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Commit 24d6e2a8 authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
Browse files

hwmon: (lm73) Make detection less problematic 



Word reads can cause trouble with some I2C devices, so do as much
detection as we can using only byte reads, and only use a word read in
the end to confirm the positive match. Also properly handle read
errors.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
Acked-by: default avatarGuenter Roeck <guenter.roeck@ericsson.com>
Cc: Robert Casanova <robertcasanova@nanometrics.ca>
parent 746cdfbf

drivers/hwmon/lm73.c

+18 −4
Original line number Diff line number Diff line
@@ -150,17 +150,31 @@ static int lm73_detect(struct i2c_client *new_client, 
			struct i2c_board_info *info)

{

	struct i2c_adapter *adapter = new_client->adapter;

	u16 id;

	u8 ctrl;

	int id, ctrl, conf;



	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |

					I2C_FUNC_SMBUS_WORD_DATA))

		return -ENODEV;



	/*

	 * Do as much detection as possible with byte reads first, as word

	 * reads can confuse other devices.

	 */

	ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);

	if (ctrl < 0 || (ctrl & 0x10))

		return -ENODEV;



	conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);

	if (conf < 0 || (conf & 0x0c))

		return -ENODEV;



	id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);

	if (id < 0 || id != (LM73_ID & 0xff))

		return -ENODEV;



	/* Check device ID */

	id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);

	ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);

	if ((id != LM73_ID) || (ctrl & 0x10))

	if (id < 0 || id != LM73_ID)

		return -ENODEV;



	strlcpy(info->type, "lm73", I2C_NAME_SIZE);