then a loop with 1000 retries was implemented, each time reading the clock
stable bit.

Fixes: 4cf9a888fd3c ("serial: max310x: Check the clock readiness")
Cc: stable@vger.kernel.org
Suggested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://www.spinics.net/lists/linux-serial/msg35773.html
Link: https://lore.kernel.org/all/20240110174015.6f20195fde08e5c9e64e5675@hugovil.com/raw
Link: https://github.com/boundarydevices/linux/commit/e5dfe3e4a751392515d78051973190301a37ca9a
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240116213001.3691629-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: set default value when reading clock ready bit

If regmap_read() returns a non-zero value, the 'val' variable can be left
uninitialized.

Clear it before calling regmap_read() to make sure we properly detect
the clock ready bit.

Fixes: 4cf9a888fd3c ("serial: max310x: Check the clock readiness")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240116213001.3691629-2-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: change confusing comment about Tx FIFO

The comment wording can be confusing, as txlen will return the number of
bytes available in the FIFO, which can be less than the maximum theoretical
Tx FIFO size.

Change the comment so that it is unambiguous.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231122175957.3875102-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: remove trailing whitespaces

Fix coding style. No functional changes.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231011130317.3562401-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: fix typos in comments

cotroller -> controller.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230803175931.981625-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: add comments for membase address workaround

Add comments about workaround used to configure membase address. This
follows suggestions made during review of a sc16is7xx driver patch to
add the same workaround.

Link: https://lore.kernel.org/lkml/2936e18f-44ea-faed-9fa0-2ddefe7c3194@linux.intel.com
Link: https://lore.kernel.org/lkml/20230801131655.80bd8f97f018dda6155d65f6@hugovil.com/
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230803140551.970141-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: drivers: switch ch and flag to u8

Now that the serial layer explicitly expects 'u8' for flags and
characters, propagate this type to drivers' (RX) routines.

Note that amba-pl011's, clps711x's and st-asc's 'ch' are left unchanged
because 'ch' contains not only a character, but whole status.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@orcam.me.uk>
Cc: Taichi Sugaya <sugaya.taichi@socionext.com>
Cc: Takao Orito <orito.takao@socionext.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Hammer Hsieh <hammerh0314@gmail.com>
Acked-by: Richard GENOUD <richard.genoud@gmail.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/20230712081811.29004-11-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Switch i2c drivers back to use .probe()

After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498b5 ("i2c: Switch .probe() to not take an id parameter")
convert back to (the new) .probe() to be able to eventually drop
.probe_new() from struct i2c_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230525210147.734737-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: fix IO data corruption in batched operations

After upgrading from 5.16 to 6.1, our board with a MAX14830 started
producing lots of garbage data over UART. Bisection pointed out commit
285e76fc049c as the culprit. That patch tried to replace hand-written
code which I added in 2b4bac48c1084 ("serial: max310x: Use batched reads
when reasonably safe") with the generic regmap infrastructure for
batched operations.

Unfortunately, the `regmap_raw_read` and `regmap_raw_write` which were
used are actually functions which perform IO over *multiple* registers.
That's not what is needed for accessing these Tx/Rx FIFOs; the
appropriate functions are the `_noinc_` versions, not the `_raw_` ones.

Fix this regression by using `regmap_noinc_read()` and
`regmap_noinc_write()` along with the necessary `regmap_config` setup;
with this patch in place, our board communicates happily again. Since
our board uses SPI for talking to this chip, the I2C part is completely
untested.

Fixes: 285e76fc049c ("serial: max310x: use regmap methods for SPI batch operations")
Cc: stable@vger.kernel.org
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://lore.kernel.org/r/79db8e82aadb0e174bc82b9996423c3503c8fb37.1680732084.git.jan.kundrat@cesnet.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Make uart_handle_cts_change() status param bool active

Convert uart_handle_cts_change() to bool which is more appropriate
than unsigned int.

Rename status to active to better describe what the parameter means.
While at it, make the comment about the active parameter easier to
parse.

Cleanup callsites from operations that are not necessary with bool.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230117090358.4796-10-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Use uart_xmit_advance()

Take advantage of the new uart_xmit_advance() helper.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20221019091151.6692-22-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Make ->set_termios() old ktermios const

There should be no reason to adjust old ktermios which is going to get
discarded anyway.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

i2c: Make remove callback return void

The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

serial: Embed rs485_supported to uart_port

Embed rs485_supported to uart_port to allow serial core to tweak it as
needed.

Reviewed-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220704094515.6831-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: take termios_rwsem for ->rs485_config() & pass termios as param

To be able to alter ADDRB within ->rs485_config(), take termios_rwsem
before calling ->rs485_config() and pass termios.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Remove serial_rs485 sanitization

Serial core handles serial_rs485 sanitization.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-33-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fill in rs485_supported

Add information on supported serial_rs485 features.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-18-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: implement I2C support

I2C implementation on this chip has a few key differences
compared to SPI, as described in previous patches.
* extended register space access needs no extra logic
* slave address is used to select which UART to communicate
with

To accommodate these differences, add an I2C interface config,
set the RevID register address and implement an empty method
for setting the GlobalCommand register, since no special handling
is needed for the extended register space.

To handle the port-specific slave address, create an I2C dummy
device for each port, except the base one (UART0), which is
expected to be the one specified in firmware, and create a
regmap for each I2C device.
Add minimum and maximum slave addresses to each devtype for
sanity checking.

