wifi: wilc1000: revert reset line logic flip

This reverts commit fcf690b0b47494df51d214db5c5a714a400b0257.

When using a wilc1000 chip over a spi bus, users can optionally define a
reset gpio and a chip enable gpio. The reset line of wilc1000 is active
low, so to hold the chip in reset, a low (physical) value must be applied.

The corresponding device tree binding documentation was introduced by
commit f31ee3c0a555 ("wilc1000: Document enable-gpios and reset-gpios
properties") and correctly indicates that the reset line is an active-low
signal. The corresponding driver part, brought by commit ec031ac4792c
("wilc1000: Add reset/enable GPIO support to SPI driver") was applying the
correct logic. But commit fcf690b0b474 ("wifi: wilc1000: use correct
sequence of RESET for chip Power-UP/Down") eventually flipped this logic
and started misusing the gpiod APIs, applying an inverted logic when
powering up/down the chip (for example, setting the reset line to a logic
"1" during power up, which in fact asserts the reset line when device tree
describes the reset line as GPIO_ACTIVE_LOW). As a consequence, any
platform currently using the driver in SPI mode must use a faulty reset
line description in device tree, or else chip will be maintained in reset
and will not even allow to bring up the chip.

Fix reset line usage by inverting back the gpiod APIs usage, setting the
reset line to the logic value "0" when powering the chip, and the logic
value "1" when powering off the chip.

Fixes: fcf690b0b474 ("wifi: wilc1000: use correct sequence of RESET for chip Power-UP/Down")
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240217-wilc_1000_reset_line-v2-1-b216f433d7d5@bootlin.com

wifi: wilc1000: validate chip id during bus probe

Previously, the driver created a net device (typically wlan0) as soon
as the module was loaded. This commit changes the driver to follow
normal Linux convention of creating the net device only when bus
probing detects a supported chip.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Tested-By: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240212202057.3468714-1-davidm@egauge.net

wifi: wilc1000: correct CRC7 calculation

Document

ATWILC1000/ATWILC3000
Baremetal Wi-Fi/BLE Link Controller Software Design Guide

https://tinyurl.com/yer2xhyc

says that bit 0 of the CRC7 code must always be a 1.

I confirmed that today with a logic analyzer: setting bit 0 causes
wilc1000 to accept a command with CRC7 enabled, whereas clearing bit 0
causes wilc1000 to reject the command with a CRC error.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240207050736.2717641-1-davidm@egauge.net

wifi: wilc1000: remove setting msg.spi

Calling spi_sync() unconditionally sets the spi field of struct
spi_message. Therefore setting msg.spi = spi before calling spi_sync()
has no effect and can be removed.

(spi_message_add_tail() does not access this field.)

Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240201201248.2334798-2-dlechner@baylibre.com

wifi: fill in MODULE_DESCRIPTION()s for wilc1000

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Atmel WILC1000 SPI driver.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240130104243.3025393-9-leitao@debian.org

wifi: wilc1000: add SPI commands retry mechanism

In some situations like, chip wake-up with powersave enabled, SPI
commands are failing temporarily. Reissuing commands after reset helps
to overcome the failure. So, add the retry limit and reset command
sequence API for read/write SPI commands.

Signed-off-by: Amisha Patel <amisha.patel@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230724163955.4583-1-amisha.patel@microchip.com

wifi: wilc1000: add 'isinit' flag for SDIO bus similar to SPI

Similar to SPI priv data, add 'isinit' variable in SDIO priv. Make use
of the state to invoke hif_init() once, and acquire the lock before
accessing hif function.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220720160302.231516-7-ajay.kathat@microchip.com

wifi: wilc1000: use correct sequence of RESET for chip Power-UP/Down

For power-up sequence, WILC expects RESET set to high 5ms after making
chip_en(enable) so corrected chip power-up sequence by making RESET high.
For Power-Down sequence, the correct sequence make RESET and CHIP_EN low
without any extra delay.

