Commit 2be381de authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
Browse files

hwmon: (w83795) Improve detection routine 



Check for additional identification registers. Improve debugging
messages on failed detection.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent b2469f42

drivers/hwmon/w83795.c

+57 −23
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ MODULE_PARM_DESC(reset, "Set to 1 to reset chip, not recommended"); 
#define W83795_REG_VENDORID		0xfd

#define W83795_REG_CHIPID		0xfe

#define W83795_REG_DEVICEID		0xfb

#define W83795_REG_DEVICEID_A		0xff



#define W83795_REG_I2C_ADDR		0xfc

#define W83795_REG_CONFIG		0x01
@@ -1684,11 +1685,31 @@ static void w83795_init_client(struct i2c_client *client) 
		     w83795_read(client, W83795_REG_CONFIG) | 0x01);

}



static int w83795_get_device_id(struct i2c_client *client)

{

	int device_id;



	device_id = i2c_smbus_read_byte_data(client, W83795_REG_DEVICEID);



	/* Special case for rev. A chips; can't be checked first because later

	   revisions emulate this for compatibility */

	if (device_id < 0 || (device_id & 0xf0) != 0x50) {

		int alt_id;



		alt_id = i2c_smbus_read_byte_data(client,

						  W83795_REG_DEVICEID_A);

		if (alt_id == 0x50)

			device_id = alt_id;

	}



	return device_id;

}



/* Return 0 if detection is successful, -ENODEV otherwise */

static int w83795_detect(struct i2c_client *client,

			 struct i2c_board_info *info)

{

	u8 tmp, bank;

	int bank, vendor_id, device_id, expected, i2c_addr, config;

	struct i2c_adapter *adapter = client->adapter;

	unsigned short address = client->addr;

	const char *chip_name;
@@ -1696,33 +1717,45 @@ static int w83795_detect(struct i2c_client *client, 
	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))

		return -ENODEV;

	bank = i2c_smbus_read_byte_data(client, W83795_REG_BANKSEL);

	if (bank < 0 || (bank & 0x7c)) {

		dev_dbg(&adapter->dev,

			"w83795: Detection failed at addr 0x%02hx, check %s\n",

			address, "bank");

		return -ENODEV;

	}



	tmp = bank & 0x80 ? 0x5c : 0xa3;

	/* Check Nuvoton vendor ID */

	if (tmp != i2c_smbus_read_byte_data(client,

						W83795_REG_VENDORID)) {

		pr_debug("w83795: Detection failed at check "

			 "vendor id\n");

	vendor_id = i2c_smbus_read_byte_data(client, W83795_REG_VENDORID);

	expected = bank & 0x80 ? 0x5c : 0xa3;

	if (vendor_id != expected) {

		dev_dbg(&adapter->dev,

			"w83795: Detection failed at addr 0x%02hx, check %s\n",

			address, "vendor id");

		return -ENODEV;

	}



	/* If Nuvoton chip, address of chip and W83795_REG_I2C_ADDR

	   should match */

	if ((bank & 0x07) == 0

	 && (i2c_smbus_read_byte_data(client, W83795_REG_I2C_ADDR) & 0x7f) !=

	    address) {

		pr_debug("w83795: Detection failed at check "

			 "i2c addr\n");

	/* Check device ID */

	device_id = w83795_get_device_id(client) |

		    (i2c_smbus_read_byte_data(client, W83795_REG_CHIPID) << 8);

	if ((device_id >> 4) != 0x795) {

		dev_dbg(&adapter->dev,

			"w83795: Detection failed at addr 0x%02hx, check %s\n",

			address, "device id\n");

		return -ENODEV;

	}



	/* Determine the chip type now */

	if (0x79 != i2c_smbus_read_byte_data(client,

					     W83795_REG_CHIPID)) {

		pr_debug("w83795: Detection failed at check "

			 "chip id\n");

	/* If Nuvoton chip, address of chip and W83795_REG_I2C_ADDR

	   should match */

	if ((bank & 0x07) == 0) {

		i2c_addr = i2c_smbus_read_byte_data(client,

						    W83795_REG_I2C_ADDR);

		if ((i2c_addr & 0x7f) != address) {

			dev_dbg(&adapter->dev,

				"w83795: Detection failed at addr 0x%02hx, "

				"check %s\n", address, "i2c addr");

			return -ENODEV;

		}

	}



	/* Check 795 chip type: 795G or 795ADG

	   Usually we don't write to chips during detection, but here we don't
@@ -1731,14 +1764,15 @@ static int w83795_detect(struct i2c_client *client, 
	if ((bank & 0x07) != 0)

		i2c_smbus_write_byte_data(client, W83795_REG_BANKSEL,

					  bank & ~0x07);

	if (W83795_REG_CONFIG_CONFIG48 &

		  i2c_smbus_read_byte_data(client, W83795_REG_CONFIG)) {

	config = i2c_smbus_read_byte_data(client, W83795_REG_CONFIG);

	if (config & W83795_REG_CONFIG_CONFIG48)

		chip_name = "w83795adg";

	} else {

	else

		chip_name = "w83795g";

	}



	strlcpy(info->type, chip_name, I2C_NAME_SIZE);

	dev_info(&adapter->dev, "Found %s rev. %c at 0x%02hx\n", chip_name,

		 'A' + (device_id & 0xf), address);



	return 0;

}