media: ov5640: Handle delays when no reset_gpio set
Some module manufacturers [1][2] don't expose the RESETB and PWDN pins
of the sensor directly through the 15-pin FFC connector. Instead wiring
~PWDN gpio to the sensor pins with appropriate delays.
In such cases, reset_gpio will not be available to the driver, but it
will still be toggled when the sensor is powered on, and thus we should
still honor the wait time of >= 5ms + 1ms + 20ms (see figure 2-3 in [3])
before attempting any i/o operations over SCCB.
Also, rename the function to ov5640_powerup_sequence to better match the
datasheet (section 2.7).
[1] https://digilent.com/reference/_media/reference/add-ons/pcam-5c/pcam_5c_sch.pdf
[2] https://www.alinx.com/public/upload/file/AN5641_User_Manual.pdf
[3] https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datasheet.pdf
Fixes: 19a81c1426
("[media] add Omnivision OV5640 sensor driver")
Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Jai Luthra <j-luthra@ti.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
parent
decea0a98b
commit
d7ff691399
|
@ -2436,11 +2436,22 @@ static void ov5640_power(struct ov5640_dev *sensor, bool enable)
|
|||
gpiod_set_value_cansleep(sensor->pwdn_gpio, enable ? 0 : 1);
|
||||
}
|
||||
|
||||
static void ov5640_reset(struct ov5640_dev *sensor)
|
||||
/*
|
||||
* From section 2.7 power up sequence:
|
||||
* t0 + t1 + t2 >= 5ms Delay from DOVDD stable to PWDN pull down
|
||||
* t3 >= 1ms Delay from PWDN pull down to RESETB pull up
|
||||
* t4 >= 20ms Delay from RESETB pull up to SCCB (i2c) stable
|
||||
*
|
||||
* Some modules don't expose RESETB/PWDN pins directly, instead providing a
|
||||
* "PWUP" GPIO which is wired through appropriate delays and inverters to the
|
||||
* pins.
|
||||
*
|
||||
* In such cases, this gpio should be mapped to pwdn_gpio in the driver, and we
|
||||
* should still toggle the pwdn_gpio below with the appropriate delays, while
|
||||
* the calls to reset_gpio will be ignored.
|
||||
*/
|
||||
static void ov5640_powerup_sequence(struct ov5640_dev *sensor)
|
||||
{
|
||||
if (!sensor->reset_gpio)
|
||||
return;
|
||||
|
||||
if (sensor->pwdn_gpio) {
|
||||
gpiod_set_value_cansleep(sensor->reset_gpio, 0);
|
||||
|
||||
|
@ -2489,8 +2500,7 @@ static int ov5640_set_power_on(struct ov5640_dev *sensor)
|
|||
goto xclk_off;
|
||||
}
|
||||
|
||||
ov5640_reset(sensor);
|
||||
ov5640_power(sensor, true);
|
||||
ov5640_powerup_sequence(sensor);
|
||||
|
||||
ret = ov5640_init_slave_id(sensor);
|
||||
if (ret)
|
||||
|
|
Loading…
Reference in New Issue