[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, 11 insertions, 3 deletions

diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index e6da353b39bc..8be561ab2615 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;
                 /*
@@ -854,6 +859,9 @@ 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);