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    Subject[PATCH 12/14] IIO: Periodic timer based trigger
    Date
    Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>

    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.
    ---
    drivers/iio/Kconfig | 2 +
    drivers/iio/Makefile | 4 +-
    drivers/iio/trigger/Kconfig | 12 ++
    drivers/iio/trigger/Makefile | 5 +
    drivers/iio/trigger/iio-trig-periodic-rtc.c | 230 +++++++++++++++++++++++++++
    include/linux/iio/prtc_trigger.h | 7 +
    6 files changed, 259 insertions(+), 1 deletions(-)
    create mode 100644 drivers/iio/trigger/Kconfig
    create mode 100644 drivers/iio/trigger/Makefile
    create mode 100644 drivers/iio/trigger/iio-trig-periodic-rtc.c
    create mode 100644 include/linux/iio/prtc_trigger.h

    diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
    index 936f954..3586984 100644
    --- a/drivers/iio/Kconfig
    +++ b/drivers/iio/Kconfig
    @@ -38,3 +38,5 @@ config IIO_TRIGGER
    source drivers/iio/accel/Kconfig
    source drivers/iio/adc/Kconfig
    source drivers/iio/light/Kconfig
    +
    +source drivers/iio/trigger/Kconfig
    \ No newline at end of file
    diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
    index dea4536..7ec0218 100644
    --- a/drivers/iio/Makefile
    +++ b/drivers/iio/Makefile
    @@ -11,4 +11,6 @@ obj-$(CONFIG_IIO_SW_RING) += ring_sw.o

    obj-y += accel/
    obj-y += adc/
    -obj-y += light/
    \ No newline at end of file
    +obj-y += light/
    +
    +obj-y += trigger/
    \ No newline at end of file
    diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
    new file mode 100644
    index 0000000..0c73ccc
    --- /dev/null
    +++ b/drivers/iio/trigger/Kconfig
    @@ -0,0 +1,12 @@
    +#
    +# Industrial I/O standalone triggers
    +#
    +comment "Triggers - standalone"
    + depends on IIO
    +
    +config IIO_PERIODIC_RTC_TRIGGER
    + tristate "Periodic RTC triggers"
    + depends on IIO && IIO_TRIGGER && RTC_CLASS
    + help
    + Provides support for using periodic capable real time
    + clocks as IIO triggers.
    diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
    new file mode 100644
    index 0000000..4ae55b9
    --- /dev/null
    +++ b/drivers/iio/trigger/Makefile
    @@ -0,0 +1,5 @@
    +#
    +# Makefile for triggers not associated with iio-devices
    +#
    +obj-$(CONFIG_IIO_PERIODIC_RTC_TRIGGER) += iio-trig-periodic-rtc.o
    +
    diff --git a/drivers/iio/trigger/iio-trig-periodic-rtc.c b/drivers/iio/trigger/iio-trig-periodic-rtc.c
    new file mode 100644
    index 0000000..feac4f3
    --- /dev/null
    +++ b/drivers/iio/trigger/iio-trig-periodic-rtc.c
    @@ -0,0 +1,230 @@
    +/* 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 <linux/iio/iio.h>
    +#include <linux/iio/trigger.h>
    +#include <linux/iio/prtc_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)
    +{
    + struct iio_prtc_trigger_group *pdata = dev->dev.platform_data;
    + struct iio_prtc_trigger_info *trig_info;
    + struct iio_trigger *trig, *trig2;
    +
    + int i, ret;
    + for (i = 0; i < pdata->num_triggers; i++) {
    + 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->triggers[i].name);
    + trig_info->name = (char *)trig->name;
    + /* RTC access */
    + trig_info->rtc
    + = rtc_class_open((char *)(pdata->triggers[i].name));
    + 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;
    + iio_trigger_unregister(trig);
    + rtc_irq_unregister(trig_info->rtc, &trig_info->task);
    + rtc_class_close(trig_info->rtc);
    + kfree(trig->name);
    + kfree(trig_info);
    + iio_put_trigger(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;
    + iio_trigger_unregister(trig);
    + rtc_irq_unregister(trig_info->rtc, &trig_info->task);
    + rtc_class_close(trig_info->rtc);
    + kfree(trig->name);
    + kfree(trig_info);
    + iio_put_trigger(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");
    diff --git a/include/linux/iio/prtc_trigger.h b/include/linux/iio/prtc_trigger.h
    new file mode 100644
    index 0000000..9dabc19
    --- /dev/null
    +++ b/include/linux/iio/prtc_trigger.h
    @@ -0,0 +1,7 @@
    +struct iio_prtc_trigger {
    + const char *name;
    +};
    +struct iio_prtc_trigger_group {
    + int num_triggers;
    + struct iio_prtc_trigger *triggers;
    +};
    --
    1.6.2


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