1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Generic USB GNSS receiver driver |
4 | * |
5 | * Copyright (C) 2021 Johan Hovold <johan@kernel.org> |
6 | */ |
7 | |
8 | #include <linux/errno.h> |
9 | #include <linux/gnss.h> |
10 | #include <linux/init.h> |
11 | #include <linux/kernel.h> |
12 | #include <linux/module.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/usb.h> |
15 | |
16 | #define GNSS_USB_READ_BUF_LEN 512 |
17 | #define GNSS_USB_WRITE_TIMEOUT 1000 |
18 | |
19 | static const struct usb_device_id gnss_usb_id_table[] = { |
20 | { USB_DEVICE(0x1199, 0xb000) }, /* Sierra Wireless XM1210 */ |
21 | { } |
22 | }; |
23 | MODULE_DEVICE_TABLE(usb, gnss_usb_id_table); |
24 | |
25 | struct gnss_usb { |
26 | struct usb_device *udev; |
27 | struct usb_interface *intf; |
28 | struct gnss_device *gdev; |
29 | struct urb *read_urb; |
30 | unsigned int write_pipe; |
31 | }; |
32 | |
33 | static void gnss_usb_rx_complete(struct urb *urb) |
34 | { |
35 | struct gnss_usb *gusb = urb->context; |
36 | struct gnss_device *gdev = gusb->gdev; |
37 | int status = urb->status; |
38 | int len; |
39 | int ret; |
40 | |
41 | switch (status) { |
42 | case 0: |
43 | break; |
44 | case -ENOENT: |
45 | case -ECONNRESET: |
46 | case -ESHUTDOWN: |
47 | dev_dbg(&gdev->dev, "urb stopped: %d\n" , status); |
48 | return; |
49 | case -EPIPE: |
50 | dev_err(&gdev->dev, "urb stopped: %d\n" , status); |
51 | return; |
52 | default: |
53 | dev_dbg(&gdev->dev, "nonzero urb status: %d\n" , status); |
54 | goto resubmit; |
55 | } |
56 | |
57 | len = urb->actual_length; |
58 | if (len == 0) |
59 | goto resubmit; |
60 | |
61 | ret = gnss_insert_raw(gdev, buf: urb->transfer_buffer, count: len); |
62 | if (ret < len) |
63 | dev_dbg(&gdev->dev, "dropped %d bytes\n" , len - ret); |
64 | resubmit: |
65 | ret = usb_submit_urb(urb, GFP_ATOMIC); |
66 | if (ret && ret != -EPERM && ret != -ENODEV) |
67 | dev_err(&gdev->dev, "failed to resubmit urb: %d\n" , ret); |
68 | } |
69 | |
70 | static int gnss_usb_open(struct gnss_device *gdev) |
71 | { |
72 | struct gnss_usb *gusb = gnss_get_drvdata(gdev); |
73 | int ret; |
74 | |
75 | ret = usb_submit_urb(urb: gusb->read_urb, GFP_KERNEL); |
76 | if (ret) { |
77 | if (ret != -EPERM && ret != -ENODEV) |
78 | dev_err(&gdev->dev, "failed to submit urb: %d\n" , ret); |
79 | return ret; |
80 | } |
81 | |
82 | return 0; |
83 | } |
84 | |
85 | static void gnss_usb_close(struct gnss_device *gdev) |
86 | { |
87 | struct gnss_usb *gusb = gnss_get_drvdata(gdev); |
88 | |
89 | usb_kill_urb(urb: gusb->read_urb); |
90 | } |
91 | |
92 | static int gnss_usb_write_raw(struct gnss_device *gdev, |
93 | const unsigned char *buf, size_t count) |
94 | { |
95 | struct gnss_usb *gusb = gnss_get_drvdata(gdev); |
96 | void *tbuf; |
97 | int ret; |
98 | |
99 | tbuf = kmemdup(p: buf, size: count, GFP_KERNEL); |
100 | if (!tbuf) |
101 | return -ENOMEM; |
102 | |
103 | ret = usb_bulk_msg(usb_dev: gusb->udev, pipe: gusb->write_pipe, data: tbuf, len: count, NULL, |
104 | GNSS_USB_WRITE_TIMEOUT); |
105 | kfree(objp: tbuf); |
106 | if (ret) |
107 | return ret; |
108 | |
