Re: [PATCH 1/3] media: ov5640: Handle delays when no reset_gpio set

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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




[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]

  Powered by Linux