xref: /btstack/src/ble/gatt-service/hids_device.c (revision a3c1c955e5ea423b4e6a8e3a0f2007d809fef5cf)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
24  * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define BTSTACK_FILE__ "hids_device.c"
39 
40 /**
41  * Implementation of the GATT HIDS Device
42  * To use with your application, add '#import <hids.gatt>' to your .gatt file
43  */
44 
45 #include "hids_device.h"
46 
47 #include "ble/att_db.h"
48 #include "ble/att_server.h"
49 #include "bluetooth_gatt.h"
50 #include "btstack_util.h"
51 #include "btstack_debug.h"
52 
53 #define HIDS_DEVICE_ERROR_CODE_INAPPROPRIATE_CONNECTION_PARAMETERS    0x80
54 
55 // storage for 'generic' HID Device with single Input, Output, and Feature Report
56 static hids_device_report_t hid_reports_generic_storage[3];
57 
58 typedef struct{
59     uint16_t        con_handle;
60 
61     uint8_t         hid_country_code;
62     const uint8_t * hid_descriptor;
63     uint16_t        hid_descriptor_size;
64 
65     uint16_t        hid_report_map_handle;
66     uint8_t         hid_protocol_mode;
67     uint16_t        hid_protocol_mode_value_handle;
68 
69     uint16_t        hid_boot_mouse_input_value_handle;
70     uint16_t        hid_boot_mouse_input_client_configuration_handle;
71     uint16_t        hid_boot_mouse_input_client_configuration_value;
72 
73     uint16_t        hid_boot_keyboard_input_value_handle;
74     uint16_t        hid_boot_keyboard_input_client_configuration_handle;
75     uint16_t        hid_boot_keyboard_input_client_configuration_value;
76 
77     hids_device_report_t * hid_reports;
78 
79     uint8_t         hid_input_reports_num;
80     uint8_t         hid_output_reports_num;
81     uint8_t         hid_feature_reports_num;
82 
83     uint16_t        hid_control_point_value_handle;
84     uint8_t         hid_control_point_suspend;
85 
86     btstack_context_callback_registration_t  battery_callback;
87 } hids_device_t;
88 
89 static hids_device_t hids_device;
90 
91 static btstack_packet_handler_t packet_handler;
92 static att_service_handler_t hid_service;
93 
94 // TODO: store hids device connection into list
95 static hids_device_t * hids_device_get_instance_for_con_handle(uint16_t con_handle){
96     UNUSED(con_handle);
97     return &hids_device;
98 }
99 
100 static hids_device_t * hids_device_create_instance(void){
101     memset(&hids_device, 0, sizeof(hids_device_t));
102     return &hids_device;
103 }
104 
105 static hids_device_report_t * hids_device_get_report_for_client_configuration_handle(hids_device_t * device, uint16_t client_configuration_handle){
106     uint8_t pos;
107     uint8_t total_reports =  device->hid_input_reports_num + device->hid_output_reports_num + device->hid_feature_reports_num;
108     for (pos = 0 ; pos < total_reports ; pos++){
109         if (device->hid_reports[pos].client_configuration_handle == client_configuration_handle){
110             return &device->hid_reports[pos];
111         }
112     }
113     return NULL;
114 }
115 
116 static hids_device_report_t *
117 hids_device_get_report_for_id_and_type(hids_device_t *device, uint16_t report_id, hid_report_type_t type) {
118     uint8_t pos;
119     uint8_t total_reports =  device->hid_input_reports_num + device->hid_output_reports_num + device->hid_feature_reports_num;
120     for (pos = 0 ; pos < total_reports ; pos++){
121         if ((device->hid_reports[pos].type == type) && (device->hid_reports[pos].id == report_id)){
122             return &device->hid_reports[pos];
123         }
124     }
125     return NULL;
126 }
127 
128 static hids_device_report_t * hids_device_get_report_for_id(hids_device_t * device, uint16_t report_id){
129     uint8_t pos;
130     uint8_t total_reports =  device->hid_input_reports_num + device->hid_output_reports_num + device->hid_feature_reports_num;
131     for (pos = 0 ; pos < total_reports ; pos++){
132         if (device->hid_reports[pos].id == report_id){
133             return &device->hid_reports[pos];
134         }
135     }
136     return NULL;
137 }
138 
139 static void hids_device_emit_event_with_uint8(uint8_t event, hci_con_handle_t con_handle, uint8_t value){
140     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
141     if (!instance){
142         log_error("no instance for handle 0x%02x", con_handle);
143         return;
144     }
145 
146     if (!packet_handler) return;
147     uint8_t buffer[6];
148     buffer[0] = HCI_EVENT_HIDS_META;
