[media] msi3101: add sampling mode control

Whilst Quadrature Sampling is most common sampling technique used in
radio technology there is others too. Add control user could select
sampling mode. We currently support only quadrature sampling.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/staging/media/msi3101/sdr-msi3101.c

@@ -361,8 +361,9 @@ static const struct msi3101_gain msi3101_gain_lut_1000[] = {
 
 #define MAX_ISOC_ERRORS         20
 
-#define MSI3101_CID_SAMPLING_RATE         ((V4L2_CID_USER_BASE | 0xf000) + 0)
-#define MSI3101_CID_SAMPLING_RESOLUTION   ((V4L2_CID_USER_BASE | 0xf000) + 1)
+#define MSI3101_CID_SAMPLING_MODE         ((V4L2_CID_USER_BASE | 0xf000) + 0)
+#define MSI3101_CID_SAMPLING_RATE         ((V4L2_CID_USER_BASE | 0xf000) + 1)
+#define MSI3101_CID_SAMPLING_RESOLUTION   ((V4L2_CID_USER_BASE | 0xf000) + 2)
 #define MSI3101_CID_TUNER_RF              ((V4L2_CID_USER_BASE | 0xf000) + 10)
 #define MSI3101_CID_TUNER_BW              ((V4L2_CID_USER_BASE | 0xf000) + 11)
 #define MSI3101_CID_TUNER_IF              ((V4L2_CID_USER_BASE | 0xf000) + 12)
@@ -1418,6 +1419,7 @@ static int msi3101_s_ctrl(struct v4l2_ctrl *ctrl)
 			ctrl->minimum, ctrl->maximum, ctrl->step);
 
 	switch (ctrl->id) {
+	case MSI3101_CID_SAMPLING_MODE:
 	case MSI3101_CID_SAMPLING_RATE:
 	case MSI3101_CID_SAMPLING_RESOLUTION:
 		ret = 0;
@@ -1455,6 +1457,18 @@ static int msi3101_probe(struct usb_interface *intf,
 	struct usb_device *udev = interface_to_usbdev(intf);
 	struct msi3101_state *s = NULL;
 	int ret;
+	static const char * const ctrl_sampling_mode_qmenu_strings[] = {
+		"Quadrature Sampling",
+		NULL,
+	};
+	static const struct v4l2_ctrl_config ctrl_sampling_mode = {
+		.ops	= &msi3101_ctrl_ops,
+		.id	= MSI3101_CID_SAMPLING_MODE,
+		.type   = V4L2_CTRL_TYPE_MENU,
+		.flags  = V4L2_CTRL_FLAG_INACTIVE,
+		.name	= "Sampling Mode",
+		.qmenu  = ctrl_sampling_mode_qmenu_strings,
+	};
 	static const struct v4l2_ctrl_config ctrl_sampling_rate = {
 		.ops	= &msi3101_ctrl_ops,
 		.id	= MSI3101_CID_SAMPLING_RATE,
@@ -1553,7 +1567,8 @@ static int msi3101_probe(struct usb_interface *intf,
 	video_set_drvdata(&s->vdev, s);
 
 	/* Register controls */
-	v4l2_ctrl_handler_init(&s->ctrl_handler, 6);
+	v4l2_ctrl_handler_init(&s->ctrl_handler, 7);
+	v4l2_ctrl_new_custom(&s->ctrl_handler, &ctrl_sampling_mode, NULL);
 	s->ctrl_sampling_rate = v4l2_ctrl_new_custom(&s->ctrl_handler, &ctrl_sampling_rate, NULL);
 	v4l2_ctrl_new_custom(&s->ctrl_handler, &ctrl_sampling_resolution, NULL);
 	s->ctrl_tuner_rf = v4l2_ctrl_new_custom(&s->ctrl_handler, &ctrl_tuner_rf, NULL);