drivers/gnss/usb.c

   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, urb->transfer_buffer, 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(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(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(buf, count, GFP_KERNEL);
 100         if (!tbuf)
 101                 return -ENOMEM;
 102
 103         ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL,
 104                         GNSS_USB_WRITE_TIMEOUT);
 105         kfree(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(intf->cur_altsetting, &in, &out, NULL,
 130                         NULL);
 131         if (ret)
 132                 return ret;
 133
 134         gusb = kzalloc(sizeof(*gusb), GFP_KERNEL);
 135         if (!gusb)
 136                 return -ENOMEM;
 137
 138         gdev = gnss_allocate_device(&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, gusb);
 147
 148         urb = usb_alloc_urb(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(buf_len, GFP_KERNEL);
 157         if (!buf) {
 158                 ret = -ENOMEM;
 159                 goto err_free_urb;
 160         }
 161
 162         usb_fill_bulk_urb(urb, udev,
 163                         usb_rcvbulkpipe(udev, usb_endpoint_num(in)),
 164                         buf, buf_len, gnss_usb_rx_complete, 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, gusb);
 177
 178         return 0;
 179
 180 err_free_buf:
 181         kfree(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(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(gusb->gdev);
 197
 198         kfree(gusb->read_urb->transfer_buffer);
 199         usb_free_urb(gusb->read_urb);
 200         gnss_put_device(gusb->gdev);
 201         kfree(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");