149     buffer[1] = 4;
150     buffer[2] = event;
151     little_endian_store_16(buffer, 3, (uint16_t) con_handle);
152     buffer[5] = value;
153     (*packet_handler)(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer));
154 }
155 
156 static void hids_device_emit_event(uint8_t event, hci_con_handle_t con_handle){
157     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
158     if (!instance){
159         log_error("no instance for handle 0x%02x", con_handle);
160         return;
161     }
162 
163     if (!packet_handler) return;
164     uint8_t buffer[5];
165     buffer[0] = HCI_EVENT_HIDS_META;
166     buffer[1] = 4;
167     buffer[2] = event;
168     little_endian_store_16(buffer, 3, (uint16_t) con_handle);
169     (*packet_handler)(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer));
170 }
171 
172 static void hids_device_can_send_now(void * context){
173     hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) context;
174     // notify client
175     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
176     if (!instance){
177         log_error("no instance for handle 0x%02x", con_handle);
178         return;
179     }
180 
181     if (!packet_handler) return;
182     uint8_t buffer[5];
183     buffer[0] = HCI_EVENT_HIDS_META;
184     buffer[1] = 3;
185     buffer[2] = HIDS_SUBEVENT_CAN_SEND_NOW;
186     little_endian_store_16(buffer, 3, (uint16_t) con_handle);
187     (*packet_handler)(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer));
188 }
189 
190 // ATT Client Read Callback for Dynamic Data
191 // - if buffer == NULL, don't copy data, just return size of value
192 // - if buffer != NULL, copy data and return number bytes copied
193 static uint16_t att_read_callback(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
194     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
195     if (!instance){
196         log_error("no instance for handle 0x%02x", con_handle);
197         return HIDS_DEVICE_ERROR_CODE_INAPPROPRIATE_CONNECTION_PARAMETERS;
198     }
199 
200     if (att_handle == instance->hid_protocol_mode_value_handle){
201         log_info("Read protocol mode");
202         return att_read_callback_handle_byte(instance->hid_protocol_mode, offset, buffer, buffer_size);
203     }
204 
205     if (att_handle == instance->hid_report_map_handle){
206         log_info("Read report map");
207         return att_read_callback_handle_blob(instance->hid_descriptor, instance->hid_descriptor_size, offset, buffer, buffer_size);
208     }
209 
210     if (att_handle == instance->hid_boot_mouse_input_client_configuration_handle){
211         return att_read_callback_handle_little_endian_16(instance->hid_boot_mouse_input_client_configuration_value, offset, buffer, buffer_size);
212     }
213 
214     if (att_handle == instance->hid_boot_keyboard_input_client_configuration_handle){
215         return att_read_callback_handle_little_endian_16(instance->hid_boot_keyboard_input_client_configuration_value, offset, buffer, buffer_size);
216     }
217 
218     if (att_handle == instance->hid_control_point_value_handle){
219         if (buffer && (buffer_size >= 1u)){
220             buffer[0] = instance->hid_control_point_suspend;
221         }
222         return 1;
223     }
224 
225     hids_device_report_t * report = hids_device_get_report_for_client_configuration_handle(instance, att_handle);
226     if (report != NULL){
227         return att_read_callback_handle_little_endian_16(report->client_configuration_value, offset, buffer, buffer_size);
228     }
229     return 0;
230 }
231 
232 static int att_write_callback(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size){
233     UNUSED(transaction_mode);
234     UNUSED(buffer_size);
235     UNUSED(offset);
236 
237     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
238     if (!instance){
239         log_error("no instance for handle 0x%02x", con_handle);
240         return HIDS_DEVICE_ERROR_CODE_INAPPROPRIATE_CONNECTION_PARAMETERS;
241     }
242 
243     if (att_handle == instance->hid_boot_mouse_input_client_configuration_handle){
244         uint16_t new_value = little_endian_read_16(buffer, 0);
245         instance->hid_boot_mouse_input_client_configuration_value = new_value;
246         hids_device_emit_event_with_uint8(HIDS_SUBEVENT_BOOT_MOUSE_INPUT_REPORT_ENABLE, con_handle, (uint8_t) new_value);
247     }
248     if (att_handle == instance->hid_boot_keyboard_input_client_configuration_handle){
