input: add a gpio qdec input driver
Add a GPIO based quadrature decoder driver that reports relative axes movements using the input subsystem. Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
This commit is contained in:
Fabio Baltieri
Carles Cufí
parent
c2a730edc7
commit
2790106c33
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@ -5,5 +5,6 @@ zephyr_library_property(ALLOW_EMPTY TRUE)
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zephyr_library_sources_ifdef(CONFIG_INPUT_FT5336 input_ft5336.c)
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zephyr_library_sources_ifdef(CONFIG_INPUT_GPIO_KEYS input_gpio_keys.c)
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zephyr_library_sources_ifdef(CONFIG_INPUT_GPIO_QDEC input_gpio_qdec.c)
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zephyr_library_sources_ifdef(CONFIG_INPUT_NPCX_KBD input_npcx_kbd.c)
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zephyr_library_sources_ifdef(CONFIG_INPUT_SDL_TOUCH input_sdl_touch.c)
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@ -7,6 +7,7 @@ menu "Input drivers"
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source "drivers/input/Kconfig.ft5336"
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source "drivers/input/Kconfig.gpio_keys"
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source "drivers/input/Kconfig.gpio_qdec"
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source "drivers/input/Kconfig.npcx"
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source "drivers/input/Kconfig.sdl"
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9
drivers/input/Kconfig.gpio_qdec
Normal file
9
drivers/input/Kconfig.gpio_qdec
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@ -0,0 +1,9 @@
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# Copyright 2023 Google LLC
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# SPDX-License-Identifier: Apache-2.0
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config INPUT_GPIO_QDEC
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bool "GPIO based QDEC input driver"
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default y
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depends on DT_HAS_GPIO_QDEC_ENABLED
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help
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GPIO Quadrature Decoder input driver.
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240
drivers/input/input_gpio_qdec.c
Normal file
240
drivers/input/input_gpio_qdec.c
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@ -0,0 +1,240 @@
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/*
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* Copyright 2023 Google LLC
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT gpio_qdec
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#include <stdint.h>
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#include <stdlib.h>
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#include <zephyr/device.h>
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#include <zephyr/drivers/gpio.h>
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#include <zephyr/input/input.h>
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#include <zephyr/kernel.h>
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#include <zephyr/logging/log.h>
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LOG_MODULE_REGISTER(input_gpio_qdec, CONFIG_INPUT_LOG_LEVEL);
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#define GPIO_QDEC_GPIO_NUM 2
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struct gpio_qdec_config {
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struct gpio_dt_spec gpio[GPIO_QDEC_GPIO_NUM];
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uint32_t sample_time_us;
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uint32_t idle_timeout_ms;
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uint16_t axis;
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uint8_t steps_per_period;
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};
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struct gpio_qdec_data {
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const struct device *dev;
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struct k_timer sample_timer;
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uint8_t prev_step;
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int32_t acc;
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struct k_work event_work;
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struct k_work_delayable idle_work;
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struct gpio_callback gpio_cb;
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};
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/* Positive transitions */
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#define QDEC_LL_LH 0x01
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#define QDEC_LH_HH 0x13
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#define QDEC_HH_HL 0x32
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#define QDEC_HL_LL 0x20
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/* Negative transitions */
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#define QDEC_LL_HL 0x02
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#define QDEC_LH_LL 0x10
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#define QDEC_HH_LH 0x31
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#define QDEC_HL_HH 0x23
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static uint8_t gpio_qdec_get_step(const struct device *dev)
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{
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const struct gpio_qdec_config *cfg = dev->config;
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uint8_t step = 0x00;
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if (gpio_pin_get_dt(&cfg->gpio[0])) {
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step |= 0x01;
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}
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if (gpio_pin_get_dt(&cfg->gpio[1])) {
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step |= 0x02;
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}
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return step;
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}
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static void gpio_qdec_sample_timer_timeout(struct k_timer *timer)
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{
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const struct device *dev = k_timer_user_data_get(timer);
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const struct gpio_qdec_config *cfg = dev->config;
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struct gpio_qdec_data *data = dev->data;
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int8_t delta = 0;
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unsigned int key;
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uint8_t step;
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step = gpio_qdec_get_step(dev);
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if (data->prev_step == step) {
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return;
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}
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switch ((data->prev_step << 4U) | step) {
