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>

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;
@@ -546,14 +588,15 @@ 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))
 		return -EFAULT;
 	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,