media: imx214: Add new control with V4L2_CID_UNIT_CELL_SIZE

According to the product brief, the unit cell size is 1120 nanometers^2.

https://www.sony-semicon.co.jp/products_en/IS/sensor1/img/products/ProductBrief_IMX214_20150428.pdfSigned-off-by: NRicardo Ribalda Delgado <ribalda@kernel.org>
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/i2c/imx214.c

@@ -47,6 +47,7 @@ struct imx214 {
 	struct v4l2_ctrl *pixel_rate;
 	struct v4l2_ctrl *link_freq;
 	struct v4l2_ctrl *exposure;
+	struct v4l2_ctrl *unit_size;
 
 	struct regulator_bulk_data	supplies[IMX214_NUM_SUPPLIES];
 
@@ -948,6 +949,10 @@ static int imx214_probe(struct i2c_client *client)
 	static const s64 link_freq[] = {
 		IMX214_DEFAULT_LINK_FREQ,
 	};
+	static const struct v4l2_area unit_size = {
+		.width = 1120,
+		.height = 1120,
+	};
 	int ret;
 
 	ret = imx214_parse_fwnode(dev);
@@ -1029,6 +1034,10 @@ static int imx214_probe(struct i2c_client *client)
 					     V4L2_CID_EXPOSURE,
 					     0, 3184, 1, 0x0c70);
 
+	imx214->unit_size = v4l2_ctrl_new_std_compound(&imx214->ctrls,
+				NULL,
+				V4L2_CID_UNIT_CELL_SIZE,
+				v4l2_ctrl_ptr_create((void *)&unit_size));
 	ret = imx214->ctrls.error;
 	if (ret) {
 		dev_err(&client->dev, "%s control init failed (%d)\n",