1 // SPDX-License-Identifier: GPL-2.0
3  * GNSS receiver core
13 #include <linux/gnss.h>
41 	gdev = container_of(inode->i_cdev, struct gnss_device, cdev);  in gnss_open()
43 	get_device(&gdev->dev);  in gnss_open()
46 	file->private_data = gdev;  in gnss_open()
48 	down_write(&gdev->rwsem);  in gnss_open()
49 	if (gdev->disconnected) {  in gnss_open()
50 		ret = -ENODEV;  in gnss_open()
54 	if (gdev->count++ == 0) {  in gnss_open()
55 		ret = gdev->ops->open(gdev);  in gnss_open()
57 			gdev->count--;  in gnss_open()
60 	up_write(&gdev->rwsem);  in gnss_open()
63 		put_device(&gdev->dev);  in gnss_open()
70 	struct gnss_device *gdev = file->private_data;  in gnss_release()
72 	down_write(&gdev->rwsem);  in gnss_release()
73 	if (gdev->disconnected)  in gnss_release()
76 	if (--gdev->count == 0) {  in gnss_release()
77 		gdev->ops->close(gdev);  in gnss_release()
78 		kfifo_reset(&gdev->read_fifo);  in gnss_release()
81 	up_write(&gdev->rwsem);  in gnss_release()
83 	put_device(&gdev->dev);  in gnss_release()
91 	struct gnss_device *gdev = file->private_data;  in gnss_read()
95 	mutex_lock(&gdev->read_mutex);  in gnss_read()
96 	while (kfifo_is_empty(&gdev->read_fifo)) {  in gnss_read()
97 		mutex_unlock(&gdev->read_mutex);  in gnss_read()
99 		if (gdev->disconnected)  in gnss_read()
102 		if (file->f_flags & O_NONBLOCK)  in gnss_read()
103 			return -EAGAIN;  in gnss_read()
105 		ret = wait_event_interruptible(gdev->read_queue,  in gnss_read()
106 				gdev->disconnected ||  in gnss_read()
107 				!kfifo_is_empty(&gdev->read_fifo));  in gnss_read()
109 			return -ERESTARTSYS;  in gnss_read()
111 		mutex_lock(&gdev->read_mutex);  in gnss_read()
114 	ret = kfifo_to_user(&gdev->read_fifo, buf, count, &copied);  in gnss_read()
118 	mutex_unlock(&gdev->read_mutex);  in gnss_read()
126 	struct gnss_device *gdev = file->private_data;  in gnss_write()
130 	if (gdev->disconnected)  in gnss_write()
131 		return -EIO;  in gnss_write()
136 	if (!(gdev->flags & GNSS_FLAG_HAS_WRITE_RAW))  in gnss_write()
137 		return -EIO;  in gnss_write()
141 	ret = mutex_lock_interruptible(&gdev->write_mutex);  in gnss_write()
143 		return -ERESTARTSYS;  in gnss_write()
146 		size_t n = count - written;  in gnss_write()
151 		if (copy_from_user(gdev->write_buf, buf, n)) {  in gnss_write()
152 			ret = -EFAULT;  in gnss_write()
162 		down_read(&gdev->rwsem);  in gnss_write()
163 		if (!gdev->disconnected)  in gnss_write()
164 			ret = gdev->ops->write_raw(gdev, gdev->write_buf, n);  in gnss_write()
166 			ret = -EIO;  in gnss_write()
167 		up_read(&gdev->rwsem);  in gnss_write()
182 	mutex_unlock(&gdev->write_mutex);  in gnss_write()
189 	struct gnss_device *gdev = file->private_data;  in gnss_poll()
192 	poll_wait(file, &gdev->read_queue, wait);  in gnss_poll()
194 	if (!kfifo_is_empty(&gdev->read_fifo))  in gnss_poll()
196 	if (gdev->disconnected)  in gnss_poll()
