[PATCH v4 10/13] media: i2c: imx214: Verify chip ID

["André Apitzsch via B4 Relay" <devnull+git.apitzsch.eu@kernel.org>]

From: André Apitzsch <git@apitzsch.eu>

Check the chip ID and stop probing if it is no imx214 sensor.

Acked-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: André Apitzsch <git@apitzsch.eu>
---
 drivers/media/i2c/imx214.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c
index 91d0e892f9ac30a86cd0e1848e4b0d9befea2932..4779439974add96b0fcf5089ae40d8d3126d0ffa 100644
--- a/drivers/media/i2c/imx214.c
+++ b/drivers/media/i2c/imx214.c
@@ -20,6 +20,10 @@
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>
 
+/* Chip ID */
+#define IMX214_REG_CHIP_ID		CCI_REG16(0x0016)
+#define IMX214_CHIP_ID			0x0214
+
 #define IMX214_REG_MODE_SELECT		CCI_REG8(0x0100)
 #define IMX214_MODE_STANDBY		0x00
 #define IMX214_MODE_STREAMING		0x01
@@ -1098,6 +1102,27 @@ static int imx214_get_regulators(struct device *dev, struct imx214 *imx214)
 				       imx214->supplies);
 }
 
+/* Verify chip ID */
+static int imx214_identify_module(struct imx214 *imx214)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&imx214->sd);
+	int ret;
+	u64 val;
+
+	ret = cci_read(imx214->regmap, IMX214_REG_CHIP_ID, &val, NULL);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to read chip id %x\n",
+				     IMX214_CHIP_ID);
+
+	if (val != IMX214_CHIP_ID)
+		return dev_err_probe(&client->dev, -EIO,
+				     "chip id mismatch: %x!=%llx\n",
+				     IMX214_CHIP_ID, val);
+
+	return 0;
+}
+
 static int imx214_parse_fwnode(struct device *dev)
 {
 	struct fwnode_handle *endpoint;
@@ -1191,6 +1216,10 @@ static int imx214_probe(struct i2c_client *client)
 	 */
 	imx214_power_on(imx214->dev);
 
+	ret = imx214_identify_module(imx214);
+	if (ret)
+		goto error_power_off;
+
 	pm_runtime_set_active(imx214->dev);
 	pm_runtime_enable(imx214->dev);
 	pm_runtime_idle(imx214->dev);

-- 
2.47.1