media: imx274: get rid of mode_index

After restructuring struct imx274_frmfmt, the mode_index field is
still in use only for two dev_dbg() calls in imx274_s_stream(). Let's
remove it and avoid duplicated information.

Replacing the first usage requires some rather annoying but trivial
pointer math. The other one can be removed entirely since it would
print the same value anyway.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/i2c/imx274.c

@@ -553,8 +553,6 @@ struct imx274_ctrls {
  * @reset_gpio: Pointer to reset gpio
  * @lock: Mutex structure
  * @mode: Parameters for the selected readout mode
- *        (points to imx274_formats[mode_index])
- * @mode_index: Resolution mode index
  */
 struct stimx274 {
 	struct v4l2_subdev sd;
@@ -567,7 +565,6 @@ struct stimx274 {
 	struct gpio_desc *reset_gpio;
 	struct mutex lock; /* mutex lock for operations */
 	const struct imx274_frmfmt *mode;
-	u32 mode_index;
 };
 
 /*
@@ -880,7 +877,6 @@ static int imx274_set_fmt(struct v4l2_subdev *sd,
 		index = 0;
 	}
 
-	imx274->mode_index = index;
 	imx274->mode = &imx274_formats[index];
 
 	if (fmt->width > IMX274_MAX_WIDTH)
@@ -1028,8 +1024,9 @@ static int imx274_s_stream(struct v4l2_subdev *sd, int on)
 	struct stimx274 *imx274 = to_imx274(sd);
 	int ret = 0;
 
-	dev_dbg(&imx274->client->dev, "%s : %s, mode index = %d\n", __func__,
-		on ? "Stream Start" : "Stream Stop", imx274->mode_index);
+	dev_dbg(&imx274->client->dev, "%s : %s, mode index = %td\n", __func__,
+		on ? "Stream Start" : "Stream Stop",
+		imx274->mode - &imx274_formats[0]);
 
 	mutex_lock(&imx274->lock);
 
@@ -1068,8 +1065,7 @@ static int imx274_s_stream(struct v4l2_subdev *sd, int on)
 	}
 
 	mutex_unlock(&imx274->lock);
-	dev_dbg(&imx274->client->dev,
-		"%s : Done: mode = %d\n", __func__, imx274->mode_index);
+	dev_dbg(&imx274->client->dev, "%s : Done\n", __func__);
 	return 0;
 
 fail:
@@ -1625,8 +1621,7 @@ static int imx274_probe(struct i2c_client *client,
 	mutex_init(&imx274->lock);
 
 	/* initialize format */
-	imx274->mode_index = IMX274_MODE_3840X2160;
-	imx274->mode = &imx274_formats[imx274->mode_index];
+	imx274->mode = &imx274_formats[IMX274_MODE_3840X2160];
 	imx274->format.width = imx274->mode->size.width;
 	imx274->format.height = imx274->mode->size.height;
 	imx274->format.field = V4L2_FIELD_NONE;