firmware/target/arm/imx31/gigabeat-s/backlight-imx31.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 by Linus Nielsen Feltzing
  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 "config.h"
  22 #include "system.h"
  23 #include "backlight.h"
  24 #include "mc13783.h"
  25 #include "backlight-target.h"
  26 #include "lcd.h"
  27
  28 #ifdef HAVE_BACKLIGHT_BRIGHTNESS
  29 /* Table that uses combinations of current level and pwm fraction to get
  30  * as many uniquely-visible brightness levels as possible. The lowest current
  31  * level for any average current is used even though many combinations give
  32  * duplicate values. Current (I) values are in mA. */
  33 static const struct
  34 {
  35     unsigned char md;
  36     unsigned char pwm;
  37 } led_md_pwm_table[] =
  38 {
  39                /* I-level PWM(x/15) I-Avg */
  40     { 0,  0 }, /*    0        0      0.0  */
  41     { 1,  1 }, /*    3        1      0.2  */
  42     { 1,  2 }, /*    3        2      0.4  */
  43     { 1,  3 }, /*    3        3      0.6  */
  44     { 1,  4 }, /*    3        4      0.8  */
  45     { 1,  5 }, /*    3        5      1.0  */
  46     { 1,  6 }, /*    3        6      1.2  */
  47     { 1,  7 }, /*    3        7      1.4  */
  48     { 1,  8 }, /*    3        8      1.6  */
  49     { 1,  9 }, /*    3        9      1.8  */
  50     { 1, 10 }, /*    3       10      2.0  */
  51     { 1, 11 }, /*    3       11      2.2  */
  52     { 1, 12 }, /*    3       12      2.4  */ /* default */
  53     { 1, 13 }, /*    3       13      2.6  */
  54     { 1, 14 }, /*    3       14      2.8  */
  55     { 1, 15 }, /*    3       15      3.0  */
  56     { 2,  9 }, /*    6        9      3.6  */
  57     { 2, 10 }, /*    6       10      4.0  */
  58     { 2, 11 }, /*    6       11      4.4  */
  59     { 2, 12 }, /*    6       12      4.8  */
  60     { 2, 13 }, /*    6       13      5.2  */
  61     { 2, 14 }, /*    6       14      5.6  */
  62     { 2, 15 }, /*    6       15      6.0  */
  63     { 3, 11 }, /*    9       11      6.6  */
  64     { 3, 12 }, /*    9       12      7.2  */
  65     /* Anything higher is just too much   */
  66 };
  67 #endif /* HAVE_BACKLIGHT_BRIGHTNESS */
  68
  69 /* Bits always combined with ramping bits */
  70 #define MC13783_LED_CONTROL0_BITS \
  71     (MC13783_BOOSTEN | MC13783_ABMODE_MONCH_LEDMD1234 | \
  72      MC13783_ABREF_400MV)
  73
  74 static struct mutex backlight_mutex;    /* Block brightness change while
  75                                          * setting up fading */
  76 static bool backlight_on_status = true; /* Is on or off? */
  77 static uint32_t backlight_pwm_bits;     /* Final PWM setting for fade-in */
  78
  79 /* Backlight ramping settings */
  80 static uint32_t led_ramp_mask = MC13783_LEDMDRAMPDOWN | MC13783_LEDMDRAMPUP;
  81
  82 bool _backlight_init(void)
  83 {
  84     mutex_init(&backlight_mutex);
  85
  86     /* Set default LED register value */
  87     mc13783_write(MC13783_LED_CONTROL0,
  88                   MC13783_LED_CONTROL0_BITS | MC13783_LEDEN);
  89
  90 #ifdef HAVE_BACKLIGHT_BRIGHTNESS
  91     /* Our PWM and I-Level is different than retailos (but same apparent
  92      * brightness), so init to our default. */
  93     _backlight_set_brightness(DEFAULT_BRIGHTNESS_SETTING);
  94 #else
  95     /* Use default PWM */
  96     backlight_pwm_bits = mc13783_read(MC13783_LED_CONTROL2) & MC13783_LEDMDDC;
  97 #endif
  98
  99     return true;
 100 }
 101