Also, use a separate regmap config with no write_flag_mask,
since I2C has a R/W bit in its slave address, and set the
max register to the address of the RevID register, since the
extended register space needs no extra logic.

Finally, add the I2C driver.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220605144659.4169853-5-demonsingur@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: make accessing revision id interface-agnostic

SPI can only use 5 address bits, since one bit is reserved for
specifying R/W and 2 bits are used to specify the UART port.
To access registers that have addresses past 0x1F, an extended
register space can be enabled by writing to the GlobalCommand
register (address 0x1F).

I2C uses 8 address bits. The R/W bit is placed in the slave
address, and so is the UART port. Because of this, registers
that have addresses higher than 0x1F can be accessed normally.

To access the RevID register, on SPI, 0xCE must be written to
the 0x1F address to enable the extended register space, after
which the RevID register is accessible at address 0x5. 0xCD
must be written to the 0x1F address to disable the extended
register space.

On I2C, the RevID register is accessible at address 0x25.

Create an interface config struct, and add a method for
toggling the extended register space and a member for the RevId
register address. Implement these for SPI.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220605144659.4169853-4-demonsingur@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use a separate regmap for each port

The driver currently does manual register manipulation in
multiple places to talk to a specific UART port.

In order to talk to a specific UART port over SPI, the bits U1
and U0 of the register address can be set, as explained in the
Command byte configuration section of the datasheet.

Make this more elegant by creating regmaps for each UART port
and setting the read_flag_mask and write_flag_mask
accordingly.

All communcations regarding global registers are done on UART
port 0, so replace the global regmap entirely with the port 0
regmap.

Also, remove the 0x1f masks from reg_writeable(), reg_volatile()
and reg_precious() methods, since setting the U1 and U0 bits of
the register address happens inside the regmap core now.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220605144659.4169853-3-demonsingur@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use regmap methods for SPI batch operations

The SPI batch read/write operations can be implemented as simple
regmap raw read and write, which will also try to do a gather
write just as it is done here.

Use the regmap raw read and write methods.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220605144659.4169853-2-demonsingur@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310: remove redundant memset in rs485_config

In uart_set_rs485_config() the serial core already nullifies the padding
field of the passed serial_rs485 struct before returning it to userspace.

Doing the same in the drivers rs485_config() function is redundant, so
remove the concerning memset in this function.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-7-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: make remove callback a void function

The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

serial: max310x: Make max310x_remove() return void

Up to now max310x_remove() returns zero unconditionally. Make it return
void instead which makes it easier to see in the callers that there is
no error to handle.

Also the return value of spi remove callbacks is ignored anyway.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211012153945.2651412-18-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Use clock-names property matching to recognize EXTCLK

Dennis reported that on ACPI-based systems the clock frequency
isn't enough to configure device properly. We have to respect
the clock source as well. To achieve this match the clock-names
property against "osc" to recognize external clock connection.
On DT-based system this doesn't change anything.

Reported-and-tested-by: Dennis Giaya <dgiaya@whoi.edu>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210723125943.22039-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Unprepare and disable clock in error path

In one error case the clock may be left prepared and enabled.
Unprepare and disable clock in that case to balance state of
the hardware.

Fixes: d4d6f03c4fb3 ("serial: max310x: Try to get crystal clock rate from property")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210625153733.12911-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Try to get crystal clock rate from property

In some configurations, mainly ACPI-based, the clock frequency of the device
is supplied by very well established 'clock-frequency' property. Hence, try
to get it from the property at last if no other providers are available.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210517172930.83353-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: unregister uart driver in case of failure and abort

The macro "spi_register_driver" invokes the function
"__spi_register_driver()" which has a return type of int and can fail,
returning a negative value in such a case. This is currently ignored and
the init() function yields success even if the spi driver failed to
register.

Fix this by collecting the return value of "__spi_register_driver()" and
also unregister the uart driver in case of failure.

Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Atul Gopinathan <atulgopinathan@gmail.com>
Link: https://lore.kernel.org/r/20210503115736.2104747-12-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "serial: max310x: pass return value of spi_register_driver"

This reverts commit 51f689cc11333944c7a457f25ec75fcb41e99410.

Because of recent interactions with developers from @umn.edu, all
commits from them have been recently re-reviewed to ensure if they were
correct or not.

Upon review, this commit was found to be incorrect for the reasons
below, so it must be reverted. It will be fixed up "correctly" in a
later kernel change.

This change did not properly unwind from the error condition, so it was
not correct.

Cc: Kangjie Lu <kjlu@umn.edu>
Acked-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20210503115736.2104747-11-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: fix flexible_array.cocci warnings

Zero-length and one-element arrays are deprecated, see
Documentation/process/deprecated.rst
Flexible-array members should be used instead.

Generated by: scripts/coccinelle/misc/flexible_array.cocci

Fixes: 10d8b34a42171 ("serial: max310x: Driver rework")
CC: Denis Efremov <efremov@linux.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Link: https://lore.kernel.org/r/alpine.DEB.2.22.394.2103091516020.2892@hadrien
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "serial: max310x: rework RX interrupt handling"

This reverts commit fce3c5c1a2d9cd888f2987662ce17c0c651916b2.

