diff options
Diffstat (limited to 'drivers/iio/dummy/iio_dummy_evgen.c')
| -rw-r--r-- | drivers/iio/dummy/iio_dummy_evgen.c | 222 |
1 files changed, 222 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 000000000..5a0072727 --- /dev/null +++ b/drivers/iio/dummy/iio_dummy_evgen.c @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2011 Jonathan Cameron + * + * 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_sim.h> + +/* Fiddly bit of faking and irq without hardware */ +#define IIO_EVENTGEN_NO 10 + +/** + * struct iio_dummy_eventgen - event generator specific state + * @regs: irq regs we are faking + * @lock: protect the evgen state + * @inuse: mask of which irqs are connected + * @irq_sim: interrupt simulator + * @base: base of irq range + * @irq_sim_domain: irq simulator domain + */ +struct iio_dummy_eventgen { + struct iio_dummy_regs regs[IIO_EVENTGEN_NO]; + struct mutex lock; + bool inuse[IIO_EVENTGEN_NO]; + struct irq_domain *irq_sim_domain; +}; + +/* We can only ever have one instance of this 'device' */ +static struct iio_dummy_eventgen *iio_evgen; + +static int iio_dummy_evgen_create(void) +{ + int ret; + + iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL); + if (!iio_evgen) + return -ENOMEM; + + iio_evgen->irq_sim_domain = irq_domain_create_sim(NULL, + IIO_EVENTGEN_NO); + if (IS_ERR(iio_evgen->irq_sim_domain)) { + ret = PTR_ERR(iio_evgen->irq_sim_domain); + kfree(iio_evgen); + return ret; + } + + 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 = irq_create_mapping(iio_evgen->irq_sim_domain, 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) +{ + struct irq_data *irqd = irq_get_irq_data(irq); + + mutex_lock(&iio_evgen->lock); + iio_evgen->inuse[irqd_to_hwirq(irqd)] = false; + irq_dispose_mapping(irq); + mutex_unlock(&iio_evgen->lock); +} +EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq); + +struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq) +{ + struct irq_data *irqd = irq_get_irq_data(irq); + + return &iio_evgen->regs[irqd_to_hwirq(irqd)]; + +} +EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs); + +static void iio_dummy_evgen_free(void) +{ + irq_domain_remove_sim(iio_evgen->irq_sim_domain); + 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, irq; + + 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; + + irq = irq_find_mapping(iio_evgen->irq_sim_domain, this_attr->address); + ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true); + if (ret) + return ret; + + 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"); + ret = device_add(&iio_evgen_dev); + if (ret) + put_device(&iio_evgen_dev); + return ret; +} +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"); |