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Staging: IIO: Periodic timer based trigger 

The original posting of this driver led to a discussion in
which it was commented that a better system was needed
for dealing with the many possible periodic interrupt
sources available on some SoCs.  Unfortunately that is
a big task and as far as I know, no-one has taken it
on as yet.  So in the meantime this driver is still
in here.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
hifive-unleashed-5.1
Jonathan Cameron 2009-08-18 18:06:30 +01:00 committed by Greg Kroah-Hartman
parent 0a1231dfea
commit 7f3a1fb998
5 changed files with 254 additions and 1 deletions
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3
drivers/staging/iio/Kconfig
View File

@ -37,8 +37,11 @@ config IIO_TRIGGER
ring buffers. The triggers are effectively a 'capture
data now' interrupt.
source "drivers/staging/iio/accel/Kconfig"
source "drivers/staging/iio/adc/Kconfig"
source "drivers/staging/iio/light/Kconfig"
source "drivers/staging/iio/trigger/Kconfig"
endif # IIO

4
drivers/staging/iio/Makefile
View File

@ -11,4 +11,6 @@ obj-$(CONFIG_IIO_SW_RING) += ring_sw.o
obj-y += accel/
obj-y += adc/
obj-y += light/
obj-y += light/
obj-y += trigger/

15
drivers/staging/iio/trigger/Kconfig 100644
View File

@ -0,0 +1,15 @@
#
# Industrial I/O standalone triggers
#
comment "Triggers - standalone"
if IIO_TRIGGER
config IIO_PERIODIC_RTC_TRIGGER
tristate "Periodic RTC triggers"
depends on RTC_CLASS
help
Provides support for using periodic capable real time
clocks as IIO triggers.
endif # IIO_TRIGGER

5
drivers/staging/iio/trigger/Makefile 100644
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@ -0,0 +1,5 @@
#
# Makefile for triggers not associated with iio-devices
#
obj-$(CONFIG_IIO_PERIODIC_RTC_TRIGGER) += iio-trig-periodic-rtc.o

