This driver provide a way to utilize hrtimer as an IIO trigger source.
Signed-off-by: Marten Svanfeldt <marten@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/iio/trigger/Kconfig | 6 +
drivers/staging/iio/trigger/Makefile | 2 +
drivers/staging/iio/trigger/iio-trig-hrtimer.c | 208 ++++++++++++++++++++++++
3 files changed, 216 insertions(+), 0 deletions(-)
create mode 100644 drivers/staging/iio/trigger/iio-trig-hrtimer.c
diff --git a/drivers/staging/iio/trigger/Kconfig b/drivers/staging/iio/trigger/Kconfig
index d842a58..35d676a 100644
--- a/drivers/staging/iio/trigger/Kconfig
+++ b/drivers/staging/iio/trigger/Kconfig
@@ -18,4 +18,10 @@ config IIO_GPIO_TRIGGER
help
Provides support for using GPIO pins as IIO triggers.
+config IIO_HRTIMER_TRIGGER
+ tristate "hrtimer trigger"
+ help
+ Provides support for using hrtimer as periodic IIO
+ trigger.
+
endif # IIO_TRIGGER
diff --git a/drivers/staging/iio/trigger/Makefile b/drivers/staging/iio/trigger/Makefile
index 10aeca5..d178c66 100644
--- a/drivers/staging/iio/trigger/Makefile
+++ b/drivers/staging/iio/trigger/Makefile
@@ -4,3 +4,5 @@
obj-$(CONFIG_IIO_PERIODIC_RTC_TRIGGER) += iio-trig-periodic-rtc.o
obj-$(CONFIG_IIO_GPIO_TRIGGER) += iio-trig-gpio.o
+obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o
+
diff --git a/drivers/staging/iio/trigger/iio-trig-hrtimer.c b/drivers/staging/iio/trigger/iio-trig-hrtimer.c
new file mode 100644
index 0000000..16b5af5
--- /dev/null
+++ b/drivers/staging/iio/trigger/iio-trig-hrtimer.c
@@ -0,0 +1,208 @@
+/**
+ * The industrial I/O periodic hrtimer trigger driver
+ *
+ * Copyright (C) Intuitive Aerial AB
+ * Written by Marten Svanfeldt, marten@xxxxxxxxxxxxxxxxxxx
+ *
+ * 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 "../iio.h"
+#include "../trigger.h"
+
+static LIST_HEAD(iio_hrtimer_trigger_list);
+
+struct iio_hrtimer_trig_info {
+ struct iio_trigger *trigger;
+ unsigned int frequency;
+ struct hrtimer timer;
+};
+
+static enum hrtimer_restart iio_trig_hrtimer_trig(struct hrtimer *timer)
+{
+ struct iio_hrtimer_trig_info *trig_info = container_of(timer, struct iio_hrtimer_trig_info, timer);
+
+ iio_trigger_poll(trig_info->trigger, 0);
+ return HRTIMER_RESTART;
+}
+
+static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
+{
+ struct iio_hrtimer_trig_info *trig_info = trig->private_data;
+ if(trig_info->frequency == 0)
+ return -EINVAL;
+
+ if(state) {
+ hrtimer_start(&trig_info->timer,
+ ktime_set(0, NSEC_PER_SEC/trig_info->frequency),
+ HRTIMER_MODE_REL);
+ } else {
+ hrtimer_cancel(&trig_info->timer);
+ }
+
+ return 0;
+}
+
+static ssize_t iio_trig_hrtimer_read_freq(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_trigger *trig = dev_get_drvdata(dev);
+ struct iio_hrtimer_trig_info *trig_info = trig->private_data;
+ return sprintf(buf, "%u\n", trig_info->frequency);
+}
+
+static ssize_t iio_trig_hrtimer_write_freq(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t len)
+{
+ struct iio_trigger *trig = dev_get_drvdata(dev);
+ struct iio_hrtimer_trig_info *trig_info = trig->private_data;
+ unsigned long val;
+ int ret;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if(ret)
