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 /* dedicate two channels to temperature sensing
  29  * dedicate channel 7 to battery
  30  * and channel 6 to vddio */
  31 static int pmos_chan, nmos_chan;
  32 static int battery_chan, vddio_chan;
  33
  34 void adc_init(void)
  35 {
  36     imx233_lradc_init();
  37     battery_chan = 7;
  38     imx233_lradc_reserve_channel(7);
  39     vddio_chan = 6;
  40     imx233_lradc_reserve_channel(6);
  41
  42     pmos_chan = imx233_lradc_acquire_channel(0);
  43     if(pmos_chan < 0) panicf("No LRADC channel for PMOS !");
  44     nmos_chan = imx233_lradc_acquire_channel(0);
  45     if(nmos_chan < 0) panicf("No LRADC channel for NMOS !");
  46
  47     // setup them
  48     imx233_lradc_setup_channel(battery_chan, false, false, 0, HW_LRADC_CHANNEL_BATTERY);
  49     imx233_lradc_setup_channel(vddio_chan, false, false, 0, HW_LRADC_CHANNEL_VDDIO);
  50     imx233_lradc_setup_channel(nmos_chan, false, false, 0, HW_LRADC_CHANNEL_NMOS_THIN);
  51     imx233_lradc_setup_channel(pmos_chan, false, false, 0, HW_LRADC_CHANNEL_PMOS_THIN);
  52 }
  53
  54 int adc_read_physical_ex(int virt)
  55 {
  56     imx233_lradc_clear_channel(virt);
  57     imx233_lradc_kick_channel(virt);
  58     imx233_lradc_wait_channel(virt);
  59     int v = imx233_lradc_read_channel(virt);
  60     return v;
  61 }
  62
  63 int adc_read_physical(int src)
  64 {
  65     int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
  66     // divide by two for wider ranger
  67     imx233_lradc_setup_channel(virt, false, false, 0, src);
  68     int val = adc_read_physical_ex(virt);
  69     imx233_lradc_release_channel(virt);
  70     return val;
  71 }
  72
  73 unsigned short adc_read_virtual(int c)
  74 {
  75     switch(c)
  76     {
  77         case IMX233_ADC_BATTERY:
  78             return adc_read_physical_ex(battery_chan);
  79         case IMX233_ADC_VDDIO:
  80             return adc_read_physical_ex(vddio_chan);
  81         case IMX233_ADC_DIE_TEMP:
  82             // do kelvin to celsius conversion
  83             return imx233_lradc_sense_die_temperature(nmos_chan, pmos_chan) - 273;
  84         default:
  85             return 0;
  86     }
  87 }
  88
  89 unsigned short adc_read(int channel)
  90 {
  91     int c = imx233_adc_mapping[channel];
  92     if(c < 0)
  93         return adc_read_virtual(c);
  94     else
  95         return adc_read_physical(c);
  96 }