linux-toradex.git/drivers/input/touchscreen/elants_i2c.c, branch v6.13-rc7

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.

auto-generated by the following:

for i in `git grep -l -w asm/unaligned.h`; do
	sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
	sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

Input: elants_i2c - use device core to create driver-specific device attributes

2023-09-06T21:27:18+00:00

Instead of creating driver-specific device attributes with
devm_device_add_group() have device core do this by setting up dev_groups
pointer in the driver structure.

Reviewed-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20230729005133.1095051-9-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - simplify with dev_err_probe()

2023-07-07T23:54:28+00:00

Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and also it prints the error value.

Signed-off-by: Krzysztof Kozlowski 
Reviewed-by: Hans de Goede 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20230625162817.100397-13-krzysztof.kozlowski@linaro.org
Signed-off-by: Dmitry Torokhov

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

2023-05-17T16:59:11+00:00

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 
Link: https://lore.kernel.org/r/20230517164645.162294-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - switch to DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr()

2023-01-10T04:25:25+00:00

SIMPLE_DEV_PM_OPS() is deprecated as it requires explicit protection
against unused function warnings.  The new combination of pm_sleep_ptr()
and DEFINE_SIMPLE_DEV_PM_OPS() allows the compiler to see the functions,
thus suppressing the warning, but still allowing the unused code to be
removed. Thus also drop the __maybe_unused markings.

Signed-off-by: Jonathan Cameron 
Cc: Douglas Anderson 
Reviewed-by: Linus Walleij 
Link: https://lore.kernel.org/r/20230102181842.718010-46-jic23@kernel.org
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - delay longer with reset asserted

2022-12-09T02:19:48+00:00

The elan touchscreen datasheet says that the reset GPIO only needs to
be asserted for 500us in order to reset the regulator. The problem is
that some boards need a level shifter between the signals on the GPIO
controller and the signals on the touchscreen. All of these extra
components on the line can slow the transition of the signals. On one
board, we measured the reset line and saw that it took almost 1.8ms to
go low. Even after we bumped up the "drive strength" of the signal
from the default 2mA to 8mA we still saw it take 421us for the signal
to go low.

In order to account for this let's lengthen the amount of time that we
keep the reset asserted. Let's bump it up from 500us to 5000us.
That's still a relatively short amount of time and is much safer.

It should be noted that this fixes real problems. Case in point:
1. The touchscreen power rail may be shared with another device (like
an eDP panel). That means that at probe time power might already be
on.
2. In probe we grab the reset GPIO and assert it (make it low).
3. We turn on power (a noop since it was already on).
4. We wait 500us.
5. We deassert the reset GPIO.

With the above case and only a 500us delay we saw only a partial reset
asserted, which is bad. Giving it 5ms is overkill but feels safer in
case someone else has a different level shifter setup.

Note that bumping up the delay to 5000 means that some configs yell
about using udelay(). We'll change to using usleep_range(). We give a
small range here because:
- This isn't a delay that happens very often so we don't need to worry
about giving a big range to allow for power efficiency.
- usleep_range() is known to almost always pick the upper bound and
delay that long and we really don't want to slow down the power on
of the touchscreen that much.

Signed-off-by: Douglas Anderson
Reviewed-by: Matthias Kaehlcke
Link: https://lore.kernel.org/r/20221208180603.v2.5.I6edfb3f459662c041563a54e5b7df727c27caaba@changeid
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - delete some dead code

2022-11-29T23:02:46+00:00

We shuffled the error handling around so this condition is dead code
now.  The "error" variable is always zero.

Signed-off-by: Dan Carpenter 
Reviewed-by: Douglas Anderson 
Reviewed-by: Mattijs Korpershoek 
Link: https://lore.kernel.org/r/Y33BD9xkRC9euIdO@kili
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - don't set wake_capable and wake_irq

2022-11-22T21:59:27+00:00

The i2c-core will now handle setting the wake_irq and wake capability
for DT and ACPI systems.

Signed-off-by: Raul E Rangel 
Link: https://lore.kernel.org/r/20220929093200.v6.12.I031ffbe411e1bae20bf16a1876da5baf444c7928@changeid
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - use PM subsystem to manage wake irq

2022-11-22T21:58:48+00:00

The Elan I2C touchscreen driver is currently manually managing the wake
IRQ. This change removes the explicit enable_irq_wake/disable_irq_wake
and instead relies on the PM subsystem. This is done by calling
dev_pm_set_wake_irq.

i2c_device_probe already calls dev_pm_set_wake_irq when using device
tree, and i2c_device_remove also already calls dev_pm_clear_wake_irq.
There could be some device tree systems that have incorrectly declared
`wake` capabilities, so this change will set the wake irq if one is
missing. This matches the previous behavior.

Signed-off-by: Raul E Rangel 
Link: https://lore.kernel.org/r/20220929093200.v6.3.I5862429ee3e4de0f9ad5ba01ce07ad99eec10cf0@changeid
Signed-off-by: Dmitry Torokhov

Input: elants_i2c - properly handle the reset GPIO when power is off

2022-11-18T06:14:45+00:00

As can be seen in elants_i2c_power_off(), we want the reset GPIO
asserted when power is off. The reset GPIO is active low so we need
the reset line logic low when power is off to avoid leakage.

We have a problem, though, at probe time. At probe time we haven't
powered the regulators on yet but we have:

  devm_gpiod_get(&client->dev, "reset", GPIOD_OUT_LOW);

While that _looks_ right, it turns out that it's not. The
GPIOD_OUT_LOW doesn't mean to init the GPIO to low. It means init the
GPIO to "not asserted". Since this is an active low GPIO that inits it
to be high.

Let's fix this to properly init the GPIO. Now after both probe and
power off the state of the GPIO is consistent (it's "asserted" or
level low).

Once we fix this, we can see that at power on time we no longer to
assert the reset GPIO as the first thing. The reset GPIO is _always_
asserted before powering on. Let's fix powering on to account for
this.

Fixes: afe10358e47a ("Input: elants_i2c - wire up regulator support")
Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20221117123805.1.I9959ac561dd6e1e8e1ce7085e4de6167b27c574f@changeid
Signed-off-by: Dmitry Torokhov