FIFO is triggered 4 intervals after receiving a byte, it's good
when we don't care about the time of reception, but are only
interested in the presence of any activity on the line.
Unfortunately, this method is not suitable for all tasks,
for example, the RS-485 protocol will not work properly,
since the state machine must track the request-response time
and after the timeout expires, a decision is made that the device
on the line is not responding.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Link: https://lore.kernel.org/r/20210217080608.31192-1-shc_work@mail.ru
Fixes: fce3c5c1a2d9 ("serial: max310x: rework RX interrupt handling")
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Use devm_clk_get_optional() to get the input clock

Simplify the code which fetches the input clock by using
devm_clk_get_optional(). If no input clock is present
devm_clk_get_optional() will return NULL instead of an error
which matches the behavior of the old code.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20201007084635.594991-2-andy.shevchenko@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Make use of device properties

Device property API allows to gather device resources from different sources,
such as ACPI. Convert the drivers to unleash the power of device property API.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20201007084635.594991-1-andy.shevchenko@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: rework RX interrupt handling

Currently, the RX interrupt logic uses the RXEMPTY interrupt, with the
RXEMPTYINV bit set, which means we get an RX interrupt as soon as the
RX FIFO is non-empty.

However, with the MAX310X having a FIFO of 128 bytes, this makes very
poor use of the FIFO: we trigger an interrupt as soon as the RX FIFO
has one byte, which means a lot of interrupts, each only collecting a
few bytes from the FIFO, causing a significant CPU load.

Instead this commit relies on two other RX interrupt events:

- MAX310X_IRQ_RXFIFO_BIT, which triggers when the RX FIFO has reached
a certain threshold, which we define to be half of the FIFO
size. This ensure we get an interrupt before the RX FIFO fills up.

- MAX310X_LSR_RXTO_BIT, which triggers when the RX FIFO has received
some bytes, and then no more bytes are received for a certain
time. Arbitrarily, this time is defined to the time is takes to
receive 4 characters.

On a Microchip SAMA5D3 platform that is receiving 20 bytes every 16ms
over one MAX310X UART, this patch has allowed to reduce the CPU
consumption of the interrupt handler thread from ~25% to 6-7%.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Link: https://lore.kernel.org/r/20201001074415.349739-1-thomas.petazzoni@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control

As documented in the data-sheet, the transmitter must be disabled before
activating AutoCTS or auto transmitter flow control. Accordingly, the
transmitter must be enabled after AutoCTS or auto transmitter flow
control gets deactivated.

Signed-off-by: Christoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121746.4641-1-c.vogtlaender@sigma-surface-science.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Properly set flags in AutoCTS mode

Commit 391f93f2ec9f ("serial: core: Rework hw-assisted flow control
support") has changed the way the AutoCTS mode is handled.

According to that change, serial drivers which enable H/W AutoCTS mode must
set UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF to prevent the
serial core from inadvertently disabling RX or TX. This patch adds proper
handling of UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF flags.

Signed-off-by: Christoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121141.4570-1-c.vogtlaender@sigma-surface-science.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: fix off-by-one buffer access when storing overrun

A recent change split the insertion loop into two parts. The first part
accessed bytes 0, 1, ... (rxlen - 2), and the second part by mistake
took offset `rxlen` instead of the correct `rxlen - 1`. So one byte was
not stored, and the final access wrote past the end of the rx_buf.

Fixes: 9c12d739d69b (tty: max310x: Split uart characters insertion loop)
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/13ea227620aaad8a7231d42ed03a8508297d4eb3.1567027079.git.jan.kundrat@cesnet.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Fix external crystal register setup

The datasheet states:

Bit 4: ClockEnSet the ClockEn bit high to enable an external clocking
(crystal or clock generator at XIN). Set the ClockEn bit to 0 to disable
clocking
Bit 1: CrystalEnSet the CrystalEn bit high to enable the crystal
oscillator. When using an external clock source at XIN, CrystalEn must
be set low.

The bit 4, MAX310X_CLKSRC_EXTCLK_BIT, should be set and was not.

This was required to make the MAX3107 with an external crystal on our
board able to send or receive data.

Signed-off-by: Joe Burmeister <joe.burmeister@devtank.co.uk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Split uart characters insertion loop

Batch read mode doesn't check any conditions or flags except the Rx
overflow one. But it may only happen after the last character is pushed
into the RHR register. In this case we shouldn't push all the read
characters with overrun flag set, but only the last one caused the
FIFO overflow. This commit splits the characters retrieval loop into
two parts. First one is ordinary intsert-chars procedure without taking
the overrun status into account. Second part inserts the last character
checking whether the overrun happened and pushing a '\0' character with
TTY_OVERRUN flag to a flip-buffer.

If we left the loop the way it was the '\0' character would be inserted
after each character retrieved at the overrun occasion.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Optionally enable rs485 on startup

UART port might be pre-configured with rs485 enabled flag at the
time of the port starting up process. In this case we need to
have the hardware rs485-related registers initialized in accordance
with the rs485 flags and settings provided by the configs descriptor.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Add rx-during-tx rs485 flag support

The driver currently sets the echo suppression bit by default when rs485
is enabled. Naturally it disables any data retrieval in rs485 mode while
RTSn is pushed up. The receiver gate (RX_) can be enabled just by clearing
(or not setting) the EchoSuprs bit of mode2 register. So by setting or
clearing the bit we implement the SER_RS485_RX_DURING_TX rs485 flag
support.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Fix invalid baudrate divisors calculator

Current calculator doesn't do it' job quite correct. First of all the
max310x baud-rates generator supports the divisor being less than 16.
In this case the x2/x4 modes can be used to double or quadruple
the reference frequency. But the current baud-rate setter function
just filters all these modes out by the first condition and setups
these modes only if there is a clocks-baud division remainder. The former
doesn't seem right at all, since enabling the x2/x4 modes causes the line
noise tolerance reduction and should be only used as a last resort to
enable a requested too high baud-rate.

