toshiba_acpi: Add support for transflective LCD

Some Toshiba laptops have the transflective LCD and toshset
can control its backlight state.  I brought this feature to the
mainline.  To support transflective LCD, it's implemented by
adding an extra level to the backlight and having 0 change to
transflective mode.  It was tested on a Toshiba Portege R500.

Signed-off-by: Akio Idehara <zbe64533@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 57 insertions, 4 deletions

diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c
index 1bb128bbcfc9..f88b9d22f39e 100644
--- a/drivers/platform/x86/toshiba_acpi.c
+++ b/drivers/platform/x86/toshiba_acpi.c
@@ -95,6 +95,7 @@ MODULE_LICENSE("GPL");
 
 /* registers */
 #define HCI_FAN                         0x0004
+#define HCI_TR_BACKLIGHT                0x0005
 #define HCI_SYSTEM_EVENT                0x0016
 #define HCI_VIDEO_OUT                   0x001c
 #define HCI_HOTKEY_EVENT                0x001e
@@ -134,6 +135,7 @@ struct toshiba_acpi_dev {
         unsigned int system_event_supported:1;
         unsigned int ntfy_supported:1;
         unsigned int info_supported:1;
+        unsigned int tr_backlight_supported:1;
 
         struct mutex mutex;
 };
@@ -478,16 +480,46 @@ static const struct rfkill_ops toshiba_rfk_ops = {
         .poll = bt_rfkill_poll,
 };
 
+static int get_tr_backlight_status(struct toshiba_acpi_dev *dev, bool *enabled)
+{
+        u32 hci_result;
+        u32 status;
+
+        hci_read1(dev, HCI_TR_BACKLIGHT, &status, &hci_result);
+        *enabled = !status;
+        return hci_result == HCI_SUCCESS ? 0 : -EIO;
+}
+
+static int set_tr_backlight_status(struct toshiba_acpi_dev *dev, bool enable)
+{
+        u32 hci_result;
+        u32 value = !enable;
+
+        hci_write1(dev, HCI_TR_BACKLIGHT, value, &hci_result);
+        return hci_result == HCI_SUCCESS ? 0 : -EIO;
+}
+
 static struct proc_dir_entry *toshiba_proc_dir /*= 0*/ ;
 
 static int __get_lcd_brightness(struct toshiba_acpi_dev *dev)
 {
         u32 hci_result;
         u32 value;
+        int brightness = 0;
+
+        if (dev->tr_backlight_supported) {
+                bool enabled;
+                int ret = get_tr_backlight_status(dev, &enabled);
+                if (ret)
+                        return ret;
+                if (enabled)
+                        return 0;
+                brightness++;
+        }
 
         hci_read1(dev, HCI_LCD_BRIGHTNESS, &value, &hci_result);
         if (hci_result == HCI_SUCCESS)
-                return (value >> HCI_LCD_BRIGHTNESS_SHIFT);
+                return brightness + (value >> HCI_LCD_BRIGHTNESS_SHIFT);
 
         return -EIO;
 }
@@ -502,15 +534,16 @@ static int lcd_proc_show(struct seq_file *m, void *v)
 {
         struct toshiba_acpi_dev *dev = m->private;
         int value;
+        int levels;
 
         if (!dev->backlight_dev)
                 return -ENODEV;
 
+        levels = dev->backlight_dev->props.max_brightness + 1;
         value = get_lcd_brightness(dev->backlight_dev);
         if (value >= 0) {
                 seq_printf(m, "brightness:              %d\n", value);
-                seq_printf(m, "brightness_levels:       %d\n",
-                             HCI_LCD_BRIGHTNESS_LEVELS);
+                seq_printf(m, "brightness_levels:       %d\n", levels);
                 return 0;
         }
 
@@ -527,6 +560,15 @@ static int set_lcd_brightness(struct toshiba_acpi_dev *dev, int value)
 {
         u32 hci_result;
 
+        if (dev->tr_backlight_supported) {
+                bool enable = !value;
+                int ret = set_tr_backlight_status(dev, enable);
+                if (ret)
+                        return ret;
+                if (value)
+                        value--;
+        }
+
         value = value << HCI_LCD_BRIGHTNESS_SHIFT;
         hci_write1(dev, HCI_LCD_BRIGHTNESS, value, &hci_result);
         return hci_result == HCI_SUCCESS ? 0 : -EIO;
@@ -546,6 +588,7 @@ static ssize_t lcd_proc_write(struct file *file, const char __user *buf,
         size_t len;
         int value;
         int ret;
+        int levels = dev->backlight_dev->props.max_brightness + 1;
 
         len = min(count, sizeof(cmd) - 1);
         if (copy_from_user(cmd, buf, len))
@@ -553,7 +596,7 @@ static ssize_t lcd_proc_write(struct file *file, const char __user *buf,
         cmd[len] = '\0';
 
         if (sscanf(cmd, " brightness : %i", &value) == 1 &&
-            value >= 0 && value < HCI_LCD_BRIGHTNESS_LEVELS) {
+            value >= 0 && value < levels) {
                 ret = set_lcd_brightness(dev, value);
                 if (ret == 0)
                         ret = count;
@@ -865,6 +908,7 @@ static void remove_toshiba_proc_entries(struct toshiba_acpi_dev *dev)
 }
 
 static const struct backlight_ops toshiba_backlight_data = {
+        .options = BL_CORE_SUSPENDRESUME,
         .get_brightness = get_lcd_brightness,
         .update_status  = set_lcd_status,
 };
@@ -1030,6 +1074,7 @@ static int __devinit toshiba_acpi_setup_backlight(struct toshiba_acpi_dev *dev)
         struct backlight_properties props;
         int brightness;
         int ret;
+        bool enabled;
 
         /*
          * Some machines don't support the backlight methods at all, and
@@ -1046,10 +1091,18 @@ static int __devinit toshiba_acpi_setup_backlight(struct toshiba_acpi_dev *dev)
                 return 0;
         }
 
+        /* Determine whether or not BIOS supports transflective backlight */
+        ret = get_tr_backlight_status(dev, &enabled);
+        dev->tr_backlight_supported = !ret;
+
         props.type = BACKLIGHT_PLATFORM;
         props.max_brightness = HCI_LCD_BRIGHTNESS_LEVELS - 1;
         memset(&props, 0, sizeof(props));
 
+        /* adding an extra level and having 0 change to transflective mode */
+        if (dev->tr_backlight_supported)
+                props.max_brightness++;
+
         dev->backlight_dev = backlight_device_register("toshiba",
                                                        &dev->acpi_dev->dev,
                                                        dev,