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zmk/app/module/drivers/kscan/kscan_gpio_charlieplex.c

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/*
* Copyright (c) 2020-2023 The ZMK Contributors
*
* SPDX-License-Identifier: MIT
*/
#include <zmk/debounce.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/kscan.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/sys/__assert.h>
#include <zephyr/sys/util.h>
LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
#define DT_DRV_COMPAT zmk_kscan_gpio_charlieplex
#define INST_LEN(n) DT_INST_PROP_LEN(n, gpios)
#define INST_CHARLIEPLEX_LEN(n) (INST_LEN(n) * INST_LEN(n))
#if CONFIG_ZMK_KSCAN_DEBOUNCE_PRESS_MS >= 0
#define INST_DEBOUNCE_PRESS_MS(n) CONFIG_ZMK_KSCAN_DEBOUNCE_PRESS_MS
#else
#define INST_DEBOUNCE_PRESS_MS(n) \
DT_INST_PROP_OR(n, debounce_period, DT_INST_PROP(n, debounce_press_ms))
#endif
#if CONFIG_ZMK_KSCAN_DEBOUNCE_RELEASE_MS >= 0
#define INST_DEBOUNCE_RELEASE_MS(n) CONFIG_ZMK_KSCAN_DEBOUNCE_RELEASE_MS
#else
#define INST_DEBOUNCE_RELEASE_MS(n) \
DT_INST_PROP_OR(n, debounce_period, DT_INST_PROP(n, debounce_release_ms))
#endif
#define KSCAN_GPIO_CFG_INIT(idx, inst_idx) \
GPIO_DT_SPEC_GET_BY_IDX(DT_DRV_INST(inst_idx), gpios, idx)
#define INST_INTR_DEFINED(n) DT_INST_NODE_HAS_PROP(n, interrupt_gpios)
#define WITH_INTR(n) COND_CODE_1(INST_INTR_DEFINED(n), (+1), (+0))
#define WITHOUT_INTR(n) COND_CODE_0(INST_INTR_DEFINED(n), (+1), (+0))
#define USES_POLLING DT_INST_FOREACH_STATUS_OKAY(WITHOUT_INTR) > 0
#define USES_INTERRUPT DT_INST_FOREACH_STATUS_OKAY(WITH_INTR) > 0
#define COND_ANY_POLLING(code) COND_CODE_1(USES_POLLING, code, ())
#define COND_THIS_INTERRUPT(n, code) COND_CODE_1(INST_INTR_DEFINED(n), code, ())
#define KSCAN_INTR_CFG_INIT(inst_idx) GPIO_DT_SPEC_GET(DT_DRV_INST(inst_idx), interrupt_gpios)
struct kscan_charlieplex_data {
const struct device *dev;
kscan_callback_t callback;
struct k_work_delayable work;
int64_t scan_time; /* Timestamp of the current or scheduled scan. */
struct gpio_callback irq_callback;
/**
* Current state of the matrix as a flattened 2D array of length
* (config->cells.length ^2)
*/
struct zmk_debounce_state *charlieplex_state;
};
struct kscan_gpio_list {
const struct gpio_dt_spec *gpios;
size_t len;
};
/** Define a kscan_gpio_list from a compile-time GPIO array. */
#define KSCAN_GPIO_LIST(gpio_array) \
((struct kscan_gpio_list){.gpios = gpio_array, .len = ARRAY_SIZE(gpio_array)})
struct kscan_charlieplex_config {
struct kscan_gpio_list cells;
struct zmk_debounce_config debounce_config;
int32_t debounce_scan_period_ms;
int32_t poll_period_ms;
bool use_interrupt;
const struct gpio_dt_spec interrupt;
};
/**
* Get the index into a matrix state array from a row and column.
