[media] v4l2: Add standard controls for FM receivers

This commit introduces new class of standard controls
V4L2_CTRL_CLASS_FM_RX. This class is intended to all controls
pertaining to FM receiver chips. Also, two controls belonging to said
class are added as a part of this commit: V4L2_CID_TUNE_DEEMPHASIS and
V4L2_CID_RDS_RECEPTION.
This patch is based on the code found in the patch by Manjunatha Halli [1]
[1] http://lists-archives.com/linux-kernel/27641307-new-control-class-and-features-for-fm-rx.html

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/v4l2-core/v4l2-ctrls.c

@@ -297,8 +297,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
 		"Text",
 		NULL
 	};
-	static const char * const tune_preemphasis[] = {
+	static const char * const tune_emphasis[] = {
-		"No Preemphasis",
+		"None",
 		"50 Microseconds",
 		"75 Microseconds",
 		NULL,
@@ -508,7 +508,9 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
 	case V4L2_CID_SCENE_MODE:
 		return scene_mode;
 	case V4L2_CID_TUNE_PREEMPHASIS:
-		return tune_preemphasis;
+		return tune_emphasis;
+	case V4L2_CID_TUNE_DEEMPHASIS:
+		return tune_emphasis;
 	case V4L2_CID_FLASH_LED_MODE:
 		return flash_led_mode;
 	case V4L2_CID_FLASH_STROBE_SOURCE:
@@ -800,6 +802,9 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_DV_RX_POWER_PRESENT:	return "Power Present";
 	case V4L2_CID_DV_RX_RGB_RANGE:		return "Rx RGB Quantization Range";
 
+	case V4L2_CID_FM_RX_CLASS:		return "FM Radio Receiver Controls";
+	case V4L2_CID_TUNE_DEEMPHASIS:		return "De-Emphasis";
+	case V4L2_CID_RDS_RECEPTION:		return "RDS Reception";
 	default:
 		return NULL;
 	}
@@ -848,6 +853,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_MPEG_VIDEO_REPEAT_SEQ_HEADER:
 	case V4L2_CID_WIDE_DYNAMIC_RANGE:
 	case V4L2_CID_IMAGE_STABILIZATION:
+	case V4L2_CID_RDS_RECEPTION:
 		*type = V4L2_CTRL_TYPE_BOOLEAN;
 		*min = 0;
 		*max = *step = 1;
@@ -906,6 +912,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_DV_TX_RGB_RANGE:
 	case V4L2_CID_DV_RX_RGB_RANGE:
 	case V4L2_CID_TEST_PATTERN:
+	case V4L2_CID_TUNE_DEEMPHASIS:
 		*type = V4L2_CTRL_TYPE_MENU;
 		break;
 	case V4L2_CID_LINK_FREQ:
@@ -928,6 +935,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_IMAGE_SOURCE_CLASS:
 	case V4L2_CID_IMAGE_PROC_CLASS:
 	case V4L2_CID_DV_CLASS:
+	case V4L2_CID_FM_RX_CLASS:
 		*type = V4L2_CTRL_TYPE_CTRL_CLASS;
 		/* You can neither read not write these */
 		*flags |= V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY;

include/uapi/linux/v4l2-controls.h

@@ -59,6 +59,7 @@
 #define V4L2_CTRL_CLASS_IMAGE_SOURCE	0x009e0000	/* Image source controls */
 #define V4L2_CTRL_CLASS_IMAGE_PROC	0x009f0000	/* Image processing controls */
 #define V4L2_CTRL_CLASS_DV		0x00a00000	/* Digital Video controls */
+#define V4L2_CTRL_CLASS_FM_RX		0x00a10000	/* Digital Video controls */
 
 /* User-class control IDs */
 
@@ -835,4 +836,16 @@ enum v4l2_dv_rgb_range {
 #define	V4L2_CID_DV_RX_POWER_PRESENT		(V4L2_CID_DV_CLASS_BASE + 100)
 #define V4L2_CID_DV_RX_RGB_RANGE		(V4L2_CID_DV_CLASS_BASE + 101)
 
+#define V4L2_CID_FM_RX_CLASS_BASE		(V4L2_CTRL_CLASS_FM_RX | 0x900)
+#define V4L2_CID_FM_RX_CLASS			(V4L2_CTRL_CLASS_FM_RX | 1)
+
+#define V4L2_CID_TUNE_DEEMPHASIS		(V4L2_CID_FM_RX_CLASS_BASE + 1)
+enum v4l2_deemphasis {
+	V4L2_DEEMPHASIS_DISABLED	= V4L2_PREEMPHASIS_DISABLED,
+	V4L2_DEEMPHASIS_50_uS		= V4L2_PREEMPHASIS_50_uS,
+	V4L2_DEEMPHASIS_75_uS		= V4L2_PREEMPHASIS_75_uS,
+};
+
+#define V4L2_CID_RDS_RECEPTION			(V4L2_CID_FM_RX_CLASS_BASE + 2)
+
 #endif