109 | return count; |
110 | } |
111 | |
112 | static const struct gnss_operations gnss_usb_gnss_ops = { |
113 | .open = gnss_usb_open, |
114 | .close = gnss_usb_close, |
115 | .write_raw = gnss_usb_write_raw, |
116 | }; |
117 | |
118 | static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id) |
119 | { |
120 | struct usb_device *udev = interface_to_usbdev(intf); |
121 | struct usb_endpoint_descriptor *in, *out; |
122 | struct gnss_device *gdev; |
123 | struct gnss_usb *gusb; |
124 | struct urb *urb; |
125 | size_t buf_len; |
126 | void *buf; |
127 | int ret; |
128 | |
129 | ret = usb_find_common_endpoints(alt: intf->cur_altsetting, bulk_in: &in, bulk_out: &out, NULL, |
130 | NULL); |
131 | if (ret) |
132 | return ret; |
133 | |
134 | gusb = kzalloc(size: sizeof(*gusb), GFP_KERNEL); |
135 | if (!gusb) |
136 | return -ENOMEM; |
137 | |
138 | gdev = gnss_allocate_device(parent: &intf->dev); |
139 | if (!gdev) { |
140 | ret = -ENOMEM; |
141 | goto err_free_gusb; |
142 | } |
143 | |
144 | gdev->ops = &gnss_usb_gnss_ops; |
145 | gdev->type = GNSS_TYPE_NMEA; |
146 | gnss_set_drvdata(gdev, data: gusb); |
147 | |
148 | urb = usb_alloc_urb(iso_packets: 0, GFP_KERNEL); |
149 | if (!urb) { |
150 | ret = -ENOMEM; |
151 | goto err_put_gdev; |
152 | } |
153 | |
154 | buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN); |
155 | |
156 | buf = kzalloc(size: buf_len, GFP_KERNEL); |
157 | if (!buf) { |
158 | ret = -ENOMEM; |
159 | goto err_free_urb; |
160 | } |
161 | |
162 | usb_fill_bulk_urb(urb, dev: udev, |
163 | usb_rcvbulkpipe(udev, usb_endpoint_num(in)), |
164 | transfer_buffer: buf, buffer_length: buf_len, complete_fn: gnss_usb_rx_complete, context: gusb); |
165 | |
166 | gusb->intf = intf; |
167 | gusb->udev = udev; |
168 | gusb->gdev = gdev; |
169 | gusb->read_urb = urb; |
170 | gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out)); |
171 | |
172 | ret = gnss_register_device(gdev); |
173 | if (ret) |
174 | goto err_free_buf; |
175 | |
176 | usb_set_intfdata(intf, data: gusb); |
177 | |
178 | return 0; |
179 | |
180 | err_free_buf: |
181 | kfree(objp: buf); |
182 | err_free_urb: |
183 | usb_free_urb(urb); |
184 | err_put_gdev: |
185 | gnss_put_device(gdev); |
186 | err_free_gusb: |
187 | kfree(objp: gusb); |
188 | |
189 | return ret; |
190 | } |
191 | |
192 | static void gnss_usb_disconnect(struct usb_interface *intf) |
193 | { |
194 | struct gnss_usb *gusb = usb_get_intfdata(intf); |
195 | |
196 | gnss_deregister_device(gdev: gusb->gdev); |
197 | |
198 | kfree(objp: gusb->read_urb->transfer_buffer); |
199 | usb_free_urb(urb: gusb->read_urb); |
200 | gnss_put_device(gdev: gusb->gdev); |
201 | kfree(objp: gusb); |
202 | } |
203 | |
204 | static struct usb_driver gnss_usb_driver = { |
205 | .name = "gnss-usb" , |
206 | .probe = gnss_usb_probe, |
207 | .disconnect = gnss_usb_disconnect, |
208 | .id_table = gnss_usb_id_table, |
209 | }; |
210 | module_usb_driver(gnss_usb_driver); |
211 | |
212 | MODULE_AUTHOR("Johan Hovold <johan@kernel.org>" ); |
213 | MODULE_DESCRIPTION("Generic USB GNSS receiver driver" ); |
214 | MODULE_LICENSE("GPL v2" ); |
215 | |