ACPI: register ACPI Video LCD as generic thermal cooling device

Register ACPI video device as thermal cooling devices as they may be listed
in _TZD method and the backlight control can be used for throttling.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Thomas Sujith <sujith.thomas@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 77 insertions, 1 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index bd77e81e81c1..eab9c4213b49 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -34,6 +34,7 @@
 #include <linux/seq_file.h>
 #include <linux/input.h>
 #include <linux/backlight.h>
+#include <linux/thermal.h>
 #include <linux/video_output.h>
 #include <asm/uaccess.h>
 
@@ -179,6 +180,7 @@ struct acpi_video_device {
         struct acpi_device *dev;
         struct acpi_video_device_brightness *brightness;
         struct backlight_device *backlight;
+        struct thermal_cooling_device *cdev;
         struct output_device *output_dev;
 };
 
@@ -334,6 +336,54 @@ static struct output_properties acpi_output_properties = {
         .set_state = acpi_video_output_set,
         .get_status = acpi_video_output_get,
 };
+
+
+/* thermal cooling device callbacks */
+static int video_get_max_state(struct thermal_cooling_device *cdev, char *buf)
+{
+        struct acpi_device *device = cdev->devdata;
+        struct acpi_video_device *video = acpi_driver_data(device);
+
+        return sprintf(buf, "%d\n", video->brightness->count - 3);
+}
+
+static int video_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
+{
+        struct acpi_device *device = cdev->devdata;
+        struct acpi_video_device *video = acpi_driver_data(device);
+        unsigned long level;
+        int state;
+
+        acpi_video_device_lcd_get_level_current(video, &level);
+        for (state = 2; state < video->brightness->count; state++)
+                if (level == video->brightness->levels[state])
+                        return sprintf(buf, "%d\n",
+                                       video->brightness->count - state - 1);
+
+        return -EINVAL;
+}
+
+static int
+video_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
+{
+        struct acpi_device *device = cdev->devdata;
+        struct acpi_video_device *video = acpi_driver_data(device);
+        int level;
+
+        if ( state >= video->brightness->count - 2)
+                return -EINVAL;
+
+        state = video->brightness->count - state;
+        level = video->brightness->levels[state -1];
+        return acpi_video_device_lcd_set_level(video, level);
+}
+
+static struct thermal_cooling_device_ops video_cooling_ops = {
+        .get_max_state = video_get_max_state,
+        .get_cur_state = video_get_cur_state,
+        .set_cur_state = video_set_cur_state,
+};
+
 /* --------------------------------------------------------------------------
                                Video Management
    -------------------------------------------------------------------------- */
@@ -653,6 +703,7 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 
         if (device->cap._BCL && device->cap._BCM && device->cap._BQC && max_level > 0){
                 unsigned long tmp;
+                int result;
                 static int count = 0;
                 char *name;
                 name = kzalloc(MAX_NAME_LEN, GFP_KERNEL);
@@ -666,8 +717,25 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
                 device->backlight->props.max_brightness = max_level;
                 device->backlight->props.brightness = (int)tmp;
                 backlight_update_status(device->backlight);
-
                 kfree(name);
+
+                device->cdev = thermal_cooling_device_register("LCD",
+                                        device->dev, &video_cooling_ops);
+                if (device->cdev) {
+                        printk(KERN_INFO PREFIX
+                                "%s is registered as cooling_device%d\n",
+                                device->dev->dev.bus_id, device->cdev->id);
+                        result = sysfs_create_link(&device->dev->dev.kobj,
+                                          &device->cdev->device.kobj,
+                                          "thermal_cooling");
+                        if (result)
+                                printk(KERN_ERR PREFIX "Create sysfs link\n");
+                        result = sysfs_create_link(&device->cdev->device.kobj,
+                                          &device->dev->dev.kobj,
+                                          "device");
+                        if (result)
+                                printk(KERN_ERR PREFIX "Create sysfs link\n");
+                }
         }
         if (device->cap._DCS && device->cap._DSS){
                 static int count = 0;
@@ -1729,6 +1797,14 @@ static int acpi_video_bus_put_one_device(struct acpi_video_device *device)
                                             ACPI_DEVICE_NOTIFY,
                                             acpi_video_device_notify);
         backlight_device_unregister(device->backlight);
+        if (device->cdev) {
+                sysfs_remove_link(&device->dev->dev.kobj,
+                                  "thermal_cooling");
+                sysfs_remove_link(&device->cdev->device.kobj,
+                                  "device");
+                thermal_cooling_device_unregister(device->cdev);
+                device->cdev = NULL;
+        }
         video_output_unregister(device->output_dev);
 
         return 0;