ACPI: asus_acpi: Add support for the generic backlight device

Add support for the generic backlight interface below /sys/class/backlight.
Keep the procfs brightness handling for backward compatibility.

[apw@shadowen.org: backlight users need to select BACKLIGHT_CLASS_DEVICE]

Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 47 insertions, 16 deletions

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index bc58a3b18e06..9b64c4e6c63e 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -172,6 +172,7 @@ config ACPI_NUMA
 config ACPI_ASUS
         tristate "ASUS/Medion Laptop Extras"
         depends on X86
+        select BACKLIGHT_CLASS_DEVICE
         ---help---
           This driver provides support for extra features of ACPI-compatible
           ASUS laptops. As some of Medion laptops are made by ASUS, it may also
diff --git a/drivers/acpi/asus_acpi.c b/drivers/acpi/asus_acpi.c
index c7ac9297a204..bf7bc25e680e 100644
--- a/drivers/acpi/asus_acpi.c
+++ b/drivers/acpi/asus_acpi.c
@@ -35,6 +35,7 @@
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/proc_fs.h>
+#include <linux/backlight.h>
 #include <acpi/acpi_drivers.h>
 #include <acpi/acpi_bus.h>
 #include <asm/uaccess.h>
@@ -402,6 +403,8 @@ static struct model_data model_conf[END_MODEL] = {
 /* procdir we use */
 static struct proc_dir_entry *asus_proc_dir;
 
+static struct backlight_device *asus_backlight_device;
+
 /*
  * This header is made available to allow proper configuration given model,
  * revision number , ... this info cannot go in struct asus_hotk because it is
@@ -779,7 +782,7 @@ proc_write_lcd(struct file *file, const char __user * buffer,
         return rv;
 }
 
-static int read_brightness(void)
+static int read_brightness(struct backlight_device *bd)
 {
         int value;
 
@@ -801,9 +804,10 @@ static int read_brightness(void)
 /*
  * Change the brightness level
  */
-static void set_brightness(int value)
+static int set_brightness(int value)
 {
         acpi_status status = 0;
+        int ret = 0;
 
         /* SPLV laptop */
         if (hotk->methods->brightness_set) {
@@ -811,11 +815,12 @@ static void set_brightness(int value)
                                     value, NULL))
                         printk(KERN_WARNING
                                "Asus ACPI: Error changing brightness\n");
-                return;
+                        ret = -EIO;
+                goto out;
         }
 
         /* No SPLV method if we are here, act as appropriate */
-        value -= read_brightness();
+        value -= read_brightness(NULL);
         while (value != 0) {
                 status = acpi_evaluate_object(NULL, (value > 0) ?
                                               hotk->methods->brightness_up :
@@ -825,15 +830,22 @@ static void set_brightness(int value)
                 if (ACPI_FAILURE(status))
                         printk(KERN_WARNING
                                "Asus ACPI: Error changing brightness\n");
+                        ret = -EIO;
         }
-        return;
+out:
+        return ret;
+}
+
+static int set_brightness_status(struct backlight_device *bd)
+{
+        return set_brightness(bd->props->brightness);
 }
 
 static int
 proc_read_brn(char *page, char **start, off_t off, int count, int *eof,
               void *data)
 {
-        return sprintf(page, "%d\n", read_brightness());
+        return sprintf(page, "%d\n", read_brightness(NULL));
 }
 
 static int
@@ -1333,6 +1345,26 @@ static int asus_hotk_remove(struct acpi_device *device, int type)
         return 0;
 }
 
+static struct backlight_properties asus_backlight_data = {
+        .owner          = THIS_MODULE,
+        .get_brightness = read_brightness,
+        .update_status  = set_brightness_status,
+        .max_brightness = 15,
+};
+
+static void __exit asus_acpi_exit(void)
+{
+        if (asus_backlight_device)
+                backlight_device_unregister(asus_backlight_device);
+
+        acpi_bus_unregister_driver(&asus_hotk_driver);
+        remove_proc_entry(PROC_ASUS, acpi_root_dir);
+
+        kfree(asus_info);
+
+        return;
+}
+
 static int __init asus_acpi_init(void)
 {
         int result;
@@ -1370,17 +1402,15 @@ static int __init asus_acpi_init(void)
                 return result;
         }
 
-        return 0;
-}
-
-static void __exit asus_acpi_exit(void)
-{
-        acpi_bus_unregister_driver(&asus_hotk_driver);
-        remove_proc_entry(PROC_ASUS, acpi_root_dir);
-
-        kfree(asus_info);
+        asus_backlight_device = backlight_device_register("asus", NULL,
+                                                          &asus_backlight_data);
+        if (IS_ERR(asus_backlight_device)) {
+                printk(KERN_ERR "Could not register asus backlight device\n");
+                asus_backlight_device = NULL;
+                asus_acpi_exit();
+        }
 
-        return;
+        return 0;
 }
 
 module_init(asus_acpi_init);