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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 int32_t ao_quadrature_count[AO_QUADRATURE_COUNT];
  26 #ifndef AO_QUADRATURE_SINGLE_CODE
  27 static int8_t ao_quadrature_step[AO_QUADRATURE_COUNT];
  28 #endif
  29
  30 static uint8_t  ao_quadrature_state[AO_QUADRATURE_COUNT];
  31
  32 struct ao_debounce {
  33         uint8_t state;
  34         uint8_t count;
  35 };
  36
  37 static struct ao_debounce ao_debounce_state[AO_QUADRATURE_COUNT][2];
  38
  39 #define port(q) AO_QUADRATURE_ ## q ## _PORT
  40 #define bita(q) AO_QUADRATURE_ ## q ## _A
  41 #define bitb(q) AO_QUADRATURE_ ## q ## _B
  42 #define pina(q) AO_QUADRATURE_ ## q ## _A ## _PIN
  43 #define pinb(q) AO_QUADRATURE_ ## q ## _B ## _PIN
  44 #define isr(q)  ao_quadrature_isr_ ## q
  45
  46 #ifndef AO_QUADRATURE_DEBOUNCE
  47 #error must define AO_QUADRATURE_DEBOUNCE
  48 #endif
  49
  50 static uint8_t
  51 ao_debounce(uint8_t cur, struct ao_debounce *debounce)
  52 {
  53 #if AO_QUADRATURE_DEBOUNCE > 0
  54         if (debounce->count > 0) {
  55                 debounce->count--;
  56         } else if (cur != debounce->state) {
  57                 debounce->state = cur;
  58                 debounce->count = AO_QUADRATURE_DEBOUNCE;
  59         }
  60         return debounce->state;
  61 #else
  62         (void) debounce;
  63         return cur;
  64 #endif
  65 }
  66
  67 static uint16_t
  68 ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b, struct ao_debounce debounce_state[2]) {
  69         uint16_t        v = ~stm_gpio_get_all(gpio);
  70         uint8_t         a = (v >> pin_a) & 1;
  71         uint8_t         b = (v >> pin_b) & 1;
  72
  73         a = ao_debounce(a, &debounce_state[0]);
  74         b = ao_debounce(b, &debounce_state[1]);
  75
  76         return (uint16_t) (a | (b << 1));
  77 }
  78
  79 #define _ao_quadrature_get(q)   ao_quadrature_read(port(q), bita(q), bitb(q), ao_debounce_state[q])
  80
  81 static void
  82 _ao_quadrature_step(uint8_t q, int8_t step)
  83 {
  84 #ifndef AO_QUADRATURE_SINGLE_CODE
  85         ao_quadrature_step[q] += step;
  86         if (ao_quadrature_state[q] != 0)
  87                 return;
  88         if (ao_quadrature_step[q] >= 4) {
  89                 ao_quadrature_step[q] = 0;
  90                 step = 1;
  91         } else if (ao_quadrature_step[q] <= -4) {
  92                 ao_quadrature_step[q] = 0;
  93                 step = -1;
  94         } else
  95                 return;
  96 #endif
  97         ao_quadrature_count[q] += step;
  98 #if AO_EVENT
  99         ao_event_put_isr(AO_EVENT_QUADRATURE, q, step);
 100 #endif
 101         ao_wakeup(&ao_quadrature_count[q]);
 102 }
 103
 104 static const struct {
 105         uint8_t prev, next;
 106 } ao_quadrature_steps[4] = {
 107         [0] { .prev = 2, .next = 1 },
 108         [1] { .prev = 0, .next = 3 },
 109         [3] { .prev = 1, .next = 2 },
 110         [2] { .prev = 3, .next = 0 },
 111 };
 112
 113 static void
 114 _ao_quadrature_set(uint8_t q, uint8_t new)
 115 {
 116         uint8_t old;
 117
 118         ao_arch_block_interrupts();
 119         old = ao_quadrature_state[q];
 120         ao_quadrature_state[q] = new;
 121         ao_arch_release_interrupts();
 122
 123         if (new == ao_quadrature_steps[old].next)
