sony-laptop: keyboard backlight fixes

Restore the original state on module removal, set the latest values on
resume.
When setting the keyboard backlight mode try to turn on/off backlight
immediately.

[malattia@linux.it: patch taken from a largely modified sony-laptop.c,
ported and slightly modified to use defines already available.]
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/sony-laptop.c

@@ -138,6 +138,8 @@ MODULE_PARM_DESC(kbd_backlight_timeout,
 		 "1 for 30 seconds, 2 for 60 seconds and 3 to disable timeout "
 		 "(default: 0)");
 
+static void sony_nc_kbd_backlight_resume(void);
+
 enum sony_nc_rfkill {
 	SONY_WIFI,
 	SONY_BLUETOOTH,
@@ -1176,6 +1178,9 @@ static int sony_nc_resume(struct acpi_device *device)
 	/* re-read rfkill state */
 	sony_nc_rfkill_update();
 
+	/* restore kbd backlight states */
+	sony_nc_kbd_backlight_resume();
+
 	return 0;
 }
 
@@ -1363,6 +1368,7 @@ static void sony_nc_rfkill_setup(struct acpi_device *device)
 #define KBDBL_HANDLER	0x137
 #define KBDBL_PRESENT	0xB00
 #define	SET_MODE	0xC00
+#define SET_STATE	0xD00
 #define SET_TIMEOUT	0xE00
 
 struct kbd_backlight {
@@ -1385,6 +1391,10 @@ static ssize_t __sony_nc_kbd_backlight_mode_set(u8 value)
 				(value << 0x10) | SET_MODE, &result))
 		return -EIO;
 
+	/* Try to turn the light on/off immediately */
+	sony_call_snc_handle(KBDBL_HANDLER, (value << 0x10) | SET_STATE,
+			&result);
+
 	kbdbl_handle->mode = value;
 
 	return 0;
@@ -1466,7 +1476,7 @@ static int sony_nc_kbd_backlight_setup(struct platform_device *pd)
 {
 	int result;
 
-	if (sony_call_snc_handle(0x137, KBDBL_PRESENT, &result))
+	if (sony_call_snc_handle(KBDBL_HANDLER, KBDBL_PRESENT, &result))
 		return 0;
 	if (!(result & 0x02))
 		return 0;
@@ -1509,13 +1519,36 @@ static int sony_nc_kbd_backlight_setup(struct platform_device *pd)
 static int sony_nc_kbd_backlight_cleanup(struct platform_device *pd)
 {
 	if (kbdbl_handle) {
+		int result;
+
 		device_remove_file(&pd->dev, &kbdbl_handle->mode_attr);
 		device_remove_file(&pd->dev, &kbdbl_handle->timeout_attr);
+
+		/* restore the default hw behaviour */
+		sony_call_snc_handle(KBDBL_HANDLER, 0x1000 | SET_MODE, &result);
+		sony_call_snc_handle(KBDBL_HANDLER, SET_TIMEOUT, &result);
+
 		kfree(kbdbl_handle);
 	}
 	return 0;
 }
 
+static void sony_nc_kbd_backlight_resume(void)
+{
+	int ignore = 0;
+
+	if (!kbdbl_handle)
+		return;
+
+	if (kbdbl_handle->mode == 0)
+		sony_call_snc_handle(KBDBL_HANDLER, SET_MODE, &ignore);
+
+	if (kbdbl_handle->timeout != 0)
+		sony_call_snc_handle(KBDBL_HANDLER,
+				(kbdbl_handle->timeout << 0x10) | SET_TIMEOUT,
+				&ignore);
+}
+
 static void sony_nc_backlight_setup(void)
 {
 	acpi_handle unused;