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case QDEC_LL_LH:
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case QDEC_LH_HH:
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case QDEC_HH_HL:
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case QDEC_HL_LL:
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delta = 1;
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break;
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case QDEC_LL_HL:
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case QDEC_LH_LL:
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case QDEC_HH_LH:
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case QDEC_HL_HH:
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delta = -1;
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break;
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default:
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LOG_WRN("%s: lost steps", dev->name);
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}
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data->prev_step = step;
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key = irq_lock();
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data->acc += delta;
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irq_unlock(key);
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if (abs(data->acc) >= cfg->steps_per_period) {
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k_work_submit(&data->event_work);
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}
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k_work_reschedule(&data->idle_work, K_MSEC(cfg->idle_timeout_ms));
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}
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static void gpio_qdec_event_worker(struct k_work *work)
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{
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struct gpio_qdec_data *data = CONTAINER_OF(
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work, struct gpio_qdec_data, event_work);
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const struct device *dev = data->dev;
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const struct gpio_qdec_config *cfg = dev->config;
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unsigned int key;
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int32_t acc;
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key = irq_lock();
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acc = data->acc / cfg->steps_per_period;
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data->acc -= acc * cfg->steps_per_period;
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irq_unlock(key);
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if (acc != 0) {
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input_report_rel(data->dev, cfg->axis, acc, true, K_FOREVER);
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}
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}
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static void gpio_qdec_irq_setup(const struct device *dev, bool enable)
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{
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const struct gpio_qdec_config *cfg = dev->config;
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unsigned int flags = enable ? GPIO_INT_EDGE_BOTH : GPIO_INT_DISABLE;
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int ret;
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for (int i = 0; i < GPIO_QDEC_GPIO_NUM; i++) {
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const struct gpio_dt_spec *gpio = &cfg->gpio[i];
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ret = gpio_pin_interrupt_configure_dt(gpio, flags);
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if (ret != 0) {
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LOG_ERR("Pin %d interrupt configuration failed: %d", i, ret);
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return;
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}
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}
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}
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static void gpio_qdec_idle_worker(struct k_work *work)
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{
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struct gpio_qdec_data *data = CONTAINER_OF(
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work, struct gpio_qdec_data, idle_work);
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const struct device *dev = data->dev;
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k_timer_stop(&data->sample_timer);
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gpio_qdec_irq_setup(dev, true);
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LOG_DBG("polling stop");
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}
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static void gpio_qdec_cb(const struct device *gpio_dev, struct gpio_callback *cb,
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uint32_t pins)
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{
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struct gpio_qdec_data *data = CONTAINER_OF(
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cb, struct gpio_qdec_data, gpio_cb);
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const struct device *dev = data->dev;
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const struct gpio_qdec_config *cfg = dev->config;
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gpio_qdec_irq_setup(dev, false);
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k_timer_start(&data->sample_timer, K_NO_WAIT,
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K_USEC(cfg->sample_time_us));
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LOG_DBG("polling start");
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}
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static int gpio_qdec_init(const struct device *dev)
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{
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const struct gpio_qdec_config *cfg = dev->config;
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struct gpio_qdec_data *data = dev->data;
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int ret;
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data->dev = dev;
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k_work_init(&data->event_work, gpio_qdec_event_worker);
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k_work_init_delayable(&data->idle_work, gpio_qdec_idle_worker);
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k_timer_init(&data->sample_timer, gpio_qdec_sample_timer_timeout, NULL);
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k_timer_user_data_set(&data->sample_timer, (void *)dev);
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gpio_init_callback(&data->gpio_cb, gpio_qdec_cb,
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BIT(cfg->gpio[0].pin) | BIT(cfg->gpio[1].pin));
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for (int i = 0; i < GPIO_QDEC_GPIO_NUM; i++) {
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const struct gpio_dt_spec *gpio = &cfg->gpio[i];
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if (!gpio_is_ready_dt(gpio)) {
