iio: adc: ingenic-adc: Benefit from devm_clk_get_prepared() to simplify

Make use of devm_clk_get_prepared() to replace some code that effectively
open codes this new function.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220808204740.307667-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ingenic-adc: convert to IIO fwnode interface

Move from 'of_xlate()' to 'fwnode_xlate()'. The end goal is to completely
drop OF from the IIO inkernel interface.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220715122903.332535-8-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ingenic-adc: explicitly add proper header files

Do not trust the fact that iio.h includes of.h which in turn includes
all the headers we are relying on.

The ultimate goal is to actually drop of.h from iio.h.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220610084545.547700-7-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: add JZ4760B support to the sadc driver

The JZ4760B variant differs slightly from the JZ4760: it has a bit called VBAT_SEL in the CFG register.

In order to correctly sample the battery voltage on existing handhelds using this SOC, the bit must be cleared.

We leave the possibility to set the bit, by using the "ingenic,use-internal-divider" in the devicetree.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
Link: https://lore.kernel.org/r/20210726082033.351533-5-cbranchereau@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: add JZ4760 support to the sadc driver

The jz4760 sadc is very similar to the jz4770 one, but has a VREF of 2.5V
and 3 aux channels.

modify ingenic_adc_read_chan_info_raw() needs a change to account for it.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>

Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20210726082033.351533-4-cbranchereau@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: rename has_aux2 to has_aux_md

The jz4760(b) socs have 3 aux channels.

The purpose of has_aux2 is to set the MD bits used to select
the AUX channel to be sampled, not to describe the hardware.

Rename it to a more appropriate name.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>

Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20210726082033.351533-2-cbranchereau@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: Fix AUX/VBAT readings when touchscreen is used

When the command feature of the ADC is used, it is possible to program
the ADC, and specify at each step what input should be processed, and in
comparison to what reference.

This broke the AUX and battery readings when the touchscreen was
enabled, most likely because the CMD feature would change the VREF all
the time.

Now, when AUX or battery are read, we temporarily disable the CMD
feature, which means that we won't get touchscreen readings in that time
frame. But it now gives correct values for AUX / battery, and the
touchscreen isn't disabled for long enough to be an actual issue.

Fixes: b96952f498db ("IIO: Ingenic JZ47xx: Add touchscreen mode.")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Artur Rojek <contact@artur-rojek.eu>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201103201238.161083-1-paul@crapouillou.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: Fix battery VREF for JZ4770 SoC

The reference voltage for the battery is clearly marked as 1.2V in the
programming manual. With this fixed, the battery channel now returns
correct values.

Fixes: a515d6488505 ("IIO: Ingenic JZ47xx: Add support for JZ4770 SoC ADC.")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Artur Rojek <contact@artur-rojek.eu>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201104192843.67187-1-paul@crapouillou.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: remove unneeded semicolon

A semicolon is not needed after a switch statement.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20201027201128.1597230-1-trix@redhat.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: Ingenic JZ47xx: Add touchscreen mode.

The SADC component in JZ47xx SoCs provides support for touchscreen
operations (pen position and pen down pressure) in single-ended and
differential modes.

The touchscreen component of SADC takes a significant time to stabilize
after first receiving the clock and a delay of 50ms has been empirically
proven to be a safe value before data sampling can begin.

Of the known hardware to use this controller, GCW Zero and Anbernic RG-350
utilize the touchscreen mode by having their joystick(s) attached to the
X/Y positive/negative input pins.

JZ4770 and later SoCs introduce a low-level command feature. With it, up
to 32 commands can be programmed, each one corresponding to a sampling
job. It allows to change the low-voltage reference, the high-voltage
reference, have them connected to VCC, GND, or one of the X-/X+ or Y-/Y+
pins.

