/** * 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 #include #include #include #include #include #include #include "iio_dummy_evgen.h" #include #include #include /* 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 "); MODULE_DESCRIPTION("IIO dummy driver"); MODULE_LICENSE("GPL v2");