Re: [PATCH v6 7/7] media: imx214: Add new control with V4L2_CID_UNIT_CELL_SIZE

[Hans Verkuil]

On 9/27/19 9:33 AM, Ricardo Ribalda Delgado wrote:
> Hi Hans
> 
> On Fri, 27 Sep 2019, 09:14 Hans Verkuil, <hverkuil-cisco@xxxxxxxxx> wrote:
>>
>> On 9/20/19 3:51 PM, Ricardo Ribalda Delgado wrote:
>>> From: Ricardo Ribalda Delgado <ribalda@xxxxxxxxxx>
>>>
>>> According to the product brief, the unit cell size is 1120 nanometers^2.
>>>
>>> https://www.sony-semicon.co.jp/products_en/IS/sensor1/img/products/ProductBrief_IMX214_20150428.pdf
>>>
>>> Signed-off-by: Ricardo Ribalda Delgado <ribalda@xxxxxxxxxx>
>>> ---
>>>  drivers/media/i2c/imx214.c | 12 ++++++++++++
>>>  1 file changed, 12 insertions(+)
>>>
>>> diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c
>>> index 159a3a604f0e..57562e20c4ca 100644
>>> --- a/drivers/media/i2c/imx214.c
>>> +++ b/drivers/media/i2c/imx214.c
>>> @@ -47,6 +47,7 @@ struct imx214 {
>>>       struct v4l2_ctrl *pixel_rate;
>>>       struct v4l2_ctrl *link_freq;
>>>       struct v4l2_ctrl *exposure;
>>> +     struct v4l2_ctrl *unit_size;
>>>
>>>       struct regulator_bulk_data      supplies[IMX214_NUM_SUPPLIES];
>>>
>>> @@ -948,6 +949,13 @@ static int imx214_probe(struct i2c_client *client)
>>>       static const s64 link_freq[] = {
>>>               IMX214_DEFAULT_LINK_FREQ,
>>>       };
>>> +     struct v4l2_area unit_size = {
>>> +             .width = 1120,
>>> +             .height = 1120,
>>> +     };
>>> +     union v4l2_ctrl_ptr p_def = {
>>> +             .p_area = &unit_size,
>>> +     };
>>
>> Use static const for both.
>>
>> I think you should add a small static inline helper function to v4l2-ctrls.h that
>> takes a void pointer and returns a union v4l2_ctrl_ptr.
>>
>> Then you don't need to make a union v4l2_ctrl_ptr just to pass the unit_size pointer.
>>
> 
> That sounds useful, but can we warantee for all the arches that
> sizeof(v4l2_ctrl_ptr) <= sizeof (void *)

Yes. Everything in the union is a pointer, so sizeof(v4l2_ctrl_ptr) == sizeof (void *)

Regards,

	Hans

> 
> Of course, it sounds logic, that a union of pointers is the same size
> than a pointer... but you never know.
> 
> No matter what I will make the helper and resend. with all the changes
> from Jacopo
> 
> Thanks!
> 
>> Regards,
> 
> 
> 
>>
>>         Hans
>>
>>>       int ret;
>>>
>>>       ret = imx214_parse_fwnode(dev);
>>> @@ -1029,6 +1037,10 @@ static int imx214_probe(struct i2c_client *client)
>>>                                            V4L2_CID_EXPOSURE,
>>>                                            0, 3184, 1, 0x0c70);
>>>
>>> +     imx214->unit_size = v4l2_ctrl_new_std_compound(&imx214->ctrls,
>>> +                                                    NULL,
>>> +                                                    V4L2_CID_UNIT_CELL_SIZE,
>>> +                                                    p_def);
>>>       ret = imx214->ctrls.error;
>>>       if (ret) {
>>>               dev_err(&client->dev, "%s control init failed (%d)\n",
>>>
>>