On Fri, Dec 16, 2022 at 8:09 AM Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> 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. Can that function check if (!sensor->reset_gpio) and do the delay only if reset_gpio is not present? adam > > Cc the devicetree list and Krzysztof. > > > > > ret = ov5640_init_slave_id(sensor); > > if (ret) > > -- > Kind regards, > > Sakari Ailus
