firmware/target/arm/powermgmt-ascodec.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2009 by Michael Sevakis
  11  * Copyright (C) 2008 by Bertrik Sikken
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  ****************************************************************************/
  22 #include "config.h"
  23 #include "system.h"
  24 #include "thread.h"
  25 #include "as3514.h"
  26 #include "ascodec.h"
  27 #include "adc.h"
  28 #include "powermgmt.h"
  29 #include "power.h"
  30 #include "usb-target.h"
  31 #include "usb.h"
  32
  33 /*===========================================================================
  34  * These parameters may be defined per target:
  35  *
  36  *   BATT_FULL_VOLTAGE - Upon connect a charge cycle begins if the reading is
  37  *                       lower than this value (millivolts).
  38  *
  39  * BATT_VAUTO_RECHARGE - While left plugged after cycle completion, the
  40  *                       charger restarts automatically if the reading drops
  41  *                       below this value (millivolts). Must be less than
  42  *                       BATT_FULL_VOLTAGE.
  43  *
  44  *         ADC_BATTERY - ADC channel from which to read the battery voltage
  45  *
  46  *          BATT_CHG_V - Charger voltage regulation setting (as3514 regval)
  47  *
  48  *          BATT_CHG_I - Charger current regulation setting (as3514 regval)
  49  *
  50  * CHARGER_TOTAL_TIMER - Maximum allowed charging time (1/2-second steps)
  51  *===========================================================================
  52  */
  53
  54 /* This code assumes USB power input is not distinguishable from main
  55  * power and charger connect cannot wait for USB configuration before
  56  * considering USB charging available. Where they are distinguishable,
  57  * things get more complicated. */
  58 static bool charger_close = false;  /* Shutting down? */
  59 static int charger_total_timer = 0; /* Timeout in algorithm steps */
  60
  61 /* Current battery threshold for (re)charge:
  62  * First plugged = BATT_FULL_VOLTAGE
  63  * After charge cycle or non-start = BATT_VAUTO_RECHARGE
  64  */
  65 static unsigned int batt_threshold = 0;
  66
  67 /* ADC should read 0x3ff=5.12V */
  68 /* full-scale ADC readout (2^10) in millivolt */
  69
  70 /* Returns battery voltage from ADC [millivolts] */
  71 unsigned int battery_adc_voltage(void)
  72 {
  73     return (adc_read(ADC_BATTERY) * 5125 + 512) >> 10;
  74 }
  75
  76 /* Returns true if the unit is charging the batteries. */
  77 bool charging_state(void)
  78 {
  79     return charge_state == CHARGING;
  80 }
  81
  82 /* Reset the battery filter to a new voltage */
  83 static void battery_voltage_sync(void)
  84 {
  85     int i;
  86     unsigned int mv;
  87
  88     for (i = 0, mv = 0; i < 5; i++)
  89         mv += battery_adc_voltage();
  90
  91     reset_battery_filter(mv / 5);
  92 }
  93
  94 /* Disable charger and minimize all settings. Reset timers, etc. */
  95 static void disable_charger(void)
  96 {
  97     ascodec_write(AS3514_IRQ_ENRD0, 0);
  98     ascodec_write(AS3514_CHARGER,
  99                   TMPSUP_OFF | CHG_I_50MA | CHG_V_3_90V | CHG_OFF);
 100
 101     if (charge_state > DISCHARGING)
 102         charge_state = DISCHARGING; /* Not an error state already */
 103
 104     charger_total_timer = 0;
 105     battery_voltage_sync();
 106 }
 107
 108 /* Enable charger with specified settings. Start timers, etc. */
 109 static void enable_charger(void)
 110 {
 111     ascodec_write(AS3514_CHARGER, BATT_CHG_I | BATT_CHG_V);
 112     /* Watch for end of charge. Temperature supervision is handled in
 113      * hardware. Charger status can be read and has no interrupt enable. */
 114     ascodec_write(AS3514_IRQ_ENRD0, CHG_ENDOFCH);
 115
 116     sleep(HZ/10); /* Allow charger turn-on time (it could be gradual). */
 117
 118     ascodec_read(AS3514_IRQ_ENRD0); /* Clear out interrupts (important!) */
 119
 120     charge_state = CHARGING;
 121     charger_total_timer = CHARGER_TOTAL_TIMER;
 122     battery_voltage_sync();
 123 }
 124
 125 void powermgmt_init_target(void)
 126 {
 127     /* Everything CHARGER, OFF! */
 128     ascodec_write(AS3514_IRQ_ENRD0, 0);
 129     ascodec_write(AS3514_CHARGER,
 130                   TMPSUP_OFF | CHG_I_50MA | CHG_V_3_90V | CHG_OFF);
 131 }
 132
 133 static inline void charger_plugged(void)
 134 {
 135     batt_threshold = BATT_FULL_VOLTAGE; /* Start with topped value. */
 136     battery_voltage_sync();
 137 }
 138
 139 static inline void charger_control(void)
 140 {
 141     switch (charge_state)
 142     {
 143     case DISCHARGING:
 144     {
 145         unsigned int millivolts;
 146         unsigned int thresh = batt_threshold;
 147
 148         if (BATT_FULL_VOLTAGE == thresh)
 149         {
 150             /* Wait for CHG_status to be indicated. */
 151             if ((ascodec_read(AS3514_IRQ_ENRD0) & CHG_STATUS) == 0)
 152                 break;
 153
 154             batt_threshold = BATT_VAUTO_RECHARGE;
 155         }
 156
 157         millivolts = battery_voltage();
 158
 159         if (millivolts <= thresh)
 160             enable_charger();
 161         break;
 162         } /* DISCHARGING: */
 163
 164     case CHARGING:
 165     {
 166         if ((ascodec_read(AS3514_IRQ_ENRD0) & CHG_ENDOFCH) == 0)
 167         {
 168             if (--charger_total_timer > 0)
 169                 break;
 170
 171             /* Timer ran out - require replug. */
 172             charge_state = CHARGE_STATE_ERROR;
 173         }
 174         /* else end of charge */
 175
 176         disable_charger();
 177         break;
 178         } /* CHARGING: */
 179
 180     default:
 181         /* DISABLED, ERROR */
 182         break;
 183     }
 184 }
 185
 186 static inline void charger_unplugged(void)
 187 {
 188     disable_charger();
 189     if (charge_state >= CHARGE_STATE_ERROR)
 190         charge_state = DISCHARGING; /* Reset error */
 191 }
 192
 193 /* Main charging algorithm - called from powermgmt.c */
 194 void charging_algorithm_step(void)
 195 {
 196     switch (charger_input_state)
 197     {
 198     case NO_CHARGER:
 199         /* Nothing to do */
 200         break;
 201
 202     case CHARGER_PLUGGED:
 203         charger_plugged();
 204         break;
 205
 206     case CHARGER:
 207         charger_control();
 208         break;
 209
 210     case CHARGER_UNPLUGGED:
 211         charger_unplugged();
 212         break;
 213     }
 214
 215     if (charger_close)
 216     {
 217         /* Disable further charging and ack. */
 218         charge_state = CHARGE_STATE_DISABLED;
 219         disable_charger();
 220         charger_close = false;
 221     }
 222 }
 223
 224 /* Disable the charger and prepare for poweroff - called off-thread so we
 225  * signal the charging thread to prepare to quit. */
 226 void charging_algorithm_close(void)
 227 {
 228     charger_close = true;
 229
 230     /* Power management thread will set it false again. */
 231     while (charger_close)
 232         sleep(HZ/10);
 233 }