2006-10-13 10:24:44

by Holger Macht

Subject: [PATCH 3/3] Add support for the generic backlight device to the TOSHIBA ACPI driver

Add support for the generic backlight interface below
/sys/class/backlight. The patch keeps the procfs brightness handling for
backward compatibility.

For this to archive, the patch adds two generic functions get_lcd and
set_lcd to be used both by the procfs related and the sysfs related
methods.

Signed-off-by: Holger Macht <[email protected]>
---

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index f0bd84a..d9bb370 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -227,6 +227,7 @@ config ACPI_IBM_DOCK
config ACPI_TOSHIBA
tristate "Toshiba Laptop Extras"
depends on X86
+ select BACKLIGHT_DEVICE
---help---
This driver adds support for access to certain system settings
on "legacy free" Toshiba laptops. These laptops can be recognized by
diff --git a/drivers/acpi/toshiba_acpi.c b/drivers/acpi/toshiba_acpi.c
index 7fe0b7a..2f35f89 100644
--- a/drivers/acpi/toshiba_acpi.c
+++ b/drivers/acpi/toshiba_acpi.c
@@ -41,6 +41,8 @@ #include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
+#include <linux/backlight.h>
+
#include <asm/uaccess.h>

#include <acpi/acpi_drivers.h>
@@ -210,6 +212,7 @@ static acpi_status hci_read1(u32 reg, u3
}

static struct proc_dir_entry *toshiba_proc_dir /*= 0*/ ;
+static struct backlight_device *toshiba_backlight_device;
static int force_fan;
static int last_key_event;
static int key_event_valid;
@@ -271,14 +274,23 @@ dispatch_write(struct file *file, const
return result;
}

-static char *read_lcd(char *p)
+static int get_lcd(struct backlight_device *bd)
{
u32 hci_result;
u32 value;

hci_read1(HCI_LCD_BRIGHTNESS, &value, &hci_result);
if (hci_result == HCI_SUCCESS) {
- value = value >> HCI_LCD_BRIGHTNESS_SHIFT;
+ return (value >> HCI_LCD_BRIGHTNESS_SHIFT);
+ } else
+ return -EFAULT;
+}
+
+static char *read_lcd(char *p)
+{
+ int value = get_lcd(NULL);
+
+ if (value >= 0) {
p += sprintf(p, "brightness: %d\n", value);
p += sprintf(p, "brightness_levels: %d\n",
HCI_LCD_BRIGHTNESS_LEVELS);
@@ -289,22 +301,34 @@ static char *read_lcd(char *p)
return p;
}

+static int set_lcd(int value)
+{
+ u32 hci_result;
+
+ value = value << HCI_LCD_BRIGHTNESS_SHIFT;
+ hci_write1(HCI_LCD_BRIGHTNESS, value, &hci_result);
+ if (hci_result != HCI_SUCCESS)
+ return -EFAULT;
+
+ return 0;
+}
+
+static int set_lcd_status(struct backlight_device *bd)
+{
+ return set_lcd(bd->props->brightness);
+}
+
static unsigned long write_lcd(const char *buffer, unsigned long count)
{
int value;
- u32 hci_result;
+ int ret = count;

if (sscanf(buffer, " brightness : %i", &value) == 1 &&
- value >= 0 && value < HCI_LCD_BRIGHTNESS_LEVELS) {
- value = value << HCI_LCD_BRIGHTNESS_SHIFT;
- hci_write1(HCI_LCD_BRIGHTNESS, value, &hci_result);
- if (hci_result != HCI_SUCCESS)
- return -EFAULT;
- } else {
- return -EINVAL;
- }
-
- return count;
+ value >= 0 && value < HCI_LCD_BRIGHTNESS_LEVELS)
+ ret = set_lcd(value);
+ else
+ ret = -EINVAL;
+ return ret;
}

static char *read_video(char *p)
@@ -506,6 +530,26 @@ static acpi_status __exit remove_device(
return AE_OK;
}

+static struct backlight_properties toshiba_backlight_data = {
+ .owner = THIS_MODULE,
+ .get_brightness = get_lcd,
+ .update_status = set_lcd_status,
+ .max_brightness = HCI_LCD_BRIGHTNESS_LEVELS - 1,
+};
+
+static void __exit toshiba_acpi_exit(void)
+{
+ if (toshiba_backlight_device)
+ backlight_device_unregister(toshiba_backlight_device);
+
+ remove_device();
+
+ if (toshiba_proc_dir)
+ remove_proc_entry(PROC_TOSHIBA, acpi_root_dir);
+
+ return;
+}
+
static int __init toshiba_acpi_init(void)
{
acpi_status status = AE_OK;
@@ -546,17 +590,15 @@ static int __init toshiba_acpi_init(void
remove_proc_entry(PROC_TOSHIBA, acpi_root_dir);
}

- return (ACPI_SUCCESS(status)) ? 0 : -ENODEV;
-}
-
-static void __exit toshiba_acpi_exit(void)
-{
- remove_device();
-
- if (toshiba_proc_dir)
- remove_proc_entry(PROC_TOSHIBA, acpi_root_dir);
+ toshiba_backlight_device = backlight_device_register("toshiba", NULL,
+ &toshiba_backlight_data);
+ if (IS_ERR(toshiba_backlight_device)) {
+ printk(KERN_ERR "Could not register toshiba backlight device\n");
+ toshiba_backlight_device = NULL;
+ toshiba_acpi_exit();
+ }

- return;
+ return (ACPI_SUCCESS(status)) ? 0 : -ENODEV;
}

module_init(toshiba_acpi_init);

2006-10-13 21:57:07

by Andrew Morton

Subject: Re: [PATCH 3/3] Add support for the generic backlight device to the TOSHIBA ACPI driver

On Fri, 13 Oct 2006 12:24:19 +0200
Holger Macht <[email protected]> wrote:

> +static int set_lcd(int value)
> +{
> + u32 hci_result;
> +
> + value = value << HCI_LCD_BRIGHTNESS_SHIFT;
> + hci_write1(HCI_LCD_BRIGHTNESS, value, &hci_result);
> + if (hci_result != HCI_SUCCESS)
> + return -EFAULT;
> +
> + return 0;

-EFAULT seems a bit random. Would -EIO be more appropriate?