1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
|
// SPDX-License-Identifier: GPL-2.0+
/*
* Surface System Aggregator Module (SSAM) HID transport driver for the legacy
* keyboard interface (KBD/TC=0x08 subsystem). Provides support for the
* integrated HID keyboard on Surface Laptops 1 and 2.
*
* Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com>
*/
#include <asm/unaligned.h>
#include <linux/hid.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/surface_aggregator/controller.h>
#include "surface_hid_core.h"
/* -- SAM interface (KBD). -------------------------------------------------- */
#define KBD_FEATURE_REPORT_SIZE 7 /* 6 + report ID */
enum surface_kbd_cid {
SURFACE_KBD_CID_GET_DESCRIPTOR = 0x00,
SURFACE_KBD_CID_SET_CAPSLOCK_LED = 0x01,
SURFACE_KBD_CID_EVT_INPUT_GENERIC = 0x03,
SURFACE_KBD_CID_EVT_INPUT_HOTKEYS = 0x04,
SURFACE_KBD_CID_GET_FEATURE_REPORT = 0x0b,
};
static int ssam_kbd_get_descriptor(struct surface_hid_device *shid, u8 entry, u8 *buf, size_t len)
{
struct ssam_request rqst;
struct ssam_response rsp;
int status;
rqst.target_category = shid->uid.category;
rqst.target_id = shid->uid.target;
rqst.command_id = SURFACE_KBD_CID_GET_DESCRIPTOR;
rqst.instance_id = shid->uid.instance;
rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
rqst.length = sizeof(entry);
rqst.payload = &entry;
rsp.capacity = len;
rsp.length = 0;
rsp.pointer = buf;
status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(entry));
if (status)
return status;
if (rsp.length != len) {
dev_err(shid->dev, "invalid descriptor length: got %zu, expected, %zu\n",
rsp.length, len);
return -EPROTO;
}
return 0;
}
static int ssam_kbd_set_caps_led(struct surface_hid_device *shid, bool value)
{
struct ssam_request rqst;
u8 value_u8 = value;
rqst.target_category = shid->uid.category;
rqst.target_id = shid->uid.target;
rqst.command_id = SURFACE_KBD_CID_SET_CAPSLOCK_LED;
rqst.instance_id = shid->uid.instance;
rqst.flags = 0;
rqst.length = sizeof(value_u8);
rqst.payload = &value_u8;
return ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, NULL, sizeof(value_u8));
}
static int ssam_kbd_get_feature_report(struct surface_hid_device *shid, u8 *buf, size_t len)
{
struct ssam_request rqst;
struct ssam_response rsp;
u8 payload = 0;
int status;
rqst.target_category = shid->uid.category;
rqst.target_id = shid->uid.target;
rqst.command_id = SURFACE_KBD_CID_GET_FEATURE_REPORT;
rqst.instance_id = shid->uid.instance;
rqst.flags = SSAM_REQUEST_HAS_RESPONSE;
rqst.length = sizeof(payload);
rqst.payload = &payload;
rsp.capacity = len;
rsp.length = 0;
rsp.pointer = buf;
status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(payload));
if (status)
return status;
if (rsp.length != len) {
dev_err(shid->dev, "invalid feature report length: got %zu, expected, %zu\n",
rsp.length, len);
return -EPROTO;
}
return 0;
}
static bool ssam_kbd_is_input_event(const struct ssam_event *event)
{
if (event->command_id == SURFACE_KBD_CID_EVT_INPUT_GENERIC)
return true;
if (event->command_id == SURFACE_KBD_CID_EVT_INPUT_HOTKEYS)
return true;
return false;
}
static u32 ssam_kbd_event_fn(struct ssam_event_notifier *nf, const struct ssam_event *event)
{
struct surface_hid_device *shid = container_of(nf, struct surface_hid_device, notif);
/*
* Check against device UID manually, as registry and device target
* category doesn't line up.
