efm32: driver: implement matrix key driver

Signed-off-by: perigoso <perigoso@riseup.net>

Author: perigoso

config/families/efm32gg12b.toml

@@ -38,6 +38,7 @@ source = [
 	'usb_descriptors.c',
 	'hal/hid.c',
 	'driver/key_direct.c',
+	'driver/key_matrix.c',
 ]
 
 [dependencies]

src/platform/efm32gg/driver/key_matrix.c

@@ -0,0 +1,61 @@
+/*
+ * SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: 2021 Rafael Silva <perigoso@riseup.net>
+ */
+
+#include "platform/efm32gg/driver/key_matrix.h"
+#include "platform/efm32gg/systick.h"
+
+struct key_matrix_t key_matrix_init(
+	struct gpio_pin_t *col_pin_list,
+	u8 col_pin_list_size,
+	struct gpio_pin_t *row_pin_list,
+	u8 row_pin_list_size,
+	struct key_t *key_data,
+	u8 col_to_row)
+{
+	struct key_matrix_t matrix = {};
+
+	matrix.col_pin_list = col_pin_list;
+	matrix.col_pin_list_size = col_pin_list_size;
+	matrix.row_pin_list = row_pin_list;
+	matrix.row_pin_list_size = row_pin_list_size;
+	matrix.key_data = key_data;
+	matrix.col_to_row = col_to_row;
+	matrix.update_timestamp = systick_get_ticks();
+
+	for (size_t col = 0; col < matrix.col_pin_list_size; col++) gpio_set(col_pin_list[col], !matrix.col_to_row);
+
+	return matrix;
+}
+
+void key_matrix_scan(struct key_matrix_t *matrix)
+{
+	u16 t_delta = systick_get_ticks() - matrix->update_timestamp;
+	matrix->update_timestamp = systick_get_ticks();
+
+	for (size_t col = 0; col < matrix->col_pin_list_size; col++) {
+		/* set col output */
+		gpio_set(matrix->col_pin_list[col], matrix->col_to_row);
+
+		for (size_t row = 0; row < matrix->row_pin_list_size; row++) {
+			u8 index = (col * matrix->row_pin_list_size) + row;
+			enum key_status_t last_status = matrix->key_data[index].key_status;
+
+			/* get row input */
+			matrix->key_data[index].key_status =
+				(gpio_get(matrix->row_pin_list[row]) ^ matrix->col_to_row) ? key_released : key_pressed;
+
+			if (matrix->key_data[index].key_status != last_status)
+				matrix->key_data[index].key_t_delta = 0;
+			else
+				matrix->key_data[index].key_t_delta += t_delta;
+		}
+
+		/* clear col output */
+		gpio_set(matrix->col_pin_list[col], !matrix->col_to_row);
+
+		/* settle time */
+		delay_us(1);
+	}
+}

src/platform/efm32gg/driver/key_matrix.h

@@ -0,0 +1,31 @@
+/*
+ * SPDX-License-Identifier: MIT
+ * SPDX-FileCopyrightText: 2021 Rafael Silva <perigoso@riseup.net>
+ */
+
+#pragma once
+
+#include "util/types.h"
+
+#include "platform/efm32gg/gpio.h"
+
+#include "key_actions/key_actions.h"
+
+struct key_matrix_t {
+	struct gpio_pin_t *col_pin_list;
+	u8 col_pin_list_size;
+	struct gpio_pin_t *row_pin_list;
+	u8 row_pin_list_size;
+	struct key_t *key_data;
+	u32 update_timestamp;
+	u8 col_to_row : 1;
+};
+
+struct key_matrix_t key_matrix_init(
+	struct gpio_pin_t *col_pin_list,
+	u8 col_pin_list_size,
+	struct gpio_pin_t *row_pin_list,
+	u8 row_pin_list_size,
+	struct key_t *key_data,
+	u8 col_to_row);
+void key_matrix_scan(struct key_matrix_t *matrix);