Message-ID: <07cf3e49-da67-74d7-528c-618fe94a15ff@xs4all.nl>
Date:	Mon, 8 Aug 2016 11:37:39 +0200
From:	Hans Verkuil <hverkuil@...all.nl>
To:	Songjun Wu <songjun.wu@...rochip.com>, nicolas.ferre@...el.com,
	robh@...nel.org
Cc:	laurent.pinchart@...asonboard.com,
	linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org,
	Arnd Bergmann <arnd@...db.de>,
	Niklas Söderlund 
	<niklas.soderlund+renesas@...natech.se>,
	Benoit Parrot <bparrot@...com>, linux-kernel@...r.kernel.org,
	Andrew-CT Chen <andrew-ct.chen@...iatek.com>,
	Sudip Mukherjee <sudipm.mukherjee@...il.com>,
	Kamil Debski <kamil@...as.org>,
	Tiffany Lin <tiffany.lin@...iatek.com>,
	Peter Griffin <peter.griffin@...aro.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Mikhail Ulyanov <mikhail.ulyanov@...entembedded.com>,
	Richard Röjfors <richard@...finpack.se>,
	Hans Verkuil <hans.verkuil@...co.com>,
	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
	Simon Horman <horms+renesas@...ge.net.au>
Subject: Re: [PATCH v8 1/2] [media] atmel-isc: add the Image Sensor Controller
 code

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@...rochip.com>
> ---
> 
> 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.

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

<snip>

> +static int isc_async_complete(struct v4l2_async_notifier *notifier)
> +{
> +	struct isc_device *isc = container_of(notifier->v4l2_dev,
> +					      struct isc_device, v4l2_dev);
> +	struct isc_subdev_entity *sd_entity;
> +	struct video_device *vdev = &isc->video_dev;
> +	struct vb2_queue *q = &isc->vb2_vidq;
> +	int ret;
> +
> +	isc->current_subdev = container_of(notifier,
> +					   struct isc_subdev_entity, notifier);
> +	sd_entity = isc->current_subdev;
> +
> +	mutex_init(&isc->lock);
> +	init_completion(&isc->comp);
> +
> +	/* Initialize videobuf2 queue */
> +	q->type			= V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +	q->io_modes		= VB2_MMAP | VB2_DMABUF | VB2_READ;
> +	q->drv_priv		= isc;
> +	q->buf_struct_size	= sizeof(struct isc_buffer);
> +	q->ops			= &isc_vb2_ops;
> +	q->mem_ops		= &vb2_dma_contig_memops;
> +	q->timestamp_flags	= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	q->lock			= &isc->lock;
> +	q->min_buffers_needed	= 1;
> +	q->dev			= isc->dev;
> +
> +	ret = vb2_queue_init(q);
> +	if (ret < 0) {
> +		v4l2_err(&isc->v4l2_dev,
> +			 "vb2_queue_init() failed: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Init video dma queues */
> +	INIT_LIST_HEAD(&isc->dma_queue);
> +	spin_lock_init(&isc->dma_queue_lock);
> +
> +	/* Register video device */
> +	strlcpy(vdev->name, ATMEL_ISC_NAME, sizeof(vdev->name));
> +	vdev->release		= video_device_release_empty;
> +	vdev->fops		= &isc_fops;
> +	vdev->ioctl_ops		= &isc_ioctl_ops;
> +	vdev->v4l2_dev		= &isc->v4l2_dev;
> +	vdev->vfl_dir		= VFL_DIR_RX;
> +	vdev->queue		= q;
> +	vdev->lock		= &isc->lock;
> +	vdev->ctrl_handler	= isc->current_subdev->sd->ctrl_handler;
> +	vdev->device_caps	= V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_CAPTURE;
> +	video_set_drvdata(vdev, isc);
> +
> +	ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
> +	if (ret < 0) {
> +		v4l2_err(&isc->v4l2_dev,
> +			 "video_register_device failed: %d\n", ret);
> +		return ret;
> +	}

This should be done last. Once the device is registered apps can use it, so
everything should be configured.

> +
> +	sd_entity->config = v4l2_subdev_alloc_pad_config(sd_entity->sd);
> +	if (sd_entity->config == NULL)
> +		return -ENOMEM;
> +
> +	ret = isc_formats_init(isc);
> +	if (ret < 0) {
> +		v4l2_err(&isc->v4l2_dev,
> +			 "Init format failed: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}

Regards,

	Hans

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