1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Surface System Aggregator Module (SSAM) HID transport driver for the legacy |
4 | * keyboard interface (KBD/TC=0x08 subsystem). Provides support for the |
5 | * integrated HID keyboard on Surface Laptops 1 and 2. |
6 | * |
7 | * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com> |
8 | */ |
9 | |
10 | #include <asm/unaligned.h> |
11 | #include <linux/hid.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> |
14 | #include <linux/platform_device.h> |
15 | #include <linux/types.h> |
16 | |
17 | #include <linux/surface_aggregator/controller.h> |
18 | |
19 | #include "surface_hid_core.h" |
20 | |
21 | |
22 | /* -- SAM interface (KBD). -------------------------------------------------- */ |
23 | |
24 | #define KBD_FEATURE_REPORT_SIZE 7 /* 6 + report ID */ |
25 | |
26 | enum surface_kbd_cid { |
27 | SURFACE_KBD_CID_GET_DESCRIPTOR = 0x00, |
28 | SURFACE_KBD_CID_SET_CAPSLOCK_LED = 0x01, |
29 | SURFACE_KBD_CID_EVT_INPUT_GENERIC = 0x03, |
30 | SURFACE_KBD_CID_EVT_INPUT_HOTKEYS = 0x04, |
31 | SURFACE_KBD_CID_GET_FEATURE_REPORT = 0x0b, |
32 | }; |
33 | |
34 | static int ssam_kbd_get_descriptor(struct surface_hid_device *shid, u8 entry, u8 *buf, size_t len) |
35 | { |
36 | struct ssam_request rqst; |
37 | struct ssam_response rsp; |
38 | int status; |
39 | |
40 | rqst.target_category = shid->uid.category; |
41 | rqst.target_id = shid->uid.target; |
42 | rqst.command_id = SURFACE_KBD_CID_GET_DESCRIPTOR; |
43 | rqst.instance_id = shid->uid.instance; |
44 | rqst.flags = SSAM_REQUEST_HAS_RESPONSE; |
45 | rqst.length = sizeof(entry); |
46 | rqst.payload = &entry; |
47 | |
48 | rsp.capacity = len; |
49 | rsp.length = 0; |
50 | rsp.pointer = buf; |
51 | |
52 | status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(entry)); |
53 | if (status) |
54 | return status; |
55 | |
56 | if (rsp.length != len) { |
57 | dev_err(shid->dev, "invalid descriptor length: got %zu, expected, %zu\n" , |
58 | rsp.length, len); |
59 | return -EPROTO; |
60 | } |
61 | |
62 | return 0; |
63 | } |
64 | |
65 | static int ssam_kbd_set_caps_led(struct surface_hid_device *shid, bool value) |
66 | { |
67 | struct ssam_request rqst; |
68 | u8 value_u8 = value; |
69 | |
70 | rqst.target_category = shid->uid.category; |
71 | rqst.target_id = shid->uid.target; |
72 | rqst.command_id = SURFACE_KBD_CID_SET_CAPSLOCK_LED; |
73 | rqst.instance_id = shid->uid.instance; |
74 | rqst.flags = 0; |
75 | rqst.length = sizeof(value_u8); |
76 | rqst.payload = &value_u8; |
77 | |
78 | return ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, NULL, sizeof(value_u8)); |
79 | } |
80 | |
81 | static int ssam_kbd_get_feature_report(struct surface_hid_device *shid, u8 *buf, size_t len) |
82 | { |
83 | struct ssam_request rqst; |
84 | struct ssam_response rsp; |
85 | u8 payload = 0; |
86 | int status; |
87 | |
88 | rqst.target_category = shid->uid.category; |
89 | rqst.target_id = shid->uid.target; |
90 | rqst.command_id = SURFACE_KBD_CID_GET_FEATURE_REPORT; |
91 | rqst.instance_id = shid->uid.instance; |
92 | rqst.flags = SSAM_REQUEST_HAS_RESPONSE; |
93 | rqst.length = sizeof(payload); |
94 | rqst.payload = &payload; |
95 | |
96 | rsp.capacity = len; |
97 | rsp.length = 0; |
98 | rsp.pointer = buf; |
99 | |
100 | status = ssam_retry(ssam_request_do_sync_onstack, shid->ctrl, &rqst, &rsp, sizeof(payload)); |
