firmware/target/arm/imx31/gigabeat-s/backlight-gigabeat-s.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 bool backlight_on_status = true; /* Is on or off? */
  75 static uint32_t backlight_pwm_bits;     /* Final PWM setting for fade-in */
  76
  77 /* Backlight ramping settings */
  78 static uint32_t led_ramp_mask = MC13783_LEDMDRAMPDOWN | MC13783_LEDMDRAMPUP;
  79
  80 bool _backlight_init(void)
  81 {
  82     /* Set default LED register value */
  83     mc13783_write(MC13783_LED_CONTROL0,
  84                   MC13783_LED_CONTROL0_BITS | MC13783_LEDEN);
  85
  86 #ifdef HAVE_BACKLIGHT_BRIGHTNESS
  87     /* Our PWM and I-Level is different than retailos (but same apparent
  88      * brightness), so init to our default. */
  89     _backlight_set_brightness(DEFAULT_BRIGHTNESS_SETTING);
  90 #else
  91     /* Use default PWM */
  92     backlight_pwm_bits = mc13783_read(MC13783_LED_CONTROL2) & MC13783_LEDMDDC;
  93 #endif
  94
  95     return true;
  96 }
  97
  98 void backlight_set_fade_out(bool value)
  99 {
 100     if (value)
 101         led_ramp_mask |= MC13783_LEDMDRAMPDOWN;
 102     else
 103         led_ramp_mask &= ~MC13783_LEDMDRAMPDOWN;
 104 }
 105
 106 void backlight_set_fade_in(bool value)
 107 {
 108     if (value)
 109         led_ramp_mask |= MC13783_LEDMDRAMPUP;
 110     else
 111         led_ramp_mask &= ~MC13783_LEDMDRAMPUP;
 112 }
 113
 114 void _backlight_on(void)
 115 {
 116     static const char regs[2] =
 117     {
 118         MC13783_LED_CONTROL0,
 119         MC13783_LED_CONTROL2
 120     };
 121
 122     uint32_t data[2];
 123
 124 #ifdef HAVE_LCD_ENABLE
 125     lcd_enable(true);
 126 #endif
 127
 128     /* Set/clear LEDRAMPUP bit, clear LEDRAMPDOWN bit,
 129      * Ensure LED supply is on. */
 130     data[0] = MC13783_LED_CONTROL0_BITS | MC13783_LEDEN;
 131
 132     if (!backlight_on_status)
 133         data[0] |= led_ramp_mask & MC13783_LEDMDRAMPUP;
 134
 135     backlight_on_status = true;
 136
 137     /* Specify final PWM setting */
 138     data[1] = mc13783_read(MC13783_LED_CONTROL2);
 139
 140     if (data[1] != MC13783_DATA_ERROR)
 141     {
 142         data[1] &= ~MC13783_LEDMDDC;
 143         data[1] |= backlight_pwm_bits;
 144
 145         /* Write regs within 30us of each other (requires single xfer) */
 146         mc13783_write_regs(regs, data, 2);
 147     }
 148 }
 149
 150 void _backlight_off(void)
 151 {
 152     uint32_t ctrl0 = MC13783_LED_CONTROL0_BITS | MC13783_LEDEN;
 153
 154     if (backlight_on_status)
 155         ctrl0 |= led_ramp_mask & MC13783_LEDMDRAMPDOWN;
 156
 157     backlight_on_status = false;
 158
 159     /* Set/clear LEDRAMPDOWN bit, clear LEDRAMPUP bit */
 160     mc13783_write(MC13783_LED_CONTROL0, ctrl0);
 161
 162     /* Wait 100us - 500ms */
 163     sleep(HZ/100);
 164
 165     /* Write final PWM setting */
 166     mc13783_write_masked(MC13783_LED_CONTROL2,
 167                          0 << MC13783_LEDMDDC_POS,
 168                          MC13783_LEDMDDC);
 169 }
 170
 171 #ifdef HAVE_BACKLIGHT_BRIGHTNESS
 172 /* Assumes that the backlight has been initialized - parameter should
 173  * already be range-checked in public interface. */
 174 void _backlight_set_brightness(int brightness)
 175 {
 176     uint32_t md = led_md_pwm_table[brightness].md;
 177     backlight_pwm_bits = backlight_on_status ?
 178         (led_md_pwm_table[brightness].pwm << MC13783_LEDMDDC_POS) : 0;
 179
 180     mc13783_write_masked(MC13783_LED_CONTROL2,
 181                          (md << MC13783_LEDMD_POS) | backlight_pwm_bits,
 182                          MC13783_LEDMD | MC13783_LEDMDDC);
 183 }
 184 #endif /* HAVE_BACKLIGHT_BRIGHTNESS */
 185
 186 #ifdef HAVE_LCD_SLEEP
 187 /* Turn off LED supply */
 188 void _backlight_lcd_sleep(void)
 189 {
 190     mc13783_clear(MC13783_LED_CONTROL0, MC13783_LEDEN);
 191 }
 192 #endif