Re: [PATCH v8 1/2] [media] atmel-isc: add the Image Sensor Controller code

[Hans Verkuil]

On 08/08/2016 11:37 AM, Hans Verkuil wrote:
> On 08/03/2016 10:08 AM, Songjun Wu wrote:
>> Add driver for the Image Sensor Controller. It manages
>> incoming data from a parallel based CMOS/CCD sensor.
>> It has an internal image processor, also integrates a
>> triple channel direct memory access controller master
>> interface.
>>
>> Signed-off-by: Songjun Wu <songjun.wu@xxxxxxxxxxxxx>
>> ---
>>
>> Changes in v8:
>> - Power on the sensor on the first open in function
>>   'isc_open'.
>> - Power off the sensor on the last release in function
>>   'isc_release'.
>> - Remove the switch of the pipeline.
>>
>> Changes in v7:
>> - Add enum_framesizes and enum_frameintervals.
>> - Call s_stream(0) when stream start fail.
>> - Fill the device_caps field of struct video_device
>>   with V4L2_CAP_STREAMING and V4L2_CAP_VIDEO_CAPTURE.
>> - Initialize the dev of struct vb2_queue.
>> - Set field to FIELD_NONE if the pix field is not supported.
>> - Return the result directly when call g/s_parm of subdev.
>>
>> Changes in v6: None
>> Changes in v5:
>> - Modify the macro definition and the related code.
>>
>> Changes in v4:
>> - Modify the isc clock code since the dt is changed.
>>
>> Changes in v3:
>> - Add pm runtime feature.
>> - Modify the isc clock code since the dt is changed.
>>
>> Changes in v2:
>> - Add "depends on COMMON_CLK" and "VIDEO_V4L2_SUBDEV_API"
>>   in Kconfig file.
>> - Correct typos and coding style according to Laurent's remarks
>> - Delete the loop while in 'isc_clk_enable' function.
>> - Replace 'hsync_active', 'vsync_active' and 'pclk_sample'
>>   with 'pfe_cfg0' in struct isc_subdev_entity.
>> - Add the code to support VIDIOC_CREATE_BUFS in
>>   'isc_queue_setup' function.
>> - Invoke isc_config to configure register in
>>   'isc_start_streaming' function.
>> - Add the struct completion 'comp' to synchronize with
>>   the frame end interrupt in 'isc_stop_streaming' function.
>> - Check the return value of the clk_prepare_enable
>>   in 'isc_open' function.
>> - Set the default format in 'isc_open' function.
>> - Add an exit condition in the loop while in 'isc_config'.
>> - Delete the hardware setup operation in 'isc_set_format'.
>> - Refuse format modification during streaming
>>   in 'isc_s_fmt_vid_cap' function.
>> - Invoke v4l2_subdev_alloc_pad_config to allocate and
>>   initialize the pad config in 'isc_async_complete' function.
>> - Remove the '.owner  = THIS_MODULE,' in atmel_isc_driver.
>> - Replace the module_platform_driver_probe() with
>>   module_platform_driver().
>>
>>  drivers/media/platform/Kconfig                |    1 +
>>  drivers/media/platform/Makefile               |    2 +
>>  drivers/media/platform/atmel/Kconfig          |    9 +
>>  drivers/media/platform/atmel/Makefile         |    1 +
>>  drivers/media/platform/atmel/atmel-isc-regs.h |  165 +++
>>  drivers/media/platform/atmel/atmel-isc.c      | 1503 +++++++++++++++++++++++++
>>  6 files changed, 1681 insertions(+)
>>  create mode 100644 drivers/media/platform/atmel/Kconfig
>>  create mode 100644 drivers/media/platform/atmel/Makefile
>>  create mode 100644 drivers/media/platform/atmel/atmel-isc-regs.h
>>  create mode 100644 drivers/media/platform/atmel/atmel-isc.c
>>
> 
> <snip>
> 
>> diff --git a/drivers/media/platform/atmel/atmel-isc.c b/drivers/media/platform/atmel/atmel-isc.c
>> new file mode 100644
>> index 0000000..d99d4a5
>> --- /dev/null
>> +++ b/drivers/media/platform/atmel/atmel-isc.c
> 
> <snip>
> 
>> +static int isc_set_default_fmt(struct isc_device *isc)
>> +{
>> +	u32 index = isc->num_user_formats - 1;
> 
> Why pick the last format? Strictly speaking it doesn't matter, but in practice
> the most common formats tend to be at the beginning of the format list.
> 
>> +	struct v4l2_format f = {
>> +		.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
>> +		.fmt.pix = {
>> +			.width		= VGA_WIDTH,
>> +			.height		= VGA_HEIGHT,
>> +			.field		= V4L2_FIELD_NONE,
>> +			.pixelformat	= isc->user_formats[index]->fourcc,
>> +		},
>> +	};
>> +
>> +	return isc_set_fmt(isc, &f);
>> +}
>> +
>> +static int isc_open(struct file *file)
>> +{
>> +	struct isc_device *isc = video_drvdata(file);
>> +	struct v4l2_subdev *sd = isc->current_subdev->sd;
>> +	int ret;
>> +
>> +	if (mutex_lock_interruptible(&isc->lock))
>> +		return -ERESTARTSYS;
>> +
>> +	ret = v4l2_fh_open(file);
>> +	if (ret < 0)
>> +		goto unlock;
>> +
>> +	if (!v4l2_fh_is_singular_file(file))
>> +		goto unlock;
>> +
>> +	ret = v4l2_subdev_call(sd, core, s_power, 1);
>> +	if (ret < 0 && ret != -ENOIOCTLCMD)
>> +		goto unlock;
>> +
>> +	ret = isc_set_default_fmt(isc);
> 
> This doesn't belong here, this needs to be done in isc_async_complete().
> 
> Having the code here means that every time you open the device, the format
> changes back to the default. That's not what you want.

Actually, you do need to set the format here since here is where you turn on
the sensor power, but it should be the current format, not the default format.

And in isc_set_default_fmt I recommend that you call the try fmt of the subdev
in order to let the subdev adjust the proposed default format. The 'try' doesn't
need to power on the sensor.

> 
>> +	if (ret)

You also need to power off the sd on error!

>> +		goto unlock;
>> +
>> +unlock:
>> +	mutex_unlock(&isc->lock);
>> +	return ret;
>> +}
>> +
> 

Regards,

	Hans