 102 void backlight_set_fade_out(bool value)
 103 {
 104     if (value)
 105         led_ramp_mask |= MC13783_LEDMDRAMPDOWN;
 106     else
 107         led_ramp_mask &= ~MC13783_LEDMDRAMPDOWN;
 108 }
 109
 110 void backlight_set_fade_in(bool value)
 111 {
 112     if (value)
 113         led_ramp_mask |= MC13783_LEDMDRAMPUP;
 114     else
 115         led_ramp_mask &= ~MC13783_LEDMDRAMPUP;
 116 }
 117
 118 void _backlight_on(void)
 119 {
 120     static const char regs[2] =
 121     {
 122         MC13783_LED_CONTROL0,
 123         MC13783_LED_CONTROL2
 124     };
 125
 126     uint32_t data[2];
 127
 128     mutex_lock(&backlight_mutex);
 129
 130 #ifdef HAVE_LCD_SLEEP
 131     backlight_lcd_sleep_countdown(false); /* stop counter */
 132 #endif
 133 #ifdef HAVE_LCD_ENABLE
 134     lcd_enable(true);
 135 #endif
 136
 137     /* Set/clear LEDRAMPUP bit, clear LEDRAMPDOWN bit,
 138      * Ensure LED supply is on. */
 139     data[0] = MC13783_LED_CONTROL0_BITS | MC13783_LEDEN;
 140
 141     if (!backlight_on_status)
 142         data[0] |= led_ramp_mask & MC13783_LEDMDRAMPUP;
 143
 144     backlight_on_status = true;
 145
 146     /* Specify final PWM setting */
 147     data[1] = mc13783_read(MC13783_LED_CONTROL2);
 148
 149     if (data[1] != MC13783_DATA_ERROR)
 150     {
 151         data[1] &= ~MC13783_LEDMDDC;
 152         data[1] |= backlight_pwm_bits;
 153
 154         /* Write regs within 30us of each other (requires single xfer) */
 155         mc13783_write_regset(regs, data, 2);
 156     }
 157
 158     mutex_unlock(&backlight_mutex);
 159 }
 160
 161 void _backlight_off(void)
 162 {
 163     uint32_t ctrl0 = MC13783_LED_CONTROL0_BITS | MC13783_LEDEN;
 164
 165     mutex_lock(&backlight_mutex);
 166
 167     if (backlight_on_status)
 168         ctrl0 |= led_ramp_mask & MC13783_LEDMDRAMPDOWN;
 169
 170     backlight_on_status = false;
 171
 172     /* Set/clear LEDRAMPDOWN bit, clear LEDRAMPUP bit */
 173     mc13783_write(MC13783_LED_CONTROL0, ctrl0);
 174
 175     /* Wait 100us - 500ms */
 176     sleep(HZ/100);
 177
 178     /* Write final PWM setting */
 179     mc13783_write_masked(MC13783_LED_CONTROL2, MC13783_LEDMDDCw(0),
 180                          MC13783_LEDMDDC);
 181
 182 #ifdef HAVE_LCD_SLEEP
 183     /* Disable lcd after fade completes (when lcd_sleep timeout expires) */
 184     backlight_lcd_sleep_countdown(true); /* start countdown */
 185 #endif
 186
 187     mutex_unlock(&backlight_mutex);
 188 }
 189
 190 #ifdef HAVE_BACKLIGHT_BRIGHTNESS
 191 /* Assumes that the backlight has been initialized - parameter should
 192  * already be range-checked in public interface. */
 193 void _backlight_set_brightness(int brightness)
 194 {
 195     uint32_t md;
 196
 197     mutex_lock(&backlight_mutex);
 198
 199     md = led_md_pwm_table[brightness].md;
 200     backlight_pwm_bits = backlight_on_status ?
 201         MC13783_LEDMDDCw(led_md_pwm_table[brightness].pwm) : 0;
 202
 203     mc13783_write_masked(MC13783_LED_CONTROL2,
 204                          MC13783_LEDMDw(md) | backlight_pwm_bits,
 205                          MC13783_LEDMD | MC13783_LEDMDDC);
 206
 207     mutex_unlock(&backlight_mutex);
 208 }
 209 #endif /* HAVE_BACKLIGHT_BRIGHTNESS */
 210
 211 #ifdef HAVE_LCD_SLEEP
 212 /* Turn off LED supply */
 213 void _backlight_lcd_sleep(void)
 214 {
 215     mutex_lock(&backlight_mutex);
 216
 217     mc13783_clear(MC13783_LED_CONTROL0, MC13783_LEDEN);
 218
 219     mutex_unlock(&backlight_mutex);
 220 }
 221 #endif