altos: Add fast-timer API. Use for quadrature and button drivers

This splits the fast-timer portion out of the debounce helper code and
shares that with the quadrature driver which now uses it directly.

Signed-off-by: Keith Packard <keithp@keithp.com>

3 files changed, 188 insertions, 2 deletions

diff --git a/src/core/ao.h b/src/core/ao.h
index 0886260f..caa0ec19 100644
--- a/src/core/ao.h
+++ b/src/core/ao.h
@@ -75,6 +75,7 @@ typedef AO_PORT_TYPE ao_port_t;
 #define AO_PANIC_CRASH		14	/* Processor crashed */
 #define AO_PANIC_BUFIO		15	/* Mis-using bufio API */
 #define AO_PANIC_EXTI		16	/* Mis-using exti API */
+#define AO_PANIC_FAST_TIMER	17	/* Mis-using fast timer API */
 #define AO_PANIC_SELF_TEST_CC1120	0x40 | 1	/* Self test failure */
 #define AO_PANIC_SELF_TEST_HMC5883	0x40 | 2	/* Self test failure */
 #define AO_PANIC_SELF_TEST_MPU6000	0x40 | 3	/* Self test failure */
diff --git a/src/core/ao_debounce.c b/src/core/ao_debounce.c
new file mode 100644
index 00000000..b9d67729
--- /dev/null
+++ b/src/core/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();
+}
diff --git a/src/core/ao_debounce.h b/src/core/ao_debounce.h
index ebe290e1..19c620f5 100644
--- a/src/core/ao_debounce.h
+++ b/src/core/ao_debounce.h
@@ -22,13 +22,16 @@ struct ao_debounce {
 	struct ao_debounce	*next;
 
 	/* time that pin value must be stable before accepting */
-	int8_t			hold;
+	uint8_t			hold;
 
 	/* last value reported to app; don't report it twice */
 	uint8_t			value;
 
+	/* current value received from pins */
+	uint8_t			current;
+
 	/* current count of intervals pin value has been stable */
-	int8_t			count;
+	uint8_t			count;
 
 	/* This pin is running */
 	uint8_t			running;
@@ -40,6 +43,22 @@ struct ao_debounce {
 	void 			(*_set)(struct ao_debounce *debounce, uint8_t value);
 };
 
+static inline void
+ao_debounce_config(struct ao_debounce *debounce,
+		   uint8_t (*_get)(struct ao_debounce *debounce),
+		   void (*_set)(struct ao_debounce *debounce, uint8_t value),
+		   uint8_t hold)
+{
+	debounce->next = 0;
+	debounce->hold = hold;
+	debounce->value = 0xff;
+	debounce->current = 0xff;
+	debounce->count = 0;
+	debounce->running = 0;
+	debounce->_get = _get;
+	debounce->_set = _set;
+}
+
 void
 _ao_debounce_start(struct ao_debounce *debounce);
 
@@ -49,4 +68,7 @@ _ao_debounce_stop(struct ao_debounce *debounce);
 void
 ao_debounce_init(void);
 
+void
+ao_debounce_dump(void);
+
 #endif /* _AO_DEBOUNCE_H_ */