altos/driver: Add support for one-step-per-click quadrature encoder

[fw/altos] / src / drivers / ao_quadrature.c

diff --git a/src/drivers/ao_quadrature.c b/src/drivers/ao_quadrature.c
index 66a77dfaa997b22824805cbbdc4bda9c63b5618d..98bd7c083f7eaaec4f0bdcb33f5025e0c7f0bd61 100644 (file)
--- a/src/drivers/ao_quadrature.c
+++ b/src/drivers/ao_quadrature.c
@@ -3,7 +3,8 @@
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -24,6 +25,13 @@
 __xdata int32_t ao_quadrature_count[AO_QUADRATURE_COUNT];
 static uint8_t  ao_quadrature_state[AO_QUADRATURE_COUNT];
 
+struct ao_debounce {
+       uint8_t state;
+       uint8_t count;
+};
+
+static struct ao_debounce ao_debounce_state[AO_QUADRATURE_COUNT][2];
+
 #define port(q)        AO_QUADRATURE_ ## q ## _PORT
 #define bita(q) AO_QUADRATURE_ ## q ## _A
 #define bitb(q) AO_QUADRATURE_ ## q ## _B
@@ -31,14 +39,40 @@ static uint8_t  ao_quadrature_state[AO_QUADRATURE_COUNT];
 #define pinb(q) AO_QUADRATURE_ ## q ## _B ## _PIN
 #define isr(q)  ao_quadrature_isr_ ## q
 
-static inline uint16_t
-ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b) {
-       uint16_t        v = stm_gpio_get_all(gpio);
+#ifndef AO_QUADRATURE_DEBOUNCE
+#define AO_QUADRATURE_DEBOUNCE 30
+#endif
 
-       return ~((((v >> pin_a) & 1) | (((v >> pin_b) & 1) << 1))) & 3;
+static uint8_t
+ao_debounce(uint8_t cur, struct ao_debounce *debounce)
+{
+#if AO_QUADRATURE_DEBOUNCE > 0
+       if (debounce->count > 0) {
+               debounce->count--;
+       } else if (cur != debounce->state) {
+               debounce->state = cur;
+               debounce->count = AO_QUADRATURE_DEBOUNCE;
+       }
+       return debounce->state;
+#else
+       (void) debounce;
+       return cur;
+#endif
 }
 
-#define _ao_quadrature_get(q)  ao_quadrature_read(port(q), bita(q), bitb(q))
+static uint16_t
+ao_quadrature_read(struct stm_gpio *gpio, uint8_t pin_a, uint8_t pin_b, struct ao_debounce debounce_state[2]) {
+       uint16_t        v = ~stm_gpio_get_all(gpio);
+       uint8_t         a = (v >> pin_a) & 1;
+       uint8_t         b = (v >> pin_b) & 1;
+
+       a = ao_debounce(a, &debounce_state[0]);
+       b = ao_debounce(b, &debounce_state[1]);
+
+       return a | (b << 1);
+}
+
+#define _ao_quadrature_get(q)  ao_quadrature_read(port(q), bita(q), bitb(q), ao_debounce_state[q])
 
 static void
 _ao_quadrature_queue(uint8_t q, int8_t step)
@@ -50,17 +84,38 @@ _ao_quadrature_queue(uint8_t q, int8_t step)
        ao_wakeup(&ao_quadrature_count[q]);
 }
 
+#if AO_QUADRATURE_SINGLE_CODE
+struct ao_quadrature_step {
+       uint8_t inc;
+       uint8_t dec;
+};
+
+static struct ao_quadrature_step ao_quadrature_steps[4] = {
+       [0] = { .inc = 1, .dec = 2 },
+       [1] = { .inc = 3, .dec = 0 },
+       [3] = { .inc = 2, .dec = 1 },
+       [2] = { .inc = 0, .dec = 3 },
+};
+#endif
 
 static void
 _ao_quadrature_set(uint8_t q, uint8_t new) {
        uint8_t old = ao_quadrature_state[q];
 
+#ifdef AO_QUADRATURE_SINGLE_CODE
+       if (new == ao_quadrature_steps[old].inc) {
+               _ao_quadrature_queue(q, 1);
+       } else if (new == ao_quadrature_steps[old].dec) {
+               _ao_quadrature_queue(q, -1);
+       }
+#else
        if (old != new && new == 0) {
-               if (old & 2)
+               if (old == 2)
                        _ao_quadrature_queue(q, 1);
-               else if (old & 1)
+               else if (old == 1)
                        _ao_quadrature_queue(q, -1);
        }
+#endif
        ao_quadrature_state[q] = new;
 }