media: add video control handlers using V4L2 control framework

This patch registers four standard control handlers using the corresponding
V4L2 framework.
Signed-off-by: Florian Echtler <floe@butterbrot.org>
[hans.verkuil@cisco.com: lower-cased 0x0F and 0xF0]
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/input/touchscreen/sur40.c

@@ -38,6 +38,7 @@
 #include <media/v4l2-device.h>
 #include <media/v4l2-dev.h>
 #include <media/v4l2-ioctl.h>
+#include <media/v4l2-ctrls.h>
 #include <media/videobuf2-v4l2.h>
 #include <media/videobuf2-dma-sg.h>
 
@@ -215,6 +216,7 @@ struct sur40_state {
 	struct video_device vdev;
 	struct mutex lock;
 	struct v4l2_pix_format pix_fmt;
+	struct v4l2_ctrl_handler hdl;
 
 	struct vb2_queue queue;
 	struct list_head buf_list;
@@ -224,6 +226,7 @@ struct sur40_state {
 	struct sur40_data *bulk_in_buffer;
 	size_t bulk_in_size;
 	u8 bulk_in_epaddr;
+	u8 vsvideo;
 
 	char phys[64];
 };
@@ -237,6 +240,11 @@ struct sur40_buffer {
 static const struct video_device sur40_video_device;
 static const struct vb2_queue sur40_queue;
 static void sur40_process_video(struct sur40_state *sur40);
+static int sur40_s_ctrl(struct v4l2_ctrl *ctrl);
+
+static const struct v4l2_ctrl_ops sur40_ctrl_ops = {
+	.s_ctrl = sur40_s_ctrl,
+};
 
 /*
  * Note: an earlier, non-public version of this driver used USB_RECIP_ENDPOINT
@@ -743,6 +751,36 @@ static int sur40_probe(struct usb_interface *interface,
 	sur40->vdev.queue = &sur40->queue;
 	video_set_drvdata(&sur40->vdev, sur40);
 
+	/* initialize the control handler for 4 controls */
+	v4l2_ctrl_handler_init(&sur40->hdl, 4);
+	sur40->v4l2.ctrl_handler = &sur40->hdl;
+	sur40->vsvideo = (SUR40_CONTRAST_DEF << 4) | SUR40_GAIN_DEF;
+
+	v4l2_ctrl_new_std(&sur40->hdl, &sur40_ctrl_ops, V4L2_CID_BRIGHTNESS,
+	  SUR40_BRIGHTNESS_MIN, SUR40_BRIGHTNESS_MAX, 1, clamp(brightness,
+	  (uint)SUR40_BRIGHTNESS_MIN, (uint)SUR40_BRIGHTNESS_MAX));
+
+	v4l2_ctrl_new_std(&sur40->hdl, &sur40_ctrl_ops, V4L2_CID_CONTRAST,
+	  SUR40_CONTRAST_MIN, SUR40_CONTRAST_MAX, 1, clamp(contrast,
+	  (uint)SUR40_CONTRAST_MIN, (uint)SUR40_CONTRAST_MAX));
+
+	v4l2_ctrl_new_std(&sur40->hdl, &sur40_ctrl_ops, V4L2_CID_GAIN,
+	  SUR40_GAIN_MIN, SUR40_GAIN_MAX, 1, clamp(gain,
+	  (uint)SUR40_GAIN_MIN, (uint)SUR40_GAIN_MAX));
+
+	v4l2_ctrl_new_std(&sur40->hdl, &sur40_ctrl_ops,
+	  V4L2_CID_BACKLIGHT_COMPENSATION, SUR40_BACKLIGHT_MIN,
+	  SUR40_BACKLIGHT_MAX, 1, SUR40_BACKLIGHT_DEF);
+
+	v4l2_ctrl_handler_setup(&sur40->hdl);
+
+	if (sur40->hdl.error) {
+		dev_err(&interface->dev,
+			"Unable to register video controls.");
+		v4l2_ctrl_handler_free(&sur40->hdl);
+		goto err_unreg_v4l2;
+	}
+
 	error = video_register_device(&sur40->vdev, VFL_TYPE_TOUCH, -1);
 	if (error) {
 		dev_err(&interface->dev,
@@ -775,6 +813,7 @@ static void sur40_disconnect(struct usb_interface *interface)
 {
 	struct sur40_state *sur40 = usb_get_intfdata(interface);
 
+	v4l2_ctrl_handler_free(&sur40->hdl);
 	video_unregister_device(&sur40->vdev);
 	v4l2_device_unregister(&sur40->v4l2);
 
@@ -968,6 +1007,31 @@ static int sur40_vidioc_g_fmt(struct file *file, void *priv,
 	return 0;
 }
 
+static int sur40_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct sur40_state *sur40  = container_of(ctrl->handler,
+	  struct sur40_state, hdl);
+	u8 value = sur40->vsvideo;
+
+	switch (ctrl->id) {
+	case V4L2_CID_BRIGHTNESS:
+		sur40_set_irlevel(sur40, ctrl->val);
+		break;
+	case V4L2_CID_CONTRAST:
+		value = (value & 0x0f) | (ctrl->val << 4);
+		sur40_set_vsvideo(sur40, value);
+		break;
+	case V4L2_CID_GAIN:
+		value = (value & 0xf0) | (ctrl->val);
+		sur40_set_vsvideo(sur40, value);
+		break;
+	case V4L2_CID_BACKLIGHT_COMPENSATION:
+		sur40_set_preprocessor(sur40, ctrl->val);
+		break;
+	}
+	return 0;
+}
+
 static int sur40_ioctl_parm(struct file *file, void *priv,
 			    struct v4l2_streamparm *p)
 {