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4738d8aa | 1 | /* |
e4da9142 | 2 | * dell-smo8800.c - Dell Latitude ACPI SMO88XX freefall sensor driver |
4738d8aa PR |
3 | * |
4 | * Copyright (C) 2012 Sonal Santan <sonal.santan@gmail.com> | |
5 | * Copyright (C) 2014 Pali Rohár <pali.rohar@gmail.com> | |
6 | * | |
7 | * This is loosely based on lis3lv02d driver. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | */ | |
19 | ||
20 | #define DRIVER_NAME "smo8800" | |
21 | ||
22 | #include <linux/kernel.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/acpi.h> | |
25 | #include <linux/interrupt.h> | |
26 | #include <linux/miscdevice.h> | |
27 | ||
28 | struct smo8800_device { | |
29 | u32 irq; /* acpi device irq */ | |
30 | atomic_t counter; /* count after last read */ | |
31 | struct miscdevice miscdev; /* for /dev/freefall */ | |
32 | unsigned long misc_opened; /* whether the device is open */ | |
33 | wait_queue_head_t misc_wait; /* Wait queue for the misc dev */ | |
34 | struct device *dev; /* acpi device */ | |
35 | }; | |
36 | ||
37 | static irqreturn_t smo8800_interrupt_quick(int irq, void *data) | |
38 | { | |
39 | struct smo8800_device *smo8800 = data; | |
40 | ||
41 | atomic_inc(&smo8800->counter); | |
42 | wake_up_interruptible(&smo8800->misc_wait); | |
43 | return IRQ_WAKE_THREAD; | |
44 | } | |
45 | ||
46 | static irqreturn_t smo8800_interrupt_thread(int irq, void *data) | |
47 | { | |
48 | struct smo8800_device *smo8800 = data; | |
49 | ||
50 | dev_info(smo8800->dev, "detected free fall\n"); | |
51 | return IRQ_HANDLED; | |
52 | } | |
53 | ||
54 | static acpi_status smo8800_get_resource(struct acpi_resource *resource, | |
55 | void *context) | |
56 | { | |
57 | struct acpi_resource_extended_irq *irq; | |
58 | ||
59 | if (resource->type != ACPI_RESOURCE_TYPE_EXTENDED_IRQ) | |
60 | return AE_OK; | |
61 | ||
62 | irq = &resource->data.extended_irq; | |
63 | if (!irq || !irq->interrupt_count) | |
64 | return AE_OK; | |
65 | ||
66 | *((u32 *)context) = irq->interrupts[0]; | |
67 | return AE_CTRL_TERMINATE; | |
68 | } | |
69 | ||
70 | static u32 smo8800_get_irq(struct acpi_device *device) | |
71 | { | |
72 | u32 irq = 0; | |
73 | acpi_status status; | |
74 | ||
75 | status = acpi_walk_resources(device->handle, METHOD_NAME__CRS, | |
76 | smo8800_get_resource, &irq); | |
77 | if (ACPI_FAILURE(status)) { | |
78 | dev_err(&device->dev, "acpi_walk_resources failed\n"); | |
79 | return 0; | |
80 | } | |
81 | ||
82 | return irq; | |
83 | } | |
84 | ||
85 | static ssize_t smo8800_misc_read(struct file *file, char __user *buf, | |
86 | size_t count, loff_t *pos) | |
87 | { | |
88 | struct smo8800_device *smo8800 = container_of(file->private_data, | |
89 | struct smo8800_device, miscdev); | |
90 | ||
91 | u32 data = 0; | |
92 | unsigned char byte_data = 0; | |
93 | ssize_t retval = 1; | |
94 | ||
95 | if (count < 1) | |
96 | return -EINVAL; | |
97 | ||
98 | atomic_set(&smo8800->counter, 0); | |
99 | retval = wait_event_interruptible(smo8800->misc_wait, | |
100 | (data = atomic_xchg(&smo8800->counter, 0))); | |
101 | ||
102 | if (retval) | |
103 | return retval; | |
104 | ||
105 | byte_data = 1; | |
106 | retval = 1; | |
107 | ||
108 | if (data < 255) | |
109 | byte_data = data; | |
110 | else | |
111 | byte_data = 255; | |
112 | ||
113 | if (put_user(byte_data, buf)) | |
114 | retval = -EFAULT; | |
115 | ||
116 | return retval; | |
117 | } | |
118 | ||
119 | static int smo8800_misc_open(struct inode *inode, struct file *file) | |
120 | { | |
121 | struct smo8800_device *smo8800 = container_of(file->private_data, | |
122 | struct smo8800_device, miscdev); | |
123 | ||
124 | if (test_and_set_bit(0, &smo8800->misc_opened)) | |
