eeepc-wmi: add backlight support

Add backlight support for WMI based Eee PC laptops.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Reviewed-by: Corentin Chary <corentincj@iksaif.net>

1 files changed, 197 insertions, 35 deletions

diff --git a/drivers/platform/x86/eeepc-wmi.c b/drivers/platform/x86/eeepc-wmi.c
index 0c9596c97a0f..b227eb469f49 100644
--- a/drivers/platform/x86/eeepc-wmi.c
+++ b/drivers/platform/x86/eeepc-wmi.c
@@ -32,6 +32,8 @@
 #include <linux/slab.h>
 #include <linux/input.h>
 #include <linux/input/sparse-keymap.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
 #include <linux/platform_device.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
@@ -43,14 +45,21 @@ MODULE_DESCRIPTION("Eee PC WMI Hotkey Driver");
 MODULE_LICENSE("GPL");
 
 #define EEEPC_WMI_EVENT_GUID    "ABBC0F72-8EA1-11D1-00A0-C90629100000"
+#define EEEPC_WMI_MGMT_GUID     "97845ED0-4E6D-11DE-8A39-0800200C9A66"
 
 MODULE_ALIAS("wmi:"EEEPC_WMI_EVENT_GUID);
+MODULE_ALIAS("wmi:"EEEPC_WMI_MGMT_GUID);
 
 #define NOTIFY_BRNUP_MIN        0x11
 #define NOTIFY_BRNUP_MAX        0x1f
 #define NOTIFY_BRNDOWN_MIN      0x20
 #define NOTIFY_BRNDOWN_MAX      0x2e
 
+#define EEEPC_WMI_METHODID_DEVS 0x53564544
+#define EEEPC_WMI_METHODID_DSTS 0x53544344
+
+#define EEEPC_WMI_DEVID_BACKLIGHT       0x00050012
+
 static const struct key_entry eeepc_wmi_keymap[] = {
         /* Sleep already handled via generic ACPI code */
         { KE_KEY, 0x5d, { KEY_WLAN } },
@@ -63,44 +72,18 @@ static const struct key_entry eeepc_wmi_keymap[] = {
         { KE_END, 0},
 };
 
+struct bios_args {
+        u32     dev_id;
+        u32     ctrl_param;
+};
+
 struct eeepc_wmi {
         struct input_dev *inputdev;
+        struct backlight_device *backlight_device;
 };
 
 static struct platform_device *platform_device;
 
-static void eeepc_wmi_notify(u32 value, void *context)
-{
-        struct eeepc_wmi *eeepc = context;
-        struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
-        union acpi_object *obj;
-        acpi_status status;
-        int code;
-
-        status = wmi_get_event_data(value, &response);
-        if (status != AE_OK) {
-                pr_err("bad event status 0x%x\n", status);
-                return;
-        }
-
-        obj = (union acpi_object *)response.pointer;
-
-        if (obj && obj->type == ACPI_TYPE_INTEGER) {
-                code = obj->integer.value;
-
-                if (code >= NOTIFY_BRNUP_MIN && code <= NOTIFY_BRNUP_MAX)
-                        code = NOTIFY_BRNUP_MIN;
-                else if (code >= NOTIFY_BRNDOWN_MIN && code <= NOTIFY_BRNDOWN_MAX)
-                        code = NOTIFY_BRNDOWN_MIN;
-
-                if (!sparse_keymap_report_event(eeepc->inputdev,
-                                                code, 1, true))
-                        pr_info("Unknown key %x pressed\n", code);
-        }
-
-        kfree(obj);
-}
-
 static int eeepc_wmi_input_init(struct eeepc_wmi *eeepc)
 {
         int err;
@@ -141,6 +124,174 @@ static void eeepc_wmi_input_exit(struct eeepc_wmi *eeepc)
         eeepc->inputdev = NULL;
 }
 
