2021-11-03 08:09:56

by Sakari Ailus

[permalink] [raw]
Subject: Re: [PATCH] media: i2c: ov7740: implement get_mbus_config

Hi Eugen,

Thanks for the patch.

On Tue, Nov 02, 2021 at 05:30:08PM +0200, Eugen Hristev wrote:
> Implement the get_mbus_config callback.
> ov7740 is a parallel sensor, and according to datasheet, the register
> REG12 controls the CCIR656 mode. This register is written to 0 in yuyv mode.
> According to REG12[5] , CCIR656 mode, the behavior is:
> CCIR656: disabled
> REG28 controls the polarity of the signals. This register is unused.
> The default behavior is then:
> HSYNC polarity : positive
> VSYNC polarity : positive
> HREF polarity: positive
>

Doesn't the receiver driver get this information from DT?

> Signed-off-by: Eugen Hristev <[email protected]>
> ---
> drivers/media/i2c/ov7740.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/media/i2c/ov7740.c b/drivers/media/i2c/ov7740.c
> index 2539cfee85c8..f8a717aecb6f 100644
> --- a/drivers/media/i2c/ov7740.c
> +++ b/drivers/media/i2c/ov7740.c
> @@ -873,12 +873,26 @@ static int ov7740_get_fmt(struct v4l2_subdev *sd,
> return ret;
> }
>
> +static int ov7740_get_mbus_config(struct v4l2_subdev *sd,
> + unsigned int pad,
> + struct v4l2_mbus_config *cfg)
> +{
> + cfg->type = V4L2_MBUS_PARALLEL;
> + cfg->flags = V4L2_MBUS_MASTER | V4L2_MBUS_HSYNC_ACTIVE_HIGH |
> + V4L2_MBUS_VSYNC_ACTIVE_HIGH |
> + V4L2_MBUS_PCLK_SAMPLE_RISING |
> + V4L2_MBUS_FIELD_EVEN_LOW | V4L2_MBUS_DATA_ACTIVE_HIGH;
> +
> + return 0;
> +}
> +
> static const struct v4l2_subdev_pad_ops ov7740_subdev_pad_ops = {
> .enum_frame_interval = ov7740_enum_frame_interval,
> .enum_frame_size = ov7740_enum_frame_size,
> .enum_mbus_code = ov7740_enum_mbus_code,
> .get_fmt = ov7740_get_fmt,
> .set_fmt = ov7740_set_fmt,
> + .get_mbus_config = ov7740_get_mbus_config,
> };
>
> static const struct v4l2_subdev_ops ov7740_subdev_ops = {

--
Regards,

Sakari Ailus


2021-11-03 12:40:00

by Eugen Hristev

[permalink] [raw]
Subject: Re: [PATCH] media: i2c: ov7740: implement get_mbus_config

On 11/3/21 10:08 AM, Sakari Ailus wrote:
> Hi Eugen,
>
> Thanks for the patch.
>
> On Tue, Nov 02, 2021 at 05:30:08PM +0200, Eugen Hristev wrote:
>> Implement the get_mbus_config callback.
>> ov7740 is a parallel sensor, and according to datasheet, the register
>> REG12 controls the CCIR656 mode. This register is written to 0 in yuyv mode.
>> According to REG12[5] , CCIR656 mode, the behavior is:
>> CCIR656: disabled
>> REG28 controls the polarity of the signals. This register is unused.
>> The default behavior is then:
>> HSYNC polarity : positive
>> VSYNC polarity : positive
>> HREF polarity: positive
>>
>
> Doesn't the receiver driver get this information from DT?
>

Hi Sakari,

This patch comes as a result of my discussions with Jacopo, he advised
to get mbus configuration via the get_mbus_config . I agree that this
information can be taken from DT as you said.
In the end , my understanding is that get_mbus_config should be used
only for runtime configuration which can change.
Thus, if all this information is static, then, I will proceed with
obtaining it from DT, and you can disregard this patch, as it is not useful.

Thanks,
Eugen

>> Signed-off-by: Eugen Hristev <[email protected]>
>> ---
>> drivers/media/i2c/ov7740.c | 14 ++++++++++++++
>> 1 file changed, 14 insertions(+)
>>
>> diff --git a/drivers/media/i2c/ov7740.c b/drivers/media/i2c/ov7740.c
>> index 2539cfee85c8..f8a717aecb6f 100644
>> --- a/drivers/media/i2c/ov7740.c
>> +++ b/drivers/media/i2c/ov7740.c
>> @@ -873,12 +873,26 @@ static int ov7740_get_fmt(struct v4l2_subdev *sd,
>> return ret;
>> }
>>
>> +static int ov7740_get_mbus_config(struct v4l2_subdev *sd,
>> + unsigned int pad,
>> + struct v4l2_mbus_config *cfg)
>> +{
>> + cfg->type = V4L2_MBUS_PARALLEL;
>> + cfg->flags = V4L2_MBUS_MASTER | V4L2_MBUS_HSYNC_ACTIVE_HIGH |
>> + V4L2_MBUS_VSYNC_ACTIVE_HIGH |
>> + V4L2_MBUS_PCLK_SAMPLE_RISING |
>> + V4L2_MBUS_FIELD_EVEN_LOW | V4L2_MBUS_DATA_ACTIVE_HIGH;
>> +
>> + return 0;
>> +}
>> +
>> static const struct v4l2_subdev_pad_ops ov7740_subdev_pad_ops = {
>> .enum_frame_interval = ov7740_enum_frame_interval,
>> .enum_frame_size = ov7740_enum_frame_size,
>> .enum_mbus_code = ov7740_enum_mbus_code,
>> .get_fmt = ov7740_get_fmt,
>> .set_fmt = ov7740_set_fmt,
>> + .get_mbus_config = ov7740_get_mbus_config,
>> };
>>
>> static const struct v4l2_subdev_ops ov7740_subdev_ops = {
>
> --
> Regards,
>
> Sakari Ailus
>