On 16/12/2022 14:57, Sakari Ailus wrote: > Hi Jai, > > Thanks for the set. > > On Fri, Dec 16, 2022 at 07:14:07PM +0530, Jai Luthra wrote: >> Some module manufacturers [1][2] don't expose the RESETB gpio of the >> sensor directly through the 15-pin FFC connector. Instead wiring ~PWDN >> as a proxy reset 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. >> >> [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: 19a81c1426c1 ("[media] add Omnivision OV5640 sensor driver") >> Signed-off-by: Jai Luthra <j-luthra@xxxxxx> >> --- >> drivers/media/i2c/ov5640.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c >> index e0f908af581b..4bb7bf557cfa 100644 >> --- a/drivers/media/i2c/ov5640.c >> +++ b/drivers/media/i2c/ov5640.c >> @@ -2466,6 +2466,7 @@ static int ov5640_set_power_on(struct ov5640_dev *sensor) >> >> ov5640_reset(sensor); >> ov5640_power(sensor, true); >> + usleep_range(26000, 30000); > > I think you should only do this if you don't have RESETB pin. > > I'm not sure how to best describe this in DT. It's not the same as if you > didn't have RESETB GPIO. Why it's not the same? I understand the RESETB pin is always there just sometimes going to GPIO and sometimes to some other line. Best regards, Krzysztof
