sensors: Add driver for SYNC

Useful for recording the exact time a gpio interrupt happened in the
context of sensors.

Adding it for camera vsync purposes.

BUG=b:67743747
TEST=With next patch see it work on scarlet.
BRANCH=master

Change-Id: Ic8e8fb444e08200e5d8daded8b4a5920b13431ac
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/850580
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>

1 files changed, 120 insertions, 0 deletions

diff --git a/driver/sync.c b/driver/sync.c
new file mode 100644
index 0000000000..bbf0b7f0d8
--- /dev/null
+++ b/driver/sync.c
@@ -0,0 +1,120 @@
+/* Copyright 2017 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Sync event driver.
+ * Useful for recording the exact time a gpio interrupt happened in the
+ * context of sensors. Originally created for a camera vsync signal.
+ */
+
+#include "accelgyro.h"
+#include "config.h"
+#include "console.h"
+#include "driver/sync.h"
+#include "hwtimer.h"
+#include "task.h"
+
+#define CPRINTS(format, args...) cprints(CC_MOTION_SENSE, format, ## args)
+#define CPRINTF(format, args...) cprintf(CC_MOTION_SENSE, format, ## args)
+
+#ifndef CONFIG_ACCEL_FIFO
+#error This driver needs CONFIG_ACCEL_FIFO
+#endif
+
+#ifndef CONFIG_ACCEL_INTERRUPTS
+#error This driver needs CONFIG_ACCEL_INTERRUPTS
+#endif
+
+static uint32_t previous_interrupt_timestamp, last_interrupt_timestamp;
+static int event_counter;
+struct ec_response_motion_sensor_data vector = {.flags = 0, .data = {0, 0, 0} };
+int sync_enabled;
+
+static int sync_read(const struct motion_sensor_t *s, vector_3_t v)
+{
+	v[0] = event_counter;
+	return EC_SUCCESS;
+}
+
+/*
+ * Since there's no such thing as data rate for this sensor, but the framework
+ * still depends on being able to set this to 0 to disable it, we'll just use
+ * non 0 rate values as an enable boolean.
+ */
+static int sync_set_data_rate(const struct motion_sensor_t *s,
+				int rate, int roundup)
+{
+	sync_enabled = !!rate;
+	CPRINTF("sync event driver enabling=%d\n", sync_enabled);
+	return EC_SUCCESS;
+}
+
+static int sync_get_data_rate(const struct motion_sensor_t *s)
+{
+	return sync_enabled;
+}
+
+/* Upper half of the irq handler */
+void sync_interrupt(enum gpio_signal signal)
+{
+	uint32_t timestamp = __hw_clock_source_read();
+
+	if (!sync_enabled)
+		return;
+
+	last_interrupt_timestamp = timestamp;
+	event_counter++;
+
+	task_set_event(TASK_ID_MOTIONSENSE, CONFIG_SYNC_INT_EVENT, 0);
+}
+
+/* Bottom half of the irq handler */
+static int motion_irq_handler(struct motion_sensor_t *s, uint32_t *event)
+{
+	uint32_t timestamp;
+
+	if (!(*event & CONFIG_SYNC_INT_EVENT))
+		return EC_ERROR_NOT_HANDLED;
+
+	/* this should be the atomic read */
+	timestamp = last_interrupt_timestamp;
+
+	if (previous_interrupt_timestamp == timestamp)
+		return EC_ERROR_NOT_HANDLED; /* nothing new yet */
+	previous_interrupt_timestamp = timestamp;
+
+	vector.flags = MOTIONSENSE_SENSOR_FLAG_WAKEUP;
+	vector.data[X] = event_counter;
+	motion_sense_fifo_add_data(&vector, s, 1, timestamp);
+	return EC_SUCCESS;
+}
+
+static int sync_init(const struct motion_sensor_t *s)
+{
+	last_interrupt_timestamp = __hw_clock_source_read();
+	previous_interrupt_timestamp = last_interrupt_timestamp;
+	event_counter = 0;
+	vector.sensor_num = s - motion_sensors;
+	sync_enabled = 0;
+	return 0;
+}
+
+#ifdef CONFIG_SYNC_COMMAND
+static int command_sync(int argc, char **argv)
+{
+	sync_interrupt(GPIO_SYNC_INT);
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(sync, command_sync,
+	NULL,
+	"Simulates a sync event");
+#endif
+
+const struct accelgyro_drv sync_drv = {
+	.init = sync_init,
+	.read = sync_read,
+	.set_data_rate = sync_set_data_rate,
+	.get_data_rate = sync_get_data_rate,
+	.irq_handler = motion_irq_handler,
+};
+