125 | return -EBUSY; /* already open */ | |
126 | ||
127 | atomic_set(&smo8800->counter, 0); | |
128 | return 0; | |
129 | } | |
130 | ||
131 | static int smo8800_misc_release(struct inode *inode, struct file *file) | |
132 | { | |
133 | struct smo8800_device *smo8800 = container_of(file->private_data, | |
134 | struct smo8800_device, miscdev); | |
135 | ||
136 | clear_bit(0, &smo8800->misc_opened); /* release the device */ | |
137 | return 0; | |
138 | } | |
139 | ||
140 | static const struct file_operations smo8800_misc_fops = { | |
141 | .owner = THIS_MODULE, | |
142 | .read = smo8800_misc_read, | |
143 | .open = smo8800_misc_open, | |
144 | .release = smo8800_misc_release, | |
145 | }; | |
146 | ||
147 | static int smo8800_add(struct acpi_device *device) | |
148 | { | |
149 | int err; | |
150 | struct smo8800_device *smo8800; | |
151 | ||
152 | smo8800 = devm_kzalloc(&device->dev, sizeof(*smo8800), GFP_KERNEL); | |
153 | if (!smo8800) { | |
154 | dev_err(&device->dev, "failed to allocate device data\n"); | |
155 | return -ENOMEM; | |
156 | } | |
157 | ||
158 | smo8800->dev = &device->dev; | |
159 | smo8800->miscdev.minor = MISC_DYNAMIC_MINOR; | |
160 | smo8800->miscdev.name = "freefall"; | |
161 | smo8800->miscdev.fops = &smo8800_misc_fops; | |
162 | ||
163 | init_waitqueue_head(&smo8800->misc_wait); | |
164 | ||
165 | err = misc_register(&smo8800->miscdev); | |
166 | if (err) { | |
167 | dev_err(&device->dev, "failed to register misc dev: %d\n", err); | |
168 | return err; | |
169 | } | |
170 | ||
171 | device->driver_data = smo8800; | |
172 | ||
173 | smo8800->irq = smo8800_get_irq(device); | |
174 | if (!smo8800->irq) { | |
175 | dev_err(&device->dev, "failed to obtain IRQ\n"); | |
176 | err = -EINVAL; | |
177 | goto error; | |
178 | } | |
179 | ||
180 | err = request_threaded_irq(smo8800->irq, smo8800_interrupt_quick, | |
181 | smo8800_interrupt_thread, | |
182 | IRQF_TRIGGER_RISING | IRQF_ONESHOT, | |
183 | DRIVER_NAME, smo8800); | |
184 | if (err) { | |
185 | dev_err(&device->dev, | |
186 | "failed to request thread for IRQ %d: %d\n", | |
187 | smo8800->irq, err); | |
188 | goto error; | |
189 | } | |
190 | ||
191 | dev_dbg(&device->dev, "device /dev/freefall registered with IRQ %d\n", | |
192 | smo8800->irq); | |
193 | return 0; | |
194 | ||
195 | error: | |
196 | misc_deregister(&smo8800->miscdev); | |
197 | return err; | |
198 | } | |
199 | ||
200 | static int smo8800_remove(struct acpi_device *device) | |
201 | { | |
202 | struct smo8800_device *smo8800 = device->driver_data; | |
203 | ||
204 | free_irq(smo8800->irq, smo8800); | |
205 | misc_deregister(&smo8800->miscdev); | |
206 | dev_dbg(&device->dev, "device /dev/freefall unregistered\n"); | |
207 | return 0; | |
208 | } | |
209 | ||
210 | static const struct acpi_device_id smo8800_ids[] = { | |
211 | { "SMO8800", 0 }, | |
e4da9142 | 212 | { "SMO8801", 0 }, |
4738d8aa | 213 | { "SMO8810", 0 }, |
e4da9142 PR |
214 | { "SMO8811", 0 }, |
215 | { "SMO8820", 0 }, | |
216 | { "SMO8821", 0 }, | |
217 | { "SMO8830", 0 }, | |
218 | { "SMO8831", 0 }, | |
4738d8aa PR |
219 | { "", 0 }, |
220 | }; | |
221 | ||
222 | MODULE_DEVICE_TABLE(acpi, smo8800_ids); | |
223 | ||
224 | static struct acpi_driver smo8800_driver = { | |
225 | .name = DRIVER_NAME, | |
226 | .class = "Latitude", | |
227 | .ids = smo8800_ids, | |
228 | .ops = { | |
229 | .add = smo8800_add, | |
230 | .remove = smo8800_remove, | |
231 | }, | |
232 | .owner = THIS_MODULE, | |
233 | }; | |
234 | ||
235 | module_acpi_driver(smo8800_driver); | |
236 | ||
e4da9142 | 237 | MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)"); |
4738d8aa PR |
238 | MODULE_LICENSE("GPL"); |
239 | MODULE_AUTHOR("Sonal Santan, Pali Rohár"); |