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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         (void) debounce;
  59         return cur;
  60 #endif
  61 }
  62
  63 static uint16_t
  64 ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b, struct ao_debounce debounce_state[2]) {
  65         uint16_t        v = ~stm_gpio_get_all(gpio);
  66         uint8_t         a = (v >> pin_a) & 1;
  67         uint8_t         b = (v >> pin_b) & 1;
  68
  69         a = ao_debounce(a, &debounce_state[0]);
  70         b = ao_debounce(b, &debounce_state[1]);
  71
  72         return a | (b << 1);
  73 }
  74
  75 #define _ao_quadrature_get(q)   ao_quadrature_read(port(q), bita(q), bitb(q), ao_debounce_state[q])
  76
  77 static void
  78 _ao_quadrature_queue(uint8_t q, int8_t step)
  79 {
  80         ao_quadrature_count[q] += step;
  81 #if AO_EVENT
  82         ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
  83 #endif
  84         ao_wakeup(&ao_quadrature_count[q]);
  85 }
  86
  87 #if AO_QUADRATURE_SINGLE_CODE
  88 struct ao_quadrature_step {
  89         uint8_t inc;
  90         uint8_t dec;
  91 };
  92
  93 static struct ao_quadrature_step ao_quadrature_steps[4] = {
  94         [0] = { .inc = 1, .dec = 2 },
  95         [1] = { .inc = 3, .dec = 0 },
  96         [3] = { .inc = 2, .dec = 1 },
  97         [2] = { .inc = 0, .dec = 3 },
  98 };
  99 #endif
 100
 101 static void
 102 _ao_quadrature_set(uint8_t q, uint8_t new) {
 103         uint8_t old = ao_quadrature_state[q];
 104
 105 #ifdef AO_QUADRATURE_SINGLE_CODE
 106         if (new == ao_quadrature_steps[old].inc) {
 107                 _ao_quadrature_queue(q, 1);
 108         } else if (new == ao_quadrature_steps[old].dec) {
 109                 _ao_quadrature_queue(q, -1);
 110         }
 111 #else
 112         if (old != new && new == 0) {
 113                 if (old == 2)
 114                         _ao_quadrature_queue(q, 1);
 115                 else if (old == 1)
 116                         _ao_quadrature_queue(q, -1);
 117         }
 118 #endif
 119         ao_quadrature_state[q] = new;
 120 }
 121
 122 static void
 123 ao_quadrature_isr(void)
 124 {
 125 #if AO_QUADRATURE_COUNT > 0
 126         _ao_quadrature_set(0, _ao_quadrature_get(0));
 127 #endif
 128 #if AO_QUADRATURE_COUNT > 1
 129         _ao_quadrature_set(1, _ao_quadrature_get(1));
 130 #endif
 131 }
 132
 133 int32_t
 134 ao_quadrature_poll(uint8_t q)
 135 {
 136         int32_t ret;
 137         ao_arch_critical(ret = ao_quadrature_count[q];);
 138         return ret;
 139 }
 140
 141 int32_t
 142 ao_quadrature_wait(uint8_t q)
 143 {
 144         ao_sleep(&ao_quadrature_count[q]);
 145         return ao_quadrature_poll(q);
 146 }
 147
 148 static void
 149 ao_quadrature_test(void)
 150 {
 151         uint8_t q;
 152         int32_t c;
 153         uint8_t s;
 154
 155         ao_cmd_decimal();
 156         q = ao_cmd_lex_i;
 157         if (q >= AO_QUADRATURE_COUNT) {
 158                 ao_cmd_status = ao_cmd_syntax_error;
 159                 return;
 160         }
 161
 162         c = -10000;
 163         s = 0;
 164         while (ao_quadrature_count[q] != 10) {
 165                 if (ao_quadrature_count[q] != c ||
 166                     ao_quadrature_state[q] != s) {
 167                         c = ao_quadrature_count[q];
 168                         s = ao_quadrature_state[q];
 169                         printf ("count %3d state %2x\n", c, s);
 170                         flush();
 171                 }
 172         }
 173 #if 0
 174         for (;;) {
 175                 int32_t c;
 176                 flush();
 177                 c = ao_quadrature_wait(q);
 178                 printf ("new count %6d\n", c);
 179                 if (c == 100)
 180                         break;
 181         }
 182 #endif
 183 }
 184
 185 static const struct ao_cmds ao_quadrature_cmds[] = {
 186         { ao_quadrature_test,   "q <unit>\0Test quadrature" },
 187         { 0, NULL }
 188 };
 189
 190 #define init(q) do {                                    \
 191                 ao_enable_input(port(q), bita(q), 0);   \
 192                 ao_enable_input(port(q), bitb(q), 0);   \
 193         } while (0)
 194
 195 void
 196 ao_quadrature_init(void)
 197 {
 198 #if AO_QUADRATURE_COUNT > 0
 199         init(0);
 200 #endif
 201 #if AO_QUADRATURE_COUNT > 1
 202         init(1);
 203 #endif
 204         ao_fast_timer_init();
 205         ao_fast_timer_on(ao_quadrature_isr);
 206         ao_cmd_register(&ao_quadrature_cmds[0]);
 207 }