summaryrefslogtreecommitdiffstats
path: root/keyboards/handwired/ferris/matrix.c
blob: e13c35d358b9f7e1ff3db187dc1b7e98811a0e2c (plain)
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
/*
Copyright 2013 Oleg Kostyuk <cub.uanic@gmail.com>
          2020 Pierre Chevalier <pierrechevalier83@gmail.com>

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/>.
*/

/*
 * This code was heavily inspired by the ergodox_ez keymap, and modernized
 * to take advantage of the quantum.h microcontroller agnostics gpio control
 * abstractions and use the macros defined in config.h for the wiring as opposed
 * to repeating that information all over the place.
 */

#include QMK_KEYBOARD_H
#include "i2c_master.h"

extern i2c_status_t mcp23017_status;
#define I2C_TIMEOUT 1000

// For a better understanding of the i2c protocol, this is a good read:
// https://www.robot-electronics.co.uk/i2c-tutorial

// I2C address:
// See the datasheet, section 3.3.1 on addressing I2C devices and figure 3-6 for an
// illustration
// http://ww1.microchip.com/downloads/en/devicedoc/20001952c.pdf
// All address pins of the mcp23017 are connected to the ground on the ferris
// | 0  | 1  | 0  | 0  | A2 | A1 | A0 |
// | 0  | 1  | 0  | 0  | 0  | 0  | 0  |
#define I2C_ADDR 0b0100000
#define I2C_ADDR_WRITE ((I2C_ADDR << 1) | I2C_WRITE)
#define I2C_ADDR_READ ((I2C_ADDR << 1) | I2C_READ)

// Register addresses
// See https://github.com/adafruit/Adafruit-MCP23017-Arduino-Library/blob/master/Adafruit_MCP23017.h
#define IODIRA 0x00  // i/o direction register
#define IODIRB 0x01
#define GPPUA 0x0C  // GPIO pull-up resistor register
#define GPPUB 0x0D
#define GPIOA 0x12  // general purpose i/o port register (write modifies OLAT)
#define GPIOB 0x13
#define OLATA 0x14  // output latch register
#define OLATB 0x15

bool         i2c_initialized = 0;
i2c_status_t mcp23017_status = I2C_ADDR;

uint8_t init_mcp23017(void) {
    print("starting init");
    mcp23017_status = I2C_ADDR;

    // I2C subsystem
    if (i2c_initialized == 0) {
        i2c_init();  // on pins D(1,0)
        i2c_initialized = true;
        wait_ms(I2C_TIMEOUT);
    }

    // set pin direction
    // - unused  : input  : 1
    // - input   : input  : 1
    // - driving : output : 0
    mcp23017_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    mcp23017_status = i2c_write(IODIRA, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    // This means: we will read all the bits on GPIOA
    mcp23017_status = i2c_write(0b11111111, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    // This means: we will write to the pins 0-4 on GPIOB (in select_rows)
    mcp23017_status = i2c_write(0b11110000, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    i2c_stop();

    // set pull-up
    // - unused  : on  : 1
    // - input   : on  : 1
    // - driving : off : 0
    mcp23017_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    mcp23017_status = i2c_write(GPPUA, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    // This means: we will read all the bits on GPIOA
    mcp23017_status = i2c_write(0b11111111, I2C_TIMEOUT);
    if (mcp23017_status) goto out;
    // This means: we will write to the pins 0-4 on GPIOB (in select_rows)
    mcp23017_status = i2c_write(0b11110000, I2C_TIMEOUT);
    if (mcp23017_status) goto out;

out:
    i2c_stop();
    return mcp23017_status;
}

/* matrix state(1:on, 0:off) */
static matrix_row_t matrix[MATRIX_ROWS];      // debounced values

static matrix_row_t read_cols(uint8_t row);
static void         init_cols(void);
static void         unselect_rows(void);
static void         select_row(uint8_t row);

static uint8_t mcp23017_reset_loop;

void matrix_init_custom(void) {
    // initialize row and col

    mcp23017_status = init_mcp23017();

    unselect_rows();
    init_cols();

    // initialize matrix state: all keys off
    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
        matrix[i]     = 0;
    }
}

void matrix_power_up(void) {
    mcp23017_status = init_mcp23017();

    unselect_rows();
    init_cols();

    // initialize matrix state: all keys off
    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
        matrix[i] = 0;
    }
}

// Reads and stores a row, returning
// whether a change occurred.
static inline bool store_matrix_row(matrix_row_t current_matrix[], uint8_t index) {
    matrix_row_t temp = read_cols(index);
    if (current_matrix[index] != temp) {
        current_matrix[index] = temp;
        return true;
    }
    return false;
}

bool matrix_scan_custom(matrix_row_t current_matrix[]) {
    if (mcp23017_status) {  // if there was an error
        if (++mcp23017_reset_loop == 0) {
            // if (++mcp23017_reset_loop >= 1300) {
            // since mcp23017_reset_loop is 8 bit - we'll try to reset once in 255 matrix scans
            // this will be approx bit more frequent than once per second
            dprint("trying to reset mcp23017\n");
            mcp23017_status = init_mcp23017();
            if (mcp23017_status) {
                dprint("right side not responding\n");
            } else {
                dprint("right side attached\n");
            }
        }
    }

    bool changed = false;
    for (uint8_t i = 0; i < MATRIX_ROWS_PER_SIDE; i++) {
        // select rows from left and right hands
        uint8_t left_index  = i;
        uint8_t right_index = i + MATRIX_ROWS_PER_SIDE;
        select_row(left_index);
        select_row(right_index);

