media: i2c: imx214: Explain some magic numbers

Code refinement, no functional changes.
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: André Apitzsch <git@apitzsch.eu>
[Sakari Ailus: The control handler remains in the context struct still.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/i2c/imx214.c

@@ -19,12 +19,23 @@
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>
 
+#define IMX214_REG_MODE_SELECT		0x0100
+#define IMX214_MODE_STANDBY		0x00
+#define IMX214_MODE_STREAMING		0x01
+
 #define IMX214_DEFAULT_CLK_FREQ	24000000
 #define IMX214_DEFAULT_LINK_FREQ 480000000
 #define IMX214_DEFAULT_PIXEL_RATE ((IMX214_DEFAULT_LINK_FREQ * 8LL) / 10)
 #define IMX214_FPS 30
 #define IMX214_MBUS_CODE MEDIA_BUS_FMT_SRGGB10_1X10
 
+/* Exposure control */
+#define IMX214_REG_EXPOSURE		0x0202
+#define IMX214_EXPOSURE_MIN		0
+#define IMX214_EXPOSURE_MAX		3184
+#define IMX214_EXPOSURE_STEP		1
+#define IMX214_EXPOSURE_DEFAULT		3184
+
 static const char * const imx214_supply_name[] = {
 	"vdda",
 	"vddd",
@@ -665,7 +676,7 @@ static int imx214_set_ctrl(struct v4l2_ctrl *ctrl)
 	case V4L2_CID_EXPOSURE:
 		vals[1] = ctrl->val;
 		vals[0] = ctrl->val >> 8;
-		ret = regmap_bulk_write(imx214->regmap, 0x202, vals, 2);
+		ret = regmap_bulk_write(imx214->regmap, IMX214_REG_EXPOSURE, vals, 2);
 		if (ret < 0)
 			dev_err(imx214->dev, "Error %d\n", ret);
 		ret = 0;
@@ -743,7 +754,7 @@ static int imx214_start_streaming(struct imx214 *imx214)
 		dev_err(imx214->dev, "could not sync v4l2 controls\n");
 		goto error;
 	}
-	ret = regmap_write(imx214->regmap, 0x100, 1);
+	ret = regmap_write(imx214->regmap, IMX214_REG_MODE_SELECT, IMX214_MODE_STREAMING);
 	if (ret < 0) {
 		dev_err(imx214->dev, "could not sent start table %d\n", ret);
 		goto error;
@@ -761,7 +772,7 @@ static int imx214_stop_streaming(struct imx214 *imx214)
 {
 	int ret;
 
-	ret = regmap_write(imx214->regmap, 0x100, 0);
+	ret = regmap_write(imx214->regmap, IMX214_REG_MODE_SELECT, IMX214_MODE_STANDBY);
 	if (ret < 0)
 		dev_err(imx214->dev, "could not sent stop table %d\n",	ret);
 
@@ -997,7 +1008,10 @@ static int imx214_probe(struct i2c_client *client)
 	 */
 	imx214->exposure = v4l2_ctrl_new_std(&imx214->ctrls, &imx214_ctrl_ops,
 					     V4L2_CID_EXPOSURE,
-					     0, 3184, 1, 0x0c70);
+					     IMX214_EXPOSURE_MIN,
+					     IMX214_EXPOSURE_MAX,
+					     IMX214_EXPOSURE_STEP,
+					     IMX214_EXPOSURE_DEFAULT);
 
 	imx214->unit_size = v4l2_ctrl_new_std_compound(&imx214->ctrls,
 				NULL,