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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#include <linux/fs.h>
20
21struct smo8800_device {
22 u32 irq;
23 atomic_t counter;
24 struct miscdevice miscdev;
25 unsigned long misc_opened;
26 wait_queue_head_t misc_wait;
27 struct device *dev;
28};
29
30static irqreturn_t smo8800_interrupt_quick(int irq, void *data)
31{
32 struct smo8800_device *smo8800 = data;
33
34 atomic_inc(&smo8800->counter);
35 wake_up_interruptible(&smo8800->misc_wait);
36 return IRQ_WAKE_THREAD;
37}
38
39static irqreturn_t smo8800_interrupt_thread(int irq, void *data)
40{
41 struct smo8800_device *smo8800 = data;
42
43 dev_info(smo8800->dev, "detected free fall\n");
44 return IRQ_HANDLED;
45}
46
47static acpi_status smo8800_get_resource(struct acpi_resource *resource,
48 void *context)
49{
50 struct acpi_resource_extended_irq *irq;
51
52 if (resource->type != ACPI_RESOURCE_TYPE_EXTENDED_IRQ)
53 return AE_OK;
54
55 irq = &resource->data.extended_irq;
56 if (!irq || !irq->interrupt_count)
57 return AE_OK;
58
59 *((u32 *)context) = irq->interrupts[0];
60 return AE_CTRL_TERMINATE;
61}
62
63static u32 smo8800_get_irq(struct acpi_device *device)
64{
65 u32 irq = 0;
66 acpi_status status;
67
68 status = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
69 smo8800_get_resource, &irq);
70 if (ACPI_FAILURE(status)) {
71 dev_err(&device->dev, "acpi_walk_resources failed\n");
72 return 0;
73 }
74
75 return irq;
76}
77
78static ssize_t smo8800_misc_read(struct file *file, char __user *buf,
79 size_t count, loff_t *pos)
80{
81 struct smo8800_device *smo8800 = container_of(file->private_data,
82 struct smo8800_device, miscdev);
83
84 u32 data = 0;
85 unsigned char byte_data;
86 ssize_t retval = 1;
87
88 if (count < 1)
89 return -EINVAL;
90
91 atomic_set(&smo8800->counter, 0);
92 retval = wait_event_interruptible(smo8800->misc_wait,
93 (data = atomic_xchg(&smo8800->counter, 0)));
94
95 if (retval)
96 return retval;
97
98 retval = 1;
99
100 if (data < 255)
101 byte_data = data;
102 else
103 byte_data = 255;
104
105 if (put_user(byte_data, buf))
106 retval = -EFAULT;
107
108 return retval;
109}
110
111static int smo8800_misc_open(struct inode *inode, struct file *file)
112{
113 struct smo8800_device *smo8800 = container_of(file->private_data,
114 struct smo8800_device, miscdev);
115
116 if (test_and_set_bit(0, &smo8800->misc_opened))
117 return -EBUSY;
118
119 atomic_set(&smo8800->counter, 0);
120 return 0;
121}
122
123static int smo8800_misc_release(struct inode *inode, struct file *file)
124{
125 struct smo8800_device *smo8800 = container_of(file->private_data,
126 struct smo8800_device, miscdev);
127
128 clear_bit(0, &smo8800->misc_opened);
129 return 0;
130}
131
132static const struct file_operations smo8800_misc_fops = {
133 .owner = THIS_MODULE,
134 .read = smo8800_misc_read,
135 .open = smo8800_misc_open,
136 .release = smo8800_misc_release,
137};
138
139static int smo8800_add(struct acpi_device *device)
140{
141 int err;
142 struct smo8800_device *smo8800;
143
144 smo8800 = devm_kzalloc(&device->dev, sizeof(*smo8800), GFP_KERNEL);
145 if (!smo8800) {
146 dev_err(&device->dev, "failed to allocate device data\n");
147 return -ENOMEM;
148 }
149
150 smo8800->dev = &device->dev;
151 smo8800->miscdev.minor = MISC_DYNAMIC_MINOR;
152 smo8800->miscdev.name = "freefall";
153 smo8800->miscdev.fops = &smo8800_misc_fops;
154
155 init_waitqueue_head(&smo8800->misc_wait);
156
157 err = misc_register(&smo8800->miscdev);
158 if (err) {
159 dev_err(&device->dev, "failed to register misc dev: %d\n", err);
160 return err;
161 }
162
163 device->driver_data = smo8800;
164
165 smo8800->irq = smo8800_get_irq(device);
166 if (!smo8800->irq) {
167 dev_err(&device->dev, "failed to obtain IRQ\n");
168 err = -EINVAL;
169 goto error;
170 }
171
172 err = request_threaded_irq(smo8800->irq, smo8800_interrupt_quick,
173 smo8800_interrupt_thread,
174 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
175 DRIVER_NAME, smo8800);
176 if (err) {
177 dev_err(&device->dev,
178 "failed to request thread for IRQ %d: %d\n",
179 smo8800->irq, err);
180 goto error;
181 }
182
183 dev_dbg(&device->dev, "device /dev/freefall registered with IRQ %d\n",
184 smo8800->irq);
185 return 0;
186
187error:
188 misc_deregister(&smo8800->miscdev);
189 return err;
190}
191
192static int smo8800_remove(struct acpi_device *device)
193{
194 struct smo8800_device *smo8800 = device->driver_data;
195
196 free_irq(smo8800->irq, smo8800);
197 misc_deregister(&smo8800->miscdev);
198 dev_dbg(&device->dev, "device /dev/freefall unregistered\n");
199 return 0;
200}
201
202
203static const struct acpi_device_id smo8800_ids[] = {
204 { "SMO8800", 0 },
205 { "SMO8801", 0 },
206 { "SMO8810", 0 },
207 { "SMO8811", 0 },
208 { "SMO8820", 0 },
209 { "SMO8821", 0 },
210 { "SMO8830", 0 },
211 { "SMO8831", 0 },
212 { "", 0 },
213};
214
215MODULE_DEVICE_TABLE(acpi, smo8800_ids);
216
217static struct acpi_driver smo8800_driver = {
218 .name = DRIVER_NAME,
219 .class = "Latitude",
220 .ids = smo8800_ids,
221 .ops = {
222 .add = smo8800_add,
223 .remove = smo8800_remove,
224 },
225 .owner = THIS_MODULE,
226};
227
228module_acpi_driver(smo8800_driver);
229
230MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)");
231MODULE_LICENSE("GPL");
232MODULE_AUTHOR("Sonal Santan, Pali Rohár");
233
