Jonathan Cameron | e647700 | 2011-10-14 16:34:14 +0100 | [diff] [blame] | 1 | /** |
| 2 | * Copyright (c) 2011 Jonathan Cameron |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU General Public License version 2 as published by |
| 6 | * the Free Software Foundation. |
| 7 | * |
| 8 | * Companion module to the iio simple dummy example driver. |
| 9 | * The purpose of this is to generate 'fake' event interrupts thus |
| 10 | * allowing that driver's code to be as close as possible to that of |
| 11 | * a normal driver talking to hardware. The approach used here |
| 12 | * is not intended to be general and just happens to work for this |
| 13 | * particular use case. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/interrupt.h> |
| 19 | #include <linux/irq.h> |
| 20 | #include <linux/mutex.h> |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/sysfs.h> |
| 23 | |
| 24 | #include "iio_dummy_evgen.h" |
| 25 | #include "iio.h" |
| 26 | #include "sysfs.h" |
| 27 | |
| 28 | /* Fiddly bit of faking and irq without hardware */ |
| 29 | #define IIO_EVENTGEN_NO 10 |
| 30 | /** |
| 31 | * struct iio_dummy_evgen - evgen state |
| 32 | * @chip: irq chip we are faking |
| 33 | * @base: base of irq range |
| 34 | * @enabled: mask of which irqs are enabled |
Justin P. Mattock | 4abf6f8 | 2012-02-29 22:00:38 -0800 | [diff] [blame] | 35 | * @inuse: mask of which irqs are connected |
Jonathan Cameron | e647700 | 2011-10-14 16:34:14 +0100 | [diff] [blame] | 36 | * @lock: protect the evgen state |
| 37 | */ |
| 38 | struct iio_dummy_eventgen { |
| 39 | struct irq_chip chip; |
| 40 | int base; |
| 41 | bool enabled[IIO_EVENTGEN_NO]; |
| 42 | bool inuse[IIO_EVENTGEN_NO]; |
| 43 | struct mutex lock; |
| 44 | }; |
| 45 | |
| 46 | /* We can only ever have one instance of this 'device' */ |
| 47 | static struct iio_dummy_eventgen *iio_evgen; |
| 48 | static const char *iio_evgen_name = "iio_dummy_evgen"; |
| 49 | |
| 50 | static void iio_dummy_event_irqmask(struct irq_data *d) |
| 51 | { |
| 52 | struct irq_chip *chip = irq_data_get_irq_chip(d); |
| 53 | struct iio_dummy_eventgen *evgen = |
| 54 | container_of(chip, struct iio_dummy_eventgen, chip); |
| 55 | |
| 56 | evgen->enabled[d->irq - evgen->base] = false; |
| 57 | } |
| 58 | |
| 59 | static void iio_dummy_event_irqunmask(struct irq_data *d) |
| 60 | { |
| 61 | struct irq_chip *chip = irq_data_get_irq_chip(d); |
| 62 | struct iio_dummy_eventgen *evgen = |
| 63 | container_of(chip, struct iio_dummy_eventgen, chip); |
| 64 | |
| 65 | evgen->enabled[d->irq - evgen->base] = true; |
| 66 | } |
| 67 | |
| 68 | static int iio_dummy_evgen_create(void) |
| 69 | { |
| 70 | int ret, i; |
| 71 | |
| 72 | iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL); |
| 73 | if (iio_evgen == NULL) |
| 74 | return -ENOMEM; |
| 75 | |
| 76 | iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0); |
| 77 | if (iio_evgen->base < 0) { |
| 78 | ret = iio_evgen->base; |
| 79 | kfree(iio_evgen); |
| 80 | return ret; |
| 81 | } |
| 82 | iio_evgen->chip.name = iio_evgen_name; |
| 83 | iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask; |
| 84 | iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask; |
| 85 | for (i = 0; i < IIO_EVENTGEN_NO; i++) { |
| 86 | irq_set_chip(iio_evgen->base + i, &iio_evgen->chip); |
| 87 | irq_set_handler(iio_evgen->base + i, &handle_simple_irq); |
| 88 | irq_modify_status(iio_evgen->base + i, |
| 89 | IRQ_NOREQUEST | IRQ_NOAUTOEN, |
| 90 | IRQ_NOPROBE); |
| 91 | } |
| 92 | mutex_init(&iio_evgen->lock); |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | /** |
| 97 | * iio_dummy_evgen_get_irq() - get an evgen provided irq for a device |
| 98 | * |
| 99 | * This function will give a free allocated irq to a client device. |
| 100 | * That irq can then be caused to 'fire' by using the associated sysfs file. |
| 101 | */ |
| 102 | int iio_dummy_evgen_get_irq(void) |
| 103 | { |
| 104 | int i, ret = 0; |
Sasha Levin | 5ae8f44 | 2011-11-22 08:02:21 +0200 | [diff] [blame] | 105 | |
| 106 | if (iio_evgen == NULL) |
| 107 | return -ENODEV; |
| 108 | |
Jonathan Cameron | e647700 | 2011-10-14 16:34:14 +0100 | [diff] [blame] | 109 | mutex_lock(&iio_evgen->lock); |