 124                 _ao_quadrature_step(q, 1);
 125         else if (new == ao_quadrature_steps[old].prev)
 126                 _ao_quadrature_step(q, -1);
 127 }
 128
 129 static void
 130 ao_quadrature_isr(void)
 131 {
 132 #if AO_QUADRATURE_COUNT > 0
 133         _ao_quadrature_set(0, (uint8_t) _ao_quadrature_get(0));
 134 #endif
 135 #if AO_QUADRATURE_COUNT > 1
 136         _ao_quadrature_set(1, (uint8_t) _ao_quadrature_get(1));
 137 #endif
 138 }
 139
 140 static void
 141 _ao_quadrature_start_one(uint8_t q, uint8_t new)
 142 {
 143         ao_arch_block_interrupts();
 144         ao_quadrature_state[q] = new;
 145         ao_arch_release_interrupts();
 146 }
 147
 148 int32_t
 149 ao_quadrature_poll(uint8_t q)
 150 {
 151         int32_t ret;
 152         ao_arch_critical(ret = ao_quadrature_count[q];);
 153         return ret;
 154 }
 155
 156 int32_t
 157 ao_quadrature_wait(uint8_t q)
 158 {
 159         ao_sleep(&ao_quadrature_count[q]);
 160         return ao_quadrature_poll(q);
 161 }
 162
 163 static void
 164 ao_quadrature_test(void)
 165 {
 166         uint32_t q;
 167         int32_t c;
 168         uint8_t s;
 169 #ifndef AO_QUADRATURE_SINGLE_CODE
 170         int8_t t = 0;
 171 #endif
 172
 173         q = ao_cmd_decimal();
 174         if (q >= AO_QUADRATURE_COUNT)
 175                 ao_cmd_status = ao_cmd_syntax_error;
 176         if (ao_cmd_status != ao_cmd_success)
 177                 return;
 178
 179         c = -10000;
 180         s = 0;
 181         while (ao_quadrature_count[q] != 10) {
 182                 if (ao_quadrature_count[q] != c ||
 183 #ifndef AO_QUADRATURE_SINGLE_CODE
 184                     ao_quadrature_step[q] != t ||
 185 #endif
 186                     ao_quadrature_state[q] != s)
 187                 {
 188                         c = ao_quadrature_count[q];
 189                         s = ao_quadrature_state[q];
 190 #ifndef AO_QUADRATURE_SINGLE_CODE
 191                         t = ao_quadrature_step[q];
 192                         printf("step %3d ", t);
 193 #endif
 194                         printf ("count %3ld state %2x\n", (long) c, s);
 195                         flush();
 196                 }
 197         }
 198 #if 0
 199         for (;;) {
 200                 int32_t c;
 201                 flush();
 202                 c = ao_quadrature_wait(q);
 203                 printf ("new count %6d\n", c);
 204                 if (c == 100)
 205                         break;
 206         }
 207 #endif
 208 }
 209
 210 static const struct ao_cmds ao_quadrature_cmds[] = {
 211         { ao_quadrature_test,   "q <unit>\0Test quadrature" },
 212         { 0, NULL }
 213 };
 214
 215 #define init(q) do {                                                    \
 216                 ao_enable_input(port(q), bita(q), 0);                   \
 217                 ao_enable_input(port(q), bitb(q), 0);                   \
 218                 _ao_quadrature_start_one(q, (uint8_t) _ao_quadrature_get(q)); \
 219         } while (0)
 220
 221 void
 222 ao_quadrature_init(void)
 223 {
 224 #if AO_QUADRATURE_COUNT > 0
 225         init(0);
 226 #endif
 227 #if AO_QUADRATURE_COUNT > 1
 228         init(1);
 229 #endif
 230         ao_fast_timer_init();
 231         ao_fast_timer_on(ao_quadrature_isr);
 232         ao_cmd_register(&ao_quadrature_cmds[0]);
 233 }