releases/upstream/2.6.20-rc2/0002-ACPI-ibm_acpi-Add-support-for-the-generic-backlight-device.txt

   1 From 8acb025085aa88c41063bfa0f2c3b4d0a3f2ef11 Mon Sep 17 00:00:00 2001
   2 From: Holger Macht <hmacht@suse.de>
   3 Date: Fri, 20 Oct 2006 14:30:28 -0700
   4 Subject: [PATCH 2/28] ACPI: ibm_acpi: Add support for the generic backlight device
   5
   6 Add support for the generic backlight interface below /sys/class/backlight.
   7 The patch keeps the procfs brightness handling for backward compatibility.
   8
   9 Add two generic functions brightness_get and brightness_set
  10 to be used both by the procfs related and the sysfs related methods.
  11
  12 [apw@shadowen.org: backlight users need to select BACKLIGHT_CLASS_DEVICE]
  13
  14 Signed-off-by: Holger Macht <hmacht@suse.de>
  15 Signed-off-by: Andy Whitcroft <apw@shadowen.org>
  16 Signed-off-by: Andrew Morton <akpm@osdl.org>
  17 Signed-off-by: Len Brown <len.brown@intel.com>
  18 ---
  19  drivers/acpi/Kconfig    |    1 +
  20  drivers/acpi/ibm_acpi.c |   75 ++++++++++++++++++++++++++++++++++++++---------
  21  2 files changed, 62 insertions(+), 14 deletions(-)
  22
  23 diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
  24 index 0f9d4be..bc58a3b 100644
  25 --- a/drivers/acpi/Kconfig
  26 +++ b/drivers/acpi/Kconfig
  27 @@ -200,6 +200,7 @@ config ACPI_ASUS
  28  config ACPI_IBM
  29         tristate "IBM ThinkPad Laptop Extras"
  30         depends on X86
  31 +       select BACKLIGHT_CLASS_DEVICE
  32         ---help---
  33           This is a Linux ACPI driver for the IBM ThinkPad laptops. It adds
  34           support for Fn-Fx key combinations, Bluetooth control, video
  35 diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
  36 index 003a987..cd8722e 100644
  37 --- a/drivers/acpi/ibm_acpi.c
  38 +++ b/drivers/acpi/ibm_acpi.c
  39 @@ -78,6 +78,7 @@
  40  #include <linux/init.h>
  41  #include <linux/types.h>
  42  #include <linux/proc_fs.h>
  43 +#include <linux/backlight.h>
  44  #include <asm/uaccess.h>
  45
  46  #include <acpi/acpi_drivers.h>
  47 @@ -243,6 +244,8 @@ struct ibm_struct {
  48
  49  static struct proc_dir_entry *proc_dir = NULL;
  50
  51 +static struct backlight_device *ibm_backlight_device;
  52 +
  53  #define onoff(status,bit) ((status) & (1 << (bit)) ? "on" : "off")
  54  #define enabled(status,bit) ((status) & (1 << (bit)) ? "enabled" : "disabled")
  55  #define strlencmp(a,b) (strncmp((a), (b), strlen(b)))
  56 @@ -1381,12 +1384,22 @@ static int ecdump_write(char *buf)
  57
  58  static int brightness_offset = 0x31;
  59
  60 +static int brightness_get(struct backlight_device *bd)
  61 +{
  62 +       u8 level;
  63 +       if (!acpi_ec_read(brightness_offset, &level))
  64 +               return -EIO;
  65 +
  66 +       level &= 0x7;
  67 +       return level;
  68 +}
  69 +
  70  static int brightness_read(char *p)
  71  {
  72         int len = 0;
  73 -       u8 level;
  74 +       int level;
  75
  76 -       if (!acpi_ec_read(brightness_offset, &level)) {
  77 +       if ((level = brightness_get(NULL)) < 0) {
  78                 len += sprintf(p + len, "level:\t\tunreadable\n");
  79         } else {
  80                 len += sprintf(p + len, "level:\t\t%d\n", level & 0x7);
  81 @@ -1401,16 +1414,34 @@ static int brightness_read(char *p)
  82  #define BRIGHTNESS_UP  4
  83  #define BRIGHTNESS_DOWN        5
