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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#include <linux/uaccess.h>
28
29struct smo8800_device {
30 u32 irq;
31 atomic_t counter;
32 struct miscdevice miscdev;
33 unsigned long misc_opened;
34 wait_queue_head_t misc_wait;
35 struct device *dev;
36};
37
38static irqreturn_t smo8800_interrupt_quick(int irq, void *data)
39{
40 struct smo8800_device *smo8800 = data;
41
42 atomic_inc(&smo8800->counter);
43 wake_up_interruptible(&smo8800->misc_wait);
44 return IRQ_WAKE_THREAD;
45}
46
47static irqreturn_t smo8800_interrupt_thread(int irq, void *data)
48{
49 struct smo8800_device *smo8800 = data;
50
51 dev_info(smo8800->dev, "detected free fall\n");
52 return IRQ_HANDLED;
53}
54
55static acpi_status smo8800_get_resource(struct acpi_resource *resource,
56 void *context)
57{
58 struct acpi_resource_extended_irq *irq;
59
60 if (resource->type != ACPI_RESOURCE_TYPE_EXTENDED_IRQ)
61 return AE_OK;
62
63 irq = &resource->data.extended_irq;
64 if (!irq || !irq->interrupt_count)
65 return AE_OK;
66
67 *((u32 *)context) = irq->interrupts[0];
68 return AE_CTRL_TERMINATE;
69}
70
71static u32 smo8800_get_irq(struct acpi_device *device)
72{
73 u32 irq = 0;
74 acpi_status status;
75
76 status = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
77 smo8800_get_resource, &irq);
78 if (ACPI_FAILURE(status)) {
79 dev_err(&device->dev, "acpi_walk_resources failed\n");
80 return 0;
81 }
82
83 return irq;
84}
85
86static ssize_t smo8800_misc_read(struct file *file, char __user *buf,
87 size_t count, loff_t *pos)
88{
89 struct smo8800_device *smo8800 = container_of(file->private_data,
90 struct smo8800_device, miscdev);
91
92 u32 data = 0;
93 unsigned char byte_data = 0;
94 ssize_t retval = 1;
95
96 if (count < 1)
97 return -EINVAL;
98
99 atomic_set(&smo8800->counter, 0);
100 retval = wait_event_interruptible(smo8800->misc_wait,
101 (data = atomic_xchg(&smo8800->counter, 0)));
102
103 if (retval)
104 return retval;
105
106 byte_data = 1;
107 retval = 1;
108
109 if (data < 255)
110 byte_data = data;
111 else
112 byte_data = 255;
113
114 if (put_user(byte_data, buf))
115 retval = -EFAULT;
116
117 return retval;
118}
119
120static int smo8800_misc_open(struct inode *inode, struct file *file)
121{
122 struct smo8800_device *smo8800 = container_of(file->private_data,
123 struct smo8800_device, miscdev);
124
125 if (test_and_set_bit(0, &smo8800->misc_opened))
126 return -EBUSY;
127
128 atomic_set(&smo8800->counter, 0);
129 return 0;
130}
131
132static int smo8800_misc_release(struct inode *inode, struct file *file)
133{
134 struct smo8800_device *smo8800 = container_of(file->private_data,
135 struct smo8800_device, miscdev);
136
137 clear_bit(0, &smo8800->misc_opened);
138 return 0;
139}
140
141static const struct file_operations smo8800_misc_fops = {
142 .owner = THIS_MODULE,
143 .read = smo8800_misc_read,
144 .open = smo8800_misc_open,
145 .release = smo8800_misc_release,
146};
147
148static int smo8800_add(struct acpi_device *device)
149{
150 int err;
151 struct smo8800_device *smo8800;
152
153 smo8800 = devm_kzalloc(&device->dev, sizeof(*smo8800), GFP_KERNEL);
154 if (!smo8800) {
155 dev_err(&device->dev, "failed to allocate device data\n");
156 return -ENOMEM;
157 }
158
159 smo8800->dev = &device->dev;
160 smo8800->miscdev.minor = MISC_DYNAMIC_MINOR;
161 smo8800->miscdev.name = "freefall";
162 smo8800->miscdev.fops = &smo8800_misc_fops;
163
164 init_waitqueue_head(&smo8800->misc_wait);
165
166 err = misc_register(&smo8800->miscdev);
167 if (err) {
168 dev_err(&device->dev, "failed to register misc dev: %d\n", err);
169 return err;
170 }
171
172 device->driver_data = smo8800;
173
174 smo8800->irq = smo8800_get_irq(device);
175 if (!smo8800->irq) {
176 dev_err(&device->dev, "failed to obtain IRQ\n");
177 err = -EINVAL;
178 goto error;
179 }
180
181 err = request_threaded_irq(smo8800->irq, smo8800_interrupt_quick,
182 smo8800_interrupt_thread,
183 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
184 DRIVER_NAME, smo8800);
185 if (err) {
186 dev_err(&device->dev,
187 "failed to request thread for IRQ %d: %d\n",
188 smo8800->irq, err);
189 goto error;
190 }
191
192 dev_dbg(&device->dev, "device /dev/freefall registered with IRQ %d\n",
193 smo8800->irq);
194 return 0;
195
196error:
197 misc_deregister(&smo8800->miscdev);
198 return err;
199}
200
201static int smo8800_remove(struct acpi_device *device)
202{
203 struct smo8800_device *smo8800 = device->driver_data;
204
205 free_irq(smo8800->irq, smo8800);
206 misc_deregister(&smo8800->miscdev);
207 dev_dbg(&device->dev, "device /dev/freefall unregistered\n");
208 return 0;
209}
210
211static const struct acpi_device_id smo8800_ids[] = {
212 { "SMO8800", 0 },
213 { "SMO8801", 0 },
214 { "SMO8810", 0 },
215 { "SMO8811", 0 },
216 { "SMO8820", 0 },
217 { "SMO8821", 0 },
218 { "SMO8830", 0 },
219 { "SMO8831", 0 },
220 { "", 0 },
221};
222
223MODULE_DEVICE_TABLE(acpi, smo8800_ids);
224
225static struct acpi_driver smo8800_driver = {
226 .name = DRIVER_NAME,
227 .class = "Latitude",
228 .ids = smo8800_ids,
229 .ops = {
230 .add = smo8800_add,
231 .remove = smo8800_remove,
232 },
233 .owner = THIS_MODULE,
234};
235
236module_acpi_driver(smo8800_driver);
237
238MODULE_DESCRIPTION("Dell Latitude freefall driver (ACPI SMO88XX)");
239MODULE_LICENSE("GPL");
240MODULE_AUTHOR("Sonal Santan, Pali Rohár");
241
