1 files changed, 509 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
new file mode 100644
index 000000000000..0f582df75a19
--- /dev/null
+++ b/drivers/iio/industrialio-trigger.c
@@ -0,0 +1,509 @@
+/* The industrial I/O core, trigger handling functions
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/trigger_consumer.h>
+
+/* RFC - Question of approach
+ * Make the common case (single sensor single trigger)
+ * simple by starting trigger capture from when first sensors
+ * is added.
+ *
+ * Complex simultaneous start requires use of 'hold' functionality
+ * of the trigger. (not implemented)
+ *
+ * Any other suggestions?
+ */
+
+static DEFINE_IDA(iio_trigger_ida);
+
+/* Single list of all available triggers */
+static LIST_HEAD(iio_trigger_list);
+static DEFINE_MUTEX(iio_trigger_list_lock);
+
+/**
+ * iio_trigger_read_name() - retrieve useful identifying name
+ **/
+static ssize_t iio_trigger_read_name(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_trigger *trig = dev_get_drvdata(dev);
+	return sprintf(buf, "%s\n", trig->name);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
+
+/**
+ * iio_trigger_register_sysfs() - create a device for this trigger
+ * @trig_info:	the trigger
+ *
+ * Also adds any control attribute registered by the trigger driver
+ **/
+static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
+{
+	return sysfs_add_file_to_group(&trig_info->dev.kobj,
+				       &dev_attr_name.attr,
+				       NULL);
+}
+
+static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
+{
+	sysfs_remove_file_from_group(&trig_info->dev.kobj,
+					   &dev_attr_name.attr,
+					   NULL);
+}
+
+int iio_trigger_register(struct iio_trigger *trig_info)
+{
+	int ret;
+
+	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
+	if (trig_info->id < 0) {
+		ret = trig_info->id;
+		goto error_ret;
+	}
+	/* Set the name used for the sysfs directory etc */
+	dev_set_name(&trig_info->dev, "trigger%ld",
+		     (unsigned long) trig_info->id);
+
+	ret = device_add(&trig_info->dev);
+	if (ret)
+		goto error_unregister_id;
+
+	ret = iio_trigger_register_sysfs(trig_info);
+	if (ret)
+		goto error_device_del;
+
+	/* Add to list of available triggers held by the IIO core */
+	mutex_lock(&iio_trigger_list_lock);
+	list_add_tail(&trig_info->list, &iio_trigger_list);
+	mutex_unlock(&iio_trigger_list_lock);
+
+	return 0;
+
+error_device_del:
+	device_del(&trig_info->dev);
+error_unregister_id:
+	ida_simple_remove(&iio_trigger_ida, trig_info->id);
+error_ret:
+	return ret;
+}
+EXPORT_SYMBOL(iio_trigger_register);
+
+void iio_trigger_unregister(struct iio_trigger *trig_info)
+{
+	mutex_lock(&iio_trigger_list_lock);
+	list_del(&trig_info->list);
+	mutex_unlock(&iio_trigger_list_lock);
+
+	iio_trigger_unregister_sysfs(trig_info);
+	ida_simple_remove(&iio_trigger_ida, trig_info->id);
+	/* Possible issue in here */
+	device_unregister(&trig_info->dev);
+}
+EXPORT_SYMBOL(iio_trigger_unregister);
+
+static struct iio_trigger *iio_trigger_find_by_name(const char *name,
+						    size_t len)
+{
+	struct iio_trigger *trig = NULL, *iter;
+
+	mutex_lock(&iio_trigger_list_lock);
+	list_for_each_entry(iter, &iio_trigger_list, list)
+		if (sysfs_streq(iter->name, name)) {
+			trig = iter;
+			break;
+		}
+	mutex_unlock(&iio_trigger_list_lock);
+
+	return trig;
+}
+
+void iio_trigger_poll(struct iio_trigger *trig, s64 time)
+{
+	int i;
+	if (!trig->use_count)
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
+			if (trig->subirqs[i].enabled) {
+				trig->use_count++;
+				generic_handle_irq(trig->subirq_base + i);
+			}
+}
+EXPORT_SYMBOL(iio_trigger_poll);
+
+irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
+{
+	iio_trigger_poll(private, iio_get_time_ns());
+	return IRQ_HANDLED;
+}
+EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
+
+void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
+{
+	int i;
+	if (!trig->use_count)
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
+			if (trig->subirqs[i].enabled) {
+				trig->use_count++;
+				handle_nested_irq(trig->subirq_base + i);
+			}
+}
+EXPORT_SYMBOL(iio_trigger_poll_chained);
+
+void iio_trigger_notify_done(struct iio_trigger *trig)
+{
+	trig->use_count--;
+	if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
+		if (trig->ops->try_reenable(trig))
+			/* Missed and interrupt so launch new poll now */
+			iio_trigger_poll(trig, 0);
+}
+EXPORT_SYMBOL(iio_trigger_notify_done);
+
+/* Trigger Consumer related functions */
+static int iio_trigger_get_irq(struct iio_trigger *trig)
+{
+	int ret;
+	mutex_lock(&trig->pool_lock);
+	ret = bitmap_find_free_region(trig->pool,
+				      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+				      ilog2(1));
+	mutex_unlock(&trig->pool_lock);
+	if (ret >= 0)
+		ret += trig->subirq_base;
+
+	return ret;
+}
+
+static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
+{
+	mutex_lock(&trig->pool_lock);
+	clear_bit(irq - trig->subirq_base, trig->pool);
+	mutex_unlock(&trig->pool_lock);
+}
+
+/* Complexity in here.  With certain triggers (datardy) an acknowledgement
+ * may be needed if the pollfuncs do not include the data read for the
+ * triggering device.