249         uint16_t new_value = little_endian_read_16(buffer, 0);
250         instance->hid_boot_keyboard_input_client_configuration_value = new_value;
251         hids_device_emit_event_with_uint8(HIDS_SUBEVENT_BOOT_KEYBOARD_INPUT_REPORT_ENABLE, con_handle, (uint8_t) new_value);
252     }
253 
254     if (att_handle == instance->hid_protocol_mode_value_handle){
255         instance->hid_protocol_mode = buffer[0];
256         log_info("Set protocol mode: %u", instance->hid_protocol_mode);
257         hids_device_emit_event_with_uint8(HIDS_SUBEVENT_PROTOCOL_MODE, con_handle, instance->hid_protocol_mode);
258     }
259 
260     if (att_handle == instance->hid_control_point_value_handle){
261         if (buffer_size < 1u){
262             return ATT_ERROR_INVALID_OFFSET;
263         }
264         instance->hid_control_point_suspend = buffer[0];
265         instance->con_handle = con_handle;
266         log_info("Set suspend tp: %u", instance->hid_control_point_suspend );
267         if (instance->hid_control_point_suspend == 0u){
268             hids_device_emit_event(HIDS_SUBEVENT_SUSPEND, con_handle);
269         } else if (instance->hid_control_point_suspend == 1u){
270             hids_device_emit_event(HIDS_SUBEVENT_EXIT_SUSPEND, con_handle);
271         }
272     }
273 
274     hids_device_report_t * report = hids_device_get_report_for_client_configuration_handle(instance, att_handle);
275     if (report != NULL){
276         uint16_t new_value = little_endian_read_16(buffer, 0);
277         report->client_configuration_value = new_value;
278         log_info("Enable Report (type %u) notifications: %x", (uint8_t) report->type, new_value);
279 
280         switch (report->type){
281             case HID_REPORT_TYPE_INPUT:
282                 hids_device_emit_event_with_uint8(HIDS_SUBEVENT_INPUT_REPORT_ENABLE, con_handle, (uint8_t) new_value);
283                 break;
284             case HID_REPORT_TYPE_OUTPUT:
285                 hids_device_emit_event_with_uint8(HIDS_SUBEVENT_OUTPUT_REPORT_ENABLE, con_handle, (uint8_t) new_value);
286                 break;
287             case HID_REPORT_TYPE_FEATURE:
288                 hids_device_emit_event_with_uint8(HIDS_SUBEVENT_FEATURE_REPORT_ENABLE, con_handle, (uint8_t) new_value);
289                 break;
290             default:
291                 btstack_unreachable();
292                 break;
293         }
294     }
295     return 0;
296 }
297 
298 void hids_device_init_with_storage(uint8_t hid_country_code, const uint8_t * hid_descriptor, uint16_t hid_descriptor_size,
299     uint16_t num_reports, hids_device_report_t * report_storage){
300 
301     hids_device_t * instance = hids_device_create_instance();
302 
303     btstack_assert(num_reports > 0);
304     btstack_assert(report_storage != NULL);
305 
306     instance->hid_country_code    = hid_country_code;
307     instance->hid_descriptor      = hid_descriptor;
308     instance->hid_descriptor_size = hid_descriptor_size;
309 
310     // default
311     instance->hid_protocol_mode   = 1;
312 
313     // get service handle range
314     uint16_t start_handle = 0;
315     uint16_t end_handle   = 0xffff;
316     int service_found = gatt_server_get_handle_range_for_service_with_uuid16(ORG_BLUETOOTH_SERVICE_HUMAN_INTERFACE_DEVICE, &start_handle, &end_handle);
317     btstack_assert(service_found != 0);
318     UNUSED(service_found);
319 
320     // get report map handle
321     instance->hid_report_map_handle                               = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_REPORT_MAP);
322 
323     // get report map handle
324     instance->hid_protocol_mode_value_handle                      = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_PROTOCOL_MODE);
325 
326     // get value and client configuration handles for boot mouse input, boot keyboard input and report input
327     instance->hid_boot_mouse_input_value_handle                   = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_BOOT_MOUSE_INPUT_REPORT);
328     instance->hid_boot_mouse_input_client_configuration_handle    = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_BOOT_MOUSE_INPUT_REPORT);
329 
330     instance->hid_boot_keyboard_input_value_handle                = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_BOOT_KEYBOARD_INPUT_REPORT);
331     instance->hid_boot_keyboard_input_client_configuration_handle = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_BOOT_KEYBOARD_INPUT_REPORT);