* There are effectively (n) cols and (n-1) rows, but we use the full col x row space
* as a safety measure against someone accidentally defining a transform RC at (p,p)
*/
static int state_index(const struct kscan_charlieplex_config *config, const int row,
const int col) {
__ASSERT(row < config->cells.len, "Invalid row %i", row);
__ASSERT(col < config->cells.len, "Invalid column %i", col);
__ASSERT(col != row, "Invalid column row pair %i, %i", col, row);
return (col * config->cells.len) + row;
}
static int kscan_charlieplex_set_as_input(const struct gpio_dt_spec *gpio) {
if (!device_is_ready(gpio->port)) {
LOG_ERR("GPIO is not ready: %s", gpio->port->name);
return -ENODEV;
}
gpio_flags_t pull_flag =
((gpio->dt_flags & GPIO_ACTIVE_LOW) == GPIO_ACTIVE_LOW) ? GPIO_PULL_UP : GPIO_PULL_DOWN;
int err = gpio_pin_configure_dt(gpio, GPIO_INPUT | pull_flag);
if (err) {
LOG_ERR("Unable to configure pin %u on %s for input", gpio->pin, gpio->port->name);
return err;
}
return 0;
}
static int kscan_charlieplex_set_as_output(const struct gpio_dt_spec *gpio) {
if (!device_is_ready(gpio->port)) {
LOG_ERR("GPIO is not ready: %s", gpio->port->name);
return -ENODEV;
}
int err = gpio_pin_configure_dt(gpio, GPIO_OUTPUT);
if (err) {
LOG_ERR("Unable to configure pin %u on %s for output", gpio->pin, gpio->port->name);
return err;
}
err = gpio_pin_set_dt(gpio, 1);
if (err) {
LOG_ERR("Failed to set output pin %u active: %i", gpio->pin, err);
}
return err;
}
static int kscan_charlieplex_set_all_as_input(const struct device *dev) {
const struct kscan_charlieplex_config *config = dev->config;
int err = 0;
for (int i = 0; i < config->cells.len; i++) {
err = kscan_charlieplex_set_as_input(&config->cells.gpios[i]);
if (err) {
return err;
}
}
return 0;
}
static int kscan_charlieplex_set_all_outputs(const struct device *dev, const int value) {
const struct kscan_charlieplex_config *config = dev->config;
for (int i = 0; i < config->cells.len; i++) {
const struct gpio_dt_spec *gpio = &config->cells.gpios[i];
int err = gpio_pin_configure_dt(gpio, GPIO_OUTPUT);
if (err) {
LOG_ERR("Unable to configure pin %u on %s for input", gpio->pin, gpio->port->name);
return err;
}
err = gpio_pin_set_dt(gpio, value);
if (err) {
LOG_ERR("Failed to set output %i to %i: %i", i, value, err);
return err;
}
}
return 0;
}
static int kscan_charlieplex_interrupt_configure(const struct device *dev,
const gpio_flags_t flags) {
const struct kscan_charlieplex_config *config = dev->config;
const struct gpio_dt_spec *gpio = &config->interrupt;
int err = gpio_pin_interrupt_configure_dt(gpio, flags);
if (err) {
LOG_ERR("Unable to configure interrupt for pin %u on %s", gpio->pin, gpio->port->name);
return err;
}
return 0;
}
static int kscan_charlieplex_interrupt_enable(const struct device *dev) {
int err = kscan_charlieplex_interrupt_configure(dev, GPIO_INT_LEVEL_ACTIVE);
if (err) {
return err;
}
// While interrupts are enabled, set all outputs active so an pressed key will trigger
return kscan_charlieplex_set_all_outputs(dev, 1);
}
static void kscan_charlieplex_irq_callback(const struct device *port, struct gpio_callback *cb,
const gpio_port_pins_t _pin) {
struct kscan_charlieplex_data *data =
CONTAINER_OF(cb, struct kscan_charlieplex_data, irq_callback);
// Disable our interrupt to avoid re-entry while we scan.
kscan_charlieplex_interrupt_configure(data->dev, GPIO_INT_DISABLE);
data->scan_time = k_uptime_get();
k_work_reschedule(&data->work, K_NO_WAIT);
}
static void kscan_charlieplex_read_continue(const struct device *dev) {
const struct kscan_charlieplex_config *config = dev->config;
struct kscan_charlieplex_data *data = dev->data;
data->scan_time += config->debounce_scan_period_ms;
k_work_reschedule(&data->work, K_TIMEOUT_ABS_MS(data->scan_time));
}
static void kscan_charlieplex_read_end(const struct device *dev) {
struct kscan_charlieplex_data *data = dev->data;
const struct kscan_charlieplex_config *config = dev->config;
if (config->use_interrupt) {
// Return to waiting for an interrupt.
