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| author | Guenter Roeck <guenter.roeck@ericsson.com> | 2011-03-01 13:49:18 -0800 |
|---|---|---|
| committer | Guenter Roeck <guenter.roeck@ericsson.com> | 2011-03-14 22:39:08 -0700 |
| commit | 83274c68a34094bbb465589e61f91a3714f8d026 (patch) | |
| tree | feeac423cf28ad6e5063f93620166a1954d1f4a6 | |
| parent | a3eeb453539d7ad9c0d8cced1e0883a6a8ed18f3 (diff) | |
| download | blackbird-op-linux-83274c68a34094bbb465589e61f91a3714f8d026.tar.gz blackbird-op-linux-83274c68a34094bbb465589e61f91a3714f8d026.zip | |
hwmon: (pmbus) More stringent checking of VOUT_MODE register
Some PMBus chips do not support the VOUT_MODE register. To make matters worse,
such chips may not return an error when reading the register either, but instead
return 0xff.
Check if the register exists using pmbus_check_byte_register() before reading
its value. In addition, validate the returned value and ignore it if it is 0xff
(which is invalid).
Reported-by: Greg Schnorr <gschnorr@cisco.com>
Tested-by: Greg Schnorr <gschnorr@cisco.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Greg Schnorr <gschnorr@cisco.com>
| -rw-r--r-- | drivers/hwmon/pmbus_core.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/hwmon/pmbus_core.c b/drivers/hwmon/pmbus_core.c index 0edab1c9553e..b7c64ba31f4c 100644 --- a/drivers/hwmon/pmbus_core.c +++ b/drivers/hwmon/pmbus_core.c @@ -1426,10 +1426,11 @@ static void pmbus_find_attributes(struct i2c_client *client, static int pmbus_identify_common(struct i2c_client *client, struct pmbus_data *data) { - int vout_mode, exponent; + int vout_mode = -1, exponent; - vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE); - if (vout_mode >= 0) { + if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE)) + vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE); + if (vout_mode >= 0 && vout_mode != 0xff) { /* * Not all chips support the VOUT_MODE command, * so a failure to read it is not an error. |
