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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 #ifndef AO_QUADRATURE_DEBOUNCE
  43 #define AO_QUADRATURE_DEBOUNCE  30
  44 #endif
  45
  46 static uint8_t
  47 ao_debounce(uint8_t cur, struct ao_debounce *debounce)
  48 {
  49 #if AO_QUADRATURE_DEBOUNCE > 0
  50         if (debounce->count > 0) {
  51                 debounce->count--;
  52         } else if (cur != debounce->state) {
  53                 debounce->state = cur;
  54                 debounce->count = AO_QUADRATURE_DEBOUNCE;
  55         }
  56         return debounce->state;
  57 #else
  58         return cur;
  59 #endif
  60 }
  61
  62 static uint16_t
  63 ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b, struct ao_debounce debounce_state[2]) {
  64         uint16_t        v = ~stm_gpio_get_all(gpio);
  65         uint8_t         a = (v >> pin_a) & 1;
  66         uint8_t         b = (v >> pin_b) & 1;
  67
  68         a = ao_debounce(a, &debounce_state[0]);
  69         b = ao_debounce(b, &debounce_state[1]);
  70
  71         return a | (b << 1);
  72 }
  73
  74 #define _ao_quadrature_get(q)   ao_quadrature_read(port(q), bita(q), bitb(q), ao_debounce_state[q])
  75
  76 static void
  77 _ao_quadrature_queue(uint8_t q, int8_t step)
  78 {
  79         ao_quadrature_count[q] += step;
  80 #if AO_EVENT
  81         ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
  82 #endif
  83         ao_wakeup(&ao_quadrature_count[q]);
  84 }
  85
  86 static void
  87 _ao_quadrature_set(uint8_t q, uint8_t new) {
  88         uint8_t old = ao_quadrature_state[q];
  89
  90         if (old != new && new == 0) {
  91                 if (old == 2)
  92                         _ao_quadrature_queue(q, 1);
  93                 else if (old == 1)
  94                         _ao_quadrature_queue(q, -1);
  95         }
  96         ao_quadrature_state[q] = new;
  97 }
  98
  99 static void
 100 ao_quadrature_isr(void)
 101 {
 102 #if AO_QUADRATURE_COUNT > 0
 103         _ao_quadrature_set(0, _ao_quadrature_get(0));
 104 #endif
 105 #if AO_QUADRATURE_COUNT > 1
 106         _ao_quadrature_set(1, _ao_quadrature_get(1));
 107 #endif
 108 }
 109
 110 int32_t
 111 ao_quadrature_poll(uint8_t q)
 112 {
 113         int32_t ret;
 114         ao_arch_critical(ret = ao_quadrature_count[q];);
 115         return ret;
 116 }
 117
 118 int32_t
 119 ao_quadrature_wait(uint8_t q)
 120 {
 121         ao_sleep(&ao_quadrature_count[q]);
 122         return ao_quadrature_poll(q);
 123 }
 124
 125 static void
 126 ao_quadrature_test(void)
 127 {
 128         uint8_t q;
 129         int32_t c;
 130         uint8_t s;
 131
 132         ao_cmd_decimal();
 133         q = ao_cmd_lex_i;
 134         if (q >= AO_QUADRATURE_COUNT) {
 135                 ao_cmd_status = ao_cmd_syntax_error;
 136                 return;
 137         }
 138
 139         c = -10000;
 140         s = 0;
 141         while (ao_quadrature_count[q] != 10) {
 142                 if (ao_quadrature_count[q] != c ||
 143                     ao_quadrature_state[q] != s) {
 144                         c = ao_quadrature_count[q];
 145                         s = ao_quadrature_state[q];
 146                         printf ("count %3d state %2x\n", c, s);
 147                         flush();
 148                 }
 149         }
 150 #if 0
 151         for (;;) {
 152                 int32_t c;
 153                 flush();
 154                 c = ao_quadrature_wait(q);
 155                 printf ("new count %6d\n", c);
 156                 if (c == 100)
 157                         break;
 158         }
 159 #endif
 160 }
 161
 162 static const struct ao_cmds ao_quadrature_cmds[] = {
 163         { ao_quadrature_test,   "q <unit>\0Test quadrature" },
 164         { 0, NULL }
 165 };
 166
 167 #define init(q) do {                                    \
 168                 ao_enable_input(port(q), bita(q), 0);   \
 169                 ao_enable_input(port(q), bitb(q), 0);   \
 170         } while (0)
 171
 172 void
 173 ao_quadrature_init(void)
 174 {
 175 #if AO_QUADRATURE_COUNT > 0
 176         init(0);
 177 #endif
 178 #if AO_QUADRATURE_COUNT > 1
 179         init(1);
 180 #endif
 181         ao_fast_timer_init();
 182         ao_fast_timer_on(ao_quadrature_isr);
 183         ao_cmd_register(&ao_quadrature_cmds[0]);
 184 }