This patch adds an IIO trigger driver which uses a high resolution
timer to provide a frequency based trigger.
Signed-off-by: Marten Svanfeldt <marten@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
---
drivers/iio/industrialio-configfs.c | 4 +
drivers/iio/trigger/Kconfig | 8 ++
drivers/iio/trigger/Makefile | 2 +
drivers/iio/trigger/iio-trig-hrtimer.c | 146 +++++++++++++++++++++++++++++++
include/linux/iio/iio_configfs_trigger.h | 1 +
5 files changed, 161 insertions(+)
create mode 100644 drivers/iio/trigger/iio-trig-hrtimer.c
diff --git a/drivers/iio/industrialio-configfs.c b/drivers/iio/industrialio-configfs.c
index 4d2133a..22740c0 100644
--- a/drivers/iio/industrialio-configfs.c
+++ b/drivers/iio/industrialio-configfs.c
@@ -17,6 +17,7 @@
static const char *trigger_types[] =
{
"none",
+ "hrtimer",
};
struct iio_configfs_ops iio_none_ops = {
@@ -59,6 +60,9 @@ void iio_trigger_set_configfs_ops(struct iio_configfs_trigger_info *trig_info,
case IIO_TRIGGER_TYPE_NONE:
trig_info->configfs_ops = &iio_none_ops;
break;
+ case IIO_TRIGGER_TYPE_HRTIMER:
+ trig_info->configfs_ops = &iio_hrtimer_ops;
+ break;
default:
pr_err("Setting configfs ops failed! Unknown type %d\n", type);
break;
diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
index 7999612..c856664 100644
--- a/drivers/iio/trigger/Kconfig
+++ b/drivers/iio/trigger/Kconfig
@@ -5,6 +5,14 @@
menu "Triggers - standalone"
+config IIO_TRIGGER_HRTIMER
+ tristate "High resolution timer trigger"
+ help
+ Provides a frequency based IIO trigger using hrtimers.
+
+ To compile this driver as a module, choose M here: the
+ module will be called iio-trig-hrtimer.
+
config IIO_INTERRUPT_TRIGGER
tristate "Generic interrupt trigger"
help
diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
index 0694dae..3d289f6 100644
--- a/drivers/iio/trigger/Makefile
+++ b/drivers/iio/trigger/Makefile
@@ -3,5 +3,7 @@
#
# When adding new entries keep the list in alphabetical order
+
+obj-$(CONFIG_IIO_TRIGGER_HRTIMER) += iio-trig-hrtimer.o
obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o
obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o
diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c
new file mode 100644
index 0000000..1a8beaf
--- /dev/null
+++ b/drivers/iio/trigger/iio-trig-hrtimer.c
@@ -0,0 +1,146 @@
+/**
+ * The industrial I/O periodic hrtimer trigger driver
+ *
+ * Copyright (C) Intuitive Aerial AB
+ * Written by Marten Svanfeldt, marten@xxxxxxxxxxxxxxxxxxx
+ * Copyright (C) 2012, Analog Device Inc.
