root/drivers/iio/dummy/iio_dummy_evgen.c

DEFINITIONS

1. iio_dummy_evgen_create
2. iio_dummy_evgen_get_irq
3. iio_dummy_evgen_release_irq
4. iio_dummy_evgen_get_regs
5. iio_dummy_evgen_free
6. iio_evgen_release
7. iio_evgen_poke
8. iio_dummy_evgen_init
9. iio_dummy_evgen_exit

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /**
   3  * Copyright (c) 2011 Jonathan Cameron
   4  *
   5  * Companion module to the iio simple dummy example driver.
   6  * The purpose of this is to generate 'fake' event interrupts thus
   7  * allowing that driver's code to be as close as possible to that of
   8  * a normal driver talking to hardware.  The approach used here
   9  * is not intended to be general and just happens to work for this
  10  * 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 10
  28 
  29 /**
  30  * @regs: irq regs we are faking
  31  * @lock: protect the evgen state
  32  * @inuse: mask of which irqs are connected
  33  * @irq_sim: interrupt simulator
  34  * @base: base of irq range
  35  */
  36 struct 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_sim irq_sim;
  41         int base;
  42 };
  43 
  44 /* We can only ever have one instance of this 'device' */
  45 static struct iio_dummy_eventgen *iio_evgen;
  46 
  47 static int iio_dummy_evgen_create(void)
  48 {
  49         int ret;
  50 
  51         iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
  52         if (!iio_evgen)
  53                 return -ENOMEM;
  54 
  55         ret = irq_sim_init(&iio_evgen->irq_sim, IIO_EVENTGEN_NO);
  56         if (ret < 0) {
  57                 kfree(iio_evgen);
  58                 return ret;
  59         }
  60 
  61         iio_evgen->base = irq_sim_irqnum(&iio_evgen->irq_sim, 0);
  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 device
  69  *
  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  */
  73 int 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_sim_irqnum(&iio_evgen->irq_sim, 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 }
  94 EXPORT_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 pool
  99  *
 100  * Used by client driver instances to give the irqs back when they disconnect
 101  */
 102 void iio_dummy_evgen_release_irq(int irq)
 103 {
 104         mutex_lock(&iio_evgen->lock);
 105         iio_evgen->inuse[irq - iio_evgen->base] = false;
 106         mutex_unlock(&iio_evgen->lock);
 107 }
 108 EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
 109 
 110 struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
 111 {
 112         return &iio_evgen->regs[irq - iio_evgen->base];
 113 }
 114 EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
 115 
 116 static void iio_dummy_evgen_free(void)
 117 {
 118         irq_sim_fini(&iio_evgen->irq_sim);
 119         kfree(iio_evgen);
 120 }
 121 
 122 static void iio_evgen_release(struct device *dev)
 123 {
 124         iio_dummy_evgen_free();
 125 }
 126 
 127 static ssize_t iio_evgen_poke(struct device *dev,
 128                               struct device_attribute *attr,
 129                               const char *buf,
 130                               size_t len)
 131 {
 132         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 133         unsigned long event;
 134         int ret;
 135 
 136         ret = kstrtoul(buf, 10, &event);
 137         if (ret)
 138                 return ret;
 139 
 140         iio_evgen->regs[this_attr->address].reg_id   = this_attr->address;
 141         iio_evgen->regs[this_attr->address].reg_data = event;
 142 
 143         irq_sim_fire(&iio_evgen->irq_sim, this_attr->address);
 144 
 145         return len;
 146 }
 147 
 148 static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
 149 static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
 150 static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
 151 static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
 152 static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
 153 static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
 154 static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
 155 static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
 156 static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
 157 static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);
 158 
 159 static struct attribute *iio_evgen_attrs[] = {
 160         &iio_dev_attr_poke_ev0.dev_attr.attr,
 161         &iio_dev_attr_poke_ev1.dev_attr.attr,
 162         &iio_dev_attr_poke_ev2.dev_attr.attr,
 163         &iio_dev_attr_poke_ev3.dev_attr.attr,
 164         &iio_dev_attr_poke_ev4.dev_attr.attr,
 165         &iio_dev_attr_poke_ev5.dev_attr.attr,
 166         &iio_dev_attr_poke_ev6.dev_attr.attr,
 167         &iio_dev_attr_poke_ev7.dev_attr.attr,
 168         &iio_dev_attr_poke_ev8.dev_attr.attr,
 169         &iio_dev_attr_poke_ev9.dev_attr.attr,
 170         NULL,
 171 };
 172 
 173 static const struct attribute_group iio_evgen_group = {
 174         .attrs = iio_evgen_attrs,
 175 };
 176 
 177 static const struct attribute_group *iio_evgen_groups[] = {
 178         &iio_evgen_group,
 179         NULL
 180 };
 181 
 182 static struct device iio_evgen_dev = {
 183         .bus = &iio_bus_type,
 184         .groups = iio_evgen_groups,
 185         .release = &iio_evgen_release,
 186 };
 187 
 188 static __init int iio_dummy_evgen_init(void)
 189 {
 190         int ret = iio_dummy_evgen_create();
 191 
 192         if (ret < 0)
 193                 return ret;
 194         device_initialize(&iio_evgen_dev);
 195         dev_set_name(&iio_evgen_dev, "iio_evgen");
 196         ret = device_add(&iio_evgen_dev);
 197         if (ret)
 198                 put_device(&iio_evgen_dev);
 199         return ret;
 200 }
 201 module_init(iio_dummy_evgen_init);
 202 
 203 static __exit void iio_dummy_evgen_exit(void)
 204 {
 205         device_unregister(&iio_evgen_dev);
 206 }
 207 module_exit(iio_dummy_evgen_exit);
 208 
 209 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 210 MODULE_DESCRIPTION("IIO dummy driver");
 211 MODULE_LICENSE("GPL v2");