media: i2c: Add ov7251_detect_chip()

.probe() is quite busy for this driver; make it cleaner by moving the
chip verification to a dedicated function.
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/i2c/ov7251.c

@@ -1439,11 +1439,43 @@ static int ov7251_check_hwcfg(struct ov7251 *ov7251)
 	return ret;
 }
 
+static int ov7251_detect_chip(struct ov7251 *ov7251)
+{
+	u8 chip_id_high, chip_id_low, chip_rev;
+	int ret;
+
+	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
+	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE)
+		return dev_err_probe(ov7251->dev, -ENODEV,
+				     "could not read ID high\n");
+
+	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
+	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE)
+		return dev_err_probe(ov7251->dev, -ENODEV,
+				     "could not read ID low\n");
+
+	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
+	if (ret < 0)
+		return dev_err_probe(ov7251->dev, -ENODEV,
+				     "could not read revision\n");
+	chip_rev >>= 4;
+
+	dev_info(ov7251->dev,
+		 "OV7251 revision %x (%s) detected at address 0x%02x\n",
+		 chip_rev,
+		 chip_rev == 0x4 ? "1A / 1B" :
+		 chip_rev == 0x5 ? "1C / 1D" :
+		 chip_rev == 0x6 ? "1E" :
+		 chip_rev == 0x7 ? "1F" : "unknown",
+		 ov7251->i2c_client->addr);
+
+	return 0;
+}
+
 static int ov7251_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct ov7251 *ov7251;
-	u8 chip_id_high, chip_id_low, chip_rev;
 	unsigned int rate = 0, clk_rate = 0;
 	s64 pixel_rate;
 	int ret;
@@ -1586,34 +1618,10 @@ static int ov7251_probe(struct i2c_client *client)
 		goto free_entity;
 	}
 
-	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
-	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
-		dev_err(dev, "could not read ID high\n");
-		ret = -ENODEV;
-		goto power_down;
-	}
-	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
-	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
-		dev_err(dev, "could not read ID low\n");
-		ret = -ENODEV;
-		goto power_down;
-	}
-
-	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
-	if (ret < 0) {
-		dev_err(dev, "could not read revision\n");
-		ret = -ENODEV;
+	ret = ov7251_detect_chip(ov7251);
+	if (ret)
 		goto power_down;
-	}
-	chip_rev >>= 4;
 
-	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
-		 chip_rev,
-		 chip_rev == 0x4 ? "1A / 1B" :
-		 chip_rev == 0x5 ? "1C / 1D" :
-		 chip_rev == 0x6 ? "1E" :
-		 chip_rev == 0x7 ? "1F" : "unknown",
-		 client->addr);
 
 	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
 			      &ov7251->pre_isp_00);