Fixes: ec031ac4792c ("wilc1000: Add reset/enable GPIO support to SPI driver")
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220524120606.9675-1-ajay.kathat@microchip.com

wilc1000: use min_t() to make code cleaner

Use min_t() in order to make code cleaner.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211222070815.483009-1-deng.changcheng@zte.com.cn

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>

wilc1000: Add reset/enable GPIO support to SPI driver

For the SDIO driver, the RESET/ENABLE pins of WILC1000 are controlled
through the SDIO power sequence driver. This commit adds analogous
support for the SPI driver. Specifically, during initialization, the
chip will be ENABLEd and taken out of RESET and during
deinitialization, the chip will be placed back into RESET and disabled
(both to reduce power consumption and to ensure the WiFi radio is
off).

Both RESET and ENABLE GPIOs are optional. However, if the ENABLE GPIO
is specified, then the RESET GPIO should normally also be specified as
otherwise there is no way to ensure proper timing of the ENABLE/RESET
sequence.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211221212531.4011609-2-davidm@egauge.net

wilc1000: fix double free error in probe()

Smatch complains that there is a double free in probe:

drivers/net/wireless/microchip/wilc1000/spi.c:186 wilc_bus_probe() error: double free of 'spi_priv'
drivers/net/wireless/microchip/wilc1000/sdio.c:163 wilc_sdio_probe() error: double free of 'sdio_priv'

The problem is that wilc_netdev_cleanup() function frees "wilc->bus_data".
That's confusing and a layering violation. Leave the frees in probe(),
delete the free in wilc_netdev_cleanup(), and add some new frees to the
remove() functions.

Fixes: dc8b338f3bcd ("wilc1000: use goto labels on error path")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211217150311.GC16611@kili

wilc1000: Rename SPI driver from "WILC_SPI" to "wilc1000_spi"

The name "wilc1000_spi" follows normal Linux conventions and also is
analogous to the SDIO driver, which uses "wilc1000_sdio".

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211209044411.3482259-2-davidm@egauge.net

wilc1000: Remove misleading USE_SPI_DMA macro

The USE_SPI_DMA macro name suggests that it could be set to 1 to
control whether or not SPI DMA should be used. However, that's not
what it does. If set to 1, it'll set the SPI messages'
"is_dma_mapped" flag to true, even though the tx/rx buffers aren't
actually DMA mapped by the driver. In other words, setting this flag
to 1 will break the driver.

Best to clean up this confusion by removing the macro altogether.
There is no need to explicitly initialize "is_dma_mapped" because the
message is cleared to zero anyhow, so "is_dma_mapped" is set to false
by default.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Acked-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211207002453.3193737-1-davidm@egauge.net

wilc1000: Add id_table to spi_driver

This eliminates warning message:

SPI driver WILC_SPI has no spi_device_id for microchip,wilc1000

and makes device-tree autoloading work.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211202045001.2901903-1-davidm@egauge.net

wilc1000: use correct write command sequence in wilc_spi_sync_ext()

Instead of using double read for the same register, use the write register
command after the read command.
The correct sequence is to use the read value in write command instead of
reading the same register again.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210916164902.74629-11-ajay.kathat@microchip.com

wilc1000: ignore clockless registers status response for SPI

During WILC chip wake-up sequence, the clockless status register sometimes
reports failure even when the actual status is successful. So, for the
clockless register, remove the incorrect error status reporting during the
read and write command API's.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210916164902.74629-8-ajay.kathat@microchip.com

wilc1000: handle read failure issue for clockless registers

For SPI bus, the register read fails after read/write to the clockless
register during chip wakeup sequence. Add workaround to send CMD_RESET
command during chip wake-up sequence to overcome the issue.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210916164902.74629-7-ajay.kathat@microchip.com

wilc1000: add reset/terminate/repeat command support for SPI bus

Add reset/terminate/repeat command for SPI module. In case of SPI commands
failure, the host should issue a RESET command to WILC chip to recover
from any temporary bus error.
For now, the new command support is added and later the SPI read/write
API's would be modified to make use of these commands for retry mechanism

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210916164902.74629-6-ajay.kathat@microchip.com

wilc1000: Convert module-global "isinit" to device-specific variable

Move static "isinit" variable to wilc_spi structure to allow multiple
WILC1000 devices per machine.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210828151346.3012697-1-davidm@egauge.net

wilc1000: use devm_clk_get_optional()

Use devm_clk_get_optional() for rtc clock: it simplifies a bit
the code.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210806081229.721731-4-claudiu.beznea@microchip.com

wilc1000: use goto labels on error path

Use goto labels on error path for probe functions. This makes code easier
to read. With this introduce also netdev_cleanup and call it where
necessary.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210806081229.721731-2-claudiu.beznea@microchip.com

wilc1000: Fix clock name binding

Documentation/devicetree/bindings/net/wireless/microchip,wilc1000.yaml
requires an "rtc" clock name.
drivers/net/wireless/microchip/wilc1000/sdio.c is using "rtc" clock name
as well. Comply with the binding in wilc1000/spi.c too.

