diff options
Diffstat (limited to 'drivers/hwmon/lm90.c')
| -rw-r--r-- | drivers/hwmon/lm90.c | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c index c3ccf1fb2758..f9bc20cf24c3 100644 --- a/drivers/hwmon/lm90.c +++ b/drivers/hwmon/lm90.c @@ -1730,13 +1730,42 @@ static const char *lm90_detect_gmt(struct i2c_client *client, int chip_id, int config1, int convrate) { int address = client->addr; - const char *name = NULL; - if ((address == 0x4c || address == 0x4d) && chip_id == 0x01 && - !(config1 & 0x3f) && convrate <= 0x08) - name = "g781"; + /* + * According to the datasheet, G781 is supposed to be at I2C Address + * 0x4c and have a chip ID of 0x01. G781-1 is supposed to be at I2C + * address 0x4d and have a chip ID of 0x03. However, when support + * for G781 was added, chips at 0x4c and 0x4d were found to have a + * chip ID of 0x01. A G781-1 at I2C address 0x4d was now found with + * chip ID 0x03. + * To avoid detection failures, accept chip ID 0x01 and 0x03 at both + * addresses. + * G784 reports manufacturer ID 0x47 and chip ID 0x01. A public + * datasheet is not available. Extensive testing suggests that + * the chip appears to be fully compatible with G781. + * Available register dumps show that G751 also reports manufacturer + * ID 0x47 and chip ID 0x01 even though that chip does not officially + * support those registers. This makes chip detection somewhat + * vulnerable. To improve detection quality, read the offset low byte + * and alert fault queue registers and verify that only expected bits + * are set. + */ + if ((chip_id == 0x01 || chip_id == 0x03) && + (address == 0x4c || address == 0x4d) && + !(config1 & 0x3f) && convrate <= 0x08) { + int reg; - return name; + reg = i2c_smbus_read_byte_data(client, LM90_REG_REMOTE_OFFSL); + if (reg < 0 || reg & 0x1f) + return NULL; + reg = i2c_smbus_read_byte_data(client, TMP451_REG_CONALERT); + if (reg < 0 || reg & 0xf1) + return NULL; + + return "g781"; + } + + return NULL; } static const char *lm90_detect_ti(struct i2c_client *client, int chip_id, |