media: i2c: imx258: add HDR control

The IMX258 supports High Dynamic Range with 5 levels of low/high
exposure ratio.  Add a V4L2 control for HDR (WIDE_DYNAMIC_RANGE).
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/imx258.c

@@ -61,6 +61,15 @@
 #define IMX258_DGTL_GAIN_DEFAULT	1024
 #define IMX258_DGTL_GAIN_STEP		1
 
+/* HDR control */
+#define IMX258_REG_HDR			0x0220
+#define IMX258_HDR_ON			BIT(0)
+#define IMX258_REG_HDR_RATIO		0x0222
+#define IMX258_HDR_RATIO_MIN		0
+#define IMX258_HDR_RATIO_MAX		5
+#define IMX258_HDR_RATIO_STEP		1
+#define IMX258_HDR_RATIO_DEFAULT	0x0
+
 /* Test Pattern Control */
 #define IMX258_REG_TEST_PATTERN		0x0600
 
@@ -777,6 +786,22 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
 				!ctrl->val ? REG_CONFIG_MIRROR_FLIP :
 				REG_CONFIG_FLIP_TEST_PATTERN);
 		break;
+	case V4L2_CID_WIDE_DYNAMIC_RANGE:
+		if (!ctrl->val) {
+			ret = imx258_write_reg(imx258, IMX258_REG_HDR,
+					       IMX258_REG_VALUE_08BIT,
+					       IMX258_HDR_RATIO_MIN);
+		} else {
+			ret = imx258_write_reg(imx258, IMX258_REG_HDR,
+					       IMX258_REG_VALUE_08BIT,
+					       IMX258_HDR_ON);
+			if (ret)
+				break;
+			ret = imx258_write_reg(imx258, IMX258_REG_HDR_RATIO,
+					       IMX258_REG_VALUE_08BIT,
+					       BIT(IMX258_HDR_RATIO_MAX));
+		}
+		break;
 	default:
 		dev_info(&client->dev,
 			 "ctrl(id:0x%x,val:0x%x) is not handled\n",
@@ -1193,6 +1218,9 @@ static int imx258_init_controls(struct imx258 *imx258)
 				IMX258_DGTL_GAIN_STEP,
 				IMX258_DGTL_GAIN_DEFAULT);
 
+	v4l2_ctrl_new_std(ctrl_hdlr, &imx258_ctrl_ops, V4L2_CID_WIDE_DYNAMIC_RANGE,
+				0, 1, 1, IMX258_HDR_RATIO_DEFAULT);
+
 	v4l2_ctrl_new_std_menu_items(ctrl_hdlr, &imx258_ctrl_ops,
 				V4L2_CID_TEST_PATTERN,
 				ARRAY_SIZE(imx258_test_pattern_menu) - 1,