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LOG_ERR("%s is not ready", gpio->port->name);
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return -ENODEV;
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}
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ret = gpio_pin_configure_dt(gpio, GPIO_INPUT);
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if (ret != 0) {
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LOG_ERR("Pin %d configuration failed: %d", i, ret);
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return ret;
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}
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gpio_add_callback_dt(gpio, &data->gpio_cb);
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}
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data->prev_step = gpio_qdec_get_step(dev);
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gpio_qdec_irq_setup(dev, true);
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LOG_DBG("Device %s initialized", dev->name);
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return 0;
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}
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#define QDEC_GPIO_INIT(n) \
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BUILD_ASSERT(DT_INST_PROP_LEN(n, gpios) == GPIO_QDEC_GPIO_NUM, \
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"input_gpio_qdec: gpios must have exactly two entries"); \
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\
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static const struct gpio_qdec_config gpio_qdec_cfg_##n = { \
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.gpio = {GPIO_DT_SPEC_INST_GET_BY_IDX(n, gpios, 0), \
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GPIO_DT_SPEC_INST_GET_BY_IDX(n, gpios, 1)}, \
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.sample_time_us = DT_INST_PROP(n, sample_time_us), \
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.idle_timeout_ms = DT_INST_PROP(n, idle_timeout_ms), \
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.steps_per_period = DT_INST_PROP(n, steps_per_period), \
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.axis = DT_INST_PROP(n, zephyr_axis), \
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}; \
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\
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static struct gpio_qdec_data gpio_qdec_data_##n; \
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\
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DEVICE_DT_INST_DEFINE(n, gpio_qdec_init, NULL, \
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&gpio_qdec_data_##n, \
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&gpio_qdec_cfg_##n, \
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POST_KERNEL, CONFIG_INPUT_INIT_PRIORITY, \
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NULL);
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DT_INST_FOREACH_STATUS_OKAY(QDEC_GPIO_INIT)
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63
dts/bindings/input/gpio-qdec.yaml
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63
dts/bindings/input/gpio-qdec.yaml
Normal file
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@ -0,0 +1,63 @@
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# Copyright 2023 Google LLC
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# SPDX-License-Identifier: Apache-2.0
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description: |
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GPIO based QDEC input device
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Implement an input device generating relative axis event reports for a rotary
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encoder connected to two GPIOs. The driver is normally idling until it sees a
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transition on any of the encoder signal lines, then switches to polling mode
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and samples the two signal lines periodically to track the encoder position,
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and goes back to idling after the specified timeout.
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Example configuration:
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#include <dt-bindings/input/input-event-codes.h>
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qdec {
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compatible = "gpio-qdec";
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gpios = <&gpio0 14 (GPIO_PULL_UP | GPIO_ACTIVE_HIGH)>,
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<&gpio0 13 (GPIO_PULL_UP | GPIO_ACTIVE_HIGH)>;
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steps-per-period = <4>;
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zephyr,axis = <INPUT_REL_Y>;
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sample-time-us = <2000>;
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idle-timeout-ms = <200>;
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};
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compatible: "gpio-qdec"
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include: base.yaml
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properties:
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gpios:
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type: phandle-array
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required: true
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description: |
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GPIO for the A and B encoder signals.
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steps-per-period:
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type: int
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required: true
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description: |
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How many steps to count before reporting an input event.
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zephyr,axis:
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type: int
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required: true
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description: |
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The input code for the axis to report for the device, typically any of
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INPUT_REL_*.
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sample-time-us:
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type: int
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required: true
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description: |
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How often to sample the A and B signal lines when tracking the encoder
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movement.
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idle-timeout-ms:
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type: int
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required: true
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description: |
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Timeout for the last detected transition before stopping the sampling
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timer and going back to idle state.
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