Finally the fraction is supposed to be calculated from D = Fref/(c*baud)
formulae, but not from D % 16, which causes the precision loss. So to speak
the current baud-rate calculator code works well only if the baud perfectly
fits to the uart reference input frequency.

Lets fix the calculator by implementing the algo fully compliant with
the fractional baud-rate generator described in the datasheet:
D = Fref / (c*baud), where c={16,8,4} is the x1/x2/x4 rate mode
respectively, Fref - reference input frequency. The divisor fraction is
calculated from the same formulae, but making sure it is found with a
resolution of 0.0625 (four bits).

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Don't pass stacked buffers to SPI

SPI transfer tx/rx buffers must be DMA-safe and the structure
documentation clearly states this. Data declared on the system stack isn't
DMA-safe [1]. Instead at least kernel memory should be used for the
buffers. In order to fix this here we can create the buffers at the device
probing stage and use them without any synchronization, since batch
read/write methods are called from non-reentrant contexts - either from
rx-event IRQ threaded handler or from the tx workqueue item.

[1] Documentation/DMA-API-HOWTO.txt

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Introduce max310x_one port macro-wrapper

uart_port structure instance is embedded into the max310x_one
super-structure, which is accessed by some of the uart-port callback
methods. In order to improve the callback's code readability lets
define the to_max310x_port() wrapper which just translates the passed
uart_port pointer to the max310x_one one. It is also going to be
handy in future commits.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Simplify tx-work item code

Since cmwq introduction in the kernel, workqueues've been turned into
non-reentrant execution contexts [1]. It means any work item is
guaranteed to be executed by at most one worker system-wide at any
given time. Since tx-handler max310x_handle_tx() is called by a
single work item we don't need it to be self-protected by the mutex.
We also don't need to check the tx work item pending state before
scheduling it (which in the first place was racy btw), since cmwq will
make sure to reschedule the item if it wasn't pending at the moment of
schedule_work() call.

[1] Documentation/core-api/workqueue.rst

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix to avoid potential NULL pointer dereference

of_match_device can return a NULL pointer when matching device is not
found. This patch avoids a scenario causing NULL pointer derefernce.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Correction of the initial setting of the MODE1 bits for various supported ICs.

The MODE1 register bits have different values for different ICs.
This patch corrects the initial setting of this register in accordance
with the datasheets, which will allow you to get the expected values
when debugging the driver.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Use struct_size() in devm_kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
int stuff;
void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: pass return value of spi_register_driver

spi_register_driver() may fail, so let's pass its return value upstream.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix tx_empty() callback

Function max310x_tx_empty() accesses the IRQSTS register, which is
cleared by IC when reading, so if there is an interrupt status, we
will lose it. This patch implement the transmitter check only by
the current FIFO level.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Check the clock readiness

This chip has a diagnostics status bit informing about the state and
stability of the clock subsystem. According to the datasheet (STSint
register, bit 5, ClockReady), this bit works with the crystal
oscillator, but even without the PLL. Therefore:

- ensure that the clock check is done even when PLL is not active
- warn when the chip thinks that the clock is not ready yet

There are HW features which would let us wait asynchronously (there's a
maskable IRQ for that bit), but I think that even this simple check is a
net improvement. It would have saved me two days of debugging :).

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

gpio: serial: max310x: Use HW type for gpio_chip's label

Some debugging tools (/sys/kernel/debug/gpio, `lsgpio`) use the
gpio_chip's label for displaying an additional context. Right now, the
information duplicates stuff which is already available from the
parent's device. This is how e.g. `lsgpio`'s output looks like:

GPIO chip: gpiochip2, "spi1.2", 16 GPIO lines

Comparing the output of other GPIO expanders that I have available:

gpiochip4: GPIOs 464-479, parent: spi/spi1.1, mcp23s17, can sleep:
gpiochip5: GPIOs 448-463, parent: i2c/0-0020, pca9555, can sleep:
gpiochip2: GPIOs 496-511, parent: spi/spi1.2, spi1.2, can sleep:

This patch ensures that the type of the real HW device is shown instead
of duplicating the SPI path:

gpiochip2: GPIOs 496-511, parent: spi/spi1.2, MAX14830, can sleep:

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

gpio: serial: max310x: Support open-drain configuration for GPIOs

The push-pull vs. open-drain are the only supported output modes. The
inputs are always unconditionally equipped with weak pull-downs. That's
the only mode, so there's probably no point in exporting that. I wonder
if it's worthwhile to provide a custom dbg_show method to indicate the
current status of the outputs, though.

This patch and [1] for i2c-gpio together make it possible to bit-bang an
I2C bus over GPIOs of an UART which is connected via SPI :). Yes, this
is crazy, but it's fast enough (while on a 26Mhz SPI HW bus with a
dual-core 1.6GHz CPU) to drive an I2C bus at 200kHz, according to my
scope.

[1] https://patchwork.ozlabs.org/patch/852591/

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Reduce RX work starvation

Prior to this patch, the code would happily trigger TX on some ports
before having a chance of reading the RX buffer from the rest of them.
When no flow control was used, this led to RX buffer overruns and
therefore lost data under certain circumstances.

