diff options
Diffstat (limited to 'drivers/iio/dummy/iio_dummy_evgen.c')
| -rw-r--r-- | drivers/iio/dummy/iio_dummy_evgen.c | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/drivers/iio/dummy/iio_dummy_evgen.c b/drivers/iio/dummy/iio_dummy_evgen.c new file mode 100644 index 000000000000..9e83f348df51 --- /dev/null +++ b/drivers/iio/dummy/iio_dummy_evgen.c @@ -0,0 +1,262 @@ +/** + * 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 <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/irq_work.h> + +/* Fiddly bit of faking and irq without hardware */ +#define IIO_EVENTGEN_NO 10 + +/** + * struct iio_dummy_handle_irq - helper struct to simulate interrupt generation + * @work: irq_work used to run handlers from hardirq context + * @irq: fake irq line number to trigger an interrupt + */ +struct iio_dummy_handle_irq { + struct irq_work work; + int irq; +}; + +/** + * 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 are connected + * @regs: irq regs we are faking + * @lock: protect the evgen state + * @handler: helper for a 'hardware-like' interrupt simulation + */ +struct iio_dummy_eventgen { + struct irq_chip chip; + int base; + bool enabled[IIO_EVENTGEN_NO]; + bool inuse[IIO_EVENTGEN_NO]; + struct iio_dummy_regs regs[IIO_EVENTGEN_NO]; + struct mutex lock; + struct iio_dummy_handle_irq handler; +}; + +/* 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 void iio_dummy_work_handler(struct irq_work *work) +{ + struct iio_dummy_handle_irq *irq_handler; + + irq_handler = container_of(work, struct iio_dummy_handle_irq, work); + handle_simple_irq(irq_to_desc(irq_handler->irq)); +} + +static int iio_dummy_evgen_create(void) +{ + int ret, i; + + iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL); + if (!iio_evgen) + 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); + } + init_irq_work(&iio_evgen->handler.work, iio_dummy_work_handler); + 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; + + if (!iio_evgen) + return -ENODEV; + + mutex_lock(&iio_evgen->lock); + for (i = 0; i < IIO_EVENTGEN_NO; i++) + if (!iio_evgen->inuse[i]) { + 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 + */ +void 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); +} +EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq); + +struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq) +{ + return &iio_evgen->regs[irq - iio_evgen->base]; +} +EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs); + +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); + unsigned long event; + int ret; + + ret = kstrtoul(buf, 10, &event); + if (ret) + return ret; + + iio_evgen->regs[this_attr->address].reg_id = this_attr->address; + iio_evgen->regs[this_attr->address].reg_data = event; + + iio_evgen->handler.irq = iio_evgen->base + this_attr->address; + if (iio_evgen->enabled[this_attr->address]) + irq_work_queue(&iio_evgen->handler.work); + + 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@kernel.org>"); +MODULE_DESCRIPTION("IIO dummy driver"); +MODULE_LICENSE("GPL v2"); |