media: i2c: ov4689: Implement digital gain control

The OV4689 sensor supports digital gain up to 16x. Implement
corresponding control in the driver. Default digital gain value is not
modified by this patch.
Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/i2c/ov4689.c

@@ -35,6 +35,12 @@
 #define OV4689_GAIN_STEP		1
 #define OV4689_GAIN_DEFAULT		0x80
 
+#define OV4689_REG_DIG_GAIN		CCI_REG16(0x352a)
+#define OV4689_DIG_GAIN_MIN		1
+#define OV4689_DIG_GAIN_MAX		0x7fff
+#define OV4689_DIG_GAIN_STEP		1
+#define OV4689_DIG_GAIN_DEFAULT		0x800
+
 #define OV4689_REG_HTS			CCI_REG16(0x380c)
 #define OV4689_HTS_DIVIDER		4
 #define OV4689_HTS_MAX			0x7fff
@@ -131,7 +137,6 @@ static const struct cci_reg_sequence ov4689_2688x1520_regs[] = {
 
 	/* AEC PK */
 	{ CCI_REG8(0x3503), 0x04 }, /* AEC_MANUAL gain_input_as_sensor_gain_format = 1 */
-	{ CCI_REG8(0x352a), 0x08 }, /* DIG_GAIN_FRAC_LONG dig_gain_long[14:8] = 0x08 (2x) */
 
 	/* ADC and analog control*/
 	{ CCI_REG8(0x3603), 0x40 },
@@ -624,6 +629,9 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
 				OV4689_TIMING_FLIP_MASK,
 				ctrl->val ? 0 : OV4689_TIMING_FLIP_BOTH, &ret);
 		break;
+	case V4L2_CID_DIGITAL_GAIN:
+		cci_write(regmap, OV4689_REG_DIG_GAIN, ctrl->val, &ret);
+		break;
 	default:
 		dev_warn(dev, "%s Unhandled id:0x%x, val:0x%x\n",
 			 __func__, ctrl->id, ctrl->val);
@@ -654,7 +662,7 @@ static int ov4689_initialize_controls(struct ov4689 *ov4689)
 
 	handler = &ov4689->ctrl_handler;
 	mode = ov4689->cur_mode;
-	ret = v4l2_ctrl_handler_init(handler, 12);
+	ret = v4l2_ctrl_handler_init(handler, 13);
 	if (ret)
 		return ret;
 
@@ -697,6 +705,10 @@ static int ov4689_initialize_controls(struct ov4689 *ov4689)
 	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_VFLIP, 0, 1, 1, 0);
 	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_HFLIP, 0, 1, 1, 0);
 
+	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_DIGITAL_GAIN,
+			  OV4689_DIG_GAIN_MIN, OV4689_DIG_GAIN_MAX,
+			  OV4689_DIG_GAIN_STEP, OV4689_DIG_GAIN_DEFAULT);
+
 	if (handler->error) {
 		ret = handler->error;
 		dev_err(ov4689->dev, "Failed to init controls(%d)\n", ret);