101 | if (status) |
102 | return status; |
103 | |
104 | if (rsp.length != len) { |
105 | dev_err(shid->dev, "invalid feature report length: got %zu, expected, %zu\n" , |
106 | rsp.length, len); |
107 | return -EPROTO; |
108 | } |
109 | |
110 | return 0; |
111 | } |
112 | |
113 | static bool ssam_kbd_is_input_event(const struct ssam_event *event) |
114 | { |
115 | if (event->command_id == SURFACE_KBD_CID_EVT_INPUT_GENERIC) |
116 | return true; |
117 | |
118 | if (event->command_id == SURFACE_KBD_CID_EVT_INPUT_HOTKEYS) |
119 | return true; |
120 | |
121 | return false; |
122 | } |
123 | |
124 | static u32 ssam_kbd_event_fn(struct ssam_event_notifier *nf, const struct ssam_event *event) |
125 | { |
126 | struct surface_hid_device *shid = container_of(nf, struct surface_hid_device, notif); |
127 | |
128 | /* |
129 | * Check against device UID manually, as registry and device target |
130 | * category doesn't line up. |
131 | */ |
132 | |
133 | if (shid->uid.category != event->target_category) |
134 | return 0; |
135 | |
136 | if (shid->uid.target != event->target_id) |
137 | return 0; |
138 | |
139 | if (shid->uid.instance != event->instance_id) |
140 | return 0; |
141 | |
142 | if (!ssam_kbd_is_input_event(event)) |
143 | return 0; |
144 | |
145 | hid_input_report(hid: shid->hid, type: HID_INPUT_REPORT, data: (u8 *)&event->data[0], size: event->length, interrupt: 0); |
146 | return SSAM_NOTIF_HANDLED; |
147 | } |
148 | |
149 | |
150 | /* -- Transport driver (KBD). ----------------------------------------------- */ |
151 | |
152 | static int skbd_get_caps_led_value(struct hid_device *hid, u8 rprt_id, u8 *buf, size_t len) |
153 | { |
154 | struct hid_field *field; |
155 | unsigned int offset, size; |
156 | int i; |
157 | |
158 | /* Get LED field. */ |
159 | field = hidinput_get_led_field(hid); |
160 | if (!field) |
161 | return -ENOENT; |
162 | |
163 | /* Check if we got the correct report. */ |
164 | if (len != hid_report_len(report: field->report)) |
165 | return -ENOENT; |
166 | |
167 | if (rprt_id != field->report->id) |
168 | return -ENOENT; |
169 | |
170 | /* Get caps lock LED index. */ |
171 | for (i = 0; i < field->report_count; i++) |
172 | if ((field->usage[i].hid & 0xffff) == 0x02) |
173 | break; |
174 | |
175 | if (i == field->report_count) |
176 | return -ENOENT; |
177 | |
178 | /* Extract value. */ |
179 | size = field->report_size; |
180 | offset = field->report_offset + i * size; |
181 | return !!hid_field_extract(hid, report: buf + 1, offset: size, n: offset); |
182 | } |
183 | |
184 | static int skbd_output_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len) |
185 | { |
186 | int caps_led; |
187 | int status; |
188 | |
189 | caps_led = skbd_get_caps_led_value(hid: shid->hid, rprt_id, buf, len); |
190 | if (caps_led < 0) |
191 | return -EIO; /* Only caps LED output reports are supported. */ |
192 | |
193 | status = ssam_kbd_set_caps_led(shid, value: caps_led); |
194 | if (status < 0) |
195 | return status; |
196 | |
197 | return len; |
198 | } |
199 | |
200 | static int skbd_get_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len) |
201 | { |
202 | u8 report[KBD_FEATURE_REPORT_SIZE]; |
203 | int status; |
204 | |
205 | /* |
206 | * The keyboard only has a single hard-coded read-only feature report |