| 110 | for (i = 0; i < IIO_EVENTGEN_NO; i++) |
| 111 | if (iio_evgen->inuse[i] == false) { |
| 112 | ret = iio_evgen->base + i; |
| 113 | iio_evgen->inuse[i] = true; |
| 114 | break; |
| 115 | } |
| 116 | mutex_unlock(&iio_evgen->lock); |
| 117 | if (i == IIO_EVENTGEN_NO) |
| 118 | return -ENOMEM; |
| 119 | return ret; |
| 120 | } |
| 121 | EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq); |
| 122 | |
| 123 | /** |
| 124 | * iio_dummy_evgen_release_irq() - give the irq back. |
| 125 | * @irq: irq being returned to the pool |
| 126 | * |
| 127 | * Used by client driver instances to give the irqs back when they disconnect |
| 128 | */ |
| 129 | int iio_dummy_evgen_release_irq(int irq) |
| 130 | { |
| 131 | mutex_lock(&iio_evgen->lock); |
| 132 | iio_evgen->inuse[irq - iio_evgen->base] = false; |
| 133 | mutex_unlock(&iio_evgen->lock); |
| 134 | |
| 135 | return 0; |
| 136 | } |
| 137 | EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq); |
| 138 | |
| 139 | static void iio_dummy_evgen_free(void) |
| 140 | { |
| 141 | irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO); |
| 142 | kfree(iio_evgen); |
| 143 | } |
| 144 | |
| 145 | static void iio_evgen_release(struct device *dev) |
| 146 | { |
| 147 | iio_dummy_evgen_free(); |
| 148 | } |
| 149 | |
| 150 | static ssize_t iio_evgen_poke(struct device *dev, |
| 151 | struct device_attribute *attr, |
| 152 | const char *buf, |
| 153 | size_t len) |
| 154 | { |
| 155 | struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); |
| 156 | |
| 157 | if (iio_evgen->enabled[this_attr->address]) |
| 158 | handle_nested_irq(iio_evgen->base + this_attr->address); |
| 159 | |
| 160 | return len; |
| 161 | } |
| 162 | |
| 163 | static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0); |
| 164 | static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1); |
| 165 | static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2); |
| 166 | static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3); |
| 167 | static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4); |
| 168 | static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5); |
| 169 | static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6); |
| 170 | static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7); |
| 171 | static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8); |
| 172 | static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9); |
| 173 | |
| 174 | static struct attribute *iio_evgen_attrs[] = { |
| 175 | &iio_dev_attr_poke_ev0.dev_attr.attr, |
| 176 | &iio_dev_attr_poke_ev1.dev_attr.attr, |
| 177 | &iio_dev_attr_poke_ev2.dev_attr.attr, |
| 178 | &iio_dev_attr_poke_ev3.dev_attr.attr, |
| 179 | &iio_dev_attr_poke_ev4.dev_attr.attr, |
| 180 | &iio_dev_attr_poke_ev5.dev_attr.attr, |
| 181 | &iio_dev_attr_poke_ev6.dev_attr.attr, |
| 182 | &iio_dev_attr_poke_ev7.dev_attr.attr, |
| 183 | &iio_dev_attr_poke_ev8.dev_attr.attr, |
| 184 | &iio_dev_attr_poke_ev9.dev_attr.attr, |
| 185 | NULL, |
| 186 | }; |
| 187 | |
| 188 | static const struct attribute_group iio_evgen_group = { |
| 189 | .attrs = iio_evgen_attrs, |
| 190 | }; |
| 191 | |
| 192 | static const struct attribute_group *iio_evgen_groups[] = { |
| 193 | &iio_evgen_group, |
| 194 | NULL |
| 195 | }; |
| 196 | |
| 197 | static struct device iio_evgen_dev = { |
| 198 | .bus = &iio_bus_type, |
| 199 | .groups = iio_evgen_groups, |
| 200 | .release = &iio_evgen_release, |
| 201 | }; |
| 202 | static __init int iio_dummy_evgen_init(void) |
| 203 | { |
| 204 | int ret = iio_dummy_evgen_create(); |
| 205 | if (ret < 0) |
| 206 | return ret; |
| 207 | device_initialize(&iio_evgen_dev); |
| 208 | dev_set_name(&iio_evgen_dev, "iio_evgen"); |
| 209 | return device_add(&iio_evgen_dev); |
| 210 | } |
| 211 | module_init(iio_dummy_evgen_init); |
| 212 | |
| 213 | static __exit void iio_dummy_evgen_exit(void) |
| 214 | { |
| 215 | device_unregister(&iio_evgen_dev); |
| 216 | } |
| 217 | module_exit(iio_dummy_evgen_exit); |
| 218 | |
| 219 | MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>"); |
| 220 | MODULE_DESCRIPTION("IIO dummy driver"); |
| 221 | MODULE_LICENSE("GPL v2"); |