[media] saa7115: move the autodetection code out of the probe function

As we're now seeing other variants from chinese clones, like
gm1113c, we'll need to add more bits at the detection code.
So, move it into a separate function.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Tested-by: Jon Arne Jørgensen <jonarne@jonarne.no>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/i2c/saa7115.c

@@ -1573,46 +1573,103 @@ static const struct v4l2_subdev_ops saa711x_ops = {
 
 /* ----------------------------------------------------------------------- */
 
+/**
+ * saa711x_detect_chip - Detects the saa711x (or clone) variant
+ * @client:		I2C client structure.
+ * @id:			I2C device ID structure.
+ * @name:		Name of the device to be filled.
+ * @size:		Size of the name var.
+ *
+ * Detects the Philips/NXP saa711x chip, or some clone of it.
+ * if 'id' is NULL or id->driver_data is equal to 1, it auto-probes
+ * the analog demod.
+ * If the tuner is not found, it returns -ENODEV.
+ * If auto-detection is disabled and the tuner doesn't match what it was
+ *	requred, it returns -EINVAL and fills 'name'.
+ * If the chip is found, it returns the chip ID and fills 'name'.
+ */
+static int saa711x_detect_chip(struct i2c_client *client,
+			       const struct i2c_device_id *id,
+			       char *name, unsigned size)
+{
+	char chip_ver[size - 1];
+	char chip_id;
+	int i;
+	int autodetect;
+
+	autodetect = !id || id->driver_data == 1;
+
+	/* Read the chip version register */
+	for (i = 0; i < size - 1; i++) {
+		i2c_smbus_write_byte_data(client, 0, i);
+		chip_ver[i] = i2c_smbus_read_byte_data(client, 0);
+		name[i] = (chip_ver[i] & 0x0f) + '0';
+		if (name[i] > '9')
+			name[i] += 'a' - '9' - 1;
+	}
+	name[i] = '\0';
+
+	/* Check if it is a Philips/NXP chip */
+	if (!memcmp(name + 1, "f711", 4)) {
+		chip_id = name[5];
+		snprintf(name, size, "saa711%c", chip_id);
+
+		if (!autodetect && strcmp(name, id->name))
+			return -EINVAL;
+
+		switch (chip_id) {
+		case '1':
+			if (chip_ver[0] & 0xf0) {
+				snprintf(name, size, "saa711%ca", chip_id);
+				v4l_info(client, "saa7111a variant found\n");
+				return V4L2_IDENT_SAA7111A;
+			}
+			return V4L2_IDENT_SAA7111;
+		case '3':
+			return V4L2_IDENT_SAA7113;
+		case '4':
+			return V4L2_IDENT_SAA7114;
+		case '5':
+			return V4L2_IDENT_SAA7115;
+		case '8':
+			return V4L2_IDENT_SAA7118;
+		default:
+			v4l2_info(client,
+				  "WARNING: Philips/NXP chip unknown - Falling back to saa7111\n");
+			return V4L2_IDENT_SAA7111;
+		}
+	}
+
+	/* Chip was not discovered. Return its ID and don't bind */
+	v4l_dbg(1, debug, client, "chip %*ph @ 0x%x is unknown.\n",
+		16, chip_ver, client->addr << 1);
+	return -ENODEV;
+}
+
 static int saa711x_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct saa711x_state *state;
 	struct v4l2_subdev *sd;
 	struct v4l2_ctrl_handler *hdl;
-	int i;
+	int ident;
 	char name[17];
-	char chip_id;
-	int autodetect = !id || id->driver_data == 1;
 
 	/* Check if the adapter supports the needed features */
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 		return -EIO;
 
-	for (i = 0; i < 0x0f; i++) {
-		i2c_smbus_write_byte_data(client, 0, i);
-		name[i] = (i2c_smbus_read_byte_data(client, 0) & 0x0f) + '0';
-		if (name[i] > '9')
-			name[i] += 'a' - '9' - 1;
-	}
-	name[i] = '\0';
-
-	chip_id = name[5];
-
-	/* Check whether this chip is part of the saa711x series */
-	if (memcmp(name + 1, "f711", 4)) {
-		v4l_dbg(1, debug, client, "chip found @ 0x%x (ID %s) does not match a known saa711x chip.\n",
-			client->addr << 1, name);
+	ident = saa711x_detect_chip(client, id, name, sizeof(name));
+	if (ident == -EINVAL) {
+		/* Chip exists, but doesn't match */
+		v4l_warn(client, "found %s while %s was expected\n",
+			 name, id->name);
 		return -ENODEV;
 	}
+	if (ident < 0)
+		return ident;
 
-	/* Safety check */
-	if (!autodetect && id->name[6] != chip_id) {
-		v4l_warn(client, "found saa711%c while %s was expected\n",
-			 chip_id, id->name);
-	}
-	snprintf(client->name, sizeof(client->name), "saa711%c", chip_id);
-	v4l_info(client, "saa711%c found (%s) @ 0x%x (%s)\n", chip_id, name,
-		 client->addr << 1, client->adapter->name);
+	strlcpy(client->name, name, sizeof(client->name));
 
 	state = devm_kzalloc(&client->dev, sizeof(*state), GFP_KERNEL);
 	if (state == NULL)
@@ -1648,31 +1705,7 @@ static int saa711x_probe(struct i2c_client *client,
 	state->output = SAA7115_IPORT_ON;
 	state->enable = 1;
 	state->radio = 0;
-	switch (chip_id) {
-	case '1':
-		state->ident = V4L2_IDENT_SAA7111;
-		if (saa711x_read(sd, R_00_CHIP_VERSION) & 0xf0) {
-			v4l_info(client, "saa7111a variant found\n");
-			state->ident = V4L2_IDENT_SAA7111A;
-		}
-		break;
-	case '3':
-		state->ident = V4L2_IDENT_SAA7113;
-		break;
-	case '4':
-		state->ident = V4L2_IDENT_SAA7114;
-		break;
-	case '5':
-		state->ident = V4L2_IDENT_SAA7115;
-		break;
-	case '8':
-		state->ident = V4L2_IDENT_SAA7118;
-		break;
-	default:
-		state->ident = V4L2_IDENT_SAA7111;
-		v4l2_info(sd, "WARNING: Chip is not known - Falling back to saa7111\n");
-		break;
-	}
+	state->ident = ident;
 
 	state->audclk_freq = 48000;