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   1 /*
   2  * Copyright © 2012 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include <ao.h>
  20 #include <ao_quadrature.h>
  21 #include <ao_exti.h>
  22 #include <ao_fast_timer.h>
  23 #include <ao_event.h>
  24
  25 __xdata int32_t ao_quadrature_count[AO_QUADRATURE_COUNT];
  26 static uint8_t  ao_quadrature_state[AO_QUADRATURE_COUNT];
  27
  28 struct ao_debounce {
  29         uint8_t state;
  30         uint8_t count;
  31 };
  32
  33 static struct ao_debounce ao_debounce_state[AO_QUADRATURE_COUNT][2];
  34
  35 #define port(q) AO_QUADRATURE_ ## q ## _PORT
  36 #define bita(q) AO_QUADRATURE_ ## q ## _A
  37 #define bitb(q) AO_QUADRATURE_ ## q ## _B
  38 #define pina(q) AO_QUADRATURE_ ## q ## _A ## _PIN
  39 #define pinb(q) AO_QUADRATURE_ ## q ## _B ## _PIN
  40 #define isr(q)  ao_quadrature_isr_ ## q
  41
  42 #define DEBOUNCE        10
  43
  44 static uint8_t
  45 ao_debounce(uint8_t cur, struct ao_debounce *debounce)
  46 {
  47         if (cur == debounce->state)
  48                 debounce->count = 0;
  49         else {
  50                 if (++debounce->count == DEBOUNCE) {
  51                         debounce->state = cur;
  52                         debounce->count = 0;
  53                 }
  54         }
  55         return debounce->state;
  56 }
  57
  58 static uint16_t
  59 ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b, struct ao_debounce debounce_state[2]) {
  60         uint16_t        v = ~stm_gpio_get_all(gpio);
  61         uint8_t         a = (v >> pin_a) & 1;
  62         uint8_t         b = (v >> pin_b) & 1;
  63
  64         a = ao_debounce(a, &debounce_state[0]);
  65         b = ao_debounce(b, &debounce_state[1]);
  66
  67         return a | (b << 1);
  68 }
  69
  70 #define _ao_quadrature_get(q)   ao_quadrature_read(port(q), bita(q), bitb(q), ao_debounce_state[q])
  71
  72 static void
  73 _ao_quadrature_queue(uint8_t q, int8_t step)
  74 {
  75         ao_quadrature_count[q] += step;
  76 #if AO_EVENT
  77         ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
  78 #endif
  79         ao_wakeup(&ao_quadrature_count[q]);
  80 }
  81
  82 static void
  83 _ao_quadrature_set(uint8_t q, uint8_t new) {
  84         uint8_t old = ao_quadrature_state[q];
  85
  86         if (old != new && new == 0) {
  87                 if (old & 2)
  88                         _ao_quadrature_queue(q, 1);
  89                 else if (old & 1)
  90                         _ao_quadrature_queue(q, -1);
  91         }
  92         ao_quadrature_state[q] = new;
  93 }
  94
  95 static void
  96 ao_quadrature_isr(void)
  97 {
  98 #if AO_QUADRATURE_COUNT > 0
  99         _ao_quadrature_set(0, _ao_quadrature_get(0));
 100 #endif
 101 #if AO_QUADRATURE_COUNT > 1
 102         _ao_quadrature_set(1, _ao_quadrature_get(1));
 103 #endif
 104 }
 105
 106 int32_t
 107 ao_quadrature_poll(uint8_t q)
 108 {
 109         int32_t ret;
 110         ao_arch_critical(ret = ao_quadrature_count[q];);
 111         return ret;
 112 }
 113
 114 int32_t
 115 ao_quadrature_wait(uint8_t q)
 116 {
 117         ao_sleep(&ao_quadrature_count[q]);
 118         return ao_quadrature_poll(q);
 119 }
 120
 121 static void
 122 ao_quadrature_test(void)
 123 {
 124         uint8_t q;
 125         int32_t c;
 126         uint8_t s;
 127
 128         ao_cmd_decimal();
 129         q = ao_cmd_lex_i;
 130         if (q >= AO_QUADRATURE_COUNT) {
 131                 ao_cmd_status = ao_cmd_syntax_error;
 132                 return;
 133         }
 134
 135         c = -10000;
 136         s = 0;
 137         while (ao_quadrature_count[q] != 10) {
 138                 if (ao_quadrature_count[q] != c ||
 139                     ao_quadrature_state[q] != s) {
 140                         c = ao_quadrature_count[q];
 141                         s = ao_quadrature_state[q];
 142                         printf ("count %3d state %2x\n", c, s);
 143                         flush();
 144                 }
 145         }
 146 #if 0
 147         for (;;) {
 148                 int32_t c;
 149                 flush();
 150                 c = ao_quadrature_wait(q);
 151                 printf ("new count %6d\n", c);
 152                 if (c == 100)
 153                         break;
 154         }
 155 #endif
 156 }
 157
 158 static const struct ao_cmds ao_quadrature_cmds[] = {
 159         { ao_quadrature_test,   "q <unit>\0Test quadrature" },
 160         { 0, NULL }
 161 };
 162
 163 #define init(q) do {                                    \
 164                 ao_enable_input(port(q), bita(q), 0);   \
 165                 ao_enable_input(port(q), bitb(q), 0);   \
 166         } while (0)
 167
 168 void
 169 ao_quadrature_init(void)
 170 {
 171 #if AO_QUADRATURE_COUNT > 0
 172         init(0);
 173 #endif
 174 #if AO_QUADRATURE_COUNT > 1
 175         init(1);
 176 #endif
 177         ao_fast_timer_init();
 178         ao_fast_timer_on(ao_quadrature_isr);
 179         ao_cmd_register(&ao_quadrature_cmds[0]);
 180 }