332 
333     instance->hid_control_point_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_HID_CONTROL_POINT);
334 
335     log_info("hid_report_map_handle                               0x%02x", instance->hid_report_map_handle);
336     log_info("hid_protocol_mode_value_handle                      0x%02x", instance->hid_protocol_mode_value_handle);
337     log_info("hid_boot_mouse_input_value_handle                   0x%02x", instance->hid_boot_mouse_input_value_handle);
338     log_info("hid_boot_mouse_input_client_configuration_handle    0x%02x", instance->hid_boot_mouse_input_client_configuration_handle);
339     log_info("hid_boot_keyboard_input_value_handle                0x%02x", instance->hid_boot_keyboard_input_value_handle);
340     log_info("hid_boot_keyboard_input_client_configuration_handle 0x%02x", instance->hid_boot_keyboard_input_client_configuration_handle);
341     log_info("hid_control_point_value_handle                      0x%02x", instance->hid_control_point_value_handle);
342 
343     instance->hid_reports = report_storage;
344 
345     uint16_t hid_reports_num = num_reports;
346     uint16_t assigned_reports_num = 0;
347     uint16_t start_chr_handle = start_handle;
348 
349     while ( (start_chr_handle < end_handle) && (assigned_reports_num < hid_reports_num)) {
350         uint16_t chr_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_chr_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_REPORT);
351         if (chr_value_handle == 0){
352             break;
353         }
354 
355         uint16_t chr_client_configuration_handle = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_chr_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_REPORT);
356         uint16_t report_reference_handle = gatt_server_get_descriptor_handle_for_characteristic_with_uuid16(start_chr_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_REPORT, ORG_BLUETOOTH_DESCRIPTOR_REPORT_REFERENCE);
357         uint16_t report_reference_value_len;
358         const uint8_t * report_reference_value = gatt_server_get_const_value_for_handle(report_reference_handle, &report_reference_value_len);
359 
360         if (report_reference_value == NULL){
361             break;
362         }
363         if (report_reference_value_len != 2){
364             break;
365         }
366 
367         hids_device_report_t * report = &report_storage[assigned_reports_num];
368         report->value_handle = chr_value_handle;
369         report->client_configuration_handle = chr_client_configuration_handle;
370         report->client_configuration_value = 0;
371 
372         report->id = report_reference_value[0];
373         report->type = (hid_report_type_t)report_reference_value[1];
374 
375         switch (report->type){
376             case HID_REPORT_TYPE_INPUT:
377                 instance->hid_input_reports_num++;
378                 break;
379             case HID_REPORT_TYPE_OUTPUT:
380                 instance->hid_output_reports_num++;
381                 break;
382             case HID_REPORT_TYPE_FEATURE:
383                 instance->hid_feature_reports_num++;
384                 break;
385             default:
386                 btstack_unreachable();
387                 return;
388         }
389         log_info("hid_report_value_handle                       0x%02x, id %u, type %u", report->value_handle, report->id, (uint8_t)report->type);
390         log_info("hid_report_client_configuration_handle        0x%02x", report->client_configuration_handle);
391 
392         assigned_reports_num++;
393         start_chr_handle = chr_client_configuration_handle + 1;
394     }
395 
396     // register service with ATT Server
397     hid_service.start_handle   = start_handle;
398     hid_service.end_handle     = end_handle;
399     hid_service.read_callback  = &att_read_callback;
400     hid_service.write_callback = &att_write_callback;
401     att_server_register_service_handler(&hid_service);
402 }
403 
404 /**
405  * @brief Set up HIDS Device
406  */
407 void hids_device_init(uint8_t country_code, const uint8_t * descriptor, uint16_t descriptor_size){
408     uint16_t hid_reports_num = sizeof(hid_reports_generic_storage) / sizeof(hids_device_report_t);
409     hids_device_init_with_storage(country_code, descriptor, descriptor_size, hid_reports_num, hid_reports_generic_storage);
410 }
411 
412 /**
413  * @brief Register callback for the HIDS Device client.
