sony-laptop: implement new backlight control method

Reasonably recent Vaios have a 0x12f or 0x137 handler that exposes a
fine lid backlight regulation with values ranging from 0 to 255.
The patch is based on findings and code from Javier Achirica
<achirica@gmail.com> and Marco Chiappero <marco@absence.it>

Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 79 insertions, 30 deletions

diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c
index 326a4600fad1..d28a4a58a497 100644
--- a/drivers/platform/x86/sony-laptop.c
+++ b/drivers/platform/x86/sony-laptop.c
@@ -938,11 +938,39 @@ static int sony_backlight_get_brightness(struct backlight_device *bd)
         return value - 1;
 }
 
-static struct backlight_device *sony_backlight_device;
+static int sony_nc_get_brightness_ng(struct backlight_device *bd)
+{
+        int result;
+        int *handle = (int *)bl_get_data(bd);
+
+        sony_call_snc_handle(*handle, 0x0200, &result);
+
+        return result & 0xff;
+}
+
+static int sony_nc_update_status_ng(struct backlight_device *bd)
+{
+        int value, result;
+        int *handle = (int *)bl_get_data(bd);
+
+        value = bd->props.brightness;
+        sony_call_snc_handle(*handle, 0x0100 | (value << 16), &result);
+
+        return sony_nc_get_brightness_ng(bd);
+}
+
 static const struct backlight_ops sony_backlight_ops = {
+        .options = BL_CORE_SUSPENDRESUME,
         .update_status = sony_backlight_update_status,
         .get_brightness = sony_backlight_get_brightness,
 };
+static const struct backlight_ops sony_backlight_ng_ops = {
+        .options = BL_CORE_SUSPENDRESUME,
+        .update_status = sony_nc_update_status_ng,
+        .get_brightness = sony_nc_get_brightness_ng,
+};
+static int backlight_ng_handle;
+static struct backlight_device *sony_backlight_device;
 
 /*
  * New SNC-only Vaios event mapping to driver known keys
@@ -1135,11 +1163,6 @@ static int sony_nc_resume(struct acpi_device *device)
                 sony_nc_function_setup(device);
         }
 
-        /* set the last requested brightness level */
-        if (sony_backlight_device &&
-                        sony_backlight_update_status(sony_backlight_device) < 0)
-                pr_warn(DRV_PFX "unable to restore brightness level\n");
-
         /* re-read rfkill state */
         sony_nc_rfkill_update();
 
@@ -1477,6 +1500,52 @@ static int sony_nc_kbd_backlight_cleanup(struct platform_device *pd)
         return 0;
 }
 
+static void sony_nc_backlight_setup(void)
+{
+        acpi_handle unused;
+        int max_brightness = 0;
+        const struct backlight_ops *ops = NULL;
+        struct backlight_properties props;
+
+        if (sony_find_snc_handle(0x12f) != -1) {
+                backlight_ng_handle = 0x12f;
+                ops = &sony_backlight_ng_ops;
+                max_brightness = 0xff;
+
+        } else if (sony_find_snc_handle(0x137) != -1) {
+                backlight_ng_handle = 0x137;
+                ops = &sony_backlight_ng_ops;
+                max_brightness = 0xff;
+
+        } else if (ACPI_SUCCESS(acpi_get_handle(sony_nc_acpi_handle, "GBRT",
+                                                &unused))) {
+                ops = &sony_backlight_ops;
+                max_brightness = SONY_MAX_BRIGHTNESS - 1;
+
+        } else
+                return;
+
+        memset(&props, 0, sizeof(struct backlight_properties));
+        props.type = BACKLIGHT_PLATFORM;
+        props.max_brightness = max_brightness;
+        sony_backlight_device = backlight_device_register("sony", NULL,
+                                                          &backlight_ng_handle,
+                                                          ops, &props);
+
+        if (IS_ERR(sony_backlight_device)) {
+                pr_warning(DRV_PFX "unable to register backlight device\n");
+                sony_backlight_device = NULL;
+        } else
+                sony_backlight_device->props.brightness =
+                    ops->get_brightness(sony_backlight_device);
+}
+
+static void sony_nc_backlight_cleanup(void)
+{
+        if (sony_backlight_device)
+                backlight_device_unregister(sony_backlight_device);
+}
+
 static int sony_nc_add(struct acpi_device *device)
 {
         acpi_status status;
@@ -1543,26 +1612,8 @@ static int sony_nc_add(struct acpi_device *device)
         if (acpi_video_backlight_support()) {
                 pr_info(DRV_PFX "brightness ignored, must be "
                        "controlled by ACPI video driver\n");
-        } else if (ACPI_SUCCESS(acpi_get_handle(sony_nc_acpi_handle, "GBRT",
-                                                &handle))) {
-                struct backlight_properties props;
-                memset(&props, 0, sizeof(struct backlight_properties));
-                props.type = BACKLIGHT_PLATFORM;
-                props.max_brightness = SONY_MAX_BRIGHTNESS - 1;
-                sony_backlight_device = backlight_device_register("sony", NULL,
-                                                                  NULL,
-                                                                  &sony_backlight_ops,
-                                                                  &props);
-
-                if (IS_ERR(sony_backlight_device)) {
-                        pr_warning(DRV_PFX "unable to register backlight device\n");
-                        sony_backlight_device = NULL;
-                } else {
-                        sony_backlight_device->props.brightness =
-                            sony_backlight_get_brightness
-                            (sony_backlight_device);
-                }
-
+        } else {
+                sony_nc_backlight_setup();
         }
 
         /* create sony_pf sysfs attributes related to the SNC device */
@@ -1610,8 +1661,7 @@ static int sony_nc_add(struct acpi_device *device)
         for (item = sony_nc_values; item->name; ++item) {
                 device_remove_file(&sony_pf_device->dev, &item->devattr);
         }
-        if (sony_backlight_device)
-                backlight_device_unregister(sony_backlight_device);
+        sony_nc_backlight_cleanup();
 
         sony_laptop_remove_input();
 
@@ -1633,8 +1683,7 @@ static int sony_nc_remove(struct acpi_device *device, int type)
 {
         struct sony_nc_value *item;
 
-        if (sony_backlight_device)
-                backlight_device_unregister(sony_backlight_device);
+        sony_nc_backlight_cleanup();
 
         sony_nc_acpi_device = NULL;