I was able to reproduce this with MAX14830 (that's a quad channel one)
and a simple daisy-chain of RX and TX ports on the eval board:

- TX0 -> RX1
- TX1 -> RX2
- TX2 -> RX3
- TX3 -> RX0

I was testing this by transferring 2MB of data at 115200 baud via each
port. I used a Solidrun Clearfog Base (Armada 388) which was talking to
the UART over an SPI bus clocked at 26MHz (the chip's maximum). Without
this patch, I would always get a "Possible RX FIFO overrun" in dmesg,
and fewer-than-expected amount of bytes received over ttyMAX0. Results
on ttyMAX{1,2,3} tended to be correct all the time, even without the
previous patches in this series and with PIO SPI transfers ("indirect
mode" as the Marvell datasheet calls it), so I assume that heavy
congestion is needed in order to reproduce this.

A drawback of this patch is that the throughput gets reduced "a bit".
Previously, a 115200 baud resulted in about 11.2kBps throughput as
reported by a simple `pv`. With this patch, the throughput of four
parallel streams is roughly 7kBps each, and 9kBps for three streams.
There is no slowdown for one or two parallel streams.

Situation is worse if bytes are being read one-by-one (such as if the
userspace wants to perform parity/framing/break checking) and therefore
without the batched reads.

With just this patch and no other modifications on top of 4.14, I was
only getting roughly 3.6kBps with four parallel streams. The
single-stream performance was the same, and I was seeing about 7.2kBps
with two parallel streams. `perf top` said that a substantial amount of
time was spent in `finish_task_switch`, `_raw_spin_unlock_irqrestore`
and `__timer_delay`.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Use batched reads when reasonably safe

The hardware has a 128 byte RX FIFO buffer for each independent UART.
Previously, the code was always reading that byte-by-byte via
independent SPI transactions and the associated overhead. In practice,
this led to up to eight bytes over SPI for just one byte in the UART's
RX FIFO:

- reading the global IRQ register (two bytes, one for command, the other
for data)
- reading one UART's ISR (again two bytes)
- reading the byte count (two bytes yet again)
- finally, reading one byte of the FIFO via another two-byte transaction

We cannot always use a batched read. If the TTY is set to intercept
break conditions or report framing or parity errors, then it is required
to check the Line Status Register (LSR) for each byte which is read from
the RX FIFO. The documentation does not show a way of doing that in a
single SPI transaction; registers 0x00 and 0x04 are separate.

In my testing, this is no silver bullet. I was feeding 2MB of random
data over four daisy-chaned UARTs of MAX14830, and this is the
distribution that I was getting:

- R <= 1: 7437322
- R <= 2: 162093
- R <= 4: 4093
- R <= 8: 4196
- R <= 16: 645
- R <= 32: 165
- R <= 64: 58
- R <= 128: 0

For a reference, batching the write operations works much better:

- W <= 1: 2664
- W <= 2: 1305
- W <= 4: 627
- W <= 8: 371
- W <= 16: 121
- W <= 32: 68
- W <= 64: 33
- W <= 128: 63139

That's probably because this HW/SW combination (Clearfog Base, Armada
388) is probably "good enough" to react to the chip's IRQ "fast enough"
most of the time. Still, I was getting RX overruns every now and then.
In future, I plan to improve this by letting the RX FIFO be filled a
little more (the chip has support for that and also for a "stale
timeout" to prevent additional starvation).

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use a batch write op for UART transmit

The transmit register supports batched writes. The key is simply to keep
sending additional bytes up to the FIFO size in the same SPI
transaction with the CS pin still being held low.

This duplicates the regmap infrastructure to a certain extent. There are
some provisions for multiple writes in there, but there does not appear
to be any support for those writes which are destined to the *same*
register (and also no standard for SPI bus transfers of these, anyway).

This patch does not solve every case (if the UART xmit circular buffer
wraps around, we're still doing two SPI transactions), but at least
it's not one-byte-per-transaction anymore.

This change does not touch the receive path at this time. Doing that in
the generic case appears to be impossible in the general case, because
the chips' status register contains data about the *current* byte in the
HW's Rx FIFO. We cannot read these two registers in one go,
unfortunately.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Support IRQ sharing with other devices

According to my chip's datasheet [1], the IRQ output is an open
collector pin which is suitable for sharing with other chips. The chip
also has a register which indicates which UART performed a change and
the driver checks that register already, so we have everything what is
needed to effectively share the IRQ GPIO.

[1] https://datasheets.maximintegrated.com/en/ds/MAX14830.pdf

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Do not hard-code the IRQ type

As suggested by Russell King, a driver should not really care about bits
such as the interrupt polarity or whether it is edge- or level-
triggered. The reasons for that include:

- an upstream IRQ controller which cannot support edge- or
level-triggered interrupts,
- board design with a built-in inverter

The interrupt type is being already specified by the Device Tree,
anyway. Other drivers (gpio/gpio-tc3589x.c for example) already work in
this way, delegating the proper IRQ line setup to the DT and not
specifying anything by hand.