414  * @param callback
415  */
416 void hids_device_register_packet_handler(btstack_packet_handler_t callback){
417     packet_handler = callback;
418 }
419 
420 /**
421  * @brief Request can send now event to send HID Report
422  * Generates an HIDS_SUBEVENT_CAN_SEND_NOW subevent
423  * @param hid_cid
424  */
425 void hids_device_request_can_send_now_event(hci_con_handle_t con_handle){
426     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
427     if (!instance){
428         log_error("no instance for handle 0x%02x", con_handle);
429         return;
430     }
431 
432     instance->battery_callback.callback = &hids_device_can_send_now;
433     instance->battery_callback.context  = (void*) (uintptr_t) con_handle;
434     att_server_register_can_send_now_callback(&instance->battery_callback, con_handle);
435 }
436 
437 uint8_t hids_device_send_input_report_for_id(hci_con_handle_t con_handle, uint16_t report_id, const uint8_t * report, uint16_t report_len){
438     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
439     if (!instance){
440         log_error("no instance for handle 0x%02x", con_handle);
441         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
442     }
443 
444     hids_device_report_t * report_storage = hids_device_get_report_for_id_and_type(instance, report_id,
445                                                                                    HID_REPORT_TYPE_INPUT);
446     if (report_storage == NULL){
447         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
448     }
449 
450     return att_server_notify(con_handle, report_storage->value_handle, report, report_len);
451 }
452 
453 uint8_t hids_device_send_input_report(hci_con_handle_t con_handle, const uint8_t * report, uint16_t report_len){
454     hids_device_t * device = hids_device_get_instance_for_con_handle(con_handle);
455     if (!device){
456         log_error("no instance for handle 0x%02x", con_handle);
457         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
458     }
459 
460     uint8_t pos;
461     uint8_t total_reports =  device->hid_input_reports_num + device->hid_output_reports_num + device->hid_feature_reports_num;
462     for (pos = 0 ; pos < total_reports ; pos++){
463         hids_device_report_t * report_storage = &device->hid_reports[pos];
464         if (report_storage->type == HID_REPORT_TYPE_INPUT){
465             return att_server_notify(con_handle, report_storage->value_handle, report, report_len);
466         }
467     }
468     return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
469 }
470 
471 /**
472  * @brief Send HID Boot Mouse Input Report
473  */
474 uint8_t hids_device_send_boot_mouse_input_report(hci_con_handle_t con_handle, const uint8_t * report, uint16_t report_len){
475     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
476     if (!instance){
477         log_error("no instance for handle 0x%02x", con_handle);
478         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
479     }
480     return att_server_notify(con_handle, instance->hid_boot_mouse_input_value_handle, report, report_len);
481 }
482 
483 /**
484  * @brief Send HID Boot Mouse Input Report
485  */
486 uint8_t hids_device_send_boot_keyboard_input_report(hci_con_handle_t con_handle, const uint8_t * report, uint16_t report_len){
487     hids_device_t * instance = hids_device_get_instance_for_con_handle(con_handle);
488     if (!instance){
489         log_error("no instance for handle 0x%02x", con_handle);
490         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
491     }
492     return att_server_notify(con_handle, instance->hid_boot_keyboard_input_value_handle, report, report_len);
493 }
494