circuitpython/shared-module/keypad/__init__.c

100 lines
3.9 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2021 Dan Halbert for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "shared-bindings/keypad/Keys.h"
#include "shared-bindings/keypad/KeyMatrix.h"
#include "shared-bindings/keypad/ShiftRegisterKeys.h"
#include "supervisor/shared/lock.h"
#include "supervisor/shared/tick.h"
supervisor_lock_t keypad_scanners_linked_list_lock;
void keypad_tick(void) {
// Fast path. Return immediately there are no scanners.
if (!MP_STATE_VM(keypad_scanners_linked_list)) {
return;
}
// Skip scanning if someone else has the lock. Don't wait for the lock.
if (supervisor_try_lock(&keypad_scanners_linked_list_lock)) {
mp_obj_t scanner = MP_STATE_VM(keypad_scanners_linked_list);
while (scanner) {
if (mp_obj_is_type(scanner, &keypad_keys_type)) {
keypad_keys_scan((keypad_keys_obj_t *)scanner);
} else if (mp_obj_is_type(scanner, &keypad_keymatrix_type)) {
keypad_keymatrix_scan((keypad_keymatrix_obj_t *)scanner);
} else if (mp_obj_is_type(scanner, &keypad_shiftregisterkeys_type)) {
keypad_shiftregisterkeys_scan((keypad_shiftregisterkeys_obj_t *)scanner);
}
scanner = ((keypad_scanner_obj_t *)scanner)->next;
}
supervisor_release_lock(&keypad_scanners_linked_list_lock);
}
}
void keypad_reset(void) {
while (MP_STATE_VM(keypad_scanners_linked_list)) {
keypad_deregister_scanner(MP_STATE_VM(keypad_scanners_linked_list));
}
}
// Register a Keys, KeyMatrix, etc. that will be scanned in the background
void keypad_register_scanner(keypad_scanner_obj_t *scanner) {
supervisor_acquire_lock(&keypad_scanners_linked_list_lock);
scanner->next = MP_STATE_VM(keypad_scanners_linked_list);
MP_STATE_VM(keypad_scanners_linked_list) = scanner;
supervisor_release_lock(&keypad_scanners_linked_list_lock);
// One more request for ticks.
supervisor_enable_tick();
}
// Remove scanner from the list of active scanners.
void keypad_deregister_scanner(keypad_scanner_obj_t *scanner) {
// One less request for ticks.
supervisor_disable_tick();
supervisor_acquire_lock(&keypad_scanners_linked_list_lock);
if (MP_STATE_VM(keypad_scanners_linked_list) == scanner) {
// Scanner is at the front; splice it out.
MP_STATE_VM(keypad_scanners_linked_list) = scanner->next;
scanner->next = NULL;
} else {
keypad_scanner_obj_t *current = MP_STATE_VM(keypad_scanners_linked_list);
while (current) {
if (current->next == scanner) {
// Splice myself out.
current->next = scanner->next;
scanner->next = NULL;
break;
}
current = current->next;
}
}
supervisor_release_lock(&keypad_scanners_linked_list_lock);
}