From 989c695cd0822269a5eedef3f10700d87316291e Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Mon, 13 Jul 2020 10:33:19 +0100
Subject: [PATCH] leds: Add the actpwr trigger
The actpwr trigger is a meta trigger that cycles between an inverted
mmc0 and default-on. It is written in a way that could fairly easily
be generalised to support alternative sets of source triggers.
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/leds/trigger/Kconfig | 11 ++
drivers/leds/trigger/Makefile | 1 +
drivers/leds/trigger/ledtrig-actpwr.c | 190 ++++++++++++++++++++++++++
3 files changed, 202 insertions(+)
create mode 100644 drivers/leds/trigger/ledtrig-actpwr.c
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -160,4 +160,15 @@ config LEDS_TRIGGER_TTY
When build as a module this driver will be called ledtrig-tty.
+config LEDS_TRIGGER_ACTPWR
+ tristate "ACT/PWR Input Trigger"
+ depends on LEDS_TRIGGERS
+ help
+ This trigger is intended for platforms that have one software-
+ controllable LED and no dedicated activity or power LEDs, hence the
+ need to make the one LED perform both functions. It cycles between
+ default-on and an inverted mmc0 every 500ms, guaranteeing that it is
+ on for at least half of the time.
+ If unsure, say N.
+
endif # LEDS_TRIGGERS
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV) += led
obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o
obj-$(CONFIG_LEDS_TRIGGER_AUDIO) += ledtrig-audio.o
obj-$(CONFIG_LEDS_TRIGGER_TTY) += ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_ACTPWR) += ledtrig-actpwr.o
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-actpwr.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Activity/power trigger
+ *
+ * Copyright (C) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * Based on Atsushi Nemoto's ledtrig-heartbeat.c, although there may be
+ * nothing left of the original now.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/timer.h>
+#include <linux/leds.h>
+#include "../leds.h"
+
+enum {
+ TRIG_ACT,
+ TRIG_PWR,
+
+ TRIG_COUNT
+};
+
+struct actpwr_trig_src {
+ const char *name;
+ int interval;
+ bool invert;
+};
+
+struct actpwr_vled {
+ struct led_classdev cdev;
+ struct actpwr_trig_data *parent;
+ enum led_brightness value;
+ unsigned int interval;
+ bool invert;
+};
+
+struct actpwr_trig_data {
+ struct led_trigger trig;
+ struct actpwr_vled virt_leds[TRIG_COUNT];
+ struct actpwr_vled *active;
+ struct timer_list timer;
+ int next_active;
+};
+
+static int actpwr_trig_activate(struct led_classdev *led_cdev);
+static void actpwr_trig_deactivate(struct led_classdev *led_cdev);
+
+static const struct actpwr_trig_src actpwr_trig_sources[TRIG_COUNT] = {
+ [TRIG_ACT] = { "mmc0", 500, true },
+ [TRIG_PWR] = { "default-on", 500, false },
+};
+
+static struct actpwr_trig_data actpwr_data = {
+ {
+ .name = "actpwr",
+ .activate = actpwr_trig_activate,
+ .deactivate = actpwr_trig_deactivate,
+ }
+};
+
+static void actpwr_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ struct actpwr_vled *vled = container_of(led_cdev, struct actpwr_vled,
+ cdev);
+ struct actpwr_trig_data *trig = vled->parent;
+
+ if (vled->invert)
+ value = !value;
+ vled->value = value;
+
+ if (vled == trig->active)
+ led_trigger_event(&trig->trig, value);
+}
+
+static int actpwr_brightness_set_blocking(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ actpwr_brightness_set(led_cdev, value);
+ return 0;
+}
+
+static enum led_brightness actpwr_brightness_get(struct led_classdev *led_cdev)
+{
+ struct actpwr_vled *vled = container_of(led_cdev, struct actpwr_vled,
+ cdev);
+
+ return vled->value;
+}
+
+static void actpwr_trig_cycle(struct timer_list *t)
+{
+ struct actpwr_trig_data *trig = &actpwr_data;
+ struct actpwr_vled *active;
+
+ active = &trig->virt_leds[trig->next_active];
+ trig->active = active;
+ trig->next_active = (trig->next_active + 1) % TRIG_COUNT;
+
+ led_trigger_event(&trig->trig, active->value);
+
+ mod_timer(&trig->timer, jiffies + msecs_to_jiffies(active->interval));
+}
+
+static int actpwr_trig_activate(struct led_classdev *led_cdev)
+{
+ struct actpwr_trig_data *trig = &actpwr_data;
+
+ /* Start the timer if this is the first LED */
+ if (!trig->active)
+ actpwr_trig_cycle(&trig->timer);
+ else
+ led_set_brightness_nosleep(led_cdev, trig->active->value);
+
+ return 0;
+}
+
+static void actpwr_trig_deactivate(struct led_classdev *led_cdev)
+{
+ struct actpwr_trig_data *trig = &actpwr_data;
+
+ if (list_empty(&trig->trig.led_cdevs)) {
+ del_timer_sync(&trig->timer);
+ trig->active = NULL;
+ }
+}
+
+static int __init actpwr_trig_init(void)
+{
+ struct actpwr_trig_data *trig = &actpwr_data;
+ int ret = 0;
+ int i;
+
+ timer_setup(&trig->timer, actpwr_trig_cycle, 0);
+
+ /* Register one "LED" for each source trigger */
+ for (i = 0; i < TRIG_COUNT; i++)
+ {
+ struct actpwr_vled *vled = &trig->virt_leds[i];
+ struct led_classdev *cdev = &vled->cdev;
+ const struct actpwr_trig_src *src = &actpwr_trig_sources[i];
+
+ vled->parent = trig;
+ vled->interval = src->interval;
+ vled->invert = src->invert;
+ cdev->name = src->name;
+ cdev->brightness_set = actpwr_brightness_set;
+ cdev->brightness_set_blocking = actpwr_brightness_set_blocking;
+ cdev->brightness_get = actpwr_brightness_get;
+ cdev->default_trigger = src->name;
+ ret = led_classdev_register(NULL, cdev);
+ if (ret)
+ goto error_classdev;
+ }
+
+ ret = led_trigger_register(&trig->trig);
+ if (ret)
+ goto error_classdev;
+
+ return 0;
+
+error_classdev:
+ while (i > 0)
+ {
+ i--;
+ led_classdev_unregister(&trig->virt_leds[i].cdev);
+ }
+
+ return ret;
+}
+
+static void __exit actpwr_trig_exit(void)
+{
+ int i;
+
+ led_trigger_unregister(&actpwr_data.trig);
+ for (i = 0; i < TRIG_COUNT; i++)
+ {
+ led_classdev_unregister(&actpwr_data.virt_leds[i].cdev);
+ }
+}
+
+module_init(actpwr_trig_init);
+module_exit(actpwr_trig_exit);
+
+MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
+MODULE_DESCRIPTION("ACT/PWR LED trigger");
+MODULE_LICENSE("GPL v2");