[PATCH] thinkpad_acpi: save kbdlight state on suspend and restore it on resume

[Marco Trevisan <mail@3v1n0.net>]

From: Marco Trevisan (Treviño) <mail@3v1n0.net>

Override default LED class suspend/resume handles, by keeping track of
the brightness level before suspending so that it can be automatically
restored on resume by calling default resume handler.

Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
---
 drivers/platform/x86/thinkpad_acpi.c | 43 +++++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 1f9783c..10111c2 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -5041,6 +5041,8 @@ static int kbdlight_set_level(int level)
 	return 0;
 }
 
+static int kbdlight_set_level_and_update(int level);
+
 static int kbdlight_get_level(void)
 {
 	int status = 0;
@@ -5108,7 +5110,7 @@ static void kbdlight_set_worker(struct work_struct *work)
 			container_of(work, struct tpacpi_led_classdev, work);
 
 	if (likely(tpacpi_lifecycle == TPACPI_LIFE_RUNNING))
-		kbdlight_set_level(data->new_state);
+		kbdlight_set_level_and_update(data->new_state);
 }
 
 static void kbdlight_sysfs_set(struct led_classdev *led_cdev,
@@ -5139,7 +5141,6 @@ static struct tpacpi_led_classdev tpacpi_led_kbdlight = {
 		.max_brightness	= 2,
 		.brightness_set	= &kbdlight_sysfs_set,
 		.brightness_get	= &kbdlight_sysfs_get,
-		.flags		= LED_CORE_SUSPENDRESUME,
 	}
 };
 
@@ -5177,6 +5178,20 @@ static void kbdlight_exit(void)
 	flush_workqueue(tpacpi_wq);
 }
 
+static int kbdlight_set_level_and_update(int level)
+{
+	int ret;
+	struct led_classdev *led_cdev;
+
+	ret = kbdlight_set_level(level);
+	led_cdev = &tpacpi_led_kbdlight.led_classdev;
+
+	if (ret == 0 && !(led_cdev->flags & LED_SUSPENDED))
+		led_cdev->brightness = level;
+
+	return ret;
+}
+
 static int kbdlight_read(struct seq_file *m)
 {
 	int level;
@@ -5217,13 +5232,35 @@ static int kbdlight_write(char *buf)
 	if (level == -1)
 		return -EINVAL;
 
-	return kbdlight_set_level(level);
+	return kbdlight_set_level_and_update(level);
+}
+
+static void kbdlight_suspend(void)
+{
+	struct led_classdev *led_cdev;
+
+	if (!tp_features.kbdlight)
+		return;
+
+	led_cdev = &tpacpi_led_kbdlight.led_classdev;
+	led_update_brightness(led_cdev);
+	led_classdev_suspend(led_cdev);
+}
+
+static void kbdlight_resume(void)
+{
+	if (!tp_features.kbdlight)
+		return;
+
+	led_classdev_resume(&tpacpi_led_kbdlight.led_classdev);
 }
 
 static struct ibm_struct kbdlight_driver_data = {
 	.name = "kbdlight",
 	.read = kbdlight_read,
 	.write = kbdlight_write,
+	.suspend = kbdlight_suspend,
+	.resume = kbdlight_resume,
 	.exit = kbdlight_exit,
 };
 
-- 
1.9.1