2020 November 28 Breaking Changes Update (#11053)

* Branch point for 2020 November 28 Breaking Change                                                

* Remove matrix_col_t to allow MATRIX_ROWS > 32 (#10183)                                           

* Add support for soft serial to ATmega32U2 (#10204)                                               

* Change MIDI velocity implementation to allow direct control of velocity value (#9940)            

* Add ability to build a subset of all keyboards based on platform.                                

* Actually use eeprom_driver_init().                                                               

* Make bootloader_jump weak for ChibiOS. (#10417)                                                  

* Joystick 16-bit support (#10439)                                                                 

* Per-encoder resolutions (#10259)                                                                 

* Share button state from mousekey to pointing_device (#10179)                                     

* Add hotfix for chibios keyboards not wake (#10088)                                               

* Add advanced/efficient RGB Matrix Indicators (#8564)                                             

* Naming change.                                                                                   

* Support for STM32 GPIOF,G,H,I,J,K (#10206)                                                       

* Add milc as a dependency and remove the installed milc (#10563)                                  

* ChibiOS upgrade: early init conversions (#10214)                                                 

* ChibiOS upgrade: configuration file migrator (#9952)                                             

* Haptic and solenoid cleanup (#9700)                                                              

* XD75 cleanup (#10524)                                                                            

* OLED display update interval support (#10388)                                                    

* Add definition based on currently-selected serial driver. (#10716)                               

* New feature: Retro Tapping per key (#10622)                                                      

* Allow for modification of output RGB values when using rgblight/rgb_matrix. (#10638)             

* Add housekeeping task callbacks so that keyboards/keymaps are capable of executing code for each main loop iteration. (#10530)

* Rescale both ChibiOS and AVR backlighting.                                                       

* Reduce Helix keyboard build variation (#8669)                                                    

* Minor change to behavior allowing display updates to continue between task ticks (#10750)        

* Some GPIO manipulations in matrix.c change to atomic. (#10491)                                   

* qmk cformat (#10767)                                                                             

* [Keyboard] Update the Speedo firmware for v3.0 (#10657)                                          

* Maartenwut/Maarten namechange to evyd13/Evy (#10274)                                             

* [quantum] combine repeated lines of code (#10837)                                                

* Add step sequencer feature (#9703)                                                               

* aeboards/ext65 refactor (#10820)                                                                 

* Refactor xelus/dawn60 for Rev2 later (#10584)                                                    

* add DEBUG_MATRIX_SCAN_RATE_ENABLE to common_features.mk (#10824)                                 

* [Core] Added `add_oneshot_mods` & `del_oneshot_mods` (#10549)                                    

* update chibios os usb for the otg driver (#8893)                                                 

* Remove HD44780 References, Part 4 (#10735)                                                       

* [Keyboard] Add Valor FRL TKL (+refactor) (#10512)                                                

* Fix cursor position bug in oled_write_raw functions (#10800)                                     

* Fixup version.h writing when using SKIP_VERSION=yes (#10972)                                     

* Allow for certain code in the codebase assuming length of string. (#10974)                       

* Add AT90USB support for serial.c (#10706)                                                        

* Auto shift: support repeats and early registration (#9826)                                       

* Rename ledmatrix.h to match .c file (#7949)                                                      

* Split RGB_MATRIX_ENABLE into _ENABLE and _DRIVER (#10231)                                        

* Split LED_MATRIX_ENABLE into _ENABLE and _DRIVER (#10840)                                        