Also, there's no reason to have the IRQ flags split between two places.
The SPI probing is the only entry point anyway.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix invalid memory access during GPIO init

The `max310x_spi_probe` function attempted to setup the GPIO bits before
the corresponding structs for each serial port were initialized. If the
DTS file specified a GPIO hog, this led to a crash because the GPIO
stack ended up calling `max310x_gpio_direction_output` which referenced
uninitialized memory:

[<c04598c0>] (max310x_gpio_direction_output) from [<c03f5a2c>] (_gpiod_direction_output_raw+0x94/0x2d4)
[<c03f5a2c>] (_gpiod_direction_output_raw) from [<c03f991c>] (gpiod_hog+0x6c/0x154)
[<c03f991c>] (gpiod_hog) from [<c03fa2d8>] (of_gpiochip_add+0x28c/0x444)
[<c03fa2d8>] (of_gpiochip_add) from [<c03f6b2c>] (gpiochip_add_data+0x4f8/0x760)
[<c03f6b2c>] (gpiochip_add_data) from [<c03f6dd4>] (devm_gpiochip_add_data+0x40/0x7c)
[<c03f6dd4>] (devm_gpiochip_add_data) from [<c0459fec>] (max310x_spi_probe+0x530/0x894)
[<c0459fec>] (max310x_spi_probe) from [<c0503294>] (spi_drv_probe+0x7c/0xac)
[<c0503294>] (spi_drv_probe) from [<c046628c>] (driver_probe_device+0x234/0x2e8)
[<c046628c>] (driver_probe_device) from [<c0464890>] (bus_for_each_drv+0x60/0x94)
[<c0464890>] (bus_for_each_drv) from [<c0465f78>] (__device_attach+0xb0/0x114)
[<c0465f78>] (__device_attach) from [<c0465548>] (bus_probe_device+0x84/0x8c)
[<c0465548>] (bus_probe_device) from [<c0463a00>] (device_add+0x3f4/0x580)
[<c0463a00>] (device_add) from [<c0504164>] (spi_add_device+0x9c/0x134)
[<c0504164>] (spi_add_device) from [<c0504c18>] (spi_register_controller+0x484/0x910)
[<c0504c18>] (spi_register_controller) from [<c0506ee0>] (orion_spi_probe+0x2f4/0x3b4)
[<c0506ee0>] (orion_spi_probe) from [<c0467dac>] (platform_drv_probe+0x50/0xb0)
[<c0467dac>] (platform_drv_probe) from [<c046628c>] (driver_probe_device+0x234/0x2e8)
[<c046628c>] (driver_probe_device) from [<c04663f8>] (__driver_attach+0xb8/0xbc)
[<c04663f8>] (__driver_attach) from [<c04647e8>] (bus_for_each_dev+0x68/0x9c)
[<c04647e8>] (bus_for_each_dev) from [<c046574c>] (bus_add_driver+0x104/0x210)
[<c046574c>] (bus_add_driver) from [<c0466f14>] (driver_register+0x78/0xf4)
[<c0466f14>] (driver_register) from [<c0101bdc>] (do_one_initcall+0x44/0x168)
[<c0101bdc>] (do_one_initcall) from [<c0a00dc0>] (kernel_init_freeable+0x140/0x1cc)
[<c0a00dc0>] (kernel_init_freeable) from [<c078c590>] (kernel_init+0x8/0x108)
[<c078c590>] (kernel_init) from [<c0107a50>] (ret_from_fork+0x14/0x24)

This can be easily fixed by moving the corresponding code below. And
because the UARTs are already there by the time we reach this point, the
`goto` needs changing so that more stuff is freed. (I have not tested
this error path.)

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: Remove redundant license text

Now that the SPDX tag is in all tty files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: add SPDX identifiers to all remaining files in drivers/tty/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add support for newer silicon revisions

New IC MAX14830 has 0xB4 silicon revision ID.
This patch adds support for such ICs.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Set IRQF_TRIGGER_FALLING flag when dev.of_node is not NULL

When dev.of_node is not NULL, we also need to set IRQF_TRIGGER_FALLING
flag, otherwise it may cause uncertain interrupts.

Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Assign port line automatically

This patch makes assignment of port line automatically,
so now user allow to use several MAX310X chips.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Unregister UARTs on error

Add uart_remove_one_port() for error path.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Remove duplicate bits definition

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Register UART driver at module_init

This patch moves UART registration at module_init initcall,
so this should helps to add multiple chip support in the future.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Using resource-managed function for GPIO

Use resource managed functions devm_gpiochip_add_data() to make
error & exit path a bit simpler.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix RS485 handling

RS485 IOCTLs uses spinlocks, so move regmap functions into a separate
work queue.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: use gpiochip data pointer

This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Cc: Jiri Slaby <jslaby@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: change member .dev to .parent

The name .dev in a struct is normally reserved for a struct device
that is let us say a superclass to the thing described by the struct.
struct gpio_chip stands out by confusingly using a struct device *dev
to point to the parent device (such as a platform_device) that
represents the hardware. As we want to give gpio_chip:s real devices,
this is not working. We need to rename this member to parent.

This was done by two coccinelle scripts, I guess it is possible to
combine them into one, but I don't know such stuff. They look like
this:

@@
struct gpio_chip *var;
@@
-var->dev
+var->parent

and:

@@
struct gpio_chip var;
@@
-var.dev
+var.parent

and:

@@
struct bgpio_chip *var;
@@
-var->gc.dev
+var->gc.parent

Plus a few instances of bgpio that I couldn't figure out how
to teach Coccinelle to rewrite.

This patch hits all over the place, but I *strongly* prefer this
solution to any piecemal approaches that just exercise patch
mechanics all over the place. It mainly hits drivers/gpio and
drivers/pinctrl which is my own backyard anyway.

Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Alek Du <alek.du@intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

spi: Drop owner assignment from spi_drivers

An spi_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/max310: Use the rs485 functions on serial_core

In order to unify all the rs485 ioctl handling
Use the implementation of TIOC[GS]RS485 ioctl handling on serial_core.

Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial/max310x: Remove obsolete #ifset TIOC[SG]RS485

Commit e676253b19b2 ("serial/8250: Add support for RS485 IOCTLs") added
references to TIOC[SG]RS48 on 8250_core.c. This change triggered the
need to define them in all the arches that uses tty/serial.

This made #ifdef TIOC[SG]RS48 obsolete.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

max310x: max3109_detect should use indirect addressing in SPI mode for REVID register

This patch allows to read the REV_ID register in SPI mode and consequently
to properly detect the max3109. Indeed in SPI mode, this register is only
accessible by using indirect addressing.

Signed-off-by: Gregory Hermant <gregory.hermant@calao-systems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver:gpio remove all usage of gpio_remove retval in driver

this remove all reference to gpio_remove retval in all driver
except pinctrl and gpio. the same thing is done for gpio and
pinctrl in two different patches.

Signed-off-by: Abdoulaye Berthe <berthe.ab@gmail.com>
Acked-by: Michael Büsch <m@bues.ch>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

serial: treewide: Remove empty implementations of enable_ms()

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Fix IGNBRK handling

If IGNBRK is set without either BRKINT or PARMRK set, some uart
drivers send a 0x00 byte for BREAK without the TTYBREAK flag to the
line discipline, when it should send either nothing or the TTYBREAK flag
set. This happens because the read_status_mask masks out the BI
condition, which uart_insert_char() then interprets as a normal 0x00 byte.

SUS v3 is clear regarding the meaning of IGNBRK; Section 11.2.2, General
Terminal Interface - Input Modes, states:
"If IGNBRK is set, a break condition detected on input shall be ignored;
that is, not put on the input queue and therefore not read by any
process."

Fix read_status_mask to include the BI bit if IGNBRK is set; the
lsr status retains the BI bit if a BREAK is recv'd, which is
subsequently ignored in uart_insert_char() when masked with the
ignore_status_mask.

Affected drivers:
8250 - all
serial_txx9
mfd
amba-pl010
amba-pl011
atmel_serial
bfin_uart
dz
ip22zilog
max310x
mxs-auart
netx-serial
pnx8xxx_uart
pxa
sb1250-duart
sccnxp
serial_ks8695
sirfsoc_uart
st-asc
vr41xx_siu
zs
sunzilog
fsl_lpuart
sunsab
ucc_uart
bcm63xx_uart
sunsu
efm32-uart
pmac_zilog
mpsc
msm_serial
m32r_sio

Unaffected drivers:
omap-serial
rp2
sa1100
imx
icom

Annotated for fixes:
altera_uart
mcf

Drivers without break detection:
21285
xilinx-uartps
altera_jtaguart
apbuart
arc-uart
clps711x
max3100
uartlite
msm_serial_hs
nwpserial
lantiq
vt8500_serial

Unknown:
samsung
mpc52xx_uart
bfin_sport_uart
cpm_uart/core

Fixes: Bugzilla #71651, '8250_core.c incorrectly handles IGNBRK flag'
Reported-by: Ivan <athlon_@mail.ru>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add missing #include <linux/uaccess.h>

cris allmodconfig:

drivers/tty/serial/max310x.c: In function 'max310x_ioctl':
drivers/tty/serial/max310x.c:885:3: error: implicit declaration of function 'copy_from_user' [-Werror=implicit-function-declaration]
drivers/tty/serial/max310x.c:916:3: error: implicit declaration of function 'copy_to_user' [-Werror=implicit-function-declaration]

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix sparse warnings

sparse warnings: (new ones prefixed by >>)

>> drivers/tty/serial/max310x.c:906:45: sparse: incorrect type in argument 2 (different address spaces)
drivers/tty/serial/max310x.c:906:45: expected void const [noderef] <asn:1>*from
drivers/tty/serial/max310x.c:906:45: got struct serial_rs485 *<noident>
>> drivers/tty/serial/max310x.c:938:35: sparse: incorrect type in argument 1 (different address spaces)
drivers/tty/serial/max310x.c:938:35: expected void [noderef] <asn:1>*to
drivers/tty/serial/max310x.c:938:35: got struct serial_rs485 *<noident>

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix build error

This is a temporary solution to fix following issue:
config: make ARCH=alpha allyesconfig

All error/warnings:

drivers/tty/serial/max310x.c: In function 'max310x_ioctl':
>> drivers/tty/serial/max310x.c:905:7: error: 'TIOCSRS485' undeclared (first use in this function)
drivers/tty/serial/max310x.c:905:7: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/tty/serial/max310x.c:906:3: error: implicit declaration of function 'copy_from_user' [-Werror=implicit-function-declaration]
>> drivers/tty/serial/max310x.c:929:7: error: 'TIOCGRS485' undeclared (first use in this function)
>> drivers/tty/serial/max310x.c:938:3: error: implicit declaration of function 'copy_to_user' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "serial: max310x: Fix build error"

This reverts commit e3c6ea9b1b81b87de96c01d5d37764009d546636 as it
didn't help anything, and caused more problems than expected.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix build warning

config: x86_64-randconfig-x006 (attached as .config)