*/
if (shid->uid.category != event->target_category)
return 0;
if (shid->uid.target != event->target_id)
return 0;
if (shid->uid.instance != event->instance_id)
return 0;
if (!ssam_kbd_is_input_event(event))
return 0;
hid_input_report(shid->hid, HID_INPUT_REPORT, (u8 *)&event->data[0], event->length, 0);
return SSAM_NOTIF_HANDLED;
}
/* -- Transport driver (KBD). ----------------------------------------------- */
static int skbd_get_caps_led_value(struct hid_device *hid, u8 rprt_id, u8 *buf, size_t len)
{
struct hid_field *field;
unsigned int offset, size;
int i;
/* Get LED field. */
field = hidinput_get_led_field(hid);
if (!field)
return -ENOENT;
/* Check if we got the correct report. */
if (len != hid_report_len(field->report))
return -ENOENT;
if (rprt_id != field->report->id)
return -ENOENT;
/* Get caps lock LED index. */
for (i = 0; i < field->report_count; i++)
if ((field->usage[i].hid & 0xffff) == 0x02)
break;
if (i == field->report_count)
return -ENOENT;
/* Extract value. */
size = field->report_size;
offset = field->report_offset + i * size;
return !!hid_field_extract(hid, buf + 1, size, offset);
}
static int skbd_output_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
{
int caps_led;
int status;
caps_led = skbd_get_caps_led_value(shid->hid, rprt_id, buf, len);
if (caps_led < 0)
return -EIO; /* Only caps LED output reports are supported. */
status = ssam_kbd_set_caps_led(shid, caps_led);
if (status < 0)
return status;
return len;
}
static int skbd_get_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
{
u8 report[KBD_FEATURE_REPORT_SIZE];
int status;
/*
* The keyboard only has a single hard-coded read-only feature report
* of size KBD_FEATURE_REPORT_SIZE. Try to load it and compare its
* report ID against the requested one.
*/
if (len < ARRAY_SIZE(report))
return -ENOSPC;
status = ssam_kbd_get_feature_report(shid, report, ARRAY_SIZE(report));
if (status < 0)
return status;
if (rprt_id != report[0])
return -ENOENT;
memcpy(buf, report, ARRAY_SIZE(report));
return len;
}
static int skbd_set_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len)
{
/* Not supported. See skbd_get_feature_report() for details. */
return -EIO;
}
/* -- Driver setup. --------------------------------------------------------- */
static int surface_kbd_probe(struct platform_device *pdev)
{
struct ssam_controller *ctrl;
struct surface_hid_device *shid;
/* Add device link to EC. */
ctrl = ssam_client_bind(&pdev->dev);
if (IS_ERR(ctrl))
return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);
shid = devm_kzalloc(&pdev->dev, sizeof(*shid), GFP_KERNEL);
if (!shid)
return -ENOMEM;
shid->dev = &pdev->dev;
shid->ctrl = ctrl;
shid->uid.domain = SSAM_DOMAIN_SERIALHUB;
shid->uid.category = SSAM_SSH_TC_KBD;
shid->uid.target = SSAM_SSH_TID_KIP;
shid->uid.instance = 0;
shid->uid.function = 0;
shid->notif.base.priority = 1;
shid->notif.base.fn = ssam_kbd_event_fn;
shid->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
shid->notif.event.id.target_category = shid->uid.category;
shid->notif.event.id.instance = shid->uid.instance;
shid->notif.event.mask = SSAM_EVENT_MASK_NONE;
shid->notif.event.flags = 0;
shid->ops.get_descriptor = ssam_kbd_get_descriptor;
shid->ops.output_report = skbd_output_report;
shid->ops.get_feature_report = skbd_get_feature_report;
shid->ops.set_feature_report = skbd_set_feature_report;
platform_set_drvdata(pdev, shid);
return surface_hid_device_add(shid);
}
static void surface_kbd_remove(struct platform_device *pdev)
{
surface_hid_device_destroy(platform_get_drvdata(pdev));
}
static const struct acpi_device_id surface_kbd_match[] = {
{ "MSHW0096" },
{ },
};
MODULE_DEVICE_TABLE(acpi, surface_kbd_match);
static struct platform_driver surface_kbd_driver = {
.probe = surface_kbd_probe,
.remove_new = surface_kbd_remove,
.driver = {
.name = "surface_keyboard",
.acpi_match_table = surface_kbd_match,
.pm = &surface_hid_pm_ops,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
};
module_platform_driver(surface_kbd_driver);
MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
MODULE_DESCRIPTION("HID legacy transport driver for Surface System Aggregator Module");
MODULE_LICENSE("GPL");
|