kscan_charlieplex_interrupt_enable(dev);
} else {
data->scan_time += config->poll_period_ms;
// Return to polling slowly.
k_work_reschedule(&data->work, K_TIMEOUT_ABS_MS(data->scan_time));
}
}
static int kscan_charlieplex_read(const struct device *dev) {
struct kscan_charlieplex_data *data = dev->data;
const struct kscan_charlieplex_config *config = dev->config;
bool continue_scan = false;
// NOTE: RR vs MATRIX: set all pins as input, in case there was a failure on a
// previous scan, and one of the pins is still set as output
int err = kscan_charlieplex_set_all_as_input(dev);
if (err) {
return err;
}
// Scan the matrix.
for (int row = 0; row < config->cells.len; row++) {
const struct gpio_dt_spec *out_gpio = &config->cells.gpios[row];
err = kscan_charlieplex_set_as_output(out_gpio);
if (err) {
return err;
}
#if CONFIG_ZMK_KSCAN_CHARLIEPLEX_WAIT_BEFORE_INPUTS > 0
k_busy_wait(CONFIG_ZMK_KSCAN_CHARLIEPLEX_WAIT_BEFORE_INPUTS);
#endif
for (int col = 0; col < config->cells.len; col++) {
if (col == row) {
continue; // pin can't drive itself
}
const struct gpio_dt_spec *in_gpio = &config->cells.gpios[col];
const int index = state_index(config, row, col);
struct zmk_debounce_state *state = &data->charlieplex_state[index];
zmk_debounce_update(state, gpio_pin_get_dt(in_gpio), config->debounce_scan_period_ms,
&config->debounce_config);
// NOTE: RR vs MATRIX: because we don't need an input/output => row/column
// setup, we can update in the same loop.
if (zmk_debounce_get_changed(state)) {
const bool pressed = zmk_debounce_is_pressed(state);
LOG_DBG("Sending event at %i,%i state %s", row, col, pressed ? "on" : "off");
data->callback(dev, row, col, pressed);
}
continue_scan = continue_scan || zmk_debounce_is_active(state);
}
err = kscan_charlieplex_set_as_input(out_gpio);
if (err) {
return err;
}
#if CONFIG_ZMK_KSCAN_CHARLIEPLEX_WAIT_BETWEEN_OUTPUTS > 0
k_busy_wait(CONFIG_ZMK_KSCAN_CHARLIEPLEX_WAIT_BETWEEN_OUTPUTS);
#endif
}
if (continue_scan) {
// At least one key is pressed or the debouncer has not yet decided if
// it is pressed. Poll quickly until everything is released.
kscan_charlieplex_read_continue(dev);
} else {
// All keys are released. Return to normal.
kscan_charlieplex_read_end(dev);
}
return 0;
}
static void kscan_charlieplex_work_handler(struct k_work *work) {
struct k_work_delayable *dwork = CONTAINER_OF(work, struct k_work_delayable, work);
struct kscan_charlieplex_data *data = CONTAINER_OF(dwork, struct kscan_charlieplex_data, work);
kscan_charlieplex_read(data->dev);
}
static int kscan_charlieplex_configure(const struct device *dev, const kscan_callback_t callback) {
if (!callback) {
return -EINVAL;
}
struct kscan_charlieplex_data *data = dev->data;
data->callback = callback;
return 0;
}
static int kscan_charlieplex_enable(const struct device *dev) {
struct kscan_charlieplex_data *data = dev->data;
data->scan_time = k_uptime_get();
// Read will automatically start interrupts/polling once done.
