treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / platform / x86 / dell-smo8800.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  dell-smo8800.c - Dell Latitude ACPI SMO88XX freefall sensor driver
4  *
5  *  Copyright (C) 2012 Sonal Santan <sonal.santan@gmail.com>
6  *  Copyright (C) 2014 Pali Rohár <pali.rohar@gmail.com>
7  *
8  *  This is loosely based on lis3lv02d driver.
9  */
10
11 #define DRIVER_NAME "smo8800"
12
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/acpi.h>
16 #include <linux/interrupt.h>
17 #include <linux/miscdevice.h>
18 #include <linux/uaccess.h>
19
20 struct smo8800_device {
21         u32 irq;                     /* acpi device irq */
22         atomic_t counter;            /* count after last read */
23         struct miscdevice miscdev;   /* for /dev/freefall */
24         unsigned long misc_opened;   /* whether the device is open */
25         wait_queue_head_t misc_wait; /* Wait queue for the misc dev */
26         struct device *dev;          /* acpi device */
27 };
28
29 static irqreturn_t smo8800_interrupt_quick(int irq, void *data)
30 {
31         struct smo8800_device *smo8800 = data;
32
33         atomic_inc(&smo8800->counter);
34         wake_up_interruptible(&smo8800->misc_wait);
35         return IRQ_WAKE_THREAD;
36 }
37
38 static irqreturn_t smo8800_interrupt_thread(int irq, void *data)
39 {
40         struct smo8800_device *smo8800 = data;
41
42         dev_info(smo8800->dev, "detected free fall\n");
43         return IRQ_HANDLED;
44 }
45
46 static acpi_status smo8800_get_resource(struct acpi_resource *resource,
47                                         void *context)
48 {
49         struct acpi_resource_extended_irq *irq;
50
51         if (resource->type != ACPI_RESOURCE_TYPE_EXTENDED_IRQ)
52                 return AE_OK;
53
54         irq = &resource->data.extended_irq;
55         if (!irq || !irq->interrupt_count)
56                 return AE_OK;
57
58         *((u32 *)context) = irq->interrupts[0];
59         return AE_CTRL_TERMINATE;
60 }
61
62 static u32 smo8800_get_irq(struct acpi_device *device)
63 {
64         u32 irq = 0;
65         acpi_status status;
66
67         status = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
68                                      smo8800_get_resource, &irq);
69         if (ACPI_FAILURE(status)) {
70                 dev_err(&device->dev, "acpi_walk_resources failed\n");
71                 return 0;
72         }
73
74         return irq;
75 }
76
77 static ssize_t smo8800_misc_read(struct file *file, char __user *buf,
78                                  size_t count, loff_t *pos)
79 {
80         struct smo8800_device *smo8800 = container_of(file->private_data,
81                                          struct smo8800_device, miscdev);
82
83         u32 data = 0;
84         unsigned char byte_data;
85         ssize_t retval = 1;
86
87         if (count < 1)
88                 return -EINVAL;
89
90         atomic_set(&smo8800->counter, 0);
91         retval = wait_event_interruptible(smo8800->misc_wait,
92                                 (data = atomic_xchg(&smo8800->counter, 0)));
93
94         if (retval)
95                 return retval;
96
97         retval = 1;
98
99         if (data < 255)
100                 byte_data = data;
101         else
102                 byte_data = 255;
103
104         if (put_user(byte_data, buf))
105                 retval = -EFAULT;
106
107         return retval;
108 }
109
110 static int smo8800_misc_open(struct inode *inode, struct file *file)
111 {
112         struct smo8800_device *smo8800 = container_of(file->private_data,
113                                          struct smo8800_device, miscdev);
114
115         if (test_and_set_bit(0, &smo8800->misc_opened))
116                 return -EBUSY; /* already open */
117
118         atomic_set(&smo8800->counter, 0);
119         return 0;
120 }
121
122 static int smo8800_misc_release(struct inode *inode, struct file *file)
123 {
124         struct smo8800_device *smo8800 = container_of(file->private_data,
125                                          struct smo8800_device, miscdev);
126
127         clear_bit(0, &smo8800->misc_opened); /* release the device */
128         return 0;
129 }
130
131 static const struct file_operations smo8800_misc_fops = {
132         .owner = THIS_MODULE,
133         .read = smo8800_misc_read,
134         .open = smo8800_misc_open,
135         .release = smo8800_misc_release,
136 };
137
138 static int smo8800_add(struct acpi_device *device)
139 {
140         int err;
141         struct smo8800_device *smo8800;
142
143         smo8800 = devm_kzalloc(&device->dev, sizeof(*smo8800), GFP_KERNEL);
144         if (!smo8800) {
145                 dev_err(&device->dev, "failed to allocate device data\n");
146                 return -ENOMEM;
147         }
148
149         smo8800->dev = &device->dev;
150         smo8800->miscdev.minor = MISC_DYNAMIC_MINOR;
151         smo8800->miscdev.name = "freefall";
152         smo8800->miscdev.fops = &smo8800_misc_fops;
153
154         init_waitqueue_head(&smo8800->misc_wait);
155
156         err = misc_register(&smo8800->miscdev);
157         if (err) {
158                 dev_err(&device->dev, "failed to register misc dev: %d\n", err);
159                 return err;
160         }
161
162         device->driver_data = smo8800;
163
164         smo8800->irq = smo8800_get_irq(device);
165         if (!smo8800->irq) {
166                 dev_err(&device->dev, "failed to obtain IRQ\n");
167                 err = -EINVAL;
168                 goto error;
169         }
170
171         err = request_threaded_irq(smo8800->irq, smo8800_interrupt_quick,
172                                    smo8800_interrupt_thread,
173                                    IRQF_TRIGGER_RISING | IRQF_ONESHOT,
174                                    DRIVER_NAME, smo8800);
175         if (err) {
176                 dev_err(&device->dev,
177                         "failed to request thread for IRQ %d: %d\n",
178                         smo8800->irq, err);
179                 goto error;
180         }
181
182         dev_dbg(&device->dev, "device /dev/freefall registered with IRQ %d\n",
183                  smo8800->irq);
184         return 0;
185
186 error:
187         misc_deregister(&smo8800->miscdev);
188         return err;
189 }
190
191 static int smo8800_remove(struct acpi_device *device)
192 {
193         struct smo8800_device *smo8800 = device->driver_data;
194
195         free_irq(smo8800->irq, smo8800);
196         misc_deregister(&smo8800->miscdev);
197         dev_dbg(&device->dev, "device /dev/freefall unregistered\n");
198         return 0;
199 }
200
201 static const struct acpi_device_id smo8800_ids[] = {
202         { "SMO8800", 0 },
203         { "SMO8801", 0 },
204         { "SMO8810", 0 },
205         { "SMO8811", 0 },
206         { "SMO8820", 0 },
207         { "SMO8821", 0 },
208         { "SMO8830", 0 },
209         { "SMO8831", 0 },
210         { "", 0 },
211 };
212
213 MODULE_DEVICE_TABLE(acpi, smo8800_ids);
214
215 static struct acpi_driver smo8800_driver = {
216         .name = DRIVER_NAME,
217         .class = "Latitude",
218         .ids = smo8800_ids,
219         .ops = {
220                 .add = smo8800_add,
221                 .remove = smo8800_remove,
222         },
223         .owner = THIS_MODULE,
224 };
225
226 module_acpi_driver(smo8800_driver);
227
228 MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)");
229 MODULE_LICENSE("GPL");
230 MODULE_AUTHOR("Sonal Santan, Pali Rohár");