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Commit a63ee9d8 authored by Guenter Roeck's avatar Guenter Roeck
Browse files

hwmon: (tmp421) Strengthen detect function 



Not all supported chips support the entire I2C address range.
Only accept specific chips at the addresses supported by that chip.
Check for invalid values in conversion rate and status registers.

Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Reviewed-by: default avatarJean Delvare <jdelvare@suse.de>
parent e47c39b3

Documentation/hwmon/tmp421

+2 −2
Original line number Diff line number Diff line
@@ -8,11 +8,11 @@ Supported chips: 
    Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp421.html

  * Texas Instruments TMP422

    Prefix: 'tmp422'

    Addresses scanned: I2C 0x2a, 0x4c, 0x4d, 0x4e and 0x4f

    Addresses scanned: I2C 0x4c, 0x4d, 0x4e and 0x4f

    Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp421.html

  * Texas Instruments TMP423

    Prefix: 'tmp423'

    Addresses scanned: I2C 0x2a, 0x4c, 0x4d, 0x4e and 0x4f

    Addresses scanned: I2C 0x4c and 0x4d

    Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp421.html



Authors:

drivers/hwmon/tmp421.c

+14 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f, 
enum chips { tmp421, tmp422, tmp423 };



/* The TMP421 registers */

#define TMP421_STATUS_REG			0x08

#define TMP421_CONFIG_REG_1			0x09

#define TMP421_CONVERSION_RATE_REG		0x0B

#define TMP421_MANUFACTURER_ID_REG		0xFE
@@ -235,6 +236,7 @@ static int tmp421_detect(struct i2c_client *client, 
	enum chips kind;

	struct i2c_adapter *adapter = client->adapter;

	const char *names[] = { "TMP421", "TMP422", "TMP423" };

	int addr = client->addr;

	u8 reg;



	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
@@ -244,15 +246,27 @@ static int tmp421_detect(struct i2c_client *client, 
	if (reg != TMP421_MANUFACTURER_ID)

		return -ENODEV;



	reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);

	if (reg & 0xf8)

		return -ENODEV;



	reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);

	if (reg & 0x7f)

		return -ENODEV;



	reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);

	switch (reg) {

	case TMP421_DEVICE_ID:

		kind = tmp421;

		break;

	case TMP422_DEVICE_ID:

		if (addr == 0x2a)

			return -ENODEV;

		kind = tmp422;

		break;

	case TMP423_DEVICE_ID:

		if (addr != 0x4c && addr != 0x4d)

			return -ENODEV;

		kind = tmp423;

		break;

	default: