Hi Sakari, Krzysztof,
On 16/12/22 19:40, Krzysztof Kozlowski wrote:
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.
Thanks for the quick review.
I agree, will send v2 where we check if reset-gpio is missing in the DT
and in that case just toggle powerdown-gpio and wait for 26ms.
Best regards,
Krzysztof
Thanks,
Jai
