firmware/target/arm/imx233/adc-imx233.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2011 by Amaury Pouly
  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
  22 #include "adc-imx233.h"
  23
  24 void adc_init(void)
  25 {
  26 }
  27
  28 static short adc_read_physical_ex(int virt)
  29 {
  30     imx233_lradc_clear_channel(virt);
  31     imx233_lradc_kick_channel(virt);
  32     imx233_lradc_wait_channel(virt);
  33     return imx233_lradc_read_channel(virt);
  34 }
  35
  36 static short adc_read_physical(int src, bool div2)
  37 {
  38     int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  39     // divide by two for wider ranger
  40     imx233_lradc_setup_channel(virt, div2, false, 0, src);
  41     int val = adc_read_physical_ex(virt);
  42     imx233_lradc_release_channel(virt);
  43     return val;
  44 }
  45
  46 static short adc_read_virtual(int c)
  47 {
  48     switch(c)
  49     {
  50         case IMX233_ADC_BATTERY:
  51             return imx233_lradc_read_battery_voltage();
  52         case IMX233_ADC_VDDIO:
  53             /* VddIO pin has a builtin 2:1 divide */
  54             return adc_read_physical(HW_LRADC_CHANNEL_VDDIO, false);
  55         case IMX233_ADC_VDD5V:
  56             /* Vdd5V pin has a builtin 4:1 divide */
  57             return adc_read_physical(HW_LRADC_CHANNEL_5V, false) * 2;
  58         case IMX233_ADC_DIE_TEMP:
  59         {
  60             // don't block on second channel otherwise we might deadlock !
  61             int nmos_chan = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  62             int pmos_chan = imx233_lradc_acquire_channel(TIMEOUT_NOBLOCK);
  63             int val = 0;
  64             if(pmos_chan >= 0)
  65             {
  66                 val = imx233_lradc_sense_die_temperature(nmos_chan, pmos_chan) - 273;
  67                 imx233_lradc_release_channel(pmos_chan);
  68             }
  69             imx233_lradc_release_channel(nmos_chan);
  70             return val;
  71         }
  72 #ifdef IMX233_BATT_TEMP_SENSOR
  73         case IMX233_ADC_BATT_TEMP:
  74         {
  75             int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  76             int val = imx233_lradc_sense_ext_temperature(virt, IMX233_BATT_TEMP_SENSOR);
  77             imx233_lradc_release_channel(virt);
  78             return val;
  79         }
  80 #endif
  81         default:
  82             return 0;
  83     }
  84 }
  85
  86 unsigned short adc_read(int channel)
  87 {
  88     int c = imx233_adc_mapping[channel];
  89     if(c < 0)
  90         return adc_read_virtual(c);
  91     else
  92         return adc_read_physical(c, true);
  93 }