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Commit 7f3a1fb9 authored by Jonathan Cameron's avatar Jonathan Cameron Committed by Greg Kroah-Hartman
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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: default avatarJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 0a1231df

drivers/staging/iio/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -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

drivers/staging/iio/Makefile

+3 −1
Original line number Diff line number Diff line
@@ -12,3 +12,5 @@ obj-$(CONFIG_IIO_SW_RING) += ring_sw.o 
obj-y += accel/

obj-y += adc/

obj-y += light/



obj-y += trigger/
 
 No newline at end of file

drivers/staging/iio/trigger/Kconfig

0 → 100644
+15 −0
Original line number Diff line number Diff line 
#

# 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

drivers/staging/iio/trigger/Makefile

0 → 100644
+5 −0
Original line number Diff line number Diff line 
#

# Makefile for triggers not associated with iio-devices

#

obj-$(CONFIG_IIO_PERIODIC_RTC_TRIGGER) += iio-trig-periodic-rtc.o

drivers/staging/iio/trigger/iio-trig-periodic-rtc.c

0 → 100644
+228 −0
Original line number Diff line number Diff line 
/* 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");