power: supply: leds: Add power_supply_[un]register_led_trigger()

Add power_supply_[un]register_led_trigger() helper functions.

The primary goal of this is as a preparation patch for adding an activate
callback to the power-supply LED triggers to ensure that power-supply
LEDs get the correct initial value when the LED gets registered after
the power_supply has been registered (this will use the psy back pointer).

There also is quite a lot of code duplication in the existing LED trigger
registration in the form of the kasprintf() for the name-template for each
trigger + related error handling. This duplication is removed by these
new helpers.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240531134702.166145-2-hdegoede@redhat.comSigned-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/power_supply_leds.c

@@ -19,6 +19,65 @@
 
 /* Battery specific LEDs triggers. */
 
+struct power_supply_led_trigger {
+	struct led_trigger trig;
+	struct power_supply *psy;
+};
+
+#define trigger_to_psy_trigger(trigger) \
+	container_of(trigger, struct power_supply_led_trigger, trig)
+
+static int power_supply_register_led_trigger(struct power_supply *psy,
+					     const char *name_template,
+					     struct led_trigger **tp, int *err)
+{
+	struct power_supply_led_trigger *psy_trig;
+	int ret = -ENOMEM;
+
+	/* Bail on previous errors */
+	if (err && *err)
+		return *err;
+
+	psy_trig = kzalloc(sizeof(*psy_trig), GFP_KERNEL);
+	if (!psy_trig)
+		goto err_free_trigger;
+
+	psy_trig->trig.name = kasprintf(GFP_KERNEL, name_template, psy->desc->name);
+	if (!psy_trig->trig.name)
+		goto err_free_trigger;
+
+	psy_trig->psy = psy;
+
+	ret = led_trigger_register(&psy_trig->trig);
+	if (ret)
+		goto err_free_name;
+
+	*tp = &psy_trig->trig;
+	return 0;
+
+err_free_name:
+	kfree(psy_trig->trig.name);
+err_free_trigger:
+	kfree(psy_trig);
+	if (err)
+		*err = ret;
+
+	return ret;
+}
+
+static void power_supply_unregister_led_trigger(struct led_trigger *trig)
+{
+	struct power_supply_led_trigger *psy_trig;
+
+	if (!trig)
+		return;
+
+	psy_trig = trigger_to_psy_trigger(trig);
+	led_trigger_unregister(&psy_trig->trig);
+	kfree(psy_trig->trig.name);
+	kfree(psy_trig);
+}
+
 static void power_supply_update_bat_leds(struct power_supply *psy)
 {
 	union power_supply_propval status;
@@ -65,69 +124,33 @@ static void power_supply_update_bat_leds(struct power_supply *psy)
 	}
 }
 
-static int power_supply_create_bat_triggers(struct power_supply *psy)
+static void power_supply_remove_bat_triggers(struct power_supply *psy)
 {
-	psy->charging_full_trig_name = kasprintf(GFP_KERNEL,
-					"%s-charging-or-full", psy->desc->name);
-	if (!psy->charging_full_trig_name)
-		goto charging_full_failed;
-
-	psy->charging_trig_name = kasprintf(GFP_KERNEL,
-					"%s-charging", psy->desc->name);
-	if (!psy->charging_trig_name)
-		goto charging_failed;
-
-	psy->full_trig_name = kasprintf(GFP_KERNEL, "%s-full", psy->desc->name);
-	if (!psy->full_trig_name)
-		goto full_failed;
-
-	psy->charging_blink_full_solid_trig_name = kasprintf(GFP_KERNEL,
-		"%s-charging-blink-full-solid", psy->desc->name);
-	if (!psy->charging_blink_full_solid_trig_name)
-		goto charging_blink_full_solid_failed;
-
-	psy->charging_orange_full_green_trig_name = kasprintf(GFP_KERNEL,
-		"%s-charging-orange-full-green", psy->desc->name);
-	if (!psy->charging_orange_full_green_trig_name)
-		goto charging_red_full_green_failed;
-
-	led_trigger_register_simple(psy->charging_full_trig_name,
-				    &psy->charging_full_trig);
-	led_trigger_register_simple(psy->charging_trig_name,
-				    &psy->charging_trig);
-	led_trigger_register_simple(psy->full_trig_name,
-				    &psy->full_trig);
-	led_trigger_register_simple(psy->charging_blink_full_solid_trig_name,
-				    &psy->charging_blink_full_solid_trig);
-	led_trigger_register_simple(psy->charging_orange_full_green_trig_name,
-				    &psy->charging_orange_full_green_trig);
-
-	return 0;
-
-charging_red_full_green_failed:
-	kfree(psy->charging_blink_full_solid_trig_name);
-charging_blink_full_solid_failed:
-	kfree(psy->full_trig_name);
-full_failed:
-	kfree(psy->charging_trig_name);
-charging_failed:
-	kfree(psy->charging_full_trig_name);
-charging_full_failed:
-	return -ENOMEM;
+	power_supply_unregister_led_trigger(psy->charging_full_trig);
+	power_supply_unregister_led_trigger(psy->charging_trig);
+	power_supply_unregister_led_trigger(psy->full_trig);
+	power_supply_unregister_led_trigger(psy->charging_blink_full_solid_trig);
+	power_supply_unregister_led_trigger(psy->charging_orange_full_green_trig);
 }
 