return kscan_charlieplex_read(dev);
}
static int kscan_charlieplex_disable(const struct device *dev) {
struct kscan_charlieplex_data *data = dev->data;
k_work_cancel_delayable(&data->work);
const struct kscan_charlieplex_config *config = dev->config;
if (config->use_interrupt) {
return kscan_charlieplex_interrupt_configure(dev, GPIO_INT_DISABLE);
}
return 0;
}
static int kscan_charlieplex_init_inputs(const struct device *dev) {
const struct kscan_charlieplex_config *config = dev->config;
for (int i = 0; i < config->cells.len; i++) {
int err = kscan_charlieplex_set_as_input(&config->cells.gpios[i]);
if (err) {
return err;
}
}
return 0;
}
static int kscan_charlieplex_init_interrupt(const struct device *dev) {
struct kscan_charlieplex_data *data = dev->data;
const struct kscan_charlieplex_config *config = dev->config;
const struct gpio_dt_spec *gpio = &config->interrupt;
int err = kscan_charlieplex_set_as_input(gpio);
if (err) {
return err;
}
gpio_init_callback(&data->irq_callback, kscan_charlieplex_irq_callback, BIT(gpio->pin));
err = gpio_add_callback(gpio->port, &data->irq_callback);
if (err) {
LOG_ERR("Error adding the callback to the input device: %i", err);
}
return err;
}
static int kscan_charlieplex_init(const struct device *dev) {
struct kscan_charlieplex_data *data = dev->data;
data->dev = dev;
kscan_charlieplex_init_inputs(dev);
kscan_charlieplex_set_all_outputs(dev, 0);
const struct kscan_charlieplex_config *config = dev->config;
if (config->use_interrupt) {
kscan_charlieplex_init_interrupt(dev);
}
k_work_init_delayable(&data->work, kscan_charlieplex_work_handler);
return 0;
}
static const struct kscan_driver_api kscan_charlieplex_api = {
.config = kscan_charlieplex_configure,
.enable_callback = kscan_charlieplex_enable,
.disable_callback = kscan_charlieplex_disable,
};
#define KSCAN_CHARLIEPLEX_INIT(n) \
BUILD_ASSERT(INST_DEBOUNCE_PRESS_MS(n) <= DEBOUNCE_COUNTER_MAX, \
"ZMK_KSCAN_DEBOUNCE_PRESS_MS or debounce-press-ms is too large"); \
BUILD_ASSERT(INST_DEBOUNCE_RELEASE_MS(n) <= DEBOUNCE_COUNTER_MAX, \
"ZMK_KSCAN_DEBOUNCE_RELEASE_MS or debounce-release-ms is too large"); \
\
static struct zmk_debounce_state kscan_charlieplex_state_##n[INST_CHARLIEPLEX_LEN(n)]; \
static const struct gpio_dt_spec kscan_charlieplex_cells_##n[] = { \
LISTIFY(INST_LEN(n), KSCAN_GPIO_CFG_INIT, (, ), n)}; \
static struct kscan_charlieplex_data kscan_charlieplex_data_##n = { \
.charlieplex_state = kscan_charlieplex_state_##n, \
}; \
\
static struct kscan_charlieplex_config kscan_charlieplex_config_##n = { \
.cells = KSCAN_GPIO_LIST(kscan_charlieplex_cells_##n), \
.debounce_config = \
{ \
.debounce_press_ms = INST_DEBOUNCE_PRESS_MS(n), \
.debounce_release_ms = INST_DEBOUNCE_RELEASE_MS(n), \
}, \
.debounce_scan_period_ms = DT_INST_PROP(n, debounce_scan_period_ms), \
COND_ANY_POLLING((.poll_period_ms = DT_INST_PROP(n, poll_period_ms), )) \
COND_THIS_INTERRUPT(n, (.use_interrupt = INST_INTR_DEFINED(n), )) \
COND_THIS_INTERRUPT(n, (.interrupt = KSCAN_INTR_CFG_INIT(n), ))}; \
\
DEVICE_DT_INST_DEFINE(n, &kscan_charlieplex_init, NULL, &kscan_charlieplex_data_##n, \
&kscan_charlieplex_config_##n, POST_KERNEL, CONFIG_KSCAN_INIT_PRIORITY, \
&kscan_charlieplex_api);
DT_INST_FOREACH_STATUS_OKAY(KSCAN_CHARLIEPLEX_INIT);
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