Hi Nick,

On 05/04/2016 07:07 PM, Nick Dyer wrote:
> Register a video device to output T37 diagnostic data.
> 
> Signed-off-by: Nick Dyer <nick.d...@itdev.co.uk>
> ---
>  drivers/input/touchscreen/Kconfig        |   2 +
>  drivers/input/touchscreen/atmel_mxt_ts.c | 271 
> +++++++++++++++++++++++++++++++
>  2 files changed, 273 insertions(+)
> 
> diff --git a/drivers/input/touchscreen/Kconfig 
> b/drivers/input/touchscreen/Kconfig
> index 1f99e7f..4aa7609 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -105,6 +105,8 @@ config TOUCHSCREEN_AR1021_I2C
>  config TOUCHSCREEN_ATMEL_MXT
>       tristate "Atmel mXT I2C Touchscreen"
>       depends on I2C
> +     depends on VIDEO_V4L2
> +     select VIDEOBUF2_VMALLOC
>       select FW_LOADER
>       help
>         Say Y here if you have Atmel mXT series I2C touchscreen,
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c 
> b/drivers/input/touchscreen/atmel_mxt_ts.c
> index cd97713..8945235 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -28,6 +28,10 @@
>  #include <linux/of.h>
>  #include <linux/slab.h>
>  #include <asm/unaligned.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/videobuf2-v4l2.h>
> +#include <media/videobuf2-vmalloc.h>
>  
>  /* Firmware files */
>  #define MXT_FW_NAME          "maxtouch.fw"
> @@ -222,6 +226,23 @@ struct mxt_dbg {
>       struct t37_debug *t37_buf;
>       unsigned int t37_pages;
>       unsigned int t37_nodes;
> +
> +     struct v4l2_device v4l2;
> +     struct v4l2_pix_format format;
> +     struct video_device vdev;
> +     struct vb2_queue queue;
> +     struct mutex lock;
> +     int input;
> +};
> +
> +static const struct v4l2_file_operations mxt_video_fops = {
> +     .owner = THIS_MODULE,
> +     .open = v4l2_fh_open,
> +     .release = vb2_fop_release,
> +     .unlocked_ioctl = video_ioctl2,
> +     .read = vb2_fop_read,
> +     .mmap = vb2_fop_mmap,
> +     .poll = vb2_fop_poll,
>  };
>  
>  /* Each client has this additional data */
> @@ -277,6 +298,11 @@ struct mxt_data {
>       struct completion crc_completion;
>  };
>  
> +struct mxt_vb2_buffer {
> +     struct vb2_buffer       vb;
> +     struct list_head        list;
> +};
> +
>  static size_t mxt_obj_size(const struct mxt_object *obj)
>  {
>       return obj->size_minus_one + 1;
> @@ -1523,6 +1549,9 @@ static void mxt_free_input_device(struct mxt_data *data)
>  
>  static void mxt_free_object_table(struct mxt_data *data)
>  {
> +     video_unregister_device(&data->dbg.vdev);
> +     v4l2_device_unregister(&data->dbg.v4l2);
> +
>       kfree(data->object_table);
>       data->object_table = NULL;
>       kfree(data->msg_buf);
> @@ -2154,10 +2183,215 @@ wait_cmd:
>       return mxt_convert_debug_pages(data, outbuf);
>  }
>  
> +static int mxt_queue_setup(struct vb2_queue *q,
> +                    unsigned int *nbuffers, unsigned int *nplanes,
> +                    unsigned int sizes[], void *alloc_ctxs[])
> +{
> +     struct mxt_data *data = q->drv_priv;
> +
> +     *nbuffers = 1;

That's not right. You can just drop this line since you've already set 
min_buffers_needed below.

This line forces vb2 to always allocate just one buffer, even if userspace 
wants more.

And in order to correctly support VIDIOC_CREATE_BUFS you need this:

        if (*nplanes)
                return sizes[0] < data->dbg.t37_nodes * sizeof(u16) ? -EINVAL : 
0;

> +     *nplanes = 1;
> +     sizes[0] = data->dbg.t37_nodes * sizeof(u16);
> +
> +     return 0;
> +}
> +
> +static int mxt_buffer_prepare(struct vb2_buffer *vb)
> +{
> +     return 0;
> +}

Just drop this function since it doesn't do anything.