+ * Author: Lars-Peter Clausen <lars@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ */
+
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/hrtimer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+
+#include <linux/iio/iio_configfs_trigger.h>
+
+struct iio_hrtimer_trig_info {
+ struct iio_configfs_trigger_info *configfs_info;
+ unsigned int frequency;
+ struct hrtimer timer;
+ ktime_t period;
+};
+
+static enum hrtimer_restart iio_trig_hrtimer_trig(struct hrtimer *timer)
+{
+ struct iio_hrtimer_trig_info *trig_info;
+
+ trig_info = container_of(timer, struct iio_hrtimer_trig_info, timer);
+
+ hrtimer_forward_now(timer, trig_info->period);
+ iio_trigger_poll(trig_info->configfs_info->trigger);
+
+ return HRTIMER_RESTART;
+}
+
+static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
+{
+ struct iio_hrtimer_trig_info *trig_info;
+
+ trig_info = iio_trigger_get_drvdata(trig);
+
+ if (trig_info->frequency == 0)
+ return -EINVAL;
+
+ if (state) {
+ hrtimer_start(&trig_info->timer, trig_info->period,
+ HRTIMER_MODE_REL);
+ } else {
+ hrtimer_cancel(&trig_info->timer);
+ }
+
+ return 0;
+}
+
+int iio_trig_hrtimer_read_freq(struct iio_configfs_trigger_info *cinfo)
+{
+ struct iio_hrtimer_trig_info *trig_info;
+
+ trig_info = iio_trigger_get_drvdata(cinfo->trigger);
+ return trig_info->frequency;
+}
+
+int iio_trig_hrtimer_write_freq(struct iio_configfs_trigger_info *cinfo,
+ unsigned long freq)
+{
+ struct iio_hrtimer_trig_info *trig_info;
+
+ trig_info = iio_trigger_get_drvdata(cinfo->trigger);
+
+ if (freq > NSEC_PER_SEC)
+ return -EINVAL;
+
+ if (freq != 0)
+ trig_info->period = ktime_set(0, NSEC_PER_SEC / freq);
+ trig_info->frequency = freq;
+
+ return 0;
+}
+
+static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
+ .owner = THIS_MODULE,
+ .set_trigger_state = iio_trig_hrtimer_set_state,
+};
+
+static int iio_trig_hrtimer_probe(struct iio_configfs_trigger_info *cinfo)
+{
+ struct iio_hrtimer_trig_info *trig_info;
+ int ret;
+
+ trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
+ if (!trig_info)
+ return -ENOMEM;
+
+ trig_info->configfs_info = cinfo;
+
+ cinfo->trigger = iio_trigger_alloc("%s", cinfo->name);
+ if (!cinfo->trigger)
+ return -ENOMEM;
+
+ iio_trigger_set_drvdata(cinfo->trigger, trig_info);
+ cinfo->trigger->ops = &iio_hrtimer_trigger_ops;
+
+ hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ trig_info->timer.function = iio_trig_hrtimer_trig;
+ ret = iio_trigger_register(cinfo->trigger);
+ if (ret)
+ goto err_free_trigger;
+
+ return 0;
+err_free_trigger:
+ iio_trigger_free(cinfo->trigger);
+
+ return ret;
+}
+
+static int iio_trig_hrtimer_remove(struct iio_configfs_trigger_info *cinfo)
+{
+ struct iio_hrtimer_trig_info *trig_info;
+
+ trig_info = iio_trigger_get_drvdata(cinfo->trigger);
+
+ iio_trigger_unregister(cinfo->trigger);
+ hrtimer_cancel(&trig_info->timer);
+ iio_trigger_free(cinfo->trigger);
+
+ return 0;
+}
+
+struct iio_configfs_ops iio_hrtimer_ops = {
+ .get_freq = iio_trig_hrtimer_read_freq,
+ .set_freq = iio_trig_hrtimer_write_freq,
+ .probe = iio_trig_hrtimer_probe,
+ .remove = iio_trig_hrtimer_remove,
+};
+EXPORT_SYMBOL(iio_hrtimer_ops);
+
+MODULE_AUTHOR("Marten Svanfeldt <marten@xxxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/iio/iio_configfs_trigger.h b/include/linux/iio/iio_configfs_trigger.h
index e7b5777..1390474 100644
--- a/include/linux/iio/iio_configfs_trigger.h
+++ b/include/linux/iio/iio_configfs_trigger.h
@@ -2,6 +2,7 @@
#define __IIO_CONFIGFS_TRIGGER
#define IIO_TRIGGER_TYPE_NONE 0
+#define IIO_TRIGGER_TYPE_HRTIMER 1
struct iio_configfs_trigger_info {
const char *name;
--
1.9.1
--
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