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// SPDX-License-Identifier: GPL-2.0
/*
* Generic USB GNSS receiver driver
*
* Copyright (C) 2021 Johan Hovold <johan@kernel.org>
*/
#include <linux/errno.h>
#include <linux/gnss.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#define GNSS_USB_READ_BUF_LEN 512
#define GNSS_USB_WRITE_TIMEOUT 1000
static const struct usb_device_id gnss_usb_id_table[] = {
{ USB_DEVICE(0x1199, 0xb000) }, /* Sierra Wireless XM1210 */
{ }
};
MODULE_DEVICE_TABLE(usb, gnss_usb_id_table);
struct gnss_usb {
struct usb_device *udev;
struct usb_interface *intf;
struct gnss_device *gdev;
struct urb *read_urb;
unsigned int write_pipe;
};
static void gnss_usb_rx_complete(struct urb *urb)
{
struct gnss_usb *gusb = urb->context;
struct gnss_device *gdev = gusb->gdev;
int status = urb->status;
int len;
int ret;
switch (status) {
case 0:
break;
case -ENOENT:
case -ECONNRESET:
case -ESHUTDOWN:
dev_dbg(&gdev->dev, "urb stopped: %d\n", status);
return;
case -EPIPE:
dev_err(&gdev->dev, "urb stopped: %d\n", status);
return;
default:
dev_dbg(&gdev->dev, "nonzero urb status: %d\n", status);
goto resubmit;
}
len = urb->actual_length;
if (len == 0)
goto resubmit;
ret = gnss_insert_raw(gdev, urb->transfer_buffer, len);
if (ret < len)
dev_dbg(&gdev->dev, "dropped %d bytes\n", len - ret);
resubmit:
ret = usb_submit_urb(urb, GFP_ATOMIC);
if (ret && ret != -EPERM && ret != -ENODEV)
dev_err(&gdev->dev, "failed to resubmit urb: %d\n", ret);
}
static int gnss_usb_open(struct gnss_device *gdev)
{
struct gnss_usb *gusb = gnss_get_drvdata(gdev);
int ret;
ret = usb_submit_urb(gusb->read_urb, GFP_KERNEL);
if (ret) {
if (ret != -EPERM && ret != -ENODEV)
dev_err(&gdev->dev, "failed to submit urb: %d\n", ret);
return ret;
}
return 0;
}
static void gnss_usb_close(struct gnss_device *gdev)
{
struct gnss_usb *gusb = gnss_get_drvdata(gdev);
usb_kill_urb(gusb->read_urb);
}
static int gnss_usb_write_raw(struct gnss_device *gdev,
const unsigned char *buf, size_t count)
{
struct gnss_usb *gusb = gnss_get_drvdata(gdev);
void *tbuf;
int ret;
tbuf = kmemdup(buf, count, GFP_KERNEL);
if (!tbuf)
return -ENOMEM;
ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL,
GNSS_USB_WRITE_TIMEOUT);
kfree(tbuf);
if (ret)
return ret;
return count;
}
static const struct gnss_operations gnss_usb_gnss_ops = {
.open = gnss_usb_open,
.close = gnss_usb_close,
.write_raw = gnss_usb_write_raw,
};
static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
struct usb_device *udev = interface_to_usbdev(intf);
struct usb_endpoint_descriptor *in, *out;
struct gnss_device *gdev;
struct gnss_usb *gusb;
struct urb *urb;
size_t buf_len;
void *buf;
int ret;
ret = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL,
NULL);
if (ret)
return ret;
gusb = kzalloc(sizeof(*gusb), GFP_KERNEL);
if (!gusb)
return -ENOMEM;
gdev = gnss_allocate_device(&intf->dev);
if (!gdev) {
ret = -ENOMEM;
goto err_free_gusb;
}
gdev->ops = &gnss_usb_gnss_ops;
gdev->type = GNSS_TYPE_NMEA;
gnss_set_drvdata(gdev, gusb);
urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb) {
ret = -ENOMEM;
goto err_put_gdev;
}
buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN);
buf = kzalloc(buf_len, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto err_free_urb;
}
usb_fill_bulk_urb(urb, udev,
usb_rcvbulkpipe(udev, usb_endpoint_num(in)),
buf, buf_len, gnss_usb_rx_complete, gusb);
gusb->intf = intf;
gusb->udev = udev;
gusb->gdev = gdev;
gusb->read_urb = urb;
gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out));
ret = gnss_register_device(gdev);
if (ret)
goto err_free_buf;
usb_set_intfdata(intf, gusb);
return 0;
err_free_buf:
kfree(buf);
err_free_urb:
usb_free_urb(urb);
err_put_gdev:
gnss_put_device(gdev);
err_free_gusb:
kfree(gusb);
return ret;
}
static void gnss_usb_disconnect(struct usb_interface *intf)
{
struct gnss_usb *gusb = usb_get_intfdata(intf);
gnss_deregister_device(gusb->gdev);
kfree(gusb->read_urb->transfer_buffer);
usb_free_urb(gusb->read_urb);
gnss_put_device(gusb->gdev);
kfree(gusb);
}
static struct usb_driver gnss_usb_driver = {
.name = "gnss-usb",
.probe = gnss_usb_probe,
.disconnect = gnss_usb_disconnect,
.id_table = gnss_usb_id_table,
};
module_usb_driver(gnss_usb_driver);
MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
MODULE_DESCRIPTION("Generic USB GNSS receiver driver");
MODULE_LICENSE("GPL v2");
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