This patch adds high resolution timer trigger support for iio framework.
Signed-off-by: Denis Ciocca <denis.ciocca@xxxxxx>
---
drivers/iio/trigger/Kconfig | 9 +
drivers/iio/trigger/Makefile | 1 +
drivers/iio/trigger/iio-trig-hrtimer.c | 284 ++++++++++++++++++++++++++++++++
3 files changed, 294 insertions(+)
create mode 100644 drivers/iio/trigger/iio-trig-hrtimer.c
diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
index 7999612..131e171 100644
--- a/drivers/iio/trigger/Kconfig
+++ b/drivers/iio/trigger/Kconfig
@@ -25,4 +25,13 @@ config IIO_SYSFS_TRIGGER
To compile this driver as a module, choose M here: the
module will be called iio-trig-sysfs.
+config IIO_HRTIMER_TRIGGER
+ tristate "HRTIMER trigger"
+ help
+ Provides support for using HRTIMER entries as IIO triggers.
+ If unsure, say N (but it's safe to say "Y").
+
+ To compile this driver as a module, choose M here: the
+ module will be called iio-trig-hrtimer.
+
endmenu
diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
index 0694dae..4e1876d 100644
--- a/drivers/iio/trigger/Makefile
+++ b/drivers/iio/trigger/Makefile
@@ -5,3 +5,4 @@
# When adding new entries keep the list in alphabetical order
obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o
obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o
+obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.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..a743672
--- /dev/null
+++ b/drivers/iio/trigger/iio-trig-hrtimer.c
@@ -0,0 +1,284 @@
+/*
+ * Industrial I/O - hrtimer trigger support
+ *
+ * Copyright 2013 STMicroelectronics Inc.
+ * Denis Ciocca <denis.ciocca@xxxxxx>
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/hrtimer.h>
+#include <linux/ktime.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+
+#define MAX_UNSIGNED_INT16 (65535U)
+
+struct iio_hrtimer_trigger_data {
+ struct iio_trigger *trig;
+ struct hrtimer timer;
+ struct list_head l;
+ ktime_t period;
+ u16 freq;
+ int id;
+};
+
+static LIST_HEAD(iio_hrtimer_trigger_list);
+static DEFINE_MUTEX(iio_hrtimer_trigger_list_mut);
+
+static int iio_hrtimer_trigger_probe(int id);
+static int iio_hrtimer_trigger_remove(int id);
+
+static ssize_t iio_sysfs_hrtimer_trig_add(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int ret;
+ unsigned int input;
+
+ ret = kstrtouint(buf, 10, &input);
+ if (ret)
+ return ret;
+
+ ret = iio_hrtimer_trigger_probe(input);
+ if (ret)
+ return ret;
+
+ return len;
+}
+static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_hrtimer_trig_add);
+
+static ssize_t iio_sysfs_hrtimer_trig_remove(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int ret;
+ unsigned int input;
+
+ ret = kstrtouint(buf, 10, &input);
+ if (ret)
+ return ret;
+
+ ret = iio_hrtimer_trigger_remove(input);
+ if (ret)
+ return ret;
+
+ return len;
+}
+static DEVICE_ATTR(remove_trigger, S_IWUSR,
+ NULL, &iio_sysfs_hrtimer_trig_remove);
+
+static struct attribute *iio_hrtimer_trig_attrs[] = {
+ &dev_attr_add_trigger.attr,
+ &dev_attr_remove_trigger.attr,
+ NULL,
+};
+
+static const struct attribute_group iio_hrtimer_trig_group = {
+ .attrs = iio_hrtimer_trig_attrs,
+};
+
+static const struct attribute_group *iio_hrtimer_trig_groups[] = {
+ &iio_hrtimer_trig_group,
+ NULL,
+};
+
+static struct device iio_hrtimer_trig_dev = {
+ .bus = &iio_bus_type,
+ .groups = iio_hrtimer_trig_groups,
+};
+
+static int iio_hrtimer_trig_set_state(struct iio_trigger *trig, bool state)
+{
+ struct iio_hrtimer_trigger_data *trig_data =
+ iio_trigger_get_drvdata(trig);
+
+ if (trig_data->freq == 0)
+ return -EINVAL;
+
+ if (state)
+ hrtimer_start(&trig_data->timer,
+ trig_data->period, HRTIMER_MODE_REL);
+ else
+ hrtimer_cancel(&trig_data->timer);
+
+ return 0;
+}
+
+static ssize_t iio_hrtimer_trigger_set_freq_value(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int ret;
+ u16 frequency;
+ struct iio_trigger *trig = to_iio_trigger(dev);
+ struct iio_hrtimer_trigger_data *trig_data =
+ iio_trigger_get_drvdata(trig);
+
+ ret = kstrtou16(buf, 10, &frequency);
+ if (ret < 0)
+ return ret;
+
+ if (frequency > MAX_UNSIGNED_INT16)
+ return -EINVAL;
+
+ trig_data->freq = frequency;
+
+ if (frequency)
+ trig_data->period =
+ ktime_set(0, NSEC_PER_SEC / trig_data->freq);
+
+ return len;
+}
+
+static ssize_t iio_hrtimer_trigger_get_freq_value(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_trigger *trig = to_iio_trigger(dev);
+ struct iio_hrtimer_trigger_data *trig_data =
+ iio_trigger_get_drvdata(trig);
+
+ return sprintf(buf, "%hu\n", trig_data->freq);
+}
+
+static DEVICE_ATTR(frequency, S_IWUSR | S_IRUGO,
+ iio_hrtimer_trigger_get_freq_value,
+ iio_hrtimer_trigger_set_freq_value);
+
+static struct attribute *iio_hrtimer_trigger_attrs[] = {
+ &dev_attr_frequency.attr,
+ NULL,
+};
+
+static const struct attribute_group iio_hrtimer_trigger_attr_group = {
+ .attrs = iio_hrtimer_trigger_attrs,
+};
+
+static const struct attribute_group *iio_hrtimer_trigger_attr_groups[] = {
+ &iio_hrtimer_trigger_attr_group,
+ NULL,
+};
+
+static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
+ .owner = THIS_MODULE,
+ .set_trigger_state = &iio_hrtimer_trig_set_state,
+};
+
+enum hrtimer_restart iio_hrtimer_trigger_func(struct hrtimer *timer)
+{
+ struct iio_hrtimer_trigger_data *trig_data;
+
+ trig_data = container_of(timer, struct iio_hrtimer_trigger_data, timer);
+
+ hrtimer_forward_now(timer, trig_data->period);
+ iio_trigger_poll(trig_data->trig, 0);
+
+ return HRTIMER_RESTART;
+}
+
+static int iio_hrtimer_trigger_probe(int id)
+{
+ int err;
+ bool foundit = false;
+ struct iio_hrtimer_trigger_data *trig_data;
+
+ mutex_lock(&iio_hrtimer_trigger_list_mut);
+ list_for_each_entry(trig_data, &iio_hrtimer_trigger_list, l) {
+ if (id == trig_data->id) {
+ foundit = true;
+ break;
+ }
+ }
+ if (foundit) {
+ err = -EINVAL;
+ goto iio_hrtimer_mutex_unlock;
+ }
+
+ trig_data = kmalloc(sizeof(*trig_data), GFP_KERNEL);
+ if (trig_data == NULL) {
+ err = -ENOMEM;
+ goto iio_hrtimer_mutex_unlock;
+ }
+
+ trig_data->id = id;
+ trig_data->trig = iio_trigger_alloc("hrtimer_trig%d", id);
+ if (!trig_data->trig) {
+ err = -ENOMEM;
+ goto iio_hrtimer_free_trig_data;
+ }
+
+ trig_data->trig->dev.groups = iio_hrtimer_trigger_attr_groups;
+ trig_data->trig->ops = &iio_hrtimer_trigger_ops;
+ trig_data->trig->dev.parent = &iio_hrtimer_trig_dev;
+ iio_trigger_set_drvdata(trig_data->trig, trig_data);
+
+ trig_data->freq = 0;
+ hrtimer_init(&trig_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ trig_data->timer.function = &iio_hrtimer_trigger_func;
+
+ err = iio_trigger_register(trig_data->trig);
+ if (err)
+ goto iio_hrtimer_free_trig_data;
+
+ list_add(&trig_data->l, &iio_hrtimer_trigger_list);
+ __module_get(THIS_MODULE);
+ mutex_unlock(&iio_hrtimer_trigger_list_mut);
+
+ return 0;
+
+iio_hrtimer_free_trig_data:
+ kfree(trig_data);
+iio_hrtimer_mutex_unlock:
+ mutex_unlock(&iio_hrtimer_trigger_list_mut);
+ return err;
+}
+
+static int iio_hrtimer_trigger_remove(int id)
+{
+ bool foundit = false;
+ struct iio_hrtimer_trigger_data *trig_data;
+
+ mutex_lock(&iio_hrtimer_trigger_list_mut);
+ list_for_each_entry(trig_data, &iio_hrtimer_trigger_list, l) {
+ if (id == trig_data->id) {
+ foundit = true;
+ break;
+ }
+ }
+ if (!foundit) {
+ mutex_unlock(&iio_hrtimer_trigger_list_mut);
+ return -EINVAL;
+ }
+
+ iio_trigger_unregister(trig_data->trig);
+ iio_trigger_free(trig_data->trig);
+
+ list_del(&trig_data->l);
+ kfree(trig_data);
+ module_put(THIS_MODULE);
+ mutex_unlock(&iio_hrtimer_trigger_list_mut);
+
+ return 0;
+}
+
+static int __init iio_hrtimer_trig_init(void)
+{
+ device_initialize(&iio_hrtimer_trig_dev);
+ dev_set_name(&iio_hrtimer_trig_dev, "iio_hrtimer_trigger");
+ return device_add(&iio_hrtimer_trig_dev);
+}
+module_init(iio_hrtimer_trig_init);
+
+static void __exit iio_hrtimer_trig_exit(void)
+{
+ device_unregister(&iio_hrtimer_trig_dev);
+}
+module_exit(iio_hrtimer_trig_exit);
+
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@xxxxxx>");
+MODULE_DESCRIPTION("Hrtimer trigger for the iio subsystem");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5
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