All warnings:

drivers/tty/serial/max310x.c: In function 'max310x_probe':
>> drivers/tty/serial/max310x.c:1240:1: warning: label 'out_uart' defined but not used [-Wunused-label]

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix build error

config: make ARCH=alpha allyesconfig

All error/warnings:

drivers/tty/serial/max310x.c: In function 'max310x_ioctl':
>> drivers/tty/serial/max310x.c:905:7: error: 'TIOCSRS485' undeclared (first use in this function)
drivers/tty/serial/max310x.c:905:7: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/tty/serial/max310x.c:906:3: error: implicit declaration of function 'copy_from_user' [-Werror=implicit-function-declaration]
>> drivers/tty/serial/max310x.c:929:7: error: 'TIOCGRS485' undeclared (first use in this function)
>> drivers/tty/serial/max310x.c:938:3: error: implicit declaration of function 'copy_to_user' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add devicetree support

This patch adds devicetree support for the MAX310X serial driver.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Driver cleanup

This patch removes some unused definitions from driver code and
sort #includes alphabetically.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add support for RS-485 mode

This patch adds support for RS-485 (TIOCSRS485/TIOCGRS485) IOCTLs.
As a result this patch eliminate private driver header.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add missing mutex_destroy() on driver exit

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Always use dynamic GPIO ID assignment

Always register GPIOs and use dynamic GPIO ID assignment.
This is no much worth if GPIOs is not used, but helps remove
private driver header and add DT support in the future.
Additionally, patch adds missing uart_unregister_driver()
call if probe() fails.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Migrate to CLK API

This patch removes "frequency" parameter from MAX310X platform_data
and uses CLK API for getting clock. Clock type (XTAL/OSC) is
determined by clk name.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Move all SPI-dependent stuff in one place

Patch move all SPI-dependent stuff in one place. This include move
PM-function definitions out of CONFIG_SPI_MASTER and move regmap
initialization out of common probe into CONFIG_SPI_MASTER which
may help to add I2C support in the future for this driver.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Remove IRQ validation

This patch removes excess IRQ checks at driver probe().
IRQ validation is already provided by request_threaded_irq().

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add the loopback mode support

This patch replaces loopback mode support from platform data to
dynamic setup with TIOCMSET ioctl.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Remove excess port configure at startup

Serial core calls set_termios() after port startup, so there are
no reason to setup port twice.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Remove init() and exit() callbacks

These callbacks were previously used for the IC power initialization.
If this initialization will be needed in the future, it should be
implemented with the regulator API.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Setup baud rate generator more precisely

This patch provide more precisely setup of baud rate generator.
If the result of division has a remainder, we use the multiplier
for the base frequency. Additionally, we report result baud rate
back to serial core.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: Remove unnecessary semicolons

These aren't necessary after switch and while blocks.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Fix dev_pm_ops

This patch fixes wrong dev_pm_ops which caused by commit:
serial: max310x: Driver rework.

CC drivers/tty/serial/max310x.o
LD drivers/video/fb.o
CC drivers/w1/slaves/w1_ds2433.o
CC drivers/w1/slaves/w1_ds2760.o
CC drivers/xen/balloon.o
CC drivers/video/backlight/adp8870_bl.o
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.suspend') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.resume') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.freeze') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.thaw') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.poweroff') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.restore') [enabled by default]

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add MAX14830 support

This patch adds support for MAX14830 (advanced quad universal asynchronous
receiver-transmitter) into max310x driver.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Add MAX3109 support

This patch adds support for MAX3109 (advanced dual universal asynchronous
receiver-transmitter) into max310x driver.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Driver rework

This patch rework max310x driver.
Major changes have been made:
- Prepare driver to support ICs with more than one UART.
- Prepare driver to support work with I2C-bus.
The patch changes almost every function and can not be divided into parts.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: max310x: Use dev_pm_ops

Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
max310x driver.

Cc: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

TTY: switch tty_flip_buffer_push

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: max310x: Setup missing "can_sleep" field for GPIO

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: remove use of __devexit

CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: remove use of __devinit

CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: remove use of __devexit_p

CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: max310x: Add terminating entry for spi_device_id table

The spi_device_id table is supposed to be zero-terminated.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: max310x: Remove explicit use of devm_kfree

There is no reason to explicitly call devm_kfree
in probe or remove functions.

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: max310x: Check return code of gpiochip_remove

The gpiochip_remove function may fail to remove a gpio_chip
if any GPIOs are still requested. This patch informs the caller
of such a senario.

Sparse is warning because the function prototype has a
__must_check annotation.

Sparse warning:
drivers/tty/serial/max310x.c:1223:18: warning:
ignoring return value of ‘gpiochip_remove’,
declared with attribute warn_unused_result
[-Wunused-result]

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: New serial driver MAX310X

This driver is a replacement for a MAX3107 driver with a lot of
improvements and new features.
The main differences from the old version:
- Using the regmap.
- Using devm_XXX-related functions.
- The use of threaded IRQ with IRQF_ONESHOT flag allows the driver to
the hardware that supports only level IRQ.
- Improved error handling of serial port, improved FIFO handling,
improved hardware & software flow control.
- Advanced flags allows turn on RS-485 mode (Auto direction control).
- Ability to load multiple instances of drivers.
- Added support for MAX3108.
- GPIO support.
- Driver is quite ready for adding I2C support and support other ICs
with compatible registers set (MAX3109, MAX14830).

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>