altos: Rename 'core' to 'kernel'

[fw/altos] / src / kernel / ao_debounce.c

diff --git a/src/kernel/ao_debounce.c b/src/kernel/ao_debounce.c
new file mode 100644 (file)
index 0000000..b9d6772
--- /dev/null
+++ b/src/kernel/ao_debounce.c
@@ -0,0 +1,163 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao.h>
+#include <ao_debounce.h>
+#include <ao_fast_timer.h>
+
+static uint8_t                 ao_debounce_initialized;
+static uint8_t                 ao_debounce_running;
+static struct ao_debounce      *ao_debounce;
+
+static uint8_t values[64];
+static uint8_t n;
+
+#define d_step(n)      (((n) + 1) & 63)
+
+static void
+_ao_debounce_set(struct ao_debounce *debounce, uint8_t value)
+{
+       if (value != debounce->value) {
+               values[n] = value;
+               n = (n + 1) & 63;
+               debounce->value = value;
+               debounce->_set(debounce, value);
+       }
+       _ao_debounce_stop(debounce);
+}
+
+void
+ao_debounce_dump(void)
+{
+       uint8_t s;
+
+       for (s = 0; s < n; s++) {
+               printf ("%d: %d\n",
+                       s, values[s]);
+       }
+       n = 0;
+}
+
+/*
+ * Get the current value, set the result when we've
+ * reached the debounce count limit
+ */
+static void
+_ao_debounce_check(struct ao_debounce *debounce)
+{
+       uint8_t next = debounce->_get(debounce);
+
+       if (next == debounce->current) {
+               if (debounce->count < debounce->hold) {
+                       if (++debounce->count == debounce->hold)
+                               _ao_debounce_set(debounce, debounce->current);
+               }
+       } else {
+               debounce->count = 0;
+               debounce->current = next;
+       }
+}
+
+static void
+_ao_debounce_isr(void)
+{
+       struct ao_debounce *debounce, *next;
+
+       for (debounce = ao_debounce; debounce; debounce = next) {
+               next = debounce->next;
+               _ao_debounce_check(debounce);
+       }
+}
+
+static void
+ao_debounce_on(void)
+{
+       ao_fast_timer_on(_ao_debounce_isr);
+}
+
+static void
+ao_debounce_off(void)
+{
+       ao_fast_timer_off(_ao_debounce_isr);
+}
+
+/*
+ * Start monitoring one pin
+ */
+void
+_ao_debounce_start(struct ao_debounce *debounce)
+{
+       uint32_t        m;
+
+       m = ao_arch_irqsave();
+       if (!debounce->running) {
+               debounce->running = 1;
+
+               /* Reset the counter */
+               debounce->count = 0;
+
+               /* Link into list */
+               debounce->next = ao_debounce;
+               ao_debounce = debounce;
+
+               /* Make sure the timer is running */
+               if (!ao_debounce_running++)
+                       ao_debounce_on();
+
+               /* And go check the current value */
+               _ao_debounce_check(debounce);
+       }
+       ao_arch_irqrestore(m);
+}
+
+/*
+ * Stop monitoring one pin
+ */
+void
+_ao_debounce_stop(struct ao_debounce *debounce)
+{
+       struct ao_debounce **prev;
+       uint32_t m;
+
+       m = ao_arch_irqsave();
+       if (debounce->running) {
+               debounce->running = 0;
+
+               /* Unlink */
+               for (prev = &ao_debounce; (*prev); prev = &((*prev)->next)) {
+                       if (*prev == debounce) {
+                               *prev = debounce->next;
+                               break;
+                       }
+               }
+               debounce->next = NULL;
+
+               /* Turn off the timer if possible */
+               if (!--ao_debounce_running)
+                       ao_debounce_off();
+       }
+       ao_arch_irqrestore(m);
+}
+
+void
+ao_debounce_init(void)
+{
+       if (ao_debounce_initialized)
+               return;
+       ao_debounce_initialized = 1;
+       ao_fast_timer_init();
+}