1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // Copyright (C) 2018 Sean Young <sean@mess.org>
4
5 #include <linux/module.h>
6 #include <linux/usb.h>
7 #include <linux/usb/input.h>
8 #include <media/rc-core.h>
9
10 /* Each bit is 250us */
11 #define BIT_DURATION 250
12
13 struct imon {
14 struct device *dev;
15 struct urb *ir_urb;
16 struct rc_dev *rcdev;
17 __be64 *ir_buf;
18 char phys[64];
19 };
20
21 /*
22 * The first 5 bytes of data represent IR pulse or space. Each bit, starting
23 * from highest bit in the first byte, represents 250µs of data. It is 1
24 * for space and 0 for pulse.
25 *
26 * The station sends 10 packets, and the 7th byte will be number 1 to 10, so
27 * when we receive 10 we assume all the data has arrived.
28 */
imon_ir_data(struct imon * imon)29 static void imon_ir_data(struct imon *imon)
30 {
31 struct ir_raw_event rawir = {};
32 u64 data = be64_to_cpup(imon->ir_buf);
33 u8 packet_no = data & 0xff;
34 int offset = 40;
35 int bit;
36
37 if (packet_no == 0xff)
38 return;
39
40 dev_dbg(imon->dev, "data: %*ph", 8, imon->ir_buf);
41
42 /*
43 * Only the first 5 bytes contain IR data. Right shift so we move
44 * the IR bits to the lower 40 bits.
45 */
46 data >>= 24;
47
48 do {
49 /*
50 * Find highest set bit which is less or equal to offset
51 *
52 * offset is the bit above (base 0) where we start looking.
53 *
54 * data & (BIT_ULL(offset) - 1) masks off any unwanted bits,
55 * so we have just bits less than offset.
56 *
57 * fls will tell us the highest bit set plus 1 (or 0 if no
58 * bits are set).
59 */
60 rawir.pulse = !rawir.pulse;
61 bit = fls64(data & (BIT_ULL(offset) - 1));
62 if (bit < offset) {
63 dev_dbg(imon->dev, "%s: %d bits",
64 rawir.pulse ? "pulse" : "space", offset - bit);
65 rawir.duration = (offset - bit) * BIT_DURATION;
66 ir_raw_event_store_with_filter(imon->rcdev, &rawir);
67
68 offset = bit;
69 }
70
71 data = ~data;
72 } while (offset > 0);
73
74 if (packet_no == 0x0a && !imon->rcdev->idle) {
75 ir_raw_event_set_idle(imon->rcdev, true);
76 ir_raw_event_handle(imon->rcdev);
77 }
78 }
79
imon_ir_rx(struct urb * urb)80 static void imon_ir_rx(struct urb *urb)
81 {
82 struct imon *imon = urb->context;
83 int ret;
84
85 switch (urb->status) {
86 case 0:
87 imon_ir_data(imon);
88 break;
89 case -ECONNRESET:
90 case -ENOENT:
91 case -ESHUTDOWN:
92 usb_unlink_urb(urb);
93 return;
94 case -EPIPE:
95 default:
96 dev_dbg(imon->dev, "error: urb status = %d", urb->status);
97 break;
98 }
99
100 ret = usb_submit_urb(urb, GFP_ATOMIC);
101 if (ret && ret != -ENODEV)
102 dev_warn(imon->dev, "failed to resubmit urb: %d", ret);
103 }
104
imon_probe(struct usb_interface * intf,const struct usb_device_id * id)105 static int imon_probe(struct usb_interface *intf,
106 const struct usb_device_id *id)
107 {
108 struct usb_endpoint_descriptor *ir_ep = NULL;
109 struct usb_host_interface *idesc;
110 struct usb_device *udev;
111 struct rc_dev *rcdev;
112 struct imon *imon;
113 int i, ret;
114
115 udev = interface_to_usbdev(intf);
116 idesc = intf->cur_altsetting;
117
118 for (i = 0; i < idesc->desc.bNumEndpoints; i++) {
119 struct usb_endpoint_descriptor *ep = &idesc->endpoint[i].desc;
120
121 if (usb_endpoint_is_int_in(ep)) {
122 ir_ep = ep;
123 break;
124 }
125 }
126
127 if (!ir_ep) {
128 dev_err(&intf->dev, "IR endpoint missing");
129 return -ENODEV;
130 }
131
132 imon = devm_kmalloc(&intf->dev, sizeof(*imon), GFP_KERNEL);
133 if (!imon)
134 return -ENOMEM;
135
136 imon->ir_urb = usb_alloc_urb(0, GFP_KERNEL);
137 if (!imon->ir_urb)
138 return -ENOMEM;
139
140 imon->ir_buf = kmalloc(sizeof(__be64), GFP_KERNEL);
141 if (!imon->ir_buf) {
142 ret = -ENOMEM;
143 goto free_urb;
144 }
145
146 imon->dev = &intf->dev;
147 usb_fill_int_urb(imon->ir_urb, udev,
148 usb_rcvintpipe(udev, ir_ep->bEndpointAddress),
149 imon->ir_buf, sizeof(__be64),
150 imon_ir_rx, imon, ir_ep->bInterval);
151
152 rcdev = devm_rc_allocate_device(&intf->dev, RC_DRIVER_IR_RAW);
153 if (!rcdev) {
154 ret = -ENOMEM;
155 goto free_urb;
156 }
157
158 usb_make_path(udev, imon->phys, sizeof(imon->phys));
159
160 rcdev->device_name = "iMON Station";
161 rcdev->driver_name = KBUILD_MODNAME;
162 rcdev->input_phys = imon->phys;
163 usb_to_input_id(udev, &rcdev->input_id);
164 rcdev->dev.parent = &intf->dev;
165 rcdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
166 rcdev->map_name = RC_MAP_IMON_RSC;
167 rcdev->rx_resolution = BIT_DURATION;
168 rcdev->priv = imon;
169
170 ret = devm_rc_register_device(&intf->dev, rcdev);
171 if (ret)
172 goto free_urb;
173
174 imon->rcdev = rcdev;
175
176 ret = usb_submit_urb(imon->ir_urb, GFP_KERNEL);
177 if (ret)
178 goto free_urb;
179
180 usb_set_intfdata(intf, imon);
181
182 return 0;
183
184 free_urb:
185 usb_free_urb(imon->ir_urb);
186 kfree(imon->ir_buf);
187 return ret;
188 }
189
imon_disconnect(struct usb_interface * intf)190 static void imon_disconnect(struct usb_interface *intf)
191 {
192 struct imon *imon = usb_get_intfdata(intf);
193
194 usb_kill_urb(imon->ir_urb);
195 usb_free_urb(imon->ir_urb);
196 kfree(imon->ir_buf);
197 }
198
199 static const struct usb_device_id imon_table[] = {
200 /* SoundGraph iMON (IR only) -- sg_imon.inf */
201 { USB_DEVICE(0x04e8, 0xff30) },
202 {}
203 };
204
205 static struct usb_driver imon_driver = {
206 .name = KBUILD_MODNAME,
207 .probe = imon_probe,
208 .disconnect = imon_disconnect,
209 .id_table = imon_table
210 };
211
212 module_usb_driver(imon_driver);
213
214 MODULE_DESCRIPTION("Early raw iMON IR devices");
215 MODULE_AUTHOR("Sean Young <sean@mess.org>");
216 MODULE_LICENSE("GPL");
217 MODULE_DEVICE_TABLE(usb, imon_table);
218