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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>
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Jonathan Cameron
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Greg Kroah-Hartman
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Oct 17, 2011
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -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" | ||
|
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||
| /* 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); | ||
|
|
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| 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); | ||
|
|
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| evgen->enabled[d->irq - evgen->base] = true; | ||
| } | ||
|
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| static int iio_dummy_evgen_create(void) | ||
| { | ||
| int ret, i; | ||
|
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| 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); | ||
|
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| static void iio_dummy_evgen_free(void) | ||
| { | ||
| irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO); | ||
| kfree(iio_evgen); | ||
| } | ||
|
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| static void iio_evgen_release(struct device *dev) | ||
| { | ||
| iio_dummy_evgen_free(); | ||
| } | ||
|
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| 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); | ||
|
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| if (iio_evgen->enabled[this_attr->address]) | ||
| handle_nested_irq(iio_evgen->base + this_attr->address); | ||
|
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| return len; | ||
| } | ||
|
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| 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); | ||
|
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| 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, | ||
| }; | ||
|
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| static const struct attribute_group iio_evgen_group = { | ||
| .attrs = iio_evgen_attrs, | ||
| }; | ||
|
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| static const struct attribute_group *iio_evgen_groups[] = { | ||
| &iio_evgen_group, | ||
| NULL | ||
| }; | ||
|
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| 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); | ||
|
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| static __exit void iio_dummy_evgen_exit(void) | ||
| { | ||
| device_unregister(&iio_evgen_dev); | ||
| } | ||
| module_exit(iio_dummy_evgen_exit); | ||
|
|
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| MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>"); | ||
| MODULE_DESCRIPTION("IIO dummy driver"); | ||
| MODULE_LICENSE("GPL v2"); |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,2 @@ | ||
| int iio_dummy_evgen_get_irq(void); | ||
| int iio_dummy_evgen_release_irq(int irq); |
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