sony_acpi: Add backlight support to the sony_acpi

Make the sony_acpi use the backlight subsystem to adjust brightness value
instead of using the /proc/sony/brightness file.  (Other settings will
still have a /proc/sony/...  entry)

Signed-off-by: Alessandro Guido <alessandro.guido@gmail.com>
Cc: Stelian Pop <stelian@popies.net>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 48 insertions, 12 deletions

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index e11371fb9191..364e6fe8ec35 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -255,6 +255,7 @@ config ACPI_TOSHIBA
 config ACPI_SONY
         tristate "Sony Laptop Extras"
         depends on X86 && ACPI
+        select BACKLIGHT_CLASS_DEVICE
         default m
           ---help---
           This mini-driver drives the ACPI SNC device present in the
diff --git a/drivers/acpi/sony_acpi.c b/drivers/acpi/sony_acpi.c
index f323c2c40a11..d509468a58a2 100644
--- a/drivers/acpi/sony_acpi.c
+++ b/drivers/acpi/sony_acpi.c
@@ -27,13 +27,19 @@
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/backlight.h>
+#include <linux/err.h>
 #include <acpi/acpi_drivers.h>
 #include <acpi/acpi_bus.h>
 #include <asm/uaccess.h>
 
 #define ACPI_SNC_CLASS          "sony"
 #define ACPI_SNC_HID            "SNY5001"
-#define ACPI_SNC_DRIVER_NAME    "ACPI Sony Notebook Control Driver v0.2"
+#define ACPI_SNC_DRIVER_NAME    "ACPI Sony Notebook Control Driver v0.3"
+
+/* the device uses 1-based values, while the backlight subsystem uses
+   0-based values */
+#define SONY_MAX_BRIGHTNESS     8
 
 #define LOG_PFX                 KERN_WARNING "sony_acpi: "
 
@@ -49,6 +55,16 @@ MODULE_PARM_DESC(debug, "set this to 1 (and RTFM) if you want to help "
 static acpi_handle sony_acpi_handle;
 static struct proc_dir_entry *sony_acpi_dir;
 
+static int sony_backlight_update_status(struct backlight_device *bd);
+static int sony_backlight_get_brightness(struct backlight_device *bd);
+static struct backlight_device *sony_backlight_device;
+static struct backlight_properties sony_backlight_properties = {
+        .owner          = THIS_MODULE,
+        .update_status  = sony_backlight_update_status,
+        .get_brightness = sony_backlight_get_brightness,
+        .max_brightness = SONY_MAX_BRIGHTNESS - 1,
+};
+
 static struct sony_acpi_value {
         char                    *name;   /* name of the entry */
         struct proc_dir_entry   *proc;   /* /proc entry */
@@ -61,19 +77,11 @@ static struct sony_acpi_value {
         int                     debug;   /* active only in debug mode ? */
 } sony_acpi_values[] = {
         {
-                .name           = "brightness",
-                .acpiget        = "GBRT",
-                .acpiset        = "SBRT",
-                .min            = 1,
-                .max            = 8,
-                .debug          = 0,
-        },
-        {
                 .name           = "brightness_default",
                 .acpiget        = "GPBR",
                 .acpiset        = "SPBR",
                 .min            = 1,
-                .max            = 8,
+                .max            = SONY_MAX_BRIGHTNESS,
                 .debug          = 0,
         },
         {
@@ -276,6 +284,7 @@ static int sony_acpi_add(struct acpi_device *device)
 {
         acpi_status status;
         int result;
+        acpi_handle handle;
         struct sony_acpi_value *item;
 
         sony_acpi_handle = device->handle;
@@ -303,9 +312,15 @@ static int sony_acpi_add(struct acpi_device *device)
                 }
         }
 
-        for (item = sony_acpi_values; item->name; ++item) {
-                acpi_handle handle;
+        if (ACPI_SUCCESS(acpi_get_handle(sony_acpi_handle, "GBRT", &handle))) {
+                sony_backlight_device = backlight_device_register("sony", NULL,
+                                        &sony_backlight_properties);
+                if (IS_ERR(sony_backlight_device)) {
+                        printk(LOG_PFX "unable to register backlight device\n");
+                }
+        }
 
+        for (item = sony_acpi_values; item->name; ++item) {
                 if (!debug && item->debug)
                         continue;
 
@@ -358,6 +373,9 @@ static int sony_acpi_remove(struct acpi_device *device, int type)
         acpi_status status;
         struct sony_acpi_value *item;
 
+        if (sony_backlight_device)
+                backlight_device_unregister(sony_backlight_device);
+
         if (debug) {
                 status = acpi_remove_notify_handler(sony_acpi_handle,
                                                     ACPI_DEVICE_NOTIFY,
@@ -375,6 +393,23 @@ static int sony_acpi_remove(struct acpi_device *device, int type)
         return 0;
 }
 
+static int sony_backlight_update_status(struct backlight_device *bd)
+{
+        return acpi_callsetfunc(sony_acpi_handle, "SBRT",
+                                bd->props->brightness + 1,
+                                NULL);
+}
+
+static int sony_backlight_get_brightness(struct backlight_device *bd)
+{
+        int value;
+
+        if (acpi_callgetfunc(sony_acpi_handle, "GBRT", &value))
+                return 0;
+        /* brightness levels are 1-based, while backlight ones are 0-based */
+        return value - 1;
+}
+
 static struct acpi_driver sony_acpi_driver = {
         .name   = ACPI_SNC_DRIVER_NAME,
         .class  = ACPI_SNC_CLASS,