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authorGuenter Roeck2021-11-14 22:06:35 -0800
committerGuenter Roeck2021-12-26 15:02:05 -0800
commitff9b8778797940628934205010d12b7084c85447 (patch)
treeb77ad4bea139b649dc4d7cc1efeb450a4cb5847a /drivers/hwmon
parentff300b71ba3860d282f77774d2b02ec49ad0e9cf (diff)
hwmon: (adm1021) Improve detection of LM84, MAX1617, and MAX1617A
The adm1021 driver is quite generous with its automatic chip detection and easily misdetects several chips. Strengthen detection of MAX1617, MAX1617A, and LM84 to make the driver less vulnerable to false matches. Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/adm1021.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/drivers/hwmon/adm1021.c b/drivers/hwmon/adm1021.c
index 38b447c6e8cd..91ecfee243bf 100644
--- a/drivers/hwmon/adm1021.c
+++ b/drivers/hwmon/adm1021.c
@@ -324,7 +324,7 @@ static int adm1021_detect(struct i2c_client *client,
{
struct i2c_adapter *adapter = client->adapter;
const char *type_name;
- int conv_rate, status, config, man_id, dev_id;
+ int reg, conv_rate, status, config, man_id, dev_id;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
pr_debug("detect failed, smbus byte data not supported!\n");
@@ -349,9 +349,19 @@ static int adm1021_detect(struct i2c_client *client,
if (man_id < 0 || dev_id < 0)
return -ENODEV;
- if (man_id == 0x4d && dev_id == 0x01)
+ if (man_id == 0x4d && dev_id == 0x01) {
+ /*
+ * dev_id 0x01 matches MAX6680, MAX6695, MAX6696, and possibly
+ * others. Read register which is unsupported on MAX1617 but
+ * exists on all those chips and compare with the dev_id
+ * register. If it matches, it may be a MAX1617A.
+ */
+ reg = i2c_smbus_read_byte_data(client,
+ ADM1023_REG_REM_TEMP_PREC);
+ if (reg != dev_id)
+ return -ENODEV;
type_name = "max1617a";
- else if (man_id == 0x41) {
+ } else if (man_id == 0x41) {
if ((dev_id & 0xF0) == 0x30)
type_name = "adm1023";
else if ((dev_id & 0xF0) == 0x00)
@@ -395,13 +405,18 @@ static int adm1021_detect(struct i2c_client *client,
/*
* LM84 Mfr ID is in a different place,
- * and it has more unused bits.
+ * and it has more unused bits. Registers at 0xfe and 0xff
+ * are undefined and return the most recently read value,
+ * here the value of the configuration register.
*/
if (conv_rate == 0x00
+ && man_id == config && dev_id == config
&& (config & 0x7F) == 0x00
&& (status & 0xAB) == 0x00) {
type_name = "lm84";
} else {
+ if ((config & 0x3f) || (status & 0x03))
+ return -ENODEV;
/* fail if low limits are larger than high limits */
if ((s8)llo > lhi || (s8)rlo > rhi)
return -ENODEV;