staging:iio:dummy Add event support + fake event generator
The event generator is not very pretty but does the job and
allows this driver to look a lot more like a normal driver
than it otherwise would.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/iio/iio_dummy_evgen.c b/drivers/staging/iio/iio_dummy_evgen.c
new file mode 100644
index 0000000..da657d1
--- /dev/null
+++ b/drivers/staging/iio/iio_dummy_evgen.c
@@ -0,0 +1,217 @@
+/**
+ * Copyright (c) 2011 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.
+ *
+ * Companion module to the iio simple dummy example driver.
+ * The purpose of this is to generate 'fake' event interrupts thus
+ * allowing that driver's code to be as close as possible to that of
+ * a normal driver talking to hardware. The approach used here
+ * is not intended to be general and just happens to work for this
+ * particular use case.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/sysfs.h>
+
+#include "iio_dummy_evgen.h"
+#include "iio.h"
+#include "sysfs.h"
+
+/* Fiddly bit of faking and irq without hardware */
+#define IIO_EVENTGEN_NO 10
+/**
+ * struct iio_dummy_evgen - evgen state
+ * @chip: irq chip we are faking
+ * @base: base of irq range
+ * @enabled: mask of which irqs are enabled
+ * @inuse: mask of which irqs actually have anyone connected
+ * @lock: protect the evgen state
+ */
+struct iio_dummy_eventgen {
+ struct irq_chip chip;
+ int base;
+ bool enabled[IIO_EVENTGEN_NO];
+ bool inuse[IIO_EVENTGEN_NO];
+ struct mutex lock;
+};
+
+/* We can only ever have one instance of this 'device' */
+static struct iio_dummy_eventgen *iio_evgen;
+static const char *iio_evgen_name = "iio_dummy_evgen";
+
+static void iio_dummy_event_irqmask(struct irq_data *d)
+{
+ struct irq_chip *chip = irq_data_get_irq_chip(d);
+ struct iio_dummy_eventgen *evgen =
+ container_of(chip, struct iio_dummy_eventgen, chip);
+
+ evgen->enabled[d->irq - evgen->base] = false;
+}
+
+static void iio_dummy_event_irqunmask(struct irq_data *d)
+{
+ struct irq_chip *chip = irq_data_get_irq_chip(d);
+ struct iio_dummy_eventgen *evgen =
+ container_of(chip, struct iio_dummy_eventgen, chip);
+
+ evgen->enabled[d->irq - evgen->base] = true;
+}
+
+static int iio_dummy_evgen_create(void)
+{
+ int ret, i;
+
+ iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
+ if (iio_evgen == NULL)
+ return -ENOMEM;
+
+ iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
+ if (iio_evgen->base < 0) {
+ ret = iio_evgen->base;
+ kfree(iio_evgen);
+ return ret;
+ }
+ iio_evgen->chip.name = iio_evgen_name;
+ iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
+ iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
+ for (i = 0; i < IIO_EVENTGEN_NO; i++) {
+ irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
+ irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
+ irq_modify_status(iio_evgen->base + i,
+ IRQ_NOREQUEST | IRQ_NOAUTOEN,
+ IRQ_NOPROBE);
+ }
+ mutex_init(&iio_evgen->lock);
+ return 0;
+}
+
+/**
+ * iio_dummy_evgen_get_irq() - get an evgen provided irq for a device
+ *
+ * This function will give a free allocated irq to a client device.
+ * That irq can then be caused to 'fire' by using the associated sysfs file.
+ */
+int iio_dummy_evgen_get_irq(void)
+{
+ int i, ret = 0;
+ mutex_lock(&iio_evgen->lock);
+ for (i = 0; i < IIO_EVENTGEN_NO; i++)
+ if (iio_evgen->inuse[i] == false) {
+ ret = iio_evgen->base + i;
+ iio_evgen->inuse[i] = true;
+ break;
+ }
+ mutex_unlock(&iio_evgen->lock);
+ if (i == IIO_EVENTGEN_NO)
+ return -ENOMEM;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
+
+/**
+ * iio_dummy_evgen_release_irq() - give the irq back.
+ * @irq: irq being returned to the pool
+ *
+ * Used by client driver instances to give the irqs back when they disconnect
+ */
+int iio_dummy_evgen_release_irq(int irq)
+{
+ mutex_lock(&iio_evgen->lock);
+ iio_evgen->inuse[irq - iio_evgen->base] = false;
+ mutex_unlock(&iio_evgen->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
+
+static void iio_dummy_evgen_free(void)
+{
+ irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
+ kfree(iio_evgen);
+}
+
+static void iio_evgen_release(struct device *dev)
+{
+ iio_dummy_evgen_free();
+}
+
+static ssize_t iio_evgen_poke(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t len)
+{
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+ if (iio_evgen->enabled[this_attr->address])
+ handle_nested_irq(iio_evgen->base + this_attr->address);
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
+static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
+static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
+static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
+static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
+static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
+static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
+static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
+static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
+static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);
+
+static struct attribute *iio_evgen_attrs[] = {
+ &iio_dev_attr_poke_ev0.dev_attr.attr,
+ &iio_dev_attr_poke_ev1.dev_attr.attr,
+ &iio_dev_attr_poke_ev2.dev_attr.attr,
+ &iio_dev_attr_poke_ev3.dev_attr.attr,
+ &iio_dev_attr_poke_ev4.dev_attr.attr,
+ &iio_dev_attr_poke_ev5.dev_attr.attr,
+ &iio_dev_attr_poke_ev6.dev_attr.attr,
+ &iio_dev_attr_poke_ev7.dev_attr.attr,
+ &iio_dev_attr_poke_ev8.dev_attr.attr,
+ &iio_dev_attr_poke_ev9.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group iio_evgen_group = {
+ .attrs = iio_evgen_attrs,
+};
+
+static const struct attribute_group *iio_evgen_groups[] = {
+ &iio_evgen_group,
+ NULL
+};
+
+static struct device iio_evgen_dev = {
+ .bus = &iio_bus_type,
+ .groups = iio_evgen_groups,
+ .release = &iio_evgen_release,
+};
+static __init int iio_dummy_evgen_init(void)
+{
+ int ret = iio_dummy_evgen_create();
+ if (ret < 0)
+ return ret;
+ device_initialize(&iio_evgen_dev);
+ dev_set_name(&iio_evgen_dev, "iio_evgen");
+ return device_add(&iio_evgen_dev);
+}
+module_init(iio_dummy_evgen_init);
+
+static __exit void iio_dummy_evgen_exit(void)
+{
+ device_unregister(&iio_evgen_dev);
+}
+module_exit(iio_dummy_evgen_exit);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
+MODULE_DESCRIPTION("IIO dummy driver");
+MODULE_LICENSE("GPL v2");