diff options
| -rw-r--r-- | Documentation/hwmon/lm75 | 5 | ||||
| -rw-r--r-- | drivers/hwmon/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/hwmon/lm75.c | 56 |
3 files changed, 47 insertions, 16 deletions
diff --git a/Documentation/hwmon/lm75 b/Documentation/hwmon/lm75 index 8e6356fe05d7..a1790401fdde 100644 --- a/Documentation/hwmon/lm75 +++ b/Documentation/hwmon/lm75 @@ -7,6 +7,11 @@ Supported chips: Addresses scanned: I2C 0x48 - 0x4f Datasheet: Publicly available at the National Semiconductor website http://www.national.com/ + * National Semiconductor LM75A + Prefix: 'lm75a' + Addresses scanned: I2C 0x48 - 0x4f + Datasheet: Publicly available at the National Semiconductor website + http://www.national.com/ * Dallas Semiconductor DS75 Prefix: 'lm75' Addresses scanned: I2C 0x48 - 0x4f diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 47621abb9a05..19d72bcf966a 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -521,7 +521,7 @@ config SENSORS_LM75 - Dallas Semiconductor DS75 and DS1775 - Maxim MAX6625 and MAX6626 - Microchip MCP980x - - National Semiconductor LM75 + - National Semiconductor LM75, LM75A - NXP's LM75A - ST Microelectronics STDS75 - TelCom (now Microchip) TCN75 diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c index f36eb80d227f..638dd0586e3f 100644 --- a/drivers/hwmon/lm75.c +++ b/drivers/hwmon/lm75.c @@ -232,6 +232,8 @@ static const struct i2c_device_id lm75_ids[] = { }; MODULE_DEVICE_TABLE(i2c, lm75_ids); +#define LM75A_ID 0xA1 + /* Return 0 if detection is successful, -ENODEV otherwise */ static int lm75_detect(struct i2c_client *new_client, struct i2c_board_info *info) @@ -239,6 +241,7 @@ static int lm75_detect(struct i2c_client *new_client, struct i2c_adapter *adapter = new_client->adapter; int i; int cur, conf, hyst, os; + bool is_lm75a = 0; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) @@ -250,23 +253,43 @@ static int lm75_detect(struct i2c_client *new_client, addresses 0x04-0x07 returning the last read value. The cycling+unused addresses combination is not tested, since it would significantly slow the detection down and would - hardly add any value. */ + hardly add any value. + + The National Semiconductor LM75A is different than earlier + LM75s. It has an ID byte of 0xaX (where X is the chip + revision, with 1 being the only revision in existence) in + register 7, and unused registers return 0xff rather than the + last read value. */ - /* Unused addresses */ cur = i2c_smbus_read_word_data(new_client, 0); conf = i2c_smbus_read_byte_data(new_client, 1); - hyst = i2c_smbus_read_word_data(new_client, 2); - if (i2c_smbus_read_word_data(new_client, 4) != hyst - || i2c_smbus_read_word_data(new_client, 5) != hyst - || i2c_smbus_read_word_data(new_client, 6) != hyst - || i2c_smbus_read_word_data(new_client, 7) != hyst) - return -ENODEV; - os = i2c_smbus_read_word_data(new_client, 3); - if (i2c_smbus_read_word_data(new_client, 4) != os - || i2c_smbus_read_word_data(new_client, 5) != os - || i2c_smbus_read_word_data(new_client, 6) != os - || i2c_smbus_read_word_data(new_client, 7) != os) - return -ENODEV; + + /* First check for LM75A */ + if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { + /* LM75A returns 0xff on unused registers so + just to be sure we check for that too. */ + if (i2c_smbus_read_byte_data(new_client, 4) != 0xff + || i2c_smbus_read_byte_data(new_client, 5) != 0xff + || i2c_smbus_read_byte_data(new_client, 6) != 0xff) + return -ENODEV; + is_lm75a = 1; + hyst = i2c_smbus_read_word_data(new_client, 2); + os = i2c_smbus_read_word_data(new_client, 3); + } else { /* Traditional style LM75 detection */ + /* Unused addresses */ + hyst = i2c_smbus_read_word_data(new_client, 2); + if (i2c_smbus_read_word_data(new_client, 4) != hyst + || i2c_smbus_read_word_data(new_client, 5) != hyst + || i2c_smbus_read_word_data(new_client, 6) != hyst + || i2c_smbus_read_word_data(new_client, 7) != hyst) + return -ENODEV; + os = i2c_smbus_read_word_data(new_client, 3); + if (i2c_smbus_read_word_data(new_client, 4) != os + || i2c_smbus_read_word_data(new_client, 5) != os + || i2c_smbus_read_word_data(new_client, 6) != os + || i2c_smbus_read_word_data(new_client, 7) != os) + return -ENODEV; + } /* Unused bits */ if (conf & 0xe0) @@ -278,9 +301,12 @@ static int lm75_detect(struct i2c_client *new_client, || i2c_smbus_read_word_data(new_client, i + 2) != hyst || i2c_smbus_read_word_data(new_client, i + 3) != os) return -ENODEV; + if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) + != LM75A_ID) + return -ENODEV; } - strlcpy(info->type, "lm75", I2C_NAME_SIZE); + strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); return 0; } |