228
drivers/staging/iio/trigger/iio-trig-periodic-rtc.c 100644
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@ -0,0 +1,228 @@
/* The industrial I/O periodic RTC trigger driver
*
* Copyright (c) 2008 Jonathan Cameron
*
* 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.
*
* This is a heavily rewritten version of the periodic timer system in
* earlier version of industrialio. It supplies the same functionality
* but via a trigger rather than a specific periodic timer system.
*/
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include "../iio.h"
#include "../trigger.h"
LIST_HEAD(iio_prtc_trigger_list);
DEFINE_MUTEX(iio_prtc_trigger_list_lock);
struct iio_prtc_trigger_info {
struct rtc_device *rtc;
int frequency;
char *name;
struct rtc_task task;
};
static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
{
struct iio_prtc_trigger_info *trig_info = trig->private_data;
if (trig_info->frequency == 0)
return -EINVAL;
printk(KERN_INFO "trigger frequency is %d\n", trig_info->frequency);
return rtc_irq_set_state(trig_info->rtc, &trig_info->task, state);
}
static ssize_t iio_trig_periodic_read_freq(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_trigger *trig = dev_get_drvdata(dev);
struct iio_prtc_trigger_info *trig_info = trig->private_data;
return sprintf(buf, "%u\n", trig_info->frequency);
}
static ssize_t iio_trig_periodic_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_prtc_trigger_info *trig_info = trig->private_data;
unsigned long val;
int ret;
ret = strict_strtoul(buf, 10, &val);
if (ret)
goto error_ret;
ret = rtc_irq_set_freq(trig_info->rtc, &trig_info->task, val);
if (ret)
goto error_ret;
trig_info->frequency = val;
return len;
error_ret:
return ret;
}
static ssize_t iio_trig_periodic_read_name(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_trigger *trig = dev_get_drvdata(dev);
struct iio_prtc_trigger_info *trig_info = trig->private_data;
return sprintf(buf, "%s\n", trig_info->name);
}
DEVICE_ATTR(name, S_IRUGO,
iio_trig_periodic_read_name,
NULL);
DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
iio_trig_periodic_read_freq,
iio_trig_periodic_write_freq);
static struct attribute *iio_trig_prtc_attrs[] = {
&dev_attr_frequency.attr,
&dev_attr_name.attr,
NULL,
};
static const struct attribute_group iio_trig_prtc_attr_group = {
.attrs = iio_trig_prtc_attrs,
};
static void iio_prtc_trigger_poll(void *private_data)
{
iio_trigger_poll(private_data);
}
static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
{
char **pdata = dev->dev.platform_data;
struct iio_prtc_trigger_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 error_free_completed_registrations;
}
list_add(&trig->alloc_list, &iio_prtc_trigger_list);
trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
if (!trig_info) {
ret = -ENOMEM;
goto error_put_trigger_and_remove_from_list;
}
trig->private_data = trig_info;
trig->owner = THIS_MODULE;
trig->set_trigger_state = &iio_trig_periodic_rtc_set_state;
trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
if (trig->name == NULL) {
ret = -ENOMEM;
goto error_free_trig_info;
}
snprintf((char *)trig->name,
IIO_TRIGGER_NAME_LENGTH,
"periodic%s",
pdata[i]);
trig_info->name = (char *)trig->name;
/* RTC access */
trig_info->rtc
= rtc_class_open(pdata[i]);
if (trig_info->rtc == NULL) {
ret = -EINVAL;
goto error_free_name;
}
trig_info->task.func = iio_prtc_trigger_poll;
trig_info->task.private_data = trig;
ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
if (ret)
goto error_close_rtc;
trig->control_attrs = &iio_trig_prtc_attr_group;
ret = iio_trigger_register(trig);
if (ret)
goto error_unregister_rtc_irq;
}
return 0;
error_unregister_rtc_irq:
rtc_irq_unregister(trig_info->rtc, &trig_info->task);
error_close_rtc:
rtc_class_close(trig_info->rtc);
error_free_name:
kfree(trig->name);
error_free_trig_info:
kfree(trig_info);
error_put_trigger_and_remove_from_list:
list_del(&trig->alloc_list);
iio_put_trigger(trig);
error_free_completed_registrations:
list_for_each_entry_safe(trig,
trig2,
&iio_prtc_trigger_list,
alloc_list) {
trig_info = trig->private_data;
rtc_irq_unregister(trig_info->rtc, &trig_info->task);
rtc_class_close(trig_info->rtc);
kfree(trig->name);
kfree(trig_info);
iio_trigger_unregister(trig);
}
return ret;
}
static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
{
struct iio_trigger *trig, *trig2;
struct iio_prtc_trigger_info *trig_info;
mutex_lock(&iio_prtc_trigger_list_lock);
list_for_each_entry_safe(trig,
trig2,
&iio_prtc_trigger_list,
alloc_list) {
trig_info = trig->private_data;
rtc_irq_unregister(trig_info->rtc, &trig_info->task);
rtc_class_close(trig_info->rtc);
kfree(trig->name);
kfree(trig_info);
iio_trigger_unregister(trig);
}
mutex_unlock(&iio_prtc_trigger_list_lock);
return 0;
}
static struct platform_driver iio_trig_periodic_rtc_driver = {
.probe = iio_trig_periodic_rtc_probe,
.remove = iio_trig_periodic_rtc_remove,
.driver = {
.name = "iio_prtc_trigger",
.owner = THIS_MODULE,
},
};
static int __init iio_trig_periodic_rtc_init(void)
{
return platform_driver_register(&iio_trig_periodic_rtc_driver);
}
static void __exit iio_trig_periodic_rtc_exit(void)
{
return platform_driver_unregister(&iio_trig_periodic_rtc_driver);
}
module_init(iio_trig_periodic_rtc_init);
module_exit(iio_trig_periodic_rtc_exit);
MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
MODULE_DESCRIPTION("Periodic realtime clock trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");