1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Symbol USB barcode to serial driver |
4 | * |
5 | * Copyright (C) 2013 Johan Hovold <jhovold@gmail.com> |
6 | * Copyright (C) 2009 Greg Kroah-Hartman <gregkh@suse.de> |
7 | * Copyright (C) 2009 Novell Inc. |
8 | */ |
9 | |
10 | #include <linux/kernel.h> |
11 | #include <linux/tty.h> |
12 | #include <linux/slab.h> |
13 | #include <linux/tty_driver.h> |
14 | #include <linux/tty_flip.h> |
15 | #include <linux/module.h> |
16 | #include <linux/usb.h> |
17 | #include <linux/usb/serial.h> |
18 | #include <linux/uaccess.h> |
19 | |
20 | static const struct usb_device_id id_table[] = { |
21 | { USB_DEVICE(0x05e0, 0x0600) }, |
22 | { }, |
23 | }; |
24 | MODULE_DEVICE_TABLE(usb, id_table); |
25 | |
26 | struct symbol_private { |
27 | spinlock_t lock; /* protects the following flags */ |
28 | bool throttled; |
29 | bool actually_throttled; |
30 | }; |
31 | |
32 | static void symbol_int_callback(struct urb *urb) |
33 | { |
34 | struct usb_serial_port *port = urb->context; |
35 | struct symbol_private *priv = usb_get_serial_port_data(port); |
36 | unsigned char *data = urb->transfer_buffer; |
37 | int status = urb->status; |
38 | unsigned long flags; |
39 | int result; |
40 | int data_length; |
41 | |
42 | switch (status) { |
43 | case 0: |
44 | /* success */ |
45 | break; |
46 | case -ECONNRESET: |
47 | case -ENOENT: |
48 | case -ESHUTDOWN: |
49 | /* this urb is terminated, clean up */ |
50 | dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n" , |
51 | __func__, status); |
52 | return; |
53 | default: |
54 | dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n" , |
55 | __func__, status); |
56 | goto exit; |
57 | } |
58 | |
59 | usb_serial_debug_data(dev: &port->dev, function: __func__, size: urb->actual_length, data); |
60 | |
61 | /* |
62 | * Data from the device comes with a 1 byte header: |
63 | * |
64 | * <size of data> <data>... |
65 | */ |
66 | if (urb->actual_length > 1) { |
67 | data_length = data[0]; |
68 | if (data_length > (urb->actual_length - 1)) |
69 | data_length = urb->actual_length - 1; |
70 | tty_insert_flip_string(port: &port->port, chars: &data[1], size: data_length); |
71 | tty_flip_buffer_push(port: &port->port); |
72 | } else { |
73 | dev_dbg(&port->dev, "%s - short packet\n" , __func__); |
74 | } |
75 | |
76 | exit: |
77 | spin_lock_irqsave(&priv->lock, flags); |
78 | |
79 | /* Continue trying to always read if we should */ |
80 | if (!priv->throttled) { |
81 | result = usb_submit_urb(urb: port->interrupt_in_urb, GFP_ATOMIC); |
82 | if (result) |
83 | dev_err(&port->dev, |
84 | "%s - failed resubmitting read urb, error %d\n" , |
85 | __func__, result); |
86 | } else |
87 | priv->actually_throttled = true; |
88 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
89 | } |
90 | |
91 | static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port) |
92 | { |
93 | struct symbol_private *priv = usb_get_serial_port_data(port); |
94 | unsigned long flags; |
95 | int result = 0; |
96 | |
97 | spin_lock_irqsave(&priv->lock, flags); |
98 | priv->throttled = false; |
99 | priv->actually_throttled = false; |
100 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
101 | |
102 | /* Start reading from the device */ |
103 | result = usb_submit_urb(urb: port->interrupt_in_urb, GFP_KERNEL); |
104 | if (result) |
105 | dev_err(&port->dev, |
106 | "%s - failed resubmitting read urb, error %d\n" , |
107 | __func__, result); |
108 | return result; |
109 | } |
110 | |
111 | static void symbol_close(struct usb_serial_port *port) |
112 | { |
113 | usb_kill_urb(urb: port->interrupt_in_urb); |
114 | } |
115 | |
116 | static void symbol_throttle(struct tty_struct *tty) |
117 | { |
118 | struct usb_serial_port *port = tty->driver_data; |
119 | struct symbol_private *priv = usb_get_serial_port_data(port); |
120 | |
121 | spin_lock_irq(lock: &priv->lock); |
122 | priv->throttled = true; |
123 | spin_unlock_irq(lock: &priv->lock); |
124 | } |
125 | |
126 | static void symbol_unthrottle(struct tty_struct *tty) |
127 | { |
128 | struct usb_serial_port *port = tty->driver_data; |
129 | struct symbol_private *priv = usb_get_serial_port_data(port); |
130 | int result; |
131 | bool was_throttled; |
132 | |
133 | spin_lock_irq(lock: &priv->lock); |
134 | priv->throttled = false; |
135 | was_throttled = priv->actually_throttled; |
136 | priv->actually_throttled = false; |
137 | spin_unlock_irq(lock: &priv->lock); |
138 | |
139 | if (was_throttled) { |
140 | result = usb_submit_urb(urb: port->interrupt_in_urb, GFP_KERNEL); |
141 | if (result) |
142 | dev_err(&port->dev, |
143 | "%s - failed submitting read urb, error %d\n" , |
144 | __func__, result); |
145 | } |
146 | } |
147 | |
148 | static int symbol_port_probe(struct usb_serial_port *port) |
149 | { |
150 | struct symbol_private *priv; |
151 | |
152 | priv = kzalloc(size: sizeof(*priv), GFP_KERNEL); |
153 | if (!priv) |
154 | return -ENOMEM; |
155 | |
156 | spin_lock_init(&priv->lock); |
157 | |
158 | usb_set_serial_port_data(port, data: priv); |
159 | |
160 | return 0; |
161 | } |
162 | |
163 | static void symbol_port_remove(struct usb_serial_port *port) |
164 | { |
165 | struct symbol_private *priv = usb_get_serial_port_data(port); |
166 | |
167 | kfree(objp: priv); |
168 | } |
169 | |
170 | static struct usb_serial_driver symbol_device = { |
171 | .driver = { |
172 | .owner = THIS_MODULE, |
173 | .name = "symbol" , |
174 | }, |
175 | .id_table = id_table, |
176 | .num_ports = 1, |
177 | .num_interrupt_in = 1, |
178 | .port_probe = symbol_port_probe, |
179 | .port_remove = symbol_port_remove, |
180 | .open = symbol_open, |
181 | .close = symbol_close, |
182 | .throttle = symbol_throttle, |
183 | .unthrottle = symbol_unthrottle, |
184 | .read_int_callback = symbol_int_callback, |
185 | }; |
186 | |
187 | static struct usb_serial_driver * const serial_drivers[] = { |
188 | &symbol_device, NULL |
189 | }; |
190 | |
191 | module_usb_serial_driver(serial_drivers, id_table); |
192 | |
193 | MODULE_LICENSE("GPL v2" ); |
194 | |