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author | Bertrik Sikken <bertrik@sikken.nl> | 2009-07-29 20:42:02 +0000 |
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committer | Bertrik Sikken <bertrik@sikken.nl> | 2009-07-29 20:42:02 +0000 |
commit | 2fb73842a9b51e554a3a14feb0b4c0814c82ebec (patch) | |
tree | 25a93a7b725a5a2f6fa59929f7952fd8ccd7fcb0 /firmware/target/arm/s5l8700/yps3/backlight-yps3.c | |
parent | e30f1e83c495727d2ecd108c225499c79e467ca8 (diff) | |
download | rockbox-2fb73842a9b51e554a3a14feb0b4c0814c82ebec.tar.gz rockbox-2fb73842a9b51e554a3a14feb0b4c0814c82ebec.zip |
Start of a Rockbox port to the Samsung YP-S3.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22085 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/target/arm/s5l8700/yps3/backlight-yps3.c')
-rw-r--r-- | firmware/target/arm/s5l8700/yps3/backlight-yps3.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/firmware/target/arm/s5l8700/yps3/backlight-yps3.c b/firmware/target/arm/s5l8700/yps3/backlight-yps3.c new file mode 100644 index 0000000000..0a9cf3cc9a --- /dev/null +++ b/firmware/target/arm/s5l8700/yps3/backlight-yps3.c | |||
@@ -0,0 +1,78 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2009 by Bertrik Sikken | ||
11 | * | ||
12 | * This program is free software; you can redistribute it and/or | ||
13 | * modify it under the terms of the GNU General Public License | ||
14 | * as published by the Free Software Foundation; either version 2 | ||
15 | * of the License, or (at your option) any later version. | ||
16 | * | ||
17 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
18 | * KIND, either express or implied. | ||
19 | * | ||
20 | ****************************************************************************/ | ||
21 | #include <stdbool.h> | ||
22 | |||
23 | #include "config.h" | ||
24 | #include "backlight.h" | ||
25 | #include "backlight-target.h" | ||
26 | #include "system.h" | ||
27 | |||
28 | /* | ||
29 | Backlight driver using the PWM mode of a hardware timer. | ||
30 | |||
31 | The PWM duty cycle depends exponentially on the configured brightness | ||
32 | level. This makes the brightness curve more linear to the human eye. | ||
33 | */ | ||
34 | |||
35 | void _backlight_set_brightness(int brightness) | ||
36 | { | ||
37 | /* pwm = (sqrt(2)**x)-1, where brightness level x = 0..16 */ | ||
38 | static const unsigned char logtable[] = | ||
39 | {0, 1, 2, 3, 5, 7, 10, 15, 22, 31, 44, 63, 90, 127, 180, 255}; | ||
40 | |||
41 | /* set PWM width */ | ||
42 | TADATA0 = 255 - logtable[brightness]; | ||
43 | } | ||
44 | |||
45 | void _backlight_on(void) | ||
46 | { | ||
47 | _backlight_set_brightness(backlight_brightness); | ||
48 | } | ||
49 | |||
50 | void _backlight_off(void) | ||
51 | { | ||
52 | _backlight_set_brightness(MIN_BRIGHTNESS_SETTING); | ||
53 | } | ||
54 | |||
55 | bool _backlight_init(void) | ||
56 | { | ||
57 | /* enable backlight pin as timer output */ | ||
58 | PCON0 = ((PCON0 & ~(3 << 0)) | (2 << 0)); | ||
59 | |||
60 | /* enable timer clock */ | ||
61 | PWRCON &= ~(1 << 4); | ||
62 | |||
63 | /* configure timer */ | ||
64 | TACMD = (1 << 1); /* TC_CLR */ | ||
65 | TACON = (0 << 13) | /* TC_INT1_EN */ | ||
66 | (0 << 12) | /* TC_INT0_EN */ | ||
67 | (0 << 11) | /* TC_START */ | ||
68 | (3 << 8) | /* TC_CS = PCLK / 64 */ | ||
69 | (1 << 4); /* TC_MODE_SEL = PWM mode */ | ||
70 | TADATA1 = 255; /* set PWM period */ | ||
71 | TAPRE = 20; /* prescaler */ | ||
72 | TACMD = (1 << 0); /* TC_EN */ | ||
73 | |||
74 | _backlight_on(); | ||
75 | |||
76 | return true; | ||
77 | } | ||
78 | |||