> +
> +static void mxt_buffer_queue(struct vb2_buffer *vb)
> +{
> +     struct mxt_data *data = vb2_get_drv_priv(vb->vb2_queue);
> +     u16 *ptr;
> +     int ret;
> +
> +     ptr = vb2_plane_vaddr(vb, 0);
> +     if (!ptr) {
> +             dev_err(&data->client->dev, "Error acquiring frame ptr\n");
> +             goto fault;
> +     }
> +
> +     ret = mxt_read_diagnostic_debug(data, MXT_DIAGNOSTIC_DELTAS, ptr);
> +     if (ret)
> +             goto fault;
> +
> +     vb2_set_plane_payload(vb, 0, data->dbg.t37_nodes * sizeof(u16));
> +     vb2_buffer_done(vb, VB2_BUF_STATE_DONE);
> +     return;
> +
> +fault:
> +     vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
> +}
> +
> +/* V4L2 structures */
> +static const struct vb2_ops mxt_queue_ops = {
> +     .queue_setup            = mxt_queue_setup,
> +     .buf_prepare            = mxt_buffer_prepare,
> +     .buf_queue              = mxt_buffer_queue,
> +     .wait_prepare           = vb2_ops_wait_prepare,
> +     .wait_finish            = vb2_ops_wait_finish,
> +};
> +
> +static const struct vb2_queue mxt_queue = {
> +     .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
> +     .io_modes = VB2_MMAP,

Add VB2_USERPTR | VB2_DMABUF | VB2_READ here as well. You get that for free, so 
why not?

> +     .buf_struct_size = sizeof(struct mxt_vb2_buffer),
> +     .ops = &mxt_queue_ops,
> +     .mem_ops = &vb2_vmalloc_memops,
> +     .timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC,
> +     .min_buffers_needed = 1,
> +};
> +
> +static int mxt_vidioc_querycap(struct file *file, void *priv,
> +                              struct v4l2_capability *cap)
> +{
> +     struct mxt_data *data = video_drvdata(file);
> +
> +     strlcpy(cap->driver, "atmel_mxt_ts", sizeof(cap->driver));
> +     strlcpy(cap->card, "atmel_mxt_ts touch", sizeof(cap->card));
> +     strlcpy(cap->bus_info, data->phys, sizeof(cap->bus_info));
> +     cap->device_caps = V4L2_CAP_VIDEO_CAPTURE |
> +             V4L2_CAP_READWRITE |
> +             V4L2_CAP_STREAMING;
> +     cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;

You can drop this line: it's now done for you by the v4l2 core code.

> +
> +     return 0;
> +}
> +
> +static int mxt_vidioc_enum_input(struct file *file, void *priv,
> +                                struct v4l2_input *i)
> +{
> +     if (i->index > 0)
> +             return -EINVAL;
> +
> +     i->type = V4L2_INPUT_TYPE_CAMERA;

I think we still need an V4L2_INPUT_TYPE_TOUCH_SENSOR here: it's just plain
weird to call this a camera IMHO.

> +     i->std = V4L2_STD_UNKNOWN;
> +     i->capabilities = 0;

Drop these two lines, v4l2_input is zeroed anyway.

> +     strlcpy(i->name, "Mutual References", sizeof(i->name));
> +     return 0;
> +}
> +
> +static int mxt_set_input(struct mxt_data *data, unsigned int i)
> +{
> +     struct v4l2_pix_format *f = &data->dbg.format;
> +
> +     if (i > 0)
> +             return -EINVAL;
> +
> +     f->width = data->info.matrix_xsize;
> +     f->height = data->info.matrix_ysize;
> +     f->pixelformat = V4L2_PIX_FMT_YS16;
> +     f->field = V4L2_FIELD_NONE;
> +     f->colorspace = V4L2_COLORSPACE_SRGB;

This makes no sense. Use COLORSPACE_RAW here.

> +     f->bytesperline = f->width * sizeof(u16);
> +     f->sizeimage = f->width * f->height * sizeof(u16);
> +
> +     data->dbg.input = i;
> +
> +     return 0;
> +}
> +
> +static int mxt_vidioc_s_input(struct file *file, void *priv, unsigned int i)
> +{
> +     return mxt_set_input(video_drvdata(file), i);
> +}
> +
> +static int mxt_vidioc_g_input(struct file *file, void *priv, unsigned int *i)
> +{
> +     struct mxt_data *data = video_drvdata(file);
> +
> +     *i = data->dbg.input;
> +
> +     return 0;
> +}
> +
> +static int mxt_vidioc_fmt(struct file *file, void *priv, struct v4l2_format 
> *f)
> +{
> +     struct mxt_data *data = video_drvdata(file);
> +
> +     f->fmt.pix = data->dbg.format;
> +
> +     return 0;
> +}
> +
> +static int mxt_vidioc_enum_fmt(struct file *file, void *priv,
> +                              struct v4l2_fmtdesc *fmt)
> +{
> +     if (fmt->index > 0 || fmt->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     fmt->pixelformat = V4L2_PIX_FMT_YS16;
> +     strlcpy(fmt->description, "16-bit raw debug data",
> +             sizeof(fmt->description));

Don't set the description here. Instead set it in v4l2-ioctls.c so all drivers
that need this will use a consistent description string.

> +     fmt->flags = 0;

You can drop this line, it's zeroed when this function is called.

