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toshiba_acpi: Only register backlight device when interface is read/w…
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…rite

Currently the backlight device is registered unconditionally, but many
(probably most) Toshibas either don't support HCI_LCD_BRIGHTNESS or only
support reading from it. This patch adds a test of HCI_LCD_BRIGHTNESS
during initialization and only registers the backlight device if this
interface supports both reads and writes.

Cc: Akio Idehara <zbe64533@gmail.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
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Seth Forshee authored and Matthew Garrett committed May 31, 2012
1 parent 20a769c commit 62cce75
Showing 1 changed file with 56 additions and 24 deletions.
80 changes: 56 additions & 24 deletions drivers/platform/x86/toshiba_acpi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -480,9 +480,8 @@ static const struct rfkill_ops toshiba_rfk_ops = {

static struct proc_dir_entry *toshiba_proc_dir /*= 0*/ ;

static int get_lcd(struct backlight_device *bd)
static int __get_lcd_brightness(struct toshiba_acpi_dev *dev)
{
struct toshiba_acpi_dev *dev = bl_get_data(bd);
u32 hci_result;
u32 value;

Expand All @@ -493,6 +492,12 @@ static int get_lcd(struct backlight_device *bd)
return -EIO;
}

static int get_lcd_brightness(struct backlight_device *bd)
{
struct toshiba_acpi_dev *dev = bl_get_data(bd);
return __get_lcd_brightness(dev);
}

static int lcd_proc_show(struct seq_file *m, void *v)
{
struct toshiba_acpi_dev *dev = m->private;
Expand All @@ -501,7 +506,7 @@ static int lcd_proc_show(struct seq_file *m, void *v)
if (!dev->backlight_dev)
return -ENODEV;

value = get_lcd(dev->backlight_dev);
value = get_lcd_brightness(dev->backlight_dev);
if (value >= 0) {
seq_printf(m, "brightness: %d\n", value);
seq_printf(m, "brightness_levels: %d\n",
Expand All @@ -518,7 +523,7 @@ static int lcd_proc_open(struct inode *inode, struct file *file)
return single_open(file, lcd_proc_show, PDE(inode)->data);
}

static int set_lcd(struct toshiba_acpi_dev *dev, int value)
static int set_lcd_brightness(struct toshiba_acpi_dev *dev, int value)
{
u32 hci_result;

Expand All @@ -530,7 +535,7 @@ static int set_lcd(struct toshiba_acpi_dev *dev, int value)
static int set_lcd_status(struct backlight_device *bd)
{
struct toshiba_acpi_dev *dev = bl_get_data(bd);
return set_lcd(dev, bd->props.brightness);
return set_lcd_brightness(dev, bd->props.brightness);
}

static ssize_t lcd_proc_write(struct file *file, const char __user *buf,
Expand All @@ -549,7 +554,7 @@ static ssize_t lcd_proc_write(struct file *file, const char __user *buf,

if (sscanf(cmd, " brightness : %i", &value) == 1 &&
value >= 0 && value < HCI_LCD_BRIGHTNESS_LEVELS) {
ret = set_lcd(dev, value);
ret = set_lcd_brightness(dev, value);
if (ret == 0)
ret = count;
} else {
Expand Down Expand Up @@ -860,8 +865,8 @@ static void remove_toshiba_proc_entries(struct toshiba_acpi_dev *dev)
}

static const struct backlight_ops toshiba_backlight_data = {
.get_brightness = get_lcd,
.update_status = set_lcd_status,
.get_brightness = get_lcd_brightness,
.update_status = set_lcd_status,
};

static bool toshiba_acpi_i8042_filter(unsigned char data, unsigned char str,
Expand Down Expand Up @@ -1020,6 +1025,47 @@ static int __devinit toshiba_acpi_setup_keyboard(struct toshiba_acpi_dev *dev)
return error;
}

static int __devinit toshiba_acpi_setup_backlight(struct toshiba_acpi_dev *dev)
{
struct backlight_properties props;
int brightness;
int ret;

/*
* Some machines don't support the backlight methods at all, and
* others support it read-only. Either of these is pretty useless,
* so only register the backlight device if the backlight method
* supports both reads and writes.
*/
brightness = __get_lcd_brightness(dev);
if (brightness < 0)
return 0;
ret = set_lcd_brightness(dev, brightness);
if (ret) {
pr_debug("Backlight method is read-only, disabling backlight support\n");
return 0;
}

props.type = BACKLIGHT_PLATFORM;
props.max_brightness = HCI_LCD_BRIGHTNESS_LEVELS - 1;
memset(&props, 0, sizeof(props));

dev->backlight_dev = backlight_device_register("toshiba",
&dev->acpi_dev->dev,
dev,
&toshiba_backlight_data,
&props);
if (IS_ERR(dev->backlight_dev)) {
ret = PTR_ERR(dev->backlight_dev);
pr_err("Could not register toshiba backlight device\n");
dev->backlight_dev = NULL;
return ret;
}

dev->backlight_dev->props.brightness = brightness;
return 0;
}

static int toshiba_acpi_remove(struct acpi_device *acpi_dev, int type)
{
struct toshiba_acpi_dev *dev = acpi_driver_data(acpi_dev);
Expand Down Expand Up @@ -1078,7 +1124,6 @@ static int __devinit toshiba_acpi_add(struct acpi_device *acpi_dev)
u32 dummy;
bool bt_present;
int ret = 0;
struct backlight_properties props;

if (toshiba_acpi)
return -EBUSY;
Expand All @@ -1104,22 +1149,9 @@ static int __devinit toshiba_acpi_add(struct acpi_device *acpi_dev)

mutex_init(&dev->mutex);

memset(&props, 0, sizeof(props));
props.type = BACKLIGHT_PLATFORM;
props.max_brightness = HCI_LCD_BRIGHTNESS_LEVELS - 1;
dev->backlight_dev = backlight_device_register("toshiba",
&acpi_dev->dev,
dev,
&toshiba_backlight_data,
&props);
if (IS_ERR(dev->backlight_dev)) {
ret = PTR_ERR(dev->backlight_dev);

pr_err("Could not register toshiba backlight device\n");
dev->backlight_dev = NULL;
ret = toshiba_acpi_setup_backlight(dev);
if (ret)
goto error;
}
dev->backlight_dev->props.brightness = get_lcd(dev->backlight_dev);

/* Register rfkill switch for Bluetooth */
if (hci_get_bt_present(dev, &bt_present) == HCI_SUCCESS && bt_present) {
Expand Down

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