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