> +     return 0;
> +}
> +
> +static int mxt_vidioc_enum_framesizes(struct file *file, void *priv,
> +                                     struct v4l2_frmsizeenum *f)
> +{
> +     struct mxt_data *data = video_drvdata(file);
> +
> +     if (f->index > 0)
> +             return -EINVAL;
> +
> +     f->discrete.width = data->info.matrix_xsize;
> +     f->discrete.height = data->info.matrix_ysize;
> +     f->type = V4L2_FRMSIZE_TYPE_DISCRETE;
> +     return 0;
> +}
> +
> +static int mxt_vidioc_enum_frameintervals(struct file *file, void *priv,
> +                                       struct v4l2_frmivalenum *f)
> +{
> +     if ((f->index > 0) || (f->pixel_format != V4L2_PIX_FMT_YS16))
> +             return -EINVAL;
> +
> +     f->type = V4L2_FRMIVAL_TYPE_DISCRETE;
> +     f->discrete.denominator  = 10;
> +     f->discrete.numerator = 1;
> +     return 0;
> +}

You can drop these two callbacks: since it is all fixed there is nothing to 
enumerate.

Instead you should implement g_parm so userspace can discover the framerate. 
That's all
that is needed.

> +
> +static const struct v4l2_ioctl_ops mxt_video_ioctl_ops = {
> +     .vidioc_querycap        = mxt_vidioc_querycap,
> +
> +     .vidioc_enum_fmt_vid_cap = mxt_vidioc_enum_fmt,
> +     .vidioc_s_fmt_vid_cap   = mxt_vidioc_fmt,
> +     .vidioc_g_fmt_vid_cap   = mxt_vidioc_fmt,
> +
> +     .vidioc_enum_framesizes = mxt_vidioc_enum_framesizes,
> +     .vidioc_enum_frameintervals = mxt_vidioc_enum_frameintervals,
> +
> +     .vidioc_enum_input      = mxt_vidioc_enum_input,
> +     .vidioc_g_input         = mxt_vidioc_g_input,
> +     .vidioc_s_input         = mxt_vidioc_s_input,
> +
> +     .vidioc_reqbufs         = vb2_ioctl_reqbufs,
> +     .vidioc_create_bufs     = vb2_ioctl_create_bufs,
> +     .vidioc_querybuf        = vb2_ioctl_querybuf,
> +     .vidioc_qbuf            = vb2_ioctl_qbuf,
> +     .vidioc_dqbuf           = vb2_ioctl_dqbuf,
> +     .vidioc_expbuf          = vb2_ioctl_expbuf,
> +
> +     .vidioc_streamon        = vb2_ioctl_streamon,
> +     .vidioc_streamoff       = vb2_ioctl_streamoff,
> +};
> +
> +static const struct video_device mxt_video_device = {
> +     .name = "Atmel maxTouch",
> +     .fops = &mxt_video_fops,
> +     .ioctl_ops = &mxt_video_ioctl_ops,
> +     .release = video_device_release_empty,
> +};
> +
>  static void mxt_debug_init(struct mxt_data *data)
>  {
>       struct mxt_dbg *dbg = &data->dbg;
>       struct mxt_object *object;
> +     int error;
>  
>       object = mxt_get_object(data, MXT_GEN_COMMAND_T6);
>       if (!object)
> @@ -2187,8 +2421,45 @@ static void mxt_debug_init(struct mxt_data *data)
>       if (!dbg->t37_buf)
>               goto error;
>  
> +     /* init channel to zero */
> +     mxt_set_input(data, 0);
> +
> +     /* register video device */
> +     snprintf(dbg->v4l2.name, sizeof(dbg->v4l2.name), "%s", "atmel_mxt_ts");
> +     error = v4l2_device_register(&data->client->dev, &dbg->v4l2);
> +     if (error) {
> +             dev_err(&data->client->dev, "Unable to register video master 
> device.");
> +             goto error;
> +     }
> +
> +     /* initialize the queue */
> +     mutex_init(&dbg->lock);
> +     dbg->queue = mxt_queue;
> +     dbg->queue.drv_priv = data;
> +     dbg->queue.lock = &dbg->lock;
> +
> +     error = vb2_queue_init(&dbg->queue);
> +     if (error)
> +             goto error_unreg_v4l2;
> +
> +     dbg->vdev = mxt_video_device;
> +     dbg->vdev.v4l2_dev = &dbg->v4l2;
> +     dbg->vdev.lock = &dbg->lock;
> +     dbg->vdev.vfl_dir = VFL_DIR_RX;
> +     dbg->vdev.queue = &dbg->queue;
> +     video_set_drvdata(&dbg->vdev, data);
> +
> +     error = video_register_device(&dbg->vdev, VFL_TYPE_TOUCH_SENSOR, -1);
> +     if (error) {
> +             dev_err(&data->client->dev,
> +                             "Unable to register video subdevice.");
> +             goto error_unreg_v4l2;
> +     }
> +
>       return;
>  
> +error_unreg_v4l2:
> +     v4l2_device_unregister(&dbg->v4l2);
>  error:
>       dev_err(&data->client->dev, "Error initialising T37 diagnostic data\n");
>  }
> 

BTW, did you run v4l2-compliance? I think it should work if you just do:

v4l2-compliance -d /dev/v4l-touch0

Regards,

        Hans
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