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11#define DRIVER_NAME "smo8800"
12
13#include <linux/fs.h>
14#include <linux/interrupt.h>
15#include <linux/kernel.h>
16#include <linux/miscdevice.h>
17#include <linux/mod_devicetable.h>
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/uaccess.h>
21
22struct smo8800_device {
23 u32 irq;
24 atomic_t counter;
25 struct miscdevice miscdev;
26 unsigned long misc_opened;
27 wait_queue_head_t misc_wait;
28 struct device *dev;
29};
30
31static irqreturn_t smo8800_interrupt_quick(int irq, void *data)
32{
33 struct smo8800_device *smo8800 = data;
34
35 atomic_inc(&smo8800->counter);
36 wake_up_interruptible(&smo8800->misc_wait);
37 return IRQ_WAKE_THREAD;
38}
39
40static irqreturn_t smo8800_interrupt_thread(int irq, void *data)
41{
42 struct smo8800_device *smo8800 = data;
43
44 dev_info(smo8800->dev, "detected free fall\n");
45 return IRQ_HANDLED;
46}
47
48static ssize_t smo8800_misc_read(struct file *file, char __user *buf,
49 size_t count, loff_t *pos)
50{
51 struct smo8800_device *smo8800 = container_of(file->private_data,
52 struct smo8800_device, miscdev);
53
54 u32 data = 0;
55 unsigned char byte_data;
56 ssize_t retval = 1;
57
58 if (count < 1)
59 return -EINVAL;
60
61 atomic_set(&smo8800->counter, 0);
62 retval = wait_event_interruptible(smo8800->misc_wait,
63 (data = atomic_xchg(&smo8800->counter, 0)));
64
65 if (retval)
66 return retval;
67
68 retval = 1;
69
70 if (data < 255)
71 byte_data = data;
72 else
73 byte_data = 255;
74
75 if (put_user(byte_data, buf))
76 retval = -EFAULT;
77
78 return retval;
79}
80
81static int smo8800_misc_open(struct inode *inode, struct file *file)
82{
83 struct smo8800_device *smo8800 = container_of(file->private_data,
84 struct smo8800_device, miscdev);
85
86 if (test_and_set_bit(0, &smo8800->misc_opened))
87 return -EBUSY;
88
89 atomic_set(&smo8800->counter, 0);
90 return 0;
91}
92
93static int smo8800_misc_release(struct inode *inode, struct file *file)
94{
95 struct smo8800_device *smo8800 = container_of(file->private_data,
96 struct smo8800_device, miscdev);
97
98 clear_bit(0, &smo8800->misc_opened);
99 return 0;
100}
101
102static const struct file_operations smo8800_misc_fops = {
103 .owner = THIS_MODULE,
104 .read = smo8800_misc_read,
105 .open = smo8800_misc_open,
106 .release = smo8800_misc_release,
107};
108
109static int smo8800_probe(struct platform_device *device)
110{
111 int err;
112 struct smo8800_device *smo8800;
113
114 smo8800 = devm_kzalloc(&device->dev, sizeof(*smo8800), GFP_KERNEL);
115 if (!smo8800) {
116 dev_err(&device->dev, "failed to allocate device data\n");
117 return -ENOMEM;
118 }
119
120 smo8800->dev = &device->dev;
121 smo8800->miscdev.minor = MISC_DYNAMIC_MINOR;
122 smo8800->miscdev.name = "freefall";
123 smo8800->miscdev.fops = &smo8800_misc_fops;
124
125 init_waitqueue_head(&smo8800->misc_wait);
126
127 err = misc_register(&smo8800->miscdev);
128 if (err) {
129 dev_err(&device->dev, "failed to register misc dev: %d\n", err);
130 return err;
131 }
132
133 platform_set_drvdata(device, smo8800);
134
135 err = platform_get_irq(device, 0);
136 if (err < 0)
137 goto error;
138 smo8800->irq = err;
139
140 err = request_threaded_irq(smo8800->irq, smo8800_interrupt_quick,
141 smo8800_interrupt_thread,
142 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
143 DRIVER_NAME, smo8800);
144 if (err) {
145 dev_err(&device->dev,
146 "failed to request thread for IRQ %d: %d\n",
147 smo8800->irq, err);
148 goto error;
149 }
150
151 dev_dbg(&device->dev, "device /dev/freefall registered with IRQ %d\n",
152 smo8800->irq);
153 return 0;
154
155error:
156 misc_deregister(&smo8800->miscdev);
157 return err;
158}
159
160static int smo8800_remove(struct platform_device *device)
161{
162 struct smo8800_device *smo8800 = platform_get_drvdata(device);
163
164 free_irq(smo8800->irq, smo8800);
165 misc_deregister(&smo8800->miscdev);
166 dev_dbg(&device->dev, "device /dev/freefall unregistered\n");
167 return 0;
168}
169
170
171static const struct acpi_device_id smo8800_ids[] = {
172 { "SMO8800", 0 },
173 { "SMO8801", 0 },
174 { "SMO8810", 0 },
175 { "SMO8811", 0 },
176 { "SMO8820", 0 },
177 { "SMO8821", 0 },
178 { "SMO8830", 0 },
179 { "SMO8831", 0 },
180 { "", 0 },
181};
182MODULE_DEVICE_TABLE(acpi, smo8800_ids);
183
184static struct platform_driver smo8800_driver = {
185 .probe = smo8800_probe,
186 .remove = smo8800_remove,
187 .driver = {
188 .name = DRIVER_NAME,
189 .acpi_match_table = smo8800_ids,
190 },
191};
192module_platform_driver(smo8800_driver);
193
194MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)");
195MODULE_LICENSE("GPL");
196MODULE_AUTHOR("Sonal Santan, Pali Rohár");
197
