media: ccs: Add a sanity check for external clock frequency

The driver depends on the external clock frequency. Add a sanity check for
the frequency, by returning an error from probe if it's zero.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ccs/ccs-core.c

@@ -3275,6 +3275,11 @@ static int ccs_probe(struct i2c_client *client)
 		return -EINVAL;
 	}
 
+	if (!sensor->hwcfg.ext_clk) {
+		dev_err(&client->dev, "cannot work with xclk frequency 0\n");
+		return -EINVAL;
+	}
+
 	sensor->reset = devm_gpiod_get_optional(&client->dev, "reset",
 						GPIOD_OUT_HIGH);
 	if (IS_ERR(sensor->reset))