Currently we use the `linux,default-trigger` device tree property of a
LED to define the default trigger which should be activated for a LED.
But the LED device tree binding also documents the `trigger-sources`
property, which specifies the source device which should be triggering
the LED.
The `trigger-sources` property is currently implemented only in
drivers/usb/core/ledtrig-usbport.c.
Lets add a method to struct led_trigger which, if implemented, can check
whether this trigger should be enabled as default. This check shall be
done by checking whether the specified `trigger-sources` refers to a
device compatible with the trigger. For this two new helper functions,
of_led_count_trigger_sources and of_led_get_trigger_source, are
implemented.
Signed-off-by: Marek Behún <marek.behun@xxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
---
drivers/leds/led-triggers.c | 68 ++++++++++++++++++++++++++++++++-----
include/linux/leds.h | 25 ++++++++++++++
2 files changed, 85 insertions(+), 8 deletions(-)
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 91da90cfb11d9..a93c1b6a94282 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -243,18 +243,30 @@ void led_trigger_remove(struct led_classdev *led_cdev)
}
EXPORT_SYMBOL_GPL(led_trigger_remove);
+static bool trigger_is_default(struct led_classdev *led_cdev,
+ struct led_trigger *trig)
+{
+ if (!trigger_relevant(led_cdev, trig))
+ return false;
+
+ if (led_cdev->default_trigger &&
+ !strcmp(led_cdev->default_trigger, trig->name))
+ return true;
+
+ if (trig->has_valid_source && trig->has_valid_source(led_cdev))
+ return true;
+
+ return false;
+}
+
void led_trigger_set_default(struct led_classdev *led_cdev)
{
struct led_trigger *trig;
- if (!led_cdev->default_trigger)
- return;
-
down_read(&triggers_list_lock);
down_write(&led_cdev->trigger_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
- if (!strcmp(led_cdev->default_trigger, trig->name) &&
- trigger_relevant(led_cdev, trig)) {
+ if (trigger_is_default(led_cdev, trig)) {
led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
led_trigger_set(led_cdev, trig);
break;
@@ -306,9 +318,7 @@ int led_trigger_register(struct led_trigger *trig)
down_read(&leds_list_lock);
list_for_each_entry(led_cdev, &leds_list, node) {
down_write(&led_cdev->trigger_lock);
- if (!led_cdev->trigger && led_cdev->default_trigger &&
- !strcmp(led_cdev->default_trigger, trig->name) &&
- trigger_relevant(led_cdev, trig)) {
+ if (!led_cdev->trigger && trigger_is_default(led_cdev, trig)) {
led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
led_trigger_set(led_cdev, trig);
}
@@ -459,3 +469,45 @@ void led_trigger_unregister_simple(struct led_trigger *trig)
kfree(trig);
}
EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
+
+int of_led_count_trigger_sources(struct led_classdev *led_cdev)
+{
+ struct device_node *np;
+ int count;
+
+ np = dev_of_node(led_cdev->dev);
+ if (!np)
+ return 0;
+
+ count = of_count_phandle_with_args(np, "trigger-sources",
+ "#trigger-source-cells");
+ if (count == -ENOENT)
+ return 0;
+ else if (count < 0)
+ dev_warn(led_cdev->dev,
+ "Failed parsing trigger sources for %pOF!\n", np);
+
+ return count;
+}
+EXPORT_SYMBOL_GPL(of_led_count_trigger_sources);
+
+int of_led_get_trigger_source(struct led_classdev *led_cdev, int index,
+ struct of_phandle_args *args)
+{
+ struct device_node *np;
+ int err;
+
+ np = dev_of_node(led_cdev->dev);
+ if (!np)
+ return -ENOENT;
+
+ err = of_parse_phandle_with_args(np, "trigger-sources",
+ "#trigger-source-cells", index, args);
+ if (err < 0 && err != -ENOENT)
+ dev_warn(led_cdev->dev,
+ "Failed parsing trigger source index %i for %pOF!\n",
+ index, np);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(of_led_get_trigger_source);
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 6a8d6409c993e..c03e0a4e0e45d 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -13,6 +13,7 @@
#include <linux/kernfs.h>
#include <linux/list.h>
#include <linux/mutex.h>
+#include <linux/of.h>
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
@@ -352,6 +353,14 @@ struct led_trigger {
int (*activate)(struct led_classdev *led_cdev);
void (*deactivate)(struct led_classdev *led_cdev);
+ /*
+ * Check whether LED has defined valid source for this trigger.
+ * If yes, this trigger should be set as default trigger for LED.
+ * This should use of_led_count_trigger_sources and
+ * of_led_get_trigger_source functions.
+ */
+ bool (*has_valid_source)(struct led_classdev *led_cdev);
+
/* LED-private triggers have this set */
struct led_hw_trigger_type *trigger_type;
@@ -394,6 +403,10 @@ void led_trigger_set_default(struct led_classdev *led_cdev);
int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger);
void led_trigger_remove(struct led_classdev *led_cdev);
+int of_led_count_trigger_sources(struct led_classdev *led_cdev);
+int of_led_get_trigger_source(struct led_classdev *led_cdev, int index,
+ struct of_phandle_args *args);
+
static inline void led_set_trigger_data(struct led_classdev *led_cdev,
void *trigger_data)
{
@@ -452,6 +465,18 @@ static inline int led_trigger_set(struct led_classdev *led_cdev,
}
static inline void led_trigger_remove(struct led_classdev *led_cdev) {}
+
+static inline int of_led_count_trigger_sources(struct led_classdev *led_cdev)
+{
+ return 0;
+}
+static inline int of_led_get_trigger_source(struct led_classdev *led_cdev,
+ int index,
+ struct of_phandle_args *args)
+{
+ return -EOPNOTSUPP;
+}
+
static inline void led_set_trigger_data(struct led_classdev *led_cdev) {}
static inline void *led_get_trigger_data(struct led_classdev *led_cdev)
{
--
2.26.2
