hwmon: (pmbus) Fix low limit temperature alarms
Guenter Roeck [Sat, 10 Sep 2011 13:02:12 +0000 (06:02 -0700)]
Temperature alarms are detected by checking the alarm bit and comparing
temperature limits against the current temperature. For low limits, this
comparison needs to be reversed (temp < limit instead of temp > limit).
This was not taken into account, resulting in wrong alarms if a temperature
fell below a low limit.

Fix by adding a low limit flag in the limit data structure. When creating the
sensor entry, the order of registers to compare is now reversed for low limits.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org # 3.0+

drivers/hwmon/pmbus/pmbus_core.c

index a561c3a..397fc59 100644 (file)
@@ -978,6 +978,8 @@ static void pmbus_find_max_attr(struct i2c_client *client,
 struct pmbus_limit_attr {
        u16 reg;                /* Limit register */
        bool update;            /* True if register needs updates */
+       bool low;               /* True if low limit; for limits with compare
+                                  functions only */
        const char *attr;       /* Attribute name */
        const char *alarm;      /* Alarm attribute name */
        u32 sbit;               /* Alarm attribute status bit */
@@ -1029,7 +1031,8 @@ static bool pmbus_add_limit_attrs(struct i2c_client *client,
                                if (attr->compare) {
                                        pmbus_add_boolean_cmp(data, name,
                                                l->alarm, index,
-                                               cbase, cindex,
+                                               l->low ? cindex : cbase,
+                                               l->low ? cbase : cindex,
                                                attr->sbase + page, l->sbit);
                                } else {
                                        pmbus_add_boolean_reg(data, name,
@@ -1366,11 +1369,13 @@ static const struct pmbus_sensor_attr power_attributes[] = {
 static const struct pmbus_limit_attr temp_limit_attrs[] = {
        {
                .reg = PMBUS_UT_WARN_LIMIT,
+               .low = true,
                .attr = "min",
                .alarm = "min_alarm",
                .sbit = PB_TEMP_UT_WARNING,
        }, {
                .reg = PMBUS_UT_FAULT_LIMIT,
+               .low = true,
                .attr = "lcrit",
                .alarm = "lcrit_alarm",
                .sbit = PB_TEMP_UT_FAULT,
@@ -1399,11 +1404,13 @@ static const struct pmbus_limit_attr temp_limit_attrs[] = {
 static const struct pmbus_limit_attr temp_limit_attrs23[] = {
        {
                .reg = PMBUS_UT_WARN_LIMIT,
+               .low = true,
                .attr = "min",
                .alarm = "min_alarm",
                .sbit = PB_TEMP_UT_WARNING,
        }, {
                .reg = PMBUS_UT_FAULT_LIMIT,
+               .low = true,
                .attr = "lcrit",
                .alarm = "lcrit_alarm",
                .sbit = PB_TEMP_UT_FAULT,