This patch introduces support for 6 stream-capable channels:
- channel #0 samples X+/GND
- channel #1 samples Y+/GND
- channel #2 samples X-/GND
- channel #3 samples Y-/GND
- channel #4 samples X+/X-
- channel #5 samples Y+/Y-

Being able to sample X-/GND and Y-/GND is useful on some devices, where
one joystick is connected to the X+/Y+ pins, and a second joystick is
connected to the X-/Y- pins.

All the boards which probe this driver have the interrupt provided from
Device Tree, with no need to handle a case where the IRQ was not provided.

Co-developed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio/adc: ingenic: Retrieve channels list from soc data struct

Instead of having one array of struct iio_chan_spec for all SoCs, and
have some SoCs remove the last item of the array as they can't use it,
have each SoC define its array of supported channels.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: Ingenic JZ47xx: Add xlate cb to retrieve correct channel idx

Provide an of_xlate callback in order to retrieve the correct channel
specifier index from the IIO channels array.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: Ingenic JZ47xx: Error check clk_enable calls.

Introduce error checks for the clk_enable calls used in this driver.
As part of the changes, move clk_enable/clk_disable calls out of
ingenic_adc_set_config and into respective logic of its callers.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:adc:ingenic: drop of_match_ptr protection and include mod_devicetable.h

Whilst it's unlikely this device will ever be instantiated using
ACPI, there is little advantage not assigning the of_device_id table in all
cases and it avoids providing an example that might be coppied into new
drivers.

Also include mod_devicetable.h whilst here as of_device_id is defined
in there so including the header is best practice.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Artur Rojek <contact@artur-rojek.eu>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

iio: remove explicit IIO device parent assignment

This patch applies the semantic patch:
@@
expression I, P, SP;
@@
I = devm_iio_device_alloc(P, SP);
...
- I->dev.parent = P;

It updates 302 files and does 307 deletions.
This semantic patch also removes some comments like
'/* Establish that the iio_dev is a child of the i2c device */'

But this is is only done in case where the block is left empty.

The patch does not seem to cover all cases. It looks like in some cases a
different variable is used in some cases to assign the parent, but it
points to the same reference.
In other cases, the block covered by ... may be just too big to be covered
by the semantic patch.

However, this looks pretty good as well, as it does cover a big bulk of the
drivers that should remove the parent assignment.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ingenic: Use devm_platform_ioremap_resource

Replaces local boilerplate. Identified by coccinelle.
CHECK drivers/iio/adc/ingenic-adc.c
drivers/iio/adc/ingenic-adc.c:449:1-10: WARNING: Use devm_platform_ioremap_resource for adc -> base

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: Artur Rojek <contact@artur-rojek.eu>

IIO: Ingenic JZ47xx: Add support for JZ4770 SoC ADC.

Add support for the ADC hardware present on Ingenic JZ4770 SoC.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: Ingenic JZ47xx: Set clock divider on probe

The SADC component can run at up to 8 MHz on JZ4725B, but is fed
a 12 MHz input clock (EXT). Divide it by two to get 6 MHz, then
set up another divider to match, to produce a 10us clock.

If the clock dividers are left on their power-on defaults (a divider
of 1), the SADC mostly works, but will occasionally produce erroneous
readings. This led to button presses being detected out of nowhere on
the RS90 every few minutes. With this change, no ghost button presses
were logged in almost a day worth of testing.

The ADCLK register for configuring clock dividers doesn't exist on
JZ4740, so avoid writing it there.

A function has been introduced rather than a flag because there is a lot
of variation between the ADCLK registers on JZ47xx SoCs, both in
the internal layout of the register and in the frequency range
supported by the SADC. So this solution should make it easier
to add support for other JZ47xx SoCs later.

Fixes: 1a78daea107d ("iio: adc: probe should set clock divider")
Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ingenic: remove redundant dev_err call in ingenic_adc_probe()

There is a error message within devm_ioremap_resource
already, so remove the dev_err call to avoid redundant
error message.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: add Ingenic JZ47xx ADC driver.

Add an IIO driver for the ADC hardware present on Ingenic JZ47xx SoCs.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>