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 | * struct iio_dummy_eventgen - event generator specific state |
31 | * @regs: irq regs we are faking |
32 | * @lock: protect the evgen state |
33 | * @inuse: mask of which irqs are connected |
34 | * @irq_sim_domain: irq simulator domain |
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_domain *irq_sim_domain; |
41 | }; |
42 | |
43 | /* We can only ever have one instance of this 'device' */ |
44 | static struct iio_dummy_eventgen *iio_evgen; |
45 | |
46 | static int iio_dummy_evgen_create(void) |
47 | { |
48 | int ret; |
49 | |
50 | iio_evgen = kzalloc(size: 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(ptr: iio_evgen->irq_sim_domain)) { |
57 | ret = PTR_ERR(ptr: iio_evgen->irq_sim_domain); |
58 | kfree(objp: 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 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_create_mapping(host: iio_evgen->irq_sim_domain, hwirq: i); |
84 | iio_evgen->inuse[i] = true; |
85 | break; |
86 | } |
87 | } |
88 | mutex_unlock(lock: &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 | struct irq_data *irqd = irq_get_irq_data(irq); |
105 | |
106 | mutex_lock(&iio_evgen->lock); |
107 | iio_evgen->inuse[irqd_to_hwirq(d: irqd)] = false; |
108 | irq_dispose_mapping(virq: irq); |
109 | mutex_unlock(lock: &iio_evgen->lock); |
110 | } |
111 | EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq); |
112 | |
113 | struct 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(d: irqd)]; |
118 | |
119 | } |
120 | EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs); |
121 | |
122 | static void iio_dummy_evgen_free(void) |
123 | { |
124 | irq_domain_remove_sim(domain: iio_evgen->irq_sim_domain); |
125 | kfree(objp: iio_evgen); |
126 | } |
127 | |
128 | static void iio_evgen_release(struct device *dev) |
129 | { |
130 | iio_dummy_evgen_free(); |
131 | } |
132 | |
133 | static 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(s: buf, base: 10, res: &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(domain: iio_evgen->irq_sim_domain, hwirq: this_attr->address); |
150 | ret = irq_set_irqchip_state(irq, which: IRQCHIP_STATE_PENDING, state: true); |
151 | if (ret) |
152 | return ret; |
153 | |
154 | return len; |
155 | } |
156 | |
157 | static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0); |
158 | static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1); |
159 | static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2); |
160 | static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3); |
161 | static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4); |
162 | static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5); |
163 | static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6); |
164 | static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7); |
165 | static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8); |
166 | static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9); |
167 | |
168 | static 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 | |
182 | static const struct attribute_group iio_evgen_group = { |
183 | .attrs = iio_evgen_attrs, |
184 | }; |
185 | |
186 | static const struct attribute_group *iio_evgen_groups[] = { |
187 | &iio_evgen_group, |
188 | NULL |
189 | }; |
190 | |
191 | static struct device iio_evgen_dev = { |
192 | .bus = &iio_bus_type, |
193 | .groups = iio_evgen_groups, |
194 | .release = &iio_evgen_release, |
195 | }; |
196 | |
197 | static __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(dev: &iio_evgen_dev); |
204 | dev_set_name(dev: &iio_evgen_dev, name: "iio_evgen" ); |
205 | ret = device_add(dev: &iio_evgen_dev); |
206 | if (ret) |
207 | put_device(dev: &iio_evgen_dev); |
208 | return ret; |
209 | } |
210 | module_init(iio_dummy_evgen_init); |
211 | |
212 | static __exit void iio_dummy_evgen_exit(void) |
213 | { |
214 | device_unregister(dev: &iio_evgen_dev); |
215 | } |
216 | module_exit(iio_dummy_evgen_exit); |
217 | |
218 | MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>" ); |
219 | MODULE_DESCRIPTION("IIO dummy driver" ); |
220 | MODULE_LICENSE("GPL v2" ); |
221 | |