hwmon: (pmbus) Add get_error_flags support to regulator ops

The various PMBus status bits don't all map perfectly to the more
limited set of REGULATOR_ERROR_* flags, but there's a reasonable
number where they correspond well enough.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20220219000359.19985-1-zev@bewilderbeest.net
[groeck: Added missing locking]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index b1386a4df4cc4011832f88a3e4e21e8229b68cae..8eed7968a50efffc6977824981a0a8ff13faed9c 100644 (file)
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2432,10 +2432,124 @@ static int pmbus_regulator_disable(struct regulator_dev *rdev)
        return _pmbus_regulator_on_off(rdev, 0);
 }
 
+/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
+struct pmbus_regulator_status_assoc {
+       int pflag, rflag;
+};
+
+/* PMBus->regulator bit mappings for a PMBus status register */
+struct pmbus_regulator_status_category {
+       int func;
+       int reg;
+       const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
+};
+
+static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
+       {
+               .func = PMBUS_HAVE_STATUS_VOUT,
+               .reg = PMBUS_STATUS_VOUT,
+               .bits = (const struct pmbus_regulator_status_assoc[]) {
+                       { PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
+                       { PB_VOLTAGE_UV_FAULT,   REGULATOR_ERROR_UNDER_VOLTAGE },
+                       { PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
+                       { PB_VOLTAGE_OV_FAULT,   REGULATOR_ERROR_REGULATION_OUT },
+                       { },
+               },
+       }, {
+               .func = PMBUS_HAVE_STATUS_IOUT,
+               .reg = PMBUS_STATUS_IOUT,
+               .bits = (const struct pmbus_regulator_status_assoc[]) {
+                       { PB_IOUT_OC_WARNING,    REGULATOR_ERROR_OVER_CURRENT_WARN },
+                       { PB_IOUT_OC_FAULT,      REGULATOR_ERROR_OVER_CURRENT },
+                       { PB_IOUT_OC_LV_FAULT,   REGULATOR_ERROR_OVER_CURRENT },
+                       { },
+               },
+       }, {
+               .func = PMBUS_HAVE_STATUS_TEMP,
+               .reg = PMBUS_STATUS_TEMPERATURE,
+               .bits = (const struct pmbus_regulator_status_assoc[]) {
+                       { PB_TEMP_OT_WARNING,    REGULATOR_ERROR_OVER_TEMP_WARN },
+                       { PB_TEMP_OT_FAULT,      REGULATOR_ERROR_OVER_TEMP },
+                       { },
+               },
+       },
+};
+
+static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
+{
+       int i, status;
+       const struct pmbus_regulator_status_category *cat;
+       const struct pmbus_regulator_status_assoc *bit;
+       struct device *dev = rdev_get_dev(rdev);
+       struct i2c_client *client = to_i2c_client(dev->parent);
+       struct pmbus_data *data = i2c_get_clientdata(client);
+       u8 page = rdev_get_id(rdev);
+       int func = data->info->func[page];
+
+       *flags = 0;
+
+       mutex_lock(&data->update_lock);
+
+       for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
+               cat = &pmbus_regulator_flag_map[i];
+               if (!(func & cat->func))
+                       continue;
+
+               status = pmbus_read_byte_data(client, page, cat->reg);
+               if (status < 0) {
+                       mutex_unlock(&data->update_lock);
+                       return status;
+               }
+
+               for (bit = cat->bits; bit->pflag; bit++) {
+                       if (status & bit->pflag)
+                               *flags |= bit->rflag;
+               }
+       }
+
+       /*
+        * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
+        * bits.  Some of the other bits are tempting (especially for cases
+        * where we don't have the relevant PMBUS_HAVE_STATUS_*
+        * functionality), but there's an unfortunate ambiguity in that
+        * they're defined as indicating a fault *or* a warning, so we can't
+        * easily determine whether to report REGULATOR_ERROR_<foo> or
+        * REGULATOR_ERROR_<foo>_WARN.
+        */
+       status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
+       mutex_unlock(&data->update_lock);
+       if (status < 0)
+               return status;
+
+       if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
+               *flags |= REGULATOR_ERROR_FAIL;
+
+       /*
+        * Unlike most other status bits, PB_STATUS_{IOUT_OC,VOUT_OV} are
+        * defined strictly as fault indicators (not warnings).
+        */
+       if (status & PB_STATUS_IOUT_OC)
+               *flags |= REGULATOR_ERROR_OVER_CURRENT;
+       if (status & PB_STATUS_VOUT_OV)
+               *flags |= REGULATOR_ERROR_REGULATION_OUT;
+
+       /*
+        * If we haven't discovered any thermal faults or warnings via
+        * PMBUS_STATUS_TEMPERATURE, map PB_STATUS_TEMPERATURE to a warning as
+        * a (conservative) best-effort interpretation.
+        */
+       if (!(*flags & (REGULATOR_ERROR_OVER_TEMP | REGULATOR_ERROR_OVER_TEMP_WARN)) &&
+           (status & PB_STATUS_TEMPERATURE))
+               *flags |= REGULATOR_ERROR_OVER_TEMP_WARN;
+
+       return 0;
+}
+
 const struct regulator_ops pmbus_regulator_ops = {
        .enable = pmbus_regulator_enable,
        .disable = pmbus_regulator_disable,
        .is_enabled = pmbus_regulator_is_enabled,
+       .get_error_flags = pmbus_regulator_get_error_flags,
 };
 EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);