[PATCH v6 02/11] [media] v4l2-core: Add support for touch devices

From: Nick Dyer
Date: Thu Jun 30 2016 - 13:47:10 EST

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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@xxxxxxxxxxxxx>
---
drivers/media/media-entity.c | 2 ++
drivers/media/v4l2-core/v4l2-dev.c | 16 +++++++++++++---
drivers/media/v4l2-core/v4l2-ioctl.c | 36 +++++++++++++++++++++++++++++++-----
include/media/v4l2-dev.h | 3 ++-
include/uapi/linux/media.h | 1 +
include/uapi/linux/videodev2.h | 9 +++++++++
6 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index d8a2299..9014362 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -65,6 +65,8 @@ static inline const char *intf_type(struct media_interface *intf)
return "v4l-subdev";
case MEDIA_INTF_T_V4L_SWRADIO:
return "v4l-swradio";
+ case MEDIA_INTF_T_V4L_TOUCH:
+ return "v4l-touch";
case MEDIA_INTF_T_ALSA_PCM_CAPTURE:
return "alsa-pcm-capture";
case MEDIA_INTF_T_ALSA_PCM_PLAYBACK:
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 70b559d..21ba9b4 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -527,6 +527,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
bool is_vbi = vdev->vfl_type == VFL_TYPE_VBI;
bool is_radio = vdev->vfl_type == VFL_TYPE_RADIO;
bool is_sdr = vdev->vfl_type == VFL_TYPE_SDR;
+ bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
bool is_tx = vdev->vfl_dir != VFL_DIR_RX;

@@ -573,7 +574,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
if (ops->vidioc_enum_freq_bands || ops->vidioc_g_tuner || ops->vidioc_g_modulator)
set_bit(_IOC_NR(VIDIOC_ENUM_FREQ_BANDS), valid_ioctls);

- if (is_vid) {
+ if (is_vid || is_tch) {
/* video specific ioctls */
if ((is_rx && (ops->vidioc_enum_fmt_vid_cap ||
ops->vidioc_enum_fmt_vid_cap_mplane ||
@@ -662,7 +663,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
}

- if (is_vid || is_vbi || is_sdr) {
+ if (is_vid || is_vbi || is_sdr || is_tch) {
/* ioctls valid for video, vbi or sdr */
SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
@@ -675,7 +676,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
}

- if (is_vid || is_vbi) {
+ if (is_vid || is_vbi || is_tch) {
/* ioctls valid for video or vbi */
if (ops->vidioc_s_std)
set_bit(_IOC_NR(VIDIOC_ENUMSTD), valid_ioctls);
@@ -751,6 +752,10 @@ static int video_register_media_controller(struct video_device *vdev, int type)
intf_type = MEDIA_INTF_T_V4L_SWRADIO;
vdev->entity.function = MEDIA_ENT_F_IO_SWRADIO;
break;
+ case VFL_TYPE_TOUCH:
+ intf_type = MEDIA_INTF_T_V4L_TOUCH;
+ vdev->entity.function = MEDIA_ENT_F_IO_V4L;
+ break;
case VFL_TYPE_RADIO:
intf_type = MEDIA_INTF_T_V4L_RADIO;
/*
@@ -845,6 +850,8 @@ static int video_register_media_controller(struct video_device *vdev, int type)
* %VFL_TYPE_SUBDEV - A subdevice
*
* %VFL_TYPE_SDR - Software Defined Radio
+ *
+ * %VFL_TYPE_TOUCH - A touch sensor
*/
int __video_register_device(struct video_device *vdev, int type, int nr,
int warn_if_nr_in_use, struct module *owner)
@@ -888,6 +895,9 @@ int __video_register_device(struct video_device *vdev, int type, int nr,
/* Use device name 'swradio' because 'sdr' was already taken. */
name_base = "swradio";
break;
+ case VFL_TYPE_TOUCH:
+ name_base = "v4l-touch";
+ break;
default:
printk(KERN_ERR "%s called with unknown type: %d\n",
__func__, type);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 28e5be2..c3463f7 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);
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index 25a3190..a2bbf1c 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -25,7 +25,8 @@
#define VFL_TYPE_RADIO 2
#define VFL_TYPE_SUBDEV 3
#define VFL_TYPE_SDR 4
-#define VFL_TYPE_MAX 5
+#define VFL_TYPE_TOUCH 5
+#define VFL_TYPE_MAX 6

/* Is this a receiver, transmitter or mem-to-mem? */
/* Ignored for VFL_TYPE_SUBDEV. */
diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
index df59ede..a962ebd 100644
--- a/include/uapi/linux/media.h
+++ b/include/uapi/linux/media.h
@@ -297,6 +297,7 @@ struct media_links_enum {
#define MEDIA_INTF_T_V4L_RADIO (MEDIA_INTF_T_V4L_BASE + 2)
#define MEDIA_INTF_T_V4L_SUBDEV (MEDIA_INTF_T_V4L_BASE + 3)
#define MEDIA_INTF_T_V4L_SWRADIO (MEDIA_INTF_T_V4L_BASE + 4)
+#define MEDIA_INTF_T_V4L_TOUCH (MEDIA_INTF_T_V4L_BASE + 5)

#define MEDIA_INTF_T_ALSA_PCM_CAPTURE (MEDIA_INTF_T_ALSA_BASE)
#define MEDIA_INTF_T_ALSA_PCM_PLAYBACK (MEDIA_INTF_T_ALSA_BASE + 1)
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 8f95191..ea64f3d 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -440,6 +440,8 @@ struct v4l2_capability {
#define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */
#define V4L2_CAP_STREAMING 0x04000000 /* streaming I/O ioctls */

+#define V4L2_CAP_TOUCH 0x10000000 /* Is a touch device */
+
#define V4L2_CAP_DEVICE_CAPS 0x80000000 /* sets device capabilities field */

/*
@@ -633,6 +635,12 @@ struct v4l2_pix_format {
#define V4L2_SDR_FMT_CS14LE v4l2_fourcc('C', 'S', '1', '4') /* complex s14le */
#define V4L2_SDR_FMT_RU12LE v4l2_fourcc('R', 'U', '1', '2') /* real u12le */

+/* Touch formats - used for Touch devices */
+#define V4L2_TCH_FMT_DELTA_TD16 v4l2_fourcc('T', 'D', '1', '6') /* 16-bit signed deltas */
+#define V4L2_TCH_FMT_DELTA_TD08 v4l2_fourcc('T', 'D', '0', '8') /* 8-bit signed deltas */
+#define V4L2_TCH_FMT_TU16 v4l2_fourcc('T', 'U', '1', '6') /* 16-bit unsigned touch data */
+#define V4L2_TCH_FMT_TU08 v4l2_fourcc('T', 'U', '0', '8') /* 8-bit unsigned touch data */
+
/* priv field value to indicates that subsequent fields are valid. */
#define V4L2_PIX_FMT_PRIV_MAGIC 0xfeedcafe

@@ -1399,6 +1407,7 @@ struct v4l2_input {
/* Values for the 'type' field */
#define V4L2_INPUT_TYPE_TUNER 1
#define V4L2_INPUT_TYPE_CAMERA 2
+#define V4L2_INPUT_TYPE_TOUCH 3

/* field 'status' - general */
#define V4L2_IN_ST_NO_POWER 0x00000001 /* Attached device is off */
--
2.5.0

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