media: i2c: imx219: Fix 1920x1080 mode to use 1:1 pixel aspect ratio

Commit 0af46fbc333d ("media: i2c: imx219: Calculate crop rectangle
dynamically") meant that the 1920x1080 mode switched from using no
binning to using vertical binning but no horizontal binning, which
resulted in stretched pixels.

Until proper controls are available to independently select horizontal
and vertical binning, restore the original 1:1 pixel aspect ratio by
forcing binning to be uniform in both directions.

Cc: [e-mail]
Fixes: 0af46fbc333d ("media: i2c: imx219: Calculate crop rectangle dynamically")
Signed-off-by: Dave Stevenson <[e-mail]>
[Add comment & reword commit message]
Signed-off-by: Jai Luthra <[e-mail]>
Reviewed-by: Jacopo Mondi <[e-mail]>
Signed-off-by: Sakari Ailus <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/i2c/imx219.c

···
 	const struct imx219_mode *mode;
 	struct v4l2_mbus_framefmt *format;
 	struct v4l2_rect *crop;
-	u8 bin_h, bin_v;
+	u8 bin_h, bin_v, binning;
 	u32 prev_line_len;
 
 	format = v4l2_subdev_state_get_format(state, 0);
···
 	bin_h = min(IMX219_PIXEL_ARRAY_WIDTH / format->width, 2U);
 	bin_v = min(IMX219_PIXEL_ARRAY_HEIGHT / format->height, 2U);
 
+	/* Ensure bin_h and bin_v are same to avoid 1:2 or 2:1 stretching */
+	binning = min(bin_h, bin_v);
+
 	crop = v4l2_subdev_state_get_crop(state, 0);
-	crop->width = format->width * bin_h;
-	crop->height = format->height * bin_v;
+	crop->width = format->width * binning;
+	crop->height = format->height * binning;
 	crop->left = (IMX219_NATIVE_WIDTH - crop->width) / 2;
 	crop->top = (IMX219_NATIVE_HEIGHT - crop->height) / 2;