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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (c) 2011 Jonathan Cameron4 *5 * Companion module to the iio simple dummy example driver.6 * The purpose of this is to generate 'fake' event interrupts thus7 * allowing that driver's code to be as close as possible to that of8 * a normal driver talking to hardware. The approach used here9 * is not intended to be general and just happens to work for this10 * particular use case.11 */12 13#include <linux/kernel.h>14#include <linux/slab.h>15#include <linux/interrupt.h>16#include <linux/irq.h>17#include <linux/mutex.h>18#include <linux/module.h>19#include <linux/sysfs.h>20 21#include "iio_dummy_evgen.h"22#include <linux/iio/iio.h>23#include <linux/iio/sysfs.h>24#include <linux/irq_sim.h>25 26/* Fiddly bit of faking and irq without hardware */27#define IIO_EVENTGEN_NO 1028 29/**30 * struct iio_dummy_eventgen - event generator specific state31 * @regs: irq regs we are faking32 * @lock: protect the evgen state33 * @inuse: mask of which irqs are connected34 * @irq_sim_domain: irq simulator domain35 */36struct iio_dummy_eventgen {37 struct iio_dummy_regs regs[IIO_EVENTGEN_NO];38 struct mutex lock;39 bool inuse[IIO_EVENTGEN_NO];40 struct irq_domain *irq_sim_domain;41};42 43/* We can only ever have one instance of this 'device' */44static struct iio_dummy_eventgen *iio_evgen;45 46static int iio_dummy_evgen_create(void)47{48 int ret;49 50 iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);51 if (!iio_evgen)52 return -ENOMEM;53 54 iio_evgen->irq_sim_domain = irq_domain_create_sim(NULL,55 IIO_EVENTGEN_NO);56 if (IS_ERR(iio_evgen->irq_sim_domain)) {57 ret = PTR_ERR(iio_evgen->irq_sim_domain);58 kfree(iio_evgen);59 return ret;60 }61 62 mutex_init(&iio_evgen->lock);63 64 return 0;65}66 67/**68 * iio_dummy_evgen_get_irq() - get an evgen provided irq for a device69 *70 * This function will give a free allocated irq to a client device.71 * That irq can then be caused to 'fire' by using the associated sysfs file.72 */73int iio_dummy_evgen_get_irq(void)74{75 int i, ret = 0;76 77 if (!iio_evgen)78 return -ENODEV;79 80 mutex_lock(&iio_evgen->lock);81 for (i = 0; i < IIO_EVENTGEN_NO; i++) {82 if (!iio_evgen->inuse[i]) {83 ret = irq_create_mapping(iio_evgen->irq_sim_domain, i);84 iio_evgen->inuse[i] = true;85 break;86 }87 }88 mutex_unlock(&iio_evgen->lock);89 if (i == IIO_EVENTGEN_NO)90 return -ENOMEM;91 92 return ret;93}94EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);95 96/**97 * iio_dummy_evgen_release_irq() - give the irq back.98 * @irq: irq being returned to the pool99 *100 * Used by client driver instances to give the irqs back when they disconnect101 */102void iio_dummy_evgen_release_irq(int irq)103{104 struct irq_data *irqd = irq_get_irq_data(irq);105 106 mutex_lock(&iio_evgen->lock);107 iio_evgen->inuse[irqd_to_hwirq(irqd)] = false;108 irq_dispose_mapping(irq);109 mutex_unlock(&iio_evgen->lock);110}111EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);112 113struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)114{115 struct irq_data *irqd = irq_get_irq_data(irq);116 117 return &iio_evgen->regs[irqd_to_hwirq(irqd)];118 119}120EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);121 122static void iio_dummy_evgen_free(void)123{124 irq_domain_remove_sim(iio_evgen->irq_sim_domain);125 kfree(iio_evgen);126}127 128static void iio_evgen_release(struct device *dev)129{130 iio_dummy_evgen_free();131}132 133static ssize_t iio_evgen_poke(struct device *dev,134 struct device_attribute *attr,135 const char *buf,136 size_t len)137{138 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);139 unsigned long event;140 int ret, irq;141 142 ret = kstrtoul(buf, 10, &event);143 if (ret)144 return ret;145 146 iio_evgen->regs[this_attr->address].reg_id = this_attr->address;147 iio_evgen->regs[this_attr->address].reg_data = event;148 149 irq = irq_find_mapping(iio_evgen->irq_sim_domain, this_attr->address);150 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true);151 if (ret)152 return ret;153 154 return len;155}156 157static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);158static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);159static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);160static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);161static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);162static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);163static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);164static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);165static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);166static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);167 168static struct attribute *iio_evgen_attrs[] = {169 &iio_dev_attr_poke_ev0.dev_attr.attr,170 &iio_dev_attr_poke_ev1.dev_attr.attr,171 &iio_dev_attr_poke_ev2.dev_attr.attr,172 &iio_dev_attr_poke_ev3.dev_attr.attr,173 &iio_dev_attr_poke_ev4.dev_attr.attr,174 &iio_dev_attr_poke_ev5.dev_attr.attr,175 &iio_dev_attr_poke_ev6.dev_attr.attr,176 &iio_dev_attr_poke_ev7.dev_attr.attr,177 &iio_dev_attr_poke_ev8.dev_attr.attr,178 &iio_dev_attr_poke_ev9.dev_attr.attr,179 NULL,180};181 182static const struct attribute_group iio_evgen_group = {183 .attrs = iio_evgen_attrs,184};185 186static const struct attribute_group *iio_evgen_groups[] = {187 &iio_evgen_group,188 NULL189};190 191static struct device iio_evgen_dev = {192 .bus = &iio_bus_type,193 .groups = iio_evgen_groups,194 .release = &iio_evgen_release,195};196 197static __init int iio_dummy_evgen_init(void)198{199 int ret = iio_dummy_evgen_create();200 201 if (ret < 0)202 return ret;203 device_initialize(&iio_evgen_dev);204 dev_set_name(&iio_evgen_dev, "iio_evgen");205 ret = device_add(&iio_evgen_dev);206 if (ret)207 put_device(&iio_evgen_dev);208 return ret;209}210module_init(iio_dummy_evgen_init);211 212static __exit void iio_dummy_evgen_exit(void)213{214 device_unregister(&iio_evgen_dev);215}216module_exit(iio_dummy_evgen_exit);217 218MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");219MODULE_DESCRIPTION("IIO dummy driver");220MODULE_LICENSE("GPL v2");221