  84
  85 -static int brightness_write(char *buf)
  86 +static int brightness_set(int value)
  87  {
  88         int cmos_cmd, inc, i;
  89 -       u8 level;
  90 +       int current_value = brightness_get(NULL);
  91 +
  92 +       value &= 7;
  93 +
  94 +       cmos_cmd = value > current_value ? BRIGHTNESS_UP : BRIGHTNESS_DOWN;
  95 +       inc = value > current_value ? 1 : -1;
  96 +       for (i = current_value; i != value; i += inc) {
  97 +               if (!cmos_eval(cmos_cmd))
  98 +                       return -EIO;
  99 +               if (!acpi_ec_write(brightness_offset, i + inc))
 100 +                       return -EIO;
 101 +       }
 102 +
 103 +       return 0;
 104 +}
 105 +
 106 +static int brightness_write(char *buf)
 107 +{
 108 +       int level;
 109         int new_level;
 110         char *cmd;
 111
 112         while ((cmd = next_cmd(&buf))) {
 113 -               if (!acpi_ec_read(brightness_offset, &level))
 114 -                       return -EIO;
 115 +               if ((level = brightness_get(NULL)) < 0)
 116 +                       return level;
 117                 level &= 7;
 118
 119                 if (strlencmp(cmd, "up") == 0) {
 120 @@ -1423,19 +1454,17 @@ static int brightness_write(char *buf)
 121                 } else
 122                         return -EINVAL;
 123
 124 -               cmos_cmd = new_level > level ? BRIGHTNESS_UP : BRIGHTNESS_DOWN;
 125 -               inc = new_level > level ? 1 : -1;
 126 -               for (i = level; i != new_level; i += inc) {
 127 -                       if (!cmos_eval(cmos_cmd))
 128 -                               return -EIO;
 129 -                       if (!acpi_ec_write(brightness_offset, i + inc))
 130 -                               return -EIO;
 131 -               }
 132 +               brightness_set(new_level);
 133         }
 134
 135         return 0;
 136  }
 137
 138 +static int brightness_update_status(struct backlight_device *bd)
 139 +{
 140 +       return brightness_set(bd->props->brightness);
 141 +}
 142 +
 143  static int volume_offset = 0x30;
 144
 145  static int volume_read(char *p)
 146 @@ -1963,10 +1992,20 @@ IBM_PARAM(brightness);
 147  IBM_PARAM(volume);
 148  IBM_PARAM(fan);
 149
 150 +static struct backlight_properties ibm_backlight_data = {
 151 +        .owner          = THIS_MODULE,
 152 +        .get_brightness = brightness_get,
 153 +        .update_status  = brightness_update_status,
 154 +        .max_brightness = 7,
 155 +};
 156 +
 157  static void acpi_ibm_exit(void)
 158  {
 159         int i;
 160
 161 +       if (ibm_backlight_device)
 162 +               backlight_device_unregister(ibm_backlight_device);
 163 +
 164         for (i = ARRAY_SIZE(ibms) - 1; i >= 0; i--)
 165                 ibm_exit(&ibms[i]);
 166
 167 @@ -2034,6 +2073,14 @@ static int __init acpi_ibm_init(void)
 168                 }
 169         }
 170
 171 +       ibm_backlight_device = backlight_device_register("ibm", NULL,
 172 +                                                        &ibm_backlight_data);
 173 +        if (IS_ERR(ibm_backlight_device)) {
 174 +               printk(IBM_ERR "Could not register ibm backlight device\n");
 175 +               ibm_backlight_device = NULL;
 176 +               acpi_ibm_exit();
 177 +       }
 178 +
 179         return 0;
 180  }
 181
 182 --
 183 1.4.4.3
 184