[media] v4l2-core: Add support for touch devices

Some touch controllers send out touch data in a similar way to a
greyscale frame grabber.

Add new device type VFL_TYPE_TOUCH:
- This uses a new device prefix v4l-touch for these devices, to stop
  generic capture software from treating them as webcams. Otherwise,
  touch is treated similarly to video capture.
- Add V4L2_INPUT_TYPE_TOUCH
- Add MEDIA_INTF_T_V4L_TOUCH
- Add V4L2_CAP_TOUCH to indicate device is a touch device

Add formats:
- V4L2_TCH_FMT_DELTA_TD16 for signed 16-bit touch deltas
- V4L2_TCH_FMT_DELTA_TD08 for signed 16-bit touch deltas
- V4L2_TCH_FMT_TU16 for unsigned 16-bit touch data
- V4L2_TCH_FMT_TU08 for unsigned 8-bit touch data

This support will be used by:
- Atmel maXTouch (atmel_mxt_ts)
- Synaptics RMI4.
- sur40

Signed-off-by: Nick Dyer <nick@shmanahar.org>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 31 insertions, 5 deletions

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 51a0fa144392..eb6ccc70e9a8 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -924,6 +924,7 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
 	bool is_vid = vfd->vfl_type == VFL_TYPE_GRABBER;
 	bool is_vbi = vfd->vfl_type == VFL_TYPE_VBI;
 	bool is_sdr = vfd->vfl_type == VFL_TYPE_SDR;
+	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
 	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
 
@@ -932,7 +933,7 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
 
 	switch (type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
-		if (is_vid && is_rx &&
+		if ((is_vid || is_tch) && is_rx &&
 		    (ops->vidioc_g_fmt_vid_cap || ops->vidioc_g_fmt_vid_cap_mplane))
 			return 0;
 		break;
@@ -1243,6 +1244,10 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 	case V4L2_SDR_FMT_CS8:		descr = "Complex S8"; break;
 	case V4L2_SDR_FMT_CS14LE:	descr = "Complex S14LE"; break;
 	case V4L2_SDR_FMT_RU12LE:	descr = "Real U12LE"; break;
+	case V4L2_TCH_FMT_DELTA_TD16:	descr = "16-bit signed deltas"; break;
+	case V4L2_TCH_FMT_DELTA_TD08:	descr = "8-bit signed deltas"; break;
+	case V4L2_TCH_FMT_TU16:		descr = "16-bit unsigned touch data"; break;
+	case V4L2_TCH_FMT_TU08:		descr = "8-bit unsigned touch data"; break;
 
 	default:
 		/* Compressed formats */
@@ -1309,13 +1314,14 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
 	struct video_device *vfd = video_devdata(file);
 	bool is_vid = vfd->vfl_type == VFL_TYPE_GRABBER;
 	bool is_sdr = vfd->vfl_type == VFL_TYPE_SDR;
+	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
 	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
 	int ret = -EINVAL;
 
 	switch (p->type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
-		if (unlikely(!is_rx || !is_vid || !ops->vidioc_enum_fmt_vid_cap))
+		if (unlikely(!is_rx || (!is_vid && !is_tch) || !ops->vidioc_enum_fmt_vid_cap))
 			break;
 		ret = ops->vidioc_enum_fmt_vid_cap(file, fh, arg);
 		break;
@@ -1362,6 +1368,7 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
 	struct video_device *vfd = video_devdata(file);
 	bool is_vid = vfd->vfl_type == VFL_TYPE_GRABBER;
 	bool is_sdr = vfd->vfl_type == VFL_TYPE_SDR;
+	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
 	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
 	int ret;
@@ -1392,7 +1399,7 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
 
 	switch (p->type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
-		if (unlikely(!is_rx || !is_vid || !ops->vidioc_g_fmt_vid_cap))
+		if (unlikely(!is_rx || (!is_vid && !is_tch) || !ops->vidioc_g_fmt_vid_cap))
 			break;
 		p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
 		ret = ops->vidioc_g_fmt_vid_cap(file, fh, arg);
@@ -1451,6 +1458,21 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
 	return -EINVAL;
 }
 
+static void v4l_pix_format_touch(struct v4l2_pix_format *p)
+{
+	/*
+	 * The v4l2_pix_format structure contains fields that make no sense for
+	 * touch. Set them to default values in this case.
+	 */
+
+	p->field = V4L2_FIELD_NONE;
+	p->colorspace = V4L2_COLORSPACE_RAW;
+	p->flags = 0;
+	p->ycbcr_enc = 0;
+	p->quantization = 0;
+	p->xfer_func = 0;
+}
+
 static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 				struct file *file, void *fh, void *arg)
 {
@@ -1458,6 +1480,7 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 	struct video_device *vfd = video_devdata(file);
 	bool is_vid = vfd->vfl_type == VFL_TYPE_GRABBER;
 	bool is_sdr = vfd->vfl_type == VFL_TYPE_SDR;
+	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
 	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
 	int ret;
@@ -1469,12 +1492,14 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 
 	switch (p->type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
-		if (unlikely(!is_rx || !is_vid || !ops->vidioc_s_fmt_vid_cap))
+		if (unlikely(!is_rx || (!is_vid && !is_tch) || !ops->vidioc_s_fmt_vid_cap))
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.pix);
 		ret = ops->vidioc_s_fmt_vid_cap(file, fh, arg);
 		/* just in case the driver zeroed it again */
 		p->fmt.pix.priv = V4L2_PIX_FMT_PRIV_MAGIC;
+		if (is_tch)
+			v4l_pix_format_touch(&p->fmt.pix);
 		return ret;
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
 		if (unlikely(!is_rx || !is_vid || !ops->vidioc_s_fmt_vid_cap_mplane))
@@ -1545,6 +1570,7 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 	struct video_device *vfd = video_devdata(file);
 	bool is_vid = vfd->vfl_type == VFL_TYPE_GRABBER;
 	bool is_sdr = vfd->vfl_type == VFL_TYPE_SDR;
+	bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
 	bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
 	int ret;
@@ -1553,7 +1579,7 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 
 	switch (p->type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
-		if (unlikely(!is_rx || !is_vid || !ops->vidioc_try_fmt_vid_cap))
+		if (unlikely(!is_rx || (!is_vid && !is_tch) || !ops->vidioc_try_fmt_vid_cap))
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.pix);
 		ret = ops->vidioc_try_fmt_vid_cap(file, fh, arg);