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Commit 8acb0250 authored by Holger Macht's avatar Holger Macht Committed by Len Brown
Browse files

ACPI: ibm_acpi: Add support for the generic backlight device 



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

Add two generic functions brightness_get and brightness_set
to be used both by the procfs related and the sysfs related methods.

[apw@shadowen.org: backlight users need to select BACKLIGHT_CLASS_DEVICE]

Signed-off-by: default avatarHolger Macht <hmacht@suse.de>
Signed-off-by: default avatarAndy Whitcroft <apw@shadowen.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent c7a3bd17

drivers/acpi/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -200,6 +200,7 @@ config ACPI_ASUS 
config ACPI_IBM

	tristate "IBM ThinkPad Laptop Extras"

	depends on X86

	select BACKLIGHT_CLASS_DEVICE

	---help---

	  This is a Linux ACPI driver for the IBM ThinkPad laptops. It adds

	  support for Fn-Fx key combinations, Bluetooth control, video

drivers/acpi/ibm_acpi.c

+61 −14
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ 
#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>
@@ -243,6 +244,8 @@ struct ibm_struct { 


static struct proc_dir_entry *proc_dir = NULL;



static struct backlight_device *ibm_backlight_device;



#define onoff(status,bit) ((status) & (1 << (bit)) ? "on" : "off")

#define enabled(status,bit) ((status) & (1 << (bit)) ? "enabled" : "disabled")

#define strlencmp(a,b) (strncmp((a), (b), strlen(b)))
@@ -1381,12 +1384,22 @@ static int ecdump_write(char *buf) 


static int brightness_offset = 0x31;



static int brightness_get(struct backlight_device *bd)

{

       u8 level;

       if (!acpi_ec_read(brightness_offset, &level))

               return -EIO;



       level &= 0x7;

       return level;

}



static int brightness_read(char *p)

{

	int len = 0;

	u8 level;

	int level;



	if (!acpi_ec_read(brightness_offset, &level)) {

	if ((level = brightness_get(NULL)) < 0) {

		len += sprintf(p + len, "level:\t\tunreadable\n");

	} else {

		len += sprintf(p + len, "level:\t\t%d\n", level & 0x7);
@@ -1401,16 +1414,34 @@ static int brightness_read(char *p) 
#define BRIGHTNESS_UP	4

#define BRIGHTNESS_DOWN	5



static int brightness_write(char *buf)

static int brightness_set(int value)

{

	int cmos_cmd, inc, i;

	u8 level;

	int current_value = brightness_get(NULL);



	value &= 7;



	cmos_cmd = value > current_value ? BRIGHTNESS_UP : BRIGHTNESS_DOWN;

	inc = value > current_value ? 1 : -1;

	for (i = current_value; i != value; i += inc) {

		if (!cmos_eval(cmos_cmd))

			return -EIO;

		if (!acpi_ec_write(brightness_offset, i + inc))

			return -EIO;

	}



	return 0;

}



static int brightness_write(char *buf)

{

	int level;

	int new_level;

	char *cmd;



	while ((cmd = next_cmd(&buf))) {

		if (!acpi_ec_read(brightness_offset, &level))

			return -EIO;

		if ((level = brightness_get(NULL)) < 0)

			return level;

		level &= 7;



		if (strlencmp(cmd, "up") == 0) {
@@ -1423,19 +1454,17 @@ static int brightness_write(char *buf) 
		} else

			return -EINVAL;



		cmos_cmd = new_level > level ? BRIGHTNESS_UP : BRIGHTNESS_DOWN;

		inc = new_level > level ? 1 : -1;

		for (i = level; i != new_level; i += inc) {

			if (!cmos_eval(cmos_cmd))

				return -EIO;

			if (!acpi_ec_write(brightness_offset, i + inc))

				return -EIO;

		}

		brightness_set(new_level);

	}



	return 0;

}



static int brightness_update_status(struct backlight_device *bd)

{

	return brightness_set(bd->props->brightness);

}



static int volume_offset = 0x30;



static int volume_read(char *p)
@@ -1963,10 +1992,20 @@ IBM_PARAM(brightness); 
IBM_PARAM(volume);

IBM_PARAM(fan);



static struct backlight_properties ibm_backlight_data = {

        .owner          = THIS_MODULE,

        .get_brightness = brightness_get,

        .update_status  = brightness_update_status,

        .max_brightness = 7,

};



static void acpi_ibm_exit(void)

{

	int i;



	if (ibm_backlight_device)

		backlight_device_unregister(ibm_backlight_device);



	for (i = ARRAY_SIZE(ibms) - 1; i >= 0; i--)

		ibm_exit(&ibms[i]);
@@ -2034,6 +2073,14 @@ static int __init acpi_ibm_init(void) 
		}

	}



	ibm_backlight_device = backlight_device_register("ibm", NULL,

							 &ibm_backlight_data);

        if (IS_ERR(ibm_backlight_device)) {

		printk(IBM_ERR "Could not register ibm backlight device\n");

		ibm_backlight_device = NULL;

		acpi_ibm_exit();

	}



	return 0;

}