regulator: Add regulator_err2notif() helper

Help drivers avoid storing both supported notification and supported error
flags by supporting conversion from regulator error to notification.
This may help saving some bytes.

Add helper for finding the regulator notification corresponding to a
regulator error.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/eb1755ac0569ff07ffa466cf8912c6fd50e7c7c6.1637736436.git.matti.vaittinen@fi.rohmeurope.com
Signed-off-by: Mark Brown <broonie@kernel.org>

include/linux/regulator/driver.h

@@ -645,6 +645,40 @@ struct regulator_dev {
 	spinlock_t err_lock;
 };
 
+/*
+ * Convert error flags to corresponding notifications.
+ *
+ * Can be used by drivers which use the notification helpers to
+ * find out correct notification flags based on the error flags. Drivers
+ * can avoid storing both supported notification and error flags which
+ * may save few bytes.
+ */
+static inline int regulator_err2notif(int err)
+{
+	switch (err) {
+	case REGULATOR_ERROR_UNDER_VOLTAGE:
+		return REGULATOR_EVENT_UNDER_VOLTAGE;
+	case REGULATOR_ERROR_OVER_CURRENT:
+		return REGULATOR_EVENT_OVER_CURRENT;
+	case REGULATOR_ERROR_REGULATION_OUT:
+		return REGULATOR_EVENT_REGULATION_OUT;
+	case REGULATOR_ERROR_FAIL:
+		return REGULATOR_EVENT_FAIL;
+	case REGULATOR_ERROR_OVER_TEMP:
+		return REGULATOR_EVENT_OVER_TEMP;
+	case REGULATOR_ERROR_UNDER_VOLTAGE_WARN:
+		return REGULATOR_EVENT_UNDER_VOLTAGE_WARN;
+	case REGULATOR_ERROR_OVER_CURRENT_WARN:
+		return REGULATOR_EVENT_OVER_CURRENT_WARN;
+	case REGULATOR_ERROR_OVER_VOLTAGE_WARN:
+		return REGULATOR_EVENT_OVER_VOLTAGE_WARN;
+	case REGULATOR_ERROR_OVER_TEMP_WARN:
+		return REGULATOR_EVENT_OVER_TEMP_WARN;
+	}
+	return 0;
+}
+
+
 struct regulator_dev *
 regulator_register(const struct regulator_desc *regulator_desc,
 		   const struct regulator_config *config);