From b0b52ca73bc836336ecc70247a9ed1dd633920d9 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Mon, 6 Aug 2012 19:34:34 -0700
Subject: [PATCH] altos: Add quadrature driver

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 src/drivers/ao_quadrature.c | 108 ++++++++++++++++++++++++++++++++++++
 src/drivers/ao_quadrature.h |  30 ++++++++++
 2 files changed, 138 insertions(+)
 create mode 100644 src/drivers/ao_quadrature.c
 create mode 100644 src/drivers/ao_quadrature.h

diff --git a/src/drivers/ao_quadrature.c b/src/drivers/ao_quadrature.c
new file mode 100644
index 00000000..1cde32e7
--- /dev/null
+++ b/src/drivers/ao_quadrature.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright © 2012 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_quadrature.h>
+#include <ao_exti.h>
+
+__xdata int32_t ao_quadrature_count;
+
+static uint8_t	wait_clear;
+
+static void
+ao_quadrature_isr(void)
+{
+	if (wait_clear) {
+		wait_clear = 0;
+		ao_exti_set_mode(AO_QUADRATURE_PORT, AO_QUADRATURE_A, AO_EXTI_MODE_RISING);
+	} else {
+		wait_clear = 1;
+		ao_exti_set_mode(AO_QUADRATURE_PORT, AO_QUADRATURE_A, AO_EXTI_MODE_FALLING);
+		if (ao_gpio_get(AO_QUADRATURE_PORT, AO_QUADRATURE_B, AO_QUADRATURE_B_PIN))
+			ao_quadrature_count++;
+		else
+			ao_quadrature_count--;
+		ao_wakeup(&ao_quadrature_count);
+	}
+}
+
+int32_t
+ao_quadrature_poll(void)
+{
+	int32_t	ret;
+	ao_arch_critical(ret = ao_quadrature_count;);
+	return ret;
+}
+
+int32_t
+ao_quadrature_wait(void)
+{
+	ao_sleep(&ao_quadrature_count);
+	return ao_quadrature_poll();
+}
+
+static void
+ao_quadrature_test(void)
+{
+#if 0
+	for (;;) {
+		int32_t	c;
+		printf ("waiting...\n");
+		flush();
+		c = ao_quadrature_wait();
+		printf ("new count %d\n", c);
+		if (ao_stdin_ready)
+			break;
+	}
+#endif
+	uint8_t	a, old_a, b, old_b;
+
+	old_a = 2; old_b = 2;
+	for (;;) {
+		a = ao_gpio_get(AO_QUADRATURE_PORT, AO_QUADRATURE_A, AO_QUADRATURE_A_PIN);
+		b = ao_gpio_get(AO_QUADRATURE_PORT, AO_QUADRATURE_B, AO_QUADRATURE_B_PIN);
+		if (a != old_a || b != old_b) {
+			printf ("A %d B %d\n", a, b);
+			flush();
+			ao_yield();
+			old_a = a;
+			old_b = b;
+		}
+		if (ao_stdin_ready)
+			break;
+	}
+		
+}
+
+static const struct ao_cmds ao_quadrature_cmds[] = {
+	{ ao_quadrature_test,	"q\0Test quadrature" },
+	{ 0, NULL }
+};
+
+void
+ao_quadrature_init(void)
+{
+	ao_quadrature_count = 0;
+
+	ao_enable_port(AO_QUADRATURE_PORT);
+	ao_exti_setup(AO_QUADRATURE_PORT, AO_QUADRATURE_A,
+		      AO_EXTI_MODE_PULL_UP|AO_EXTI_MODE_FALLING|AO_EXTI_PRIORITY_MED,
+		      ao_quadrature_isr);
+	ao_exti_enable(AO_QUADRATURE_PORT, AO_QUADRATURE_A);
+	ao_enable_input(AO_QUADRATURE_PORT, AO_QUADRATURE_B, AO_EXTI_MODE_PULL_UP);
+	ao_cmd_register(&ao_quadrature_cmds[0]);
+}
diff --git a/src/drivers/ao_quadrature.h b/src/drivers/ao_quadrature.h
new file mode 100644
index 00000000..7e1048bc
--- /dev/null
+++ b/src/drivers/ao_quadrature.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2012 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.
+ */
+
+#ifndef _AO_QUADRATURE_H_
+#define _AO_QUADRATURE_H_
+
+int32_t
+ao_quadrature_wait(void);
+
+int32_t
+ao_quadrature_poll(void);
+
+void
+ao_quadrature_init(void);
+
+#endif /* _AO_QUADRATURE_H_ */
-- 
2.30.2