        // we don't need a 30us delay anymore, because selecting a
        // left-hand row requires more than 30us for i2c.

        changed |= store_matrix_row(current_matrix, left_index);
        changed |= store_matrix_row(current_matrix, right_index);

        unselect_rows();
    }

    return changed;
}

static void init_cols(void) {
    // init on mcp23017
    // not needed, already done as part of init_mcp23017()

    // init on mcu
    pin_t matrix_col_pins_mcu[MATRIX_COLS_PER_SIDE] = MATRIX_COL_PINS_MCU;
    for (int pin_index = 0; pin_index < MATRIX_COLS_PER_SIDE; pin_index++) {
        pin_t pin = matrix_col_pins_mcu[pin_index];
        setPinInput(pin);
        writePinHigh(pin);
    }
}

static matrix_row_t read_cols(uint8_t row) {
    if (row < MATRIX_ROWS_PER_SIDE) {
        pin_t        matrix_col_pins_mcu[MATRIX_COLS_PER_SIDE] = MATRIX_COL_PINS_MCU;
        matrix_row_t current_row_value                         = 0;
        // For each col...
        for (uint8_t col_index = 0; col_index < MATRIX_COLS_PER_SIDE; col_index++) {
            // Select the col pin to read (active low)
            uint8_t pin_state = readPin(matrix_col_pins_mcu[col_index]);

            // Populate the matrix row with the state of the col pin
            current_row_value |= pin_state ? 0 : (MATRIX_ROW_SHIFTER << col_index);
        }
        return current_row_value;
    } else {
        if (mcp23017_status) {  // if there was an error
            return 0;
        } else {
            uint8_t data    = 0;
            mcp23017_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
            if (mcp23017_status) goto out;
            mcp23017_status = i2c_write(GPIOA, I2C_TIMEOUT);
            if (mcp23017_status) goto out;
            mcp23017_status = i2c_start(I2C_ADDR_READ, I2C_TIMEOUT);
            if (mcp23017_status) goto out;
            mcp23017_status = i2c_read_nack(I2C_TIMEOUT);
            if (mcp23017_status < 0) goto out;
            // We read all the pins on GPIOA.
            // The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
            // The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
            // Since the pins connected to eact columns are sequential, and counting from zero up (col 5 -> GPIOA0, col 6 -> GPIOA1 and so on), the only transformation needed is a bitwise not to swap all zeroes and ones.
            data            = ~((uint8_t)mcp23017_status);
            mcp23017_status = I2C_STATUS_SUCCESS;
        out:
            i2c_stop();
            // return reverse_bits(data, MATRIX_COLS_PER_SIDE);
            return data;
        }
    }
}

static void unselect_rows(void) {
    // no need to unselect on mcp23017, because the select step sets all
    // the other row bits high, and it's not changing to a different
    // direction

    // unselect rows on microcontroller
    pin_t matrix_row_pins_mcu[MATRIX_ROWS_PER_SIDE] = MATRIX_ROW_PINS_MCU;
    for (int pin_index = 0; pin_index < MATRIX_ROWS_PER_SIDE; pin_index++) {
        pin_t pin = matrix_row_pins_mcu[pin_index];
        setPinInput(pin);
        writePinLow(pin);
    }
}

static void select_row(uint8_t row) {
    if (row < MATRIX_ROWS_PER_SIDE) {
        // select on atmega32u4
        pin_t matrix_row_pins_mcu[MATRIX_ROWS_PER_SIDE] = MATRIX_ROW_PINS_MCU;
        pin_t pin                                       = matrix_row_pins_mcu[row];
        setPinOutput(pin);
        writePinLow(pin);
    } else {
        // select on mcp23017
        if (mcp23017_status) {  // if there was an error
                                // do nothing
        } else {
            mcp23017_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
            if (mcp23017_status) goto out;
            mcp23017_status = i2c_write(GPIOB, I2C_TIMEOUT);
            if (mcp23017_status) goto out;
            // Select the desired row by writing a byte for the entire GPIOB bus where only the bit representing the row we want to select is a zero (write instruction) and every other bit is a one.
            // Note that the row - MATRIX_ROWS_PER_SIDE reflects the fact that being on the right hand, the columns are numbered from MATRIX_ROWS_PER_SIDE to MATRIX_ROWS, but the pins we want to write to are indexed from zero up on the GPIOB bus.
            mcp23017_status = i2c_write(0xFF & ~(1 << (row - MATRIX_ROWS_PER_SIDE)), I2C_TIMEOUT);

            if (mcp23017_status) goto out;
        out:
            i2c_stop();
        }
    }
}