+ * This is not currently handled.  Alternative of not enabling trigger unless
+ * the relevant function is in there may be the best option.
+ */
+/* Worth protecting against double additions?*/
+static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
+					struct iio_poll_func *pf)
+{
+	int ret = 0;
+	bool notinuse
+		= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+	/* Prevent the module being removed whilst attached to a trigger */
+	__module_get(pf->indio_dev->info->driver_module);
+	pf->irq = iio_trigger_get_irq(trig);
+	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
+				   pf->type, pf->name,
+				   pf);
+	if (ret < 0) {
+		module_put(pf->indio_dev->info->driver_module);
+		return ret;
+	}
+
+	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
+		ret = trig->ops->set_trigger_state(trig, true);
+		if (ret < 0)
+			module_put(pf->indio_dev->info->driver_module);
+	}
+
+	return ret;
+}
+
+static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
+					 struct iio_poll_func *pf)
+{
+	int ret = 0;
+	bool no_other_users
+		= (bitmap_weight(trig->pool,
+				 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
+		   == 1);
+	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
+		ret = trig->ops->set_trigger_state(trig, false);
+		if (ret)
+			goto error_ret;
+	}
+	iio_trigger_put_irq(trig, pf->irq);
+	free_irq(pf->irq, pf);
+	module_put(pf->indio_dev->info->driver_module);
+
+error_ret:
+	return ret;
+}
+
+irqreturn_t iio_pollfunc_store_time(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	pf->timestamp = iio_get_time_ns();
+	return IRQ_WAKE_THREAD;
+}
+EXPORT_SYMBOL(iio_pollfunc_store_time);
+
+struct iio_poll_func
+*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
+		    irqreturn_t (*thread)(int irq, void *p),
+		    int type,
+		    struct iio_dev *indio_dev,
+		    const char *fmt,
+		    ...)
+{
+	va_list vargs;
+	struct iio_poll_func *pf;
+
+	pf = kmalloc(sizeof *pf, GFP_KERNEL);
+	if (pf == NULL)
+		return NULL;
+	va_start(vargs, fmt);
+	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+	va_end(vargs);
+	if (pf->name == NULL) {
+		kfree(pf);
+		return NULL;
+	}
+	pf->h = h;
+	pf->thread = thread;
+	pf->type = type;
+	pf->indio_dev = indio_dev;
+
+	return pf;
+}
+EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
+
+void iio_dealloc_pollfunc(struct iio_poll_func *pf)
+{
+	kfree(pf->name);
+	kfree(pf);
+}
+EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
+
+/**
+ * iio_trigger_read_current() - trigger consumer sysfs query which trigger
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used by the device to be queried.
+ **/
+static ssize_t iio_trigger_read_current(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+
+	if (indio_dev->trig)
+		return sprintf(buf, "%s\n", indio_dev->trig->name);
+	return 0;
+}
+
+/**
+ * iio_trigger_write_current() trigger consumer sysfs set current trigger
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used for this device to be specified at run time based on the triggers
+ * name.
