media: i2c: imx290: fix reset GPIO pin handling
authorAndrey Konovalov <andrey.konovalov@linaro.org>
Fri, 12 Jun 2020 13:53:48 +0000 (15:53 +0200)
committerMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Tue, 23 Jun 2020 13:16:23 +0000 (15:16 +0200)
commit3909a92d7df622b41b9ceeeea694e641cad7667b
tree7cb7ee56aba1c8676d716698fce410229a1df20b
parent8d2d1bedb1b9af3e0c039a4444858da7b6da71f8
media: i2c: imx290: fix reset GPIO pin handling

According to https://www.kernel.org/doc/Documentation/gpio/consumer.txt,

- all of the gpiod_set_value_xxx() functions operate with the *logical*
value. So in imx290_power_on() the reset signal should be cleared
(de-asserted) with gpiod_set_value_cansleep(imx290->rst_gpio, 0), and in
imx290_power_off() the value of 1 must be used to apply/assert the reset
to the sensor. In the device tree the reset pin is described as
GPIO_ACTIVE_LOW, and gpiod_set_value_xxx() functions take this into
account,

- when devm_gpiod_get_optional() is called with GPIOD_ASIS, the GPIO is
not initialized, and the direction must be set later; using a GPIO
without setting its direction first is illegal and will result in undefined
behavior. Fix this by using GPIOD_OUT_HIGH instead of GPIOD_ASIS (this
asserts the reset signal to the sensor initially).

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
drivers/media/i2c/imx290.c