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 "config.h"
  23 #include "adc.h"
  24 #include "adc-target.h"
  25 #include "system.h"
  26 #include "adc-imx233.h"
  27
  28 void adc_init(void)
  29 {
  30 }
  31
  32 static short adc_read_physical_ex(int virt)
  33 {
  34     imx233_lradc_clear_channel(virt);
  35     imx233_lradc_kick_channel(virt);
  36     imx233_lradc_wait_channel(virt);
  37     return imx233_lradc_read_channel(virt);
  38 }
  39
  40 static short adc_read_physical(int src, bool div2)
  41 {
  42     int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  43     // divide by two for wider ranger
  44     imx233_lradc_setup_channel(virt, div2, false, 0, src);
  45     int val = adc_read_physical_ex(virt);
  46     imx233_lradc_release_channel(virt);
  47     return val;
  48 }
  49
  50 static short adc_read_virtual(int c)
  51 {
  52     switch(c)
  53     {
  54         case IMX233_ADC_BATTERY:
  55             return imx233_lradc_read_battery_voltage();
  56         case IMX233_ADC_VDDIO:
  57             /* VddIO pin has a builtin 2:1 divide */
  58             return adc_read_physical(HW_LRADC_CHANNEL_VDDIO, false);
  59         case IMX233_ADC_VDD5V:
  60             /* Vdd5V pin has a builtin 4:1 divide */
  61             return adc_read_physical(HW_LRADC_CHANNEL_5V, false) * 2;
  62         case IMX233_ADC_DIE_TEMP:
  63         {
  64             // don't block on second channel otherwise we might deadlock !
  65             int nmos_chan = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  66             int pmos_chan = imx233_lradc_acquire_channel(TIMEOUT_NOBLOCK);
  67             int val = 0;
  68             if(pmos_chan >= 0)
  69             {
  70                 val = imx233_lradc_sense_die_temperature(nmos_chan, pmos_chan) - 273;
  71                 imx233_lradc_release_channel(pmos_chan);
  72             }
  73             imx233_lradc_release_channel(nmos_chan);
  74             return val;
  75         }
  76 #ifdef IMX233_ADC_BATT_TEMP_SENSOR
  77         case IMX233_ADC_BATT_TEMP:
  78         {
  79             int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  80             int val = imx233_lradc_sense_ext_temperature(virt, IMX233_ADC_BATT_TEMP_SENSOR);
  81             imx233_lradc_release_channel(virt);
  82             return val;
  83         }
  84 #endif
  85         default:
  86             return 0;
  87     }
  88 }
  89
  90 unsigned short adc_read(int channel)
  91 {
  92     int c = imx233_adc_mapping[channel];
  93     if(c < 0)
  94         return adc_read_virtual(c);
  95     else
  96         return adc_read_physical(c, true);
  97 }