+ goto error_ret;
+
+ trig_info->frequency = val;
+
+ return len;
+
+error_ret:
+ return ret;
+}
+
+static IIO_TRIGGER_NAME_ATTR;
+static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
+ iio_trig_hrtimer_read_freq,
+ iio_trig_hrtimer_write_freq);
+
+static struct attribute *iio_trig_hrtimer_attrs[] = {
+ &dev_attr_name.attr,
+ &dev_attr_frequency.attr,
+ NULL,
+};
+
+static const struct attribute_group iio_trig_hrtimer_attr_group = {
+ .attrs = iio_trig_hrtimer_attrs,
+};
+
+static int iio_trig_hrtimer_probe(struct platform_device *dev)
+{
+ char **pdata = dev->dev.platform_data;
+ struct iio_hrtimer_trig_info *trig_info;
+ struct iio_trigger *trig, *trig2;
+
+ int i, ret;
+
+ for(i = 0;; i++) {
+ if(pdata[i] == NULL)
+ break;
+
+ trig = iio_allocate_trigger();
+ if(!trig) {
+ ret = -ENOMEM;
+ goto err_free_completed_reg;
+ }
+ list_add(&trig->alloc_list, &iio_hrtimer_trigger_list);
+
+ trig_info = kzalloc(sizeof(struct iio_hrtimer_trig_info), GFP_KERNEL);
+ if(!trig_info) {
+ ret = -ENOMEM;
+ goto err_put_trigger;
+ }
+ trig_info->trigger = trig;
+ trig->private_data = trig_info;
+ trig->owner = THIS_MODULE;
+ trig->set_trigger_state = &iio_trig_hrtimer_set_state;
+ trig->name = kasprintf(GFP_KERNEL, "hrtimer%s", pdata[i]);
+ if(!trig->name) {
+ ret = -ENOMEM;
+ goto err_free_trig_info;
+ }
+
+ // Setup a hrtimer
+ hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ trig_info->timer.function = iio_trig_hrtimer_trig;
+
+ ret = iio_trigger_register(trig);
+ if(ret)
+ goto err_free_name;
+ }
+
+ return 0;
+err_free_name:
+ kfree(trig->name);
+err_free_trig_info:
+ kfree(trig_info);
+err_put_trigger:
+ list_del(&trig->alloc_list);
+ iio_put_trigger(trig);
+err_free_completed_reg:
+ list_for_each_entry_safe(trig,
+ trig2,
+ &iio_hrtimer_trigger_list,
+ alloc_list) {
+ trig_info = trig->private_data;
+ kfree(trig->name);
+ kfree(trig_info);
+ iio_trigger_unregister(trig);
+ }
+
+ return ret;
+}
+
+static int iio_trig_hrtimer_remove(struct platform_device *dev)
+{
+ struct iio_trigger *trig, *trig2;
+ struct iio_hrtimer_trig_info *trig_info;
+
+ list_for_each_entry_safe(trig,
+ trig2,
+ &iio_hrtimer_trigger_list,
+ alloc_list) {
+ trig_info = trig->private_data;
+ hrtimer_cancel(&trig_info->timer);
+ kfree(trig->name);
+ kfree(trig_info);
+ iio_trigger_unregister(trig);
+ }
+
+ return 0;
+}
+
+static struct platform_driver iio_trig_hrtimer_driver = {
+ .driver = {
+ .name = "iio_hrtimer_trigger",
+ .owner = THIS_MODULE
+ },
+ .probe = iio_trig_hrtimer_probe,
+ .remove = iio_trig_hrtimer_remove,
+};
+
+static int __init iio_trig_hrtimer_init(void)
+{
+ return platform_driver_register(&iio_trig_hrtimer_driver);
+}
+
+static void __exit iio_trig_hrtimer_exit(void)
+{
+ return platform_driver_unregister(&iio_trig_hrtimer_driver);
+}
+
+module_init(iio_trig_hrtimer_init);
+module_exit(iio_trig_hrtimer_exit);
+MODULE_AUTHOR("Marten Svanfeldt <marten@xxxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Periodic hrtimer trigger for the iio subsystem");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platofrm:iio-trig-hrtimer");
+
--
1.7.0.4
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