[PATCH] media: i2c: ov7740: implement get_mbus_config

[PATCH] media: i2c: ov7740: implement get_mbus_config

[Eugen Hristev]

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

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
 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 = {
-- 
2.25.1

Re: [PATCH] media: i2c: ov7740: implement get_mbus_config

[Sakari Ailus]

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 <eugen.hristev@microchip.com>
> ---
>  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

Re: [PATCH] media: i2c: ov7740: implement get_mbus_config

[Eugen.Hristev]

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 <eugen.hristev@microchip.com>
>> ---
>>   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
> 

Re: [PATCH] media: i2c: ov7740: implement get_mbus_config

[Jacopo Mondi]

Hello,

   for a bit more of context

On Wed, Nov 03, 2021 at 12:39:52PM +0000, Eugen.Hristev@microchip.com wrote:
> 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

That's where getting info at runtime was suggested

https://patchwork.linuxtv.org/project/linux-media/patch/20200826065142.205000-1-eugen.hristev@microchip.com/#122336


> 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.

And the latest comment where getting it from DTS was suggested

https://patchwork.linuxtv.org/project/linux-media/patch/20211022075247.518880-4-eugen.hristev@microchip.com/#132605

Thanks
   j

>
> Thanks,
> Eugen
>
> >> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> >> ---
> >>   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
> >
>

Re: [PATCH] media: i2c: ov7740: implement get_mbus_config

[Sakari Ailus]

On Wed, Nov 03, 2021 at 12:39:52PM +0000, Eugen.Hristev@microchip.com wrote:
> 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.

Yes, please.

Getting this from DT is preferred if no dynamic configuration is needed.

-- 
Sakari Ailus