backlight: ktz8866: Correct the check for of_property_read_u32

of_property_read_u32 returns 0 when success, so reverse the
return value to get the true value.

Fixes: f8449c8f7355 ("backlight: ktz8866: Add support for Kinetic KTZ8866 backlight")
Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240129122829.16248-1-lujianhua000@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

backlight: 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.

Also fix two indention inconsistencies in the neighbourhood.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230521143844.375244-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Lee Jones <lee@kernel.org>

backlight: ktz8866: Convert to i2c's .probe_new()

The probe function doesn't make use of the i2c_device_id * parameter so
it can be trivially converted.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230127152639.1347229-1-u.kleine-koenig@pengutronix.de

backlight: ktz8866: Add support for Kinetic KTZ8866 backlight

Add support for Kinetic KTZ8866 backlight, which is used in
Xiaomi tablet, Mi Pad 5 series. This driver lightly based on
downstream implementation [1].
[1] https://github.com/MiCode/Xiaomi_Kernel_OpenSource/blob/elish-r-oss/drivers/video/backlight/ktz8866.c

Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230120155018.15376-2-lujianhua000@gmail.com