Re: [PATCH v2 8/9] media: ov2740: Add a sleep after resetting the sensor

[Bingbu Cao <bingbu.cao@linux.intel.com>]

Hans,

On 11/26/23 10:15 PM, Hans de Goede wrote:
> Split the resetting of the sensor out of the link_freq_config reg_list
> and add a delay after this.
> 
> This hopefully fixes the stream sometimes not starting, this was
> taken from the ov2740 sensor driver in the out of tree IPU6 driver:

Thanks for your patch.

I don't know the details for ov2740 here, we met some similar issues
with another OminiVision camera sensor, it is somehow related to the
OTP read. Unfortunately, we didn't find the root-cause.

Maybe you can remove the OTP read to check, I think the OTP is useless
if I don't forget anything.

Hao, do you have any details for this issue?

> 
> https://github.com/intel/ipu6-drivers/
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/media/i2c/ov2740.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
> index 8f5c33f68d42..a49c065c6cf4 100644
> --- a/drivers/media/i2c/ov2740.c
> +++ b/drivers/media/i2c/ov2740.c
> @@ -128,7 +128,6 @@ struct ov2740_mode {
>  };
>  
>  static const struct ov2740_reg mipi_data_rate_720mbps[] = {
> -	{0x0103, 0x01},
>  	{0x0302, 0x4b},
>  	{0x030d, 0x4b},
>  	{0x030e, 0x02},
> @@ -137,7 +136,6 @@ static const struct ov2740_reg mipi_data_rate_720mbps[] = {
>  };
>  
>  static const struct ov2740_reg mipi_data_rate_360mbps[] = {
> -	{0x0103, 0x01},
>  	{0x0302, 0x4b},
>  	{0x0303, 0x01},
>  	{0x030d, 0x4b},
> @@ -935,6 +933,15 @@ static int ov2740_start_streaming(struct ov2740 *ov2740)
>  	if (ov2740->nvm)
>  		ov2740_load_otp_data(ov2740->nvm);
>  
> +	/* Reset the sensor */
> +	ret = ov2740_write_reg(ov2740, 0x0103, 1, 0x01);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to reset\n");
> +		return ret;
> +	}
> +
> +	usleep_range(10000, 15000);
> +
>  	link_freq_index = ov2740->cur_mode->link_freq_index;
>  	reg_list = &link_freq_configs[link_freq_index].reg_list;
>  	ret = ov2740_write_reg_list(ov2740, reg_list);
> 

-- 
Best regards,
Bingbu Cao