217 	kfree(gdev->write_buf);  in gnss_device_release()
218 	kfifo_free(&gdev->read_fifo);  in gnss_device_release()
219 	ida_free(&gnss_minors, gdev->id);  in gnss_device_release()
234 	id = ida_alloc_max(&gnss_minors, GNSS_MINORS - 1, GFP_KERNEL);  in gnss_allocate_device()
240 	gdev->id = id;  in gnss_allocate_device()
242 	dev = &gdev->dev;  in gnss_allocate_device()
244 	dev->devt = gnss_first + id;  in gnss_allocate_device()
245 	dev->class = gnss_class;  in gnss_allocate_device()
246 	dev->parent = parent;  in gnss_allocate_device()
247 	dev->release = gnss_device_release;  in gnss_allocate_device()
249 	dev_set_name(dev, "gnss%d", id);  in gnss_allocate_device()
251 	init_rwsem(&gdev->rwsem);  in gnss_allocate_device()
252 	mutex_init(&gdev->read_mutex);  in gnss_allocate_device()
253 	mutex_init(&gdev->write_mutex);  in gnss_allocate_device()
254 	init_waitqueue_head(&gdev->read_queue);  in gnss_allocate_device()
256 	ret = kfifo_alloc(&gdev->read_fifo, GNSS_READ_FIFO_SIZE, GFP_KERNEL);  in gnss_allocate_device()
260 	gdev->write_buf = kzalloc(GNSS_WRITE_BUF_SIZE, GFP_KERNEL);  in gnss_allocate_device()
261 	if (!gdev->write_buf)  in gnss_allocate_device()
264 	cdev_init(&gdev->cdev, &gnss_fops);  in gnss_allocate_device()
265 	gdev->cdev.owner = THIS_MODULE;  in gnss_allocate_device()
278 	put_device(&gdev->dev);  in gnss_put_device()
287 	if (gdev->ops->write_raw != NULL)  in gnss_register_device()
288 		gdev->flags |= GNSS_FLAG_HAS_WRITE_RAW;  in gnss_register_device()
290 	ret = cdev_device_add(&gdev->cdev, &gdev->dev);  in gnss_register_device()
292 		dev_err(&gdev->dev, "failed to add device: %d\n", ret);  in gnss_register_device()
302 	down_write(&gdev->rwsem);  in gnss_deregister_device()
303 	gdev->disconnected = true;  in gnss_deregister_device()
304 	if (gdev->count) {  in gnss_deregister_device()
305 		wake_up_interruptible(&gdev->read_queue);  in gnss_deregister_device()
306 		gdev->ops->close(gdev);  in gnss_deregister_device()
308 	up_write(&gdev->rwsem);  in gnss_deregister_device()
310 	cdev_device_del(&gdev->cdev, &gdev->dev);  in gnss_deregister_device()
324 	ret = kfifo_in(&gdev->read_fifo, buf, count);  in gnss_insert_raw()
326 	wake_up_interruptible(&gdev->read_queue);  in gnss_insert_raw()
343 	if (gdev->type < GNSS_TYPE_COUNT)  in gnss_type_name()
344 		name = gnss_type_names[gdev->type];  in gnss_type_name()
347 		dev_WARN(&gdev->dev, "type name not defined\n");  in gnss_type_name()
365 ATTRIBUTE_GROUPS(gnss);
383 	ret = alloc_chrdev_region(&gnss_first, 0, GNSS_MINORS, "gnss");  in gnss_module_init()
389 	gnss_class = class_create("gnss");  in gnss_module_init()
396 	gnss_class->dev_groups = gnss_groups;  in gnss_module_init()
397 	gnss_class->dev_uevent = gnss_uevent;  in gnss_module_init()
399 	pr_info("GNSS driver registered with major %d\n", MAJOR(gnss_first));  in gnss_module_init()
419 MODULE_DESCRIPTION("GNSS receiver core");