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); ret = ov5640_init_slave_id(sensor); if (ret) -- 2.17.1
