hwmon: (pmbus) Improve fan detection

commit 81ae68142a0483b3791cba99eab268859858f508 upstream.

Some PMBus devices return no error when reading fan speed registers, but don't
really support fans. Strengthen fan detection by also checking if fan
configuration registers exist.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/hwmon/pmbus.c b/drivers/hwmon/pmbus.c
index b5dc8837e9ef4a8f53ffa0e37b4c9e9f3ca8e76a..931d940923aebb77c5b7d1d9bc029977c029dd14 100644 (file)
--- a/drivers/hwmon/pmbus.c
+++ b/drivers/hwmon/pmbus.c
@@ -47,12 +47,14 @@ static void pmbus_find_sensor_groups(struct i2c_client *client,
        if (info->func[0]
            && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
                info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
-       if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
+       if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
+           pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
                info->func[0] |= PMBUS_HAVE_FAN12;
                if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
                        info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
        }
-       if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
+       if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
+           pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
                info->func[0] |= PMBUS_HAVE_FAN34;
                if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
                        info->func[0] |= PMBUS_HAVE_STATUS_FAN34;