207 | * of size KBD_FEATURE_REPORT_SIZE. Try to load it and compare its |
208 | * report ID against the requested one. |
209 | */ |
210 | |
211 | if (len < ARRAY_SIZE(report)) |
212 | return -ENOSPC; |
213 | |
214 | status = ssam_kbd_get_feature_report(shid, buf: report, ARRAY_SIZE(report)); |
215 | if (status < 0) |
216 | return status; |
217 | |
218 | if (rprt_id != report[0]) |
219 | return -ENOENT; |
220 | |
221 | memcpy(buf, report, ARRAY_SIZE(report)); |
222 | return len; |
223 | } |
224 | |
225 | static int skbd_set_feature_report(struct surface_hid_device *shid, u8 rprt_id, u8 *buf, size_t len) |
226 | { |
227 | /* Not supported. See skbd_get_feature_report() for details. */ |
228 | return -EIO; |
229 | } |
230 | |
231 | |
232 | /* -- Driver setup. --------------------------------------------------------- */ |
233 | |
234 | static int surface_kbd_probe(struct platform_device *pdev) |
235 | { |
236 | struct ssam_controller *ctrl; |
237 | struct surface_hid_device *shid; |
238 | |
239 | /* Add device link to EC. */ |
240 | ctrl = ssam_client_bind(client: &pdev->dev); |
241 | if (IS_ERR(ptr: ctrl)) |
242 | return PTR_ERR(ptr: ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ptr: ctrl); |
243 | |
244 | shid = devm_kzalloc(dev: &pdev->dev, size: sizeof(*shid), GFP_KERNEL); |
245 | if (!shid) |
246 | return -ENOMEM; |
247 | |
248 | shid->dev = &pdev->dev; |
249 | shid->ctrl = ctrl; |
250 | |
251 | shid->uid.domain = SSAM_DOMAIN_SERIALHUB; |
252 | shid->uid.category = SSAM_SSH_TC_KBD; |
253 | shid->uid.target = SSAM_SSH_TID_KIP; |
254 | shid->uid.instance = 0; |
255 | shid->uid.function = 0; |
256 | |
257 | shid->notif.base.priority = 1; |
258 | shid->notif.base.fn = ssam_kbd_event_fn; |
259 | shid->notif.event.reg = SSAM_EVENT_REGISTRY_SAM; |
260 | shid->notif.event.id.target_category = shid->uid.category; |
261 | shid->notif.event.id.instance = shid->uid.instance; |
262 | shid->notif.event.mask = SSAM_EVENT_MASK_NONE; |
263 | shid->notif.event.flags = 0; |
264 | |
265 | shid->ops.get_descriptor = ssam_kbd_get_descriptor; |
266 | shid->ops.output_report = skbd_output_report; |
267 | shid->ops.get_feature_report = skbd_get_feature_report; |
268 | shid->ops.set_feature_report = skbd_set_feature_report; |
269 | |
270 | platform_set_drvdata(pdev, data: shid); |
271 | return surface_hid_device_add(shid); |
272 | } |
273 | |
274 | static int surface_kbd_remove(struct platform_device *pdev) |
275 | { |
276 | surface_hid_device_destroy(shid: platform_get_drvdata(pdev)); |
277 | return 0; |
278 | } |
279 | |
280 | static const struct acpi_device_id surface_kbd_match[] = { |
281 | { "MSHW0096" }, |
282 | { }, |
283 | }; |
284 | MODULE_DEVICE_TABLE(acpi, surface_kbd_match); |
285 | |
286 | static struct platform_driver surface_kbd_driver = { |
287 | .probe = surface_kbd_probe, |
288 | .remove = surface_kbd_remove, |
289 | .driver = { |
290 | .name = "surface_keyboard" , |
291 | .acpi_match_table = surface_kbd_match, |
292 | .pm = &surface_hid_pm_ops, |
293 | .probe_type = PROBE_PREFER_ASYNCHRONOUS, |
294 | }, |
295 | }; |
296 | module_platform_driver(surface_kbd_driver); |
297 | |
298 | MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>" ); |
299 | MODULE_DESCRIPTION("HID legacy transport driver for Surface System Aggregator Module" ); |
300 | MODULE_LICENSE("GPL" ); |
301 | |