-static void power_supply_remove_bat_triggers(struct power_supply *psy)
+static int power_supply_create_bat_triggers(struct power_supply *psy)
 {
-	led_trigger_unregister_simple(psy->charging_full_trig);
-	led_trigger_unregister_simple(psy->charging_trig);
-	led_trigger_unregister_simple(psy->full_trig);
-	led_trigger_unregister_simple(psy->charging_blink_full_solid_trig);
-	led_trigger_unregister_simple(psy->charging_orange_full_green_trig);
-	kfree(psy->charging_blink_full_solid_trig_name);
-	kfree(psy->full_trig_name);
-	kfree(psy->charging_trig_name);
-	kfree(psy->charging_full_trig_name);
-	kfree(psy->charging_orange_full_green_trig_name);
+	int err = 0;
+
+	power_supply_register_led_trigger(psy, "%s-charging-or-full",
+					  &psy->charging_full_trig, &err);
+	power_supply_register_led_trigger(psy, "%s-charging",
+					  &psy->charging_trig, &err);
+	power_supply_register_led_trigger(psy, "%s-full",
+					  &psy->full_trig, &err);
+	power_supply_register_led_trigger(psy, "%s-charging-blink-full-solid",
+					  &psy->charging_blink_full_solid_trig, &err);
+	power_supply_register_led_trigger(psy, "%s-charging-orange-full-green",
+					  &psy->charging_orange_full_green_trig, &err);
+	if (err)
+		power_supply_remove_bat_triggers(psy);
+
+	return err;
 }
 
 /* Generated power specific LEDs triggers. */
@@ -149,20 +172,12 @@ static void power_supply_update_gen_leds(struct power_supply *psy)
 
 static int power_supply_create_gen_triggers(struct power_supply *psy)
 {
-	psy->online_trig_name = kasprintf(GFP_KERNEL, "%s-online",
-					  psy->desc->name);
-	if (!psy->online_trig_name)
-		return -ENOMEM;
-
-	led_trigger_register_simple(psy->online_trig_name, &psy->online_trig);
-
-	return 0;
+	return power_supply_register_led_trigger(psy, "%s-online", &psy->online_trig, NULL);
 }
 
 static void power_supply_remove_gen_triggers(struct power_supply *psy)
 {
-	led_trigger_unregister_simple(psy->online_trig);
-	kfree(psy->online_trig_name);
+	power_supply_unregister_led_trigger(psy->online_trig);
 }
 
 /* Choice what triggers to create&update. */

include/linux/power_supply.h

@@ -310,17 +310,11 @@ struct power_supply {
 
 #ifdef CONFIG_LEDS_TRIGGERS
 	struct led_trigger *charging_full_trig;
-	char *charging_full_trig_name;
 	struct led_trigger *charging_trig;
-	char *charging_trig_name;
 	struct led_trigger *full_trig;
-	char *full_trig_name;
 	struct led_trigger *online_trig;
-	char *online_trig_name;
 	struct led_trigger *charging_blink_full_solid_trig;
-	char *charging_blink_full_solid_trig_name;
 	struct led_trigger *charging_orange_full_green_trig;
-	char *charging_orange_full_green_trig_name;
 #endif
 };