+ **/
+static ssize_t iio_trigger_write_current(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf,
+					 size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct iio_trigger *oldtrig = indio_dev->trig;
+	struct iio_trigger *trig;
+	int ret;
+
+	mutex_lock(&indio_dev->mlock);
+	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+		mutex_unlock(&indio_dev->mlock);
+		return -EBUSY;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	trig = iio_trigger_find_by_name(buf, len);
+	if (oldtrig == trig)
+		return len;
+
+	if (trig && indio_dev->info->validate_trigger) {
+		ret = indio_dev->info->validate_trigger(indio_dev, trig);
+		if (ret)
+			return ret;
+	}
+
+	if (trig && trig->ops && trig->ops->validate_device) {
+		ret = trig->ops->validate_device(trig, indio_dev);
+		if (ret)
+			return ret;
+	}
+
+	indio_dev->trig = trig;
+
+	if (oldtrig && indio_dev->trig != oldtrig)
+		iio_trigger_put(oldtrig);
+	if (indio_dev->trig)
+		iio_trigger_get(indio_dev->trig);
+
+	return len;
+}
+
+static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
+		   iio_trigger_read_current,
+		   iio_trigger_write_current);
+
+static struct attribute *iio_trigger_consumer_attrs[] = {
+	&dev_attr_current_trigger.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_trigger_consumer_attr_group = {
+	.name = "trigger",
+	.attrs = iio_trigger_consumer_attrs,
+};
+
+static void iio_trig_release(struct device *device)
+{
+	struct iio_trigger *trig = to_iio_trigger(device);
+	int i;
+
+	if (trig->subirq_base) {
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			irq_modify_status(trig->subirq_base + i,
+					  IRQ_NOAUTOEN,
+					  IRQ_NOREQUEST | IRQ_NOPROBE);
+			irq_set_chip(trig->subirq_base + i,
+				     NULL);
+			irq_set_handler(trig->subirq_base + i,
+					NULL);
+		}
+
+		irq_free_descs(trig->subirq_base,
+			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+	}
+	kfree(trig->name);
+	kfree(trig);
+}
+
+static struct device_type iio_trig_type = {
+	.release = iio_trig_release,
+};
+
+static void iio_trig_subirqmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_trigger *trig
+		= container_of(chip,
+			       struct iio_trigger, subirq_chip);
+	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
+}
+
+static void iio_trig_subirqunmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_trigger *trig
+		= container_of(chip,
+			       struct iio_trigger, subirq_chip);
+	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
+}
+
+struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
+{
+	va_list vargs;
+	struct iio_trigger *trig;
+	trig = kzalloc(sizeof *trig, GFP_KERNEL);
+	if (trig) {
+		int i;
+		trig->dev.type = &iio_trig_type;
+		trig->dev.bus = &iio_bus_type;
+		device_initialize(&trig->dev);
+		dev_set_drvdata(&trig->dev, (void *)trig);
+
+		mutex_init(&trig->pool_lock);
+		trig->subirq_base
+			= irq_alloc_descs(-1, 0,
+					  CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+					  0);
+		if (trig->subirq_base < 0) {
+			kfree(trig);
+			return NULL;
+		}
+		va_start(vargs, fmt);
+		trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+		va_end(vargs);
+		if (trig->name == NULL) {
+			irq_free_descs(trig->subirq_base,
+				       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+			kfree(trig);
+			return NULL;
+		}
+		trig->subirq_chip.name = trig->name;
+		trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
+		trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
+		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+			irq_set_chip(trig->subirq_base + i,
+				     &trig->subirq_chip);
+			irq_set_handler(trig->subirq_base + i,
+					&handle_simple_irq);
+			irq_modify_status(trig->subirq_base + i,
+					  IRQ_NOREQUEST | IRQ_NOAUTOEN,
+					  IRQ_NOPROBE);
+		}
+		get_device(&trig->dev);
+	}
+	return trig;
+}
+EXPORT_SYMBOL(iio_trigger_alloc);
+
+void iio_trigger_free(struct iio_trigger *trig)
+{
+	if (trig)
+		put_device(&trig->dev);
+}
+EXPORT_SYMBOL(iio_trigger_free);
+
+void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
+{
+	indio_dev->groups[indio_dev->groupcounter++] =
+		&iio_trigger_consumer_attr_group;
+}
+
+void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
+{
+	/* Clean up and associated but not attached triggers references */
+	if (indio_dev->trig)
+		iio_trigger_put(indio_dev->trig);
+}
+
+int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
+{
+	return iio_trigger_attach_poll_func(indio_dev->trig,
+					    indio_dev->pollfunc);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_postenable);
+
+int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
+{
+	return iio_trigger_dettach_poll_func(indio_dev->trig,
+					     indio_dev->pollfunc);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_predisable);