Fixes: 854d66df74ae ("staging: wilc1000: look for rtc_clk clock in spi mode")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210428025445.81953-1-tudor.ambarus@microchip.com

wilc1000: Add support for enabling CRC

The driver so far has always disabled CRC protection. This means any
data corruption that occurrs during the SPI transfers could go
undetected. This patch adds module parameters enable_crc7 and
enable_crc16 to selectively turn on CRC7 (for command transfers) and
CRC16 (for data transfers), respectively.

The default configuration remains unchanged, with both CRC7 and CRC16
off.

The performance impact of CRC was measured by running ttcp -t four
times in a row on a SAMA5 device:

CRC7 CRC16 Throughput: Standard deviation:
---- ----- ----------- -------------------
off off 1720 +/- 48 KB/s
on off 1658 +/- 58 KB/s
on on 1579 +/- 84 KB/s

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210227172818.1711071-4-davidm@egauge.net

wilc1000: Check for errors at end of DMA write

After a DMA write to the WILC chip, check for and report any errors.

This is based on code from the wilc driver in the linux-at91
repository.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210227172818.1711071-3-davidm@egauge.net

wilc1000: Introduce symbolic names for SPI protocol register

The WILC1000 protocol control register has bits for enabling the CRCs
(CRC7 for commands and CRC16 for data) and to set the data packet
size. Define symbolic names for those so the code is more easily
understood.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210227172818.1711071-2-davidm@egauge.net

wilc1000: Make SPI transfers work at 48MHz

For CMD_SINGLE_READ and CMD_INTERNAL_READ, WILC may insert one or more
zero bytes between the command response and the DATA Start tag (0xf3).
This behavior appears to be undocumented in "ATWILC1000 USER GUIDE"
(https://tinyurl.com/4hhshdts) but we have observed 1-4 zero bytes
when the SPI bus operates at 48MHz and none when it operates at 1MHz.

This code is derived from the equivalent code of the wilc driver in
the linux-at91 repository.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210227172818.1711071-1-davidm@egauge.net

wilc1000: changes for SPI communication stall issue found with Iperf

Added retry mechanism to ensure VMM enable bit is set during the
block transfer of data between host and WILC FW.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201208103739.28597-1-ajay.kathat@microchip.com

staging: wilc1000: Fix memleak in wilc_bus_probe

When devm_clk_get() returns -EPROBE_DEFER, spi_priv
should be freed just like when wilc_cfg80211_init()
fails.

Fixes: 854d66df74aed ("staging: wilc1000: look for rtc_clk clock in spi mode")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20200819115426.29852-1-dinghao.liu@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

wilc1000: Fix memleak in wilc_bus_probe

When devm_clk_get() returns -EPROBE_DEFER, spi_priv
should be freed just like when wilc_cfg80211_init()
fails.

Fixes: 854d66df74aed ("staging: wilc1000: look for rtc_clk clock in spi mode")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Acked-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200820055256.24333-1-dinghao.liu@zju.edu.cn

wilc1000: move wilc driver out of staging

WILC1000 is an IEEE 802.11 b/g/n IoT link controller module. The
WILC1000 connects to Microchip AVR/SMART MCUs, SMART MPUs, and other
processors with minimal resource requirements with a simple
SPI/SDIO-to-Wi-Fi interface.

WILC1000 driver has been part of staging for few years. With
contributions from the community, it has improved significantly. Full
driver review has helped in achieving the current state.
The details for those reviews are captured in 1 & 2.

[1]. https://lore.kernel.org/linux-wireless/1537957525-11467-1-git-send-email-ajay.kathat@microchip.com/
[2]. https://lore.kernel.org/linux-wireless/1562896697-8002-1-git-send-email-ajay.kathat@microchip.com/

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>