* Merge point for 2020 Nov 28 Breaking Change                                                      

1 files changed, 122 insertions, 0 deletions

diff --git a/quantum/sequencer/sequencer.h b/quantum/sequencer/sequencer.h
new file mode 100644
index 0000000000..aeca7a1e9b
--- /dev/null
+++ b/quantum/sequencer/sequencer.h
@@ -0,0 +1,122 @@
+/* Copyright 2020 Rodolphe Belouin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include "debug.h"
+#include "timer.h"
+
+// Maximum number of steps: 256
+#ifndef SEQUENCER_STEPS
+#    define SEQUENCER_STEPS 16
+#endif
+
+// Maximum number of tracks: 8
+#ifndef SEQUENCER_TRACKS
+#    define SEQUENCER_TRACKS 8
+#endif
+
+#ifndef SEQUENCER_TRACK_THROTTLE
+#    define SEQUENCER_TRACK_THROTTLE 3
+#endif
+
+#ifndef SEQUENCER_PHASE_RELEASE_TIMEOUT
+#    define SEQUENCER_PHASE_RELEASE_TIMEOUT 30
+#endif
+
+/**
+ * Make sure that the items of this enumeration follow the powers of 2, separated by a ternary variant.
+ * Check the implementation of `get_step_duration` for further explanation.
+ */
+typedef enum { SQ_RES_2, SQ_RES_2T, SQ_RES_4, SQ_RES_4T, SQ_RES_8, SQ_RES_8T, SQ_RES_16, SQ_RES_16T, SQ_RES_32, SEQUENCER_RESOLUTIONS } sequencer_resolution_t;
+
+typedef struct {
+    bool                   enabled;
+    uint8_t                steps[SEQUENCER_STEPS];
+    uint16_t               track_notes[SEQUENCER_TRACKS];
+    uint8_t                tempo;  // Is a maximum tempo of 255 reasonable?
+    sequencer_resolution_t resolution;
+} sequencer_config_t;
+
+/**
+ * Because Digital Audio Workstations get overwhelmed when too many MIDI signals are sent concurrently,
+ * We use a "phase" state machine to delay some of the events.
+ */
+typedef enum sequencer_phase_t {
+    SEQUENCER_PHASE_ATTACK,   // t=0ms, send the MIDI note on signal
+    SEQUENCER_PHASE_RELEASE,  // t=SEQUENCER_PHASE_RELEASE_TIMEOUT ms, send the MIDI note off signal
+    SEQUENCER_PHASE_PAUSE     // t=step duration ms, loop
+} sequencer_phase_t;
+
+typedef struct {
+    uint8_t           active_tracks;
+    uint8_t           current_track;
+    uint8_t           current_step;
+    uint16_t          timer;
+    sequencer_phase_t phase;
+} sequencer_state_t;
+
+extern sequencer_config_t sequencer_config;
+
+// We expose the internal state to make the feature more "unit-testable"
+extern sequencer_state_t sequencer_internal_state;
+
+bool is_sequencer_on(void);
+void sequencer_toggle(void);
+void sequencer_on(void);
+void sequencer_off(void);
+
+void sequencer_set_track_notes(const uint16_t track_notes[SEQUENCER_TRACKS]);
+
+bool is_sequencer_track_active(uint8_t track);
+void sequencer_set_track_activation(uint8_t track, bool value);
+void sequencer_toggle_track_activation(uint8_t track);
+void sequencer_toggle_single_active_track(uint8_t track);
+
+#define sequencer_activate_track(track) sequencer_set_track_activation(track, true)
+#define sequencer_deactivate_track(track) sequencer_set_track_activation(track, false)
+
+bool is_sequencer_step_on(uint8_t step);
+bool is_sequencer_step_on_for_track(uint8_t step, uint8_t track);
+void sequencer_set_step(uint8_t step, bool value);
+void sequencer_toggle_step(uint8_t step);
+void sequencer_set_all_steps(bool value);
+
+#define sequencer_set_step_on(step) sequencer_set_step(step, true)
+#define sequencer_set_step_off(step) sequencer_set_step(step, false)
+#define sequencer_set_all_steps_on() sequencer_set_all_steps(true)
+#define sequencer_set_all_steps_off() sequencer_set_all_steps(false)
+
+uint8_t sequencer_get_tempo(void);
+void    sequencer_set_tempo(uint8_t tempo);
+void    sequencer_increase_tempo(void);
+void    sequencer_decrease_tempo(void);
+
+sequencer_resolution_t sequencer_get_resolution(void);
+void                   sequencer_set_resolution(sequencer_resolution_t resolution);
+void                   sequencer_increase_resolution(void);
+void                   sequencer_decrease_resolution(void);
+
+uint8_t sequencer_get_current_step(void);
+
+uint16_t sequencer_get_beat_duration(void);
+uint16_t sequencer_get_step_duration(void);
+
+uint16_t get_beat_duration(uint8_t tempo);
+uint16_t get_step_duration(uint8_t tempo, sequencer_resolution_t resolution);
+
+void matrix_scan_sequencer(void);