+static acpi_status eeepc_wmi_get_devstate(u32 dev_id, u32 *ctrl_param)
+{
+        struct acpi_buffer input = { (acpi_size)sizeof(u32), &dev_id };
+        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+        union acpi_object *obj;
+        acpi_status status;
+        u32 tmp;
+
+        status = wmi_evaluate_method(EEEPC_WMI_MGMT_GUID,
+                        1, EEEPC_WMI_METHODID_DSTS, &input, &output);
+
+        if (ACPI_FAILURE(status))
+                return status;
+
+        obj = (union acpi_object *)output.pointer;
+        if (obj && obj->type == ACPI_TYPE_INTEGER)
+                tmp = (u32)obj->integer.value;
+        else
+                tmp = 0;
+
+        if (ctrl_param)
+                *ctrl_param = tmp;
+
+        kfree(obj);
+
+        return status;
+
+}
+
+static acpi_status eeepc_wmi_set_devstate(u32 dev_id, u32 ctrl_param)
+{
+        struct bios_args args = {
+                .dev_id = dev_id,
+                .ctrl_param = ctrl_param,
+        };
+        struct acpi_buffer input = { (acpi_size)sizeof(args), &args };
+        acpi_status status;
+
+        status = wmi_evaluate_method(EEEPC_WMI_MGMT_GUID,
+                        1, EEEPC_WMI_METHODID_DEVS, &input, NULL);
+
+        return status;
+}
+
+static int read_brightness(struct backlight_device *bd)
+{
+        static u32 ctrl_param;
+        acpi_status status;
+
+        status = eeepc_wmi_get_devstate(EEEPC_WMI_DEVID_BACKLIGHT, &ctrl_param);
+
+        if (ACPI_FAILURE(status))
+                return -1;
+        else
+                return ctrl_param & 0xFF;
+}
+
+static int update_bl_status(struct backlight_device *bd)
+{
+
+        static u32 ctrl_param;
+        acpi_status status;
+
+        ctrl_param = bd->props.brightness;
+
+        status = eeepc_wmi_set_devstate(EEEPC_WMI_DEVID_BACKLIGHT, ctrl_param);
+
+        if (ACPI_FAILURE(status))
+                return -1;
+        else
+                return 0;
+}
+
+static const struct backlight_ops eeepc_wmi_bl_ops = {
+        .get_brightness = read_brightness,
+        .update_status = update_bl_status,
+};
+
+static int eeepc_wmi_backlight_notify(struct eeepc_wmi *eeepc, int code)
+{
+        struct backlight_device *bd = eeepc->backlight_device;
+        int old = bd->props.brightness;
+        int new;
+
+        if (code >= NOTIFY_BRNUP_MIN && code <= NOTIFY_BRNUP_MAX)
+                new = code - NOTIFY_BRNUP_MIN + 1;
+        else if (code >= NOTIFY_BRNDOWN_MIN && code <= NOTIFY_BRNDOWN_MAX)
+                new = code - NOTIFY_BRNDOWN_MIN;
+
+        bd->props.brightness = new;
+        backlight_update_status(bd);
+        backlight_force_update(bd, BACKLIGHT_UPDATE_HOTKEY);
+
+        return old;
+}
+
+static int eeepc_wmi_backlight_init(struct eeepc_wmi *eeepc)
+{
+        struct backlight_device *bd;
+        struct backlight_properties props;
+
+        memset(&props, 0, sizeof(struct backlight_properties));
+        props.max_brightness = 15;
+        bd = backlight_device_register(EEEPC_WMI_FILE,
+                                       &platform_device->dev, eeepc,
+                                       &eeepc_wmi_bl_ops, &props);
+        if (IS_ERR(bd)) {
+                pr_err("Could not register backlight device\n");
+                return PTR_ERR(bd);
+        }
+
+        eeepc->backlight_device = bd;
+
+        bd->props.brightness = read_brightness(bd);
+        bd->props.power = FB_BLANK_UNBLANK;
+        backlight_update_status(bd);
+
+        return 0;
+}
+
+static void eeepc_wmi_backlight_exit(struct eeepc_wmi *eeepc)
+{
+        if (eeepc->backlight_device)
+                backlight_device_unregister(eeepc->backlight_device);
+
+        eeepc->backlight_device = NULL;
+}
+
+static void eeepc_wmi_notify(u32 value, void *context)
+{
+        struct eeepc_wmi *eeepc = context;
+        struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
+        union acpi_object *obj;
+        acpi_status status;
+        int code;
+        int orig_code;
+
+        status = wmi_get_event_data(value, &response);
+        if (status != AE_OK) {
+                pr_err("bad event status 0x%x\n", status);
+                return;
+        }
+
+        obj = (union acpi_object *)response.pointer;
+
+        if (obj && obj->type == ACPI_TYPE_INTEGER) {
+                code = obj->integer.value;
+                orig_code = code;
+
+                if (code >= NOTIFY_BRNUP_MIN && code <= NOTIFY_BRNUP_MAX)
+                        code = NOTIFY_BRNUP_MIN;
+                else if (code >= NOTIFY_BRNDOWN_MIN &&
+                         code <= NOTIFY_BRNDOWN_MAX)
+                        code = NOTIFY_BRNDOWN_MIN;
+
+                if (code == NOTIFY_BRNUP_MIN || code == NOTIFY_BRNDOWN_MIN) {
+                        if (!acpi_video_backlight_support())
+                                eeepc_wmi_backlight_notify(eeepc, orig_code);
+                }
+
+                if (!sparse_keymap_report_event(eeepc->inputdev,
+                                                code, 1, true))
+                        pr_info("Unknown key %x pressed\n", code);
+        }
+
+        kfree(obj);
+}
+
 static int __devinit eeepc_wmi_platform_probe(struct platform_device *device)
 {
         struct eeepc_wmi *eeepc;
@@ -151,7 +302,14 @@ static int __devinit eeepc_wmi_platform_probe(struct platform_device *device)
 
         err = eeepc_wmi_input_init(eeepc);
         if (err)
-                return err;
+                goto error_input;
+
+        if (!acpi_video_backlight_support()) {
+                err = eeepc_wmi_backlight_init(eeepc);
+                if (err)
+                        goto error_backlight;
+        } else
+                pr_info("Backlight controlled by ACPI video driver\n");
 
         status = wmi_install_notify_handler(EEEPC_WMI_EVENT_GUID,
                                         eeepc_wmi_notify, eeepc);
@@ -165,8 +323,10 @@ static int __devinit eeepc_wmi_platform_probe(struct platform_device *device)
         return 0;
 
 error_wmi:
+        eeepc_wmi_backlight_exit(eeepc);
+error_backlight:
         eeepc_wmi_input_exit(eeepc);
-
+error_input:
         return err;
 }
 
@@ -176,6 +336,7 @@ static int __devexit eeepc_wmi_platform_remove(struct platform_device *device)
 
         eeepc = platform_get_drvdata(device);
         wmi_remove_notify_handler(EEEPC_WMI_EVENT_GUID);
+        eeepc_wmi_backlight_exit(eeepc);
         eeepc_wmi_input_exit(eeepc);
 
         return 0;
@@ -195,7 +356,8 @@ static int __init eeepc_wmi_init(void)
         struct eeepc_wmi *eeepc;
         int err;
 
-        if (!wmi_has_guid(EEEPC_WMI_EVENT_GUID)) {
+        if (!wmi_has_guid(EEEPC_WMI_EVENT_GUID) ||
+            !wmi_has_guid(EEEPC_WMI_MGMT_GUID)) {
                 pr_warning("No known WMI GUID found\n");
                 return -ENODEV;
         }