[PATCH v4 4/5] leds: trigger: oneshot: Add initialization from Device Tree

[Krzysztof Kozlowski <krzk@xxxxxxxxxx>]

Allow initialization of delays used in oneshot trigger from Device
Tree property.

This is especially useful for embedded systems where the trigger might
be used early, before bringing up user-space.

Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
---
 drivers/leds/trigger/ledtrig-oneshot.c | 38 ++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-oneshot.c b/drivers/leds/trigger/ledtrig-oneshot.c
index 95c9be4b6e7e..71baccc00f06 100644
--- a/drivers/leds/trigger/ledtrig-oneshot.c
+++ b/drivers/leds/trigger/ledtrig-oneshot.c
@@ -130,6 +130,34 @@ static struct attribute *oneshot_trig_attrs[] = {
 };
 ATTRIBUTE_GROUPS(oneshot_trig);
 
+static void pattern_init(struct led_classdev *led_cdev)
+{
+	u32 *pattern;
+	unsigned int size = 0;
+
+	pattern = led_classdev_get_default_pattern(led_cdev, &size);
+	if (!pattern)
+		goto out_default;
+
+	if (size != 2) {
+		dev_warn(led_cdev->dev,
+			 "Expected 2 but got %u values for delays pattern\n",
+			 size);
+		goto out_default;
+	}
+
+	led_cdev->blink_delay_on = pattern[0];
+	led_cdev->blink_delay_off = pattern[1];
+	kfree(pattern);
+
+	return;
+
+out_default:
+	kfree(pattern);
+	led_cdev->blink_delay_on = DEFAULT_DELAY;
+	led_cdev->blink_delay_off = DEFAULT_DELAY;
+}
+
 static int oneshot_trig_activate(struct led_classdev *led_cdev)
 {
 	struct oneshot_trig_data *oneshot_data;
@@ -140,8 +168,14 @@ static int oneshot_trig_activate(struct led_classdev *led_cdev)
 
 	led_set_trigger_data(led_cdev, oneshot_data);
 
-	led_cdev->blink_delay_on = DEFAULT_DELAY;
-	led_cdev->blink_delay_off = DEFAULT_DELAY;
+	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
+		pattern_init(led_cdev);
+		/*
+		 * Mark as initialized even on pattern_init() error because
+		 * any consecutive call to it would produce the same error.
+		 */
+		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
+	}
 
 	return 0;
 }
-- 
2.7.4