target/linux/s3c24xx/patches-2.6.24/1295-This-patch-adds-a-framebuffer-notifier-in-order-to-d.patch

   1 From 9aa87d67df2e59eea15f70c4e58f8bde10e5953b Mon Sep 17 00:00:00 2001
   2 From: Harald Welte <laforge@openmoko.org>
   3 Date: Wed, 8 Oct 2008 11:13:46 +0100
   4 Subject: [PATCH] This patch adds a framebuffer notifier in order to detect
   5  FB_BLANK events and switch the JBT6K74 LCM controller into
   6  its power saving mode.
   7
   8 This has the potential of saving something like 50mW during screen blank.
   9
  10 Signed-off-by: Harald Welte <laforge@openmoko.org>
  11 ---
  12  drivers/video/display/jbt6k74.c |   48 +++++++++++++++++++++++++++++++++++++++
  13  1 files changed, 48 insertions(+), 0 deletions(-)
  14
  15 diff --git a/drivers/video/display/jbt6k74.c b/drivers/video/display/jbt6k74.c
  16 index b406298..9570543 100644
  17 --- a/drivers/video/display/jbt6k74.c
  18 +++ b/drivers/video/display/jbt6k74.c
  19 @@ -3,6 +3,7 @@
  20   * Copyright (C) 2006-2007 by Openmoko, Inc.
  21   * Author: Harald Welte <laforge@openmoko.org>,
  22   *        Stefan Schmidt <stefan@openmoko.org>
  23 + * Copyright (C) 2008 by Harald Welte <laforge@openmoko.org>
  24   * All rights reserved.
  25   *
  26   * This program is free software; you can redistribute it and/or
  27 @@ -21,6 +22,7 @@
  28   * MA 02111-1307 USA
  29   *
  30   */
  31 +
  32  #include <linux/kernel.h>
  33  #include <linux/types.h>
  34  #include <linux/module.h>
  35 @@ -28,6 +30,7 @@
  36  #include <linux/platform_device.h>
  37  #include <linux/delay.h>
  38  #include <linux/jbt6k74.h>
  39 +#include <linux/fb.h>
  40
  41  enum jbt_register {
  42         JBT_REG_SLEEP_IN                = 0x10,
  43 @@ -111,6 +114,7 @@ struct jbt_info {
  44         enum jbt_state state, last_state;
  45         struct spi_device *spi_dev;
  46         struct mutex lock;              /* protects tx_buf and reg_cache */
  47 +       struct notifier_block fb_notif;
  48         u16 tx_buf[8];
  49         u16 reg_cache[0xEE];
  50         int have_resumed;
  51 @@ -548,6 +552,40 @@ static struct attribute_group jbt_attr_group = {
  52         .attrs  = jbt_sysfs_entries,
  53  };
  54
  55 +static int fb_notifier_callback(struct notifier_block *self,
  56 +                               unsigned long event, void *data)
  57 +{
  58 +       struct jbt_info *jbt;
  59 +       struct fb_event *evdata = data;
  60 +       int fb_blank;
  61 +
  62 +       if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
  63 +               return 0;
  64 +
  65 +       fb_blank = *(int *)evdata->data;
  66 +       jbt = container_of(self, struct jbt_info, fb_notif);
  67 +
  68 +       switch (fb_blank) {
  69 +       case FB_BLANK_UNBLANK:
  70 +       case FB_BLANK_NORMAL:
  71 +               jbt6k74_enter_state(jbt, JBT_STATE_NORMAL);
  72 +               jbt6k74_display_onoff(jbt, 1);
  73 +               break;
  74 +       case FB_BLANK_VSYNC_SUSPEND:
  75 +       case FB_BLANK_HSYNC_SUSPEND:
  76 +               /* FIXME: we disable SLEEP since it would result in
  77 +                * a visible artefact (white screen) before the backlight
  78 +                * is dimmed to a dark enough level */
  79 +               /* jbt6k74_enter_state(jbt, JBT_STATE_SLEEP); */
  80 +               break;
  81 +       case FB_BLANK_POWERDOWN:
  82 +               jbt6k74_enter_state(jbt, JBT_STATE_DEEP_STANDBY);
  83 +               break;
  84 +       }
  85 +
  86 +       return 0;
  87 +}
  88 +
  89  /* linux device model infrastructure */
  90
  91  static int __devinit jbt_probe(struct spi_device *spi)
  92 @@ -595,8 +633,17 @@ static int __devinit jbt_probe(struct spi_device *spi)
  93                 goto err_off;
  94         }
  95
  96 +       jbt->fb_notif.notifier_call = fb_notifier_callback;
  97 +       rc = fb_register_client(&jbt->fb_notif);
  98 +       if (rc < 0) {
  99 +               dev_err(&spi->dev, "cannot register notifier\n");
 100 +               goto err_sysfs;
 101 +       }
 102 +
 103         return 0;
 104
 105 +err_sysfs:
 106 +       sysfs_remove_group(&spi->dev.kobj, &jbt_attr_group);
 107  err_off:
 108         jbt6k74_display_onoff(jbt, 0);
 109  err_standby:
 110 @@ -615,6 +662,7 @@ static int __devexit jbt_remove(struct spi_device *spi)
 111         /* We don't want to switch off the display in case the user
 112          * accidentially onloads the module (whose use count normally is 0) */
 113
 114 +       fb_unregister_client(&jbt->fb_notif);
 115         sysfs_remove_group(&spi->dev.kobj, &jbt_attr_group);
 116         dev_set_drvdata(&spi->dev, NULL);
 117         kfree(jbt);
 118 --
 119 1.5.6.5
 120