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/**
* Copyright (c) 2022 Ithinx GmbH
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT nxp_pcf8574
#include <zephyr/drivers/gpio/gpio_utils.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(pcf8574, CONFIG_GPIO_LOG_LEVEL);
struct pcf8574_pins_cfg {
uint8_t configured_as_outputs; /* 0 for input, 1 for output */
uint8_t outputs_state;
};
/** Runtime driver data of the pcf8574*/
struct pcf8574_drv_data {
/* gpio_driver_data needs to be first */
struct gpio_driver_data common;
struct pcf8574_pins_cfg pins_cfg;
sys_slist_t callbacks;
struct k_sem lock;
struct k_work work;
const struct device *dev;
struct gpio_callback int_gpio_cb;
uint8_t input_port_last;
};
/** Configuration data*/
struct pcf8574_drv_cfg {
/* gpio_driver_config needs to be first */
struct gpio_driver_config common;
struct i2c_dt_spec i2c;
struct gpio_dt_spec gpio_int;
};
/**
* @brief Reads the value of the pins from pcf8574 respectively from a connected device.
*
* @param dev Pointer to the device structure of the driver instance.
* @param value Pointer to the input value. It contains the received Byte.
*
* @retval 0 If successful.
* @retval Negative value for error code.
*/
static int pcf8574_process_input(const struct device *dev, gpio_port_value_t *value)
{
const struct pcf8574_drv_cfg *drv_cfg = dev->config;
struct pcf8574_drv_data *drv_data = dev->data;
int rc = 0;
uint8_t rx_buf;
rc = i2c_read_dt(&drv_cfg->i2c, &rx_buf, sizeof(rx_buf));
if (rc != 0) {
LOG_ERR("%s: failed to read from device: %d", dev->name, rc);
return -EIO;
}
if (value) {
*value = rx_buf;
}
drv_data->input_port_last = rx_buf;
return rc;
}
/** Register the read-task as work*/
static void pcf8574_work_handler(struct k_work *work)
{
struct pcf8574_drv_data *drv_data = CONTAINER_OF(work, struct pcf8574_drv_data, work);
k_sem_take(&drv_data->lock, K_FOREVER);
uint32_t changed_pins;
uint8_t input_port_last_temp = drv_data->input_port_last;
int rc = pcf8574_process_input(drv_data->dev, &changed_pins);
if (rc) {
LOG_ERR("Failed to read interrupt sources: %d", rc);
}
k_sem_give(&drv_data->lock);
if (input_port_last_temp != (uint8_t)changed_pins && !rc) {
/** Find changed bits*/
changed_pins ^= input_port_last_temp;
gpio_fire_callbacks(&drv_data->callbacks, drv_data->dev, changed_pins);
}
}
/** Callback for interrupt through some level changes on pcf8574 pins*/
static void pcf8574_int_gpio_handler(const struct device *dev, struct gpio_callback *gpio_cb,
uint32_t pins)
{
ARG_UNUSED(dev);
ARG_UNUSED(pins);
struct pcf8574_drv_data *drv_data =
CONTAINER_OF(gpio_cb, struct pcf8574_drv_data, int_gpio_cb);
k_work_submit(&drv_data->work);
}
/**
* @brief This function reads a value from the connected device
*
* @param dev Pointer to the device structure of a port.
* @param value Pointer to a variable where pin values will be stored.
*
* @retval 0 If successful.
* @retval Negative value for error code.
*/
static int pcf8574_port_get_raw(const struct device *dev, gpio_port_value_t *value)
{
struct pcf8574_drv_data *drv_data = dev->data;
int rc;
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
if ((~drv_data->pins_cfg.configured_as_outputs & (uint8_t)*value) != (uint8_t)*value) {
LOG_ERR("Pin(s) is/are configured as output which should be input.");
return -EOPNOTSUPP;
}
k_sem_take(&drv_data->lock, K_FOREVER);
/**
* Reading of the input port also clears the generated interrupt,
* thus the configured callbacks must be fired also here if needed.
*/
rc = pcf8574_process_input(dev, value);
k_sem_give(&drv_data->lock);
return rc;
}
/**
* @brief This function realizes the write connection to the i2c device.
*
* @param dev A pointer to the device structure
* @param mask A mask of bits to set some bits to LOW or HIGH
* @param value The value which is written via i2c to the pfc8574's output pins
* @param toggle A way to toggle some bits with xor
*
* @retval 0 If successful.
* @retval Negative value for error code.
*/
static int pcf8574_port_set_raw(const struct device *dev, uint8_t mask, uint8_t value,
uint8_t toggle)
{
const struct pcf8574_drv_cfg *drv_cfg = dev->config;
struct pcf8574_drv_data *drv_data = dev->data;
int rc = 0;
uint8_t tx_buf;
if (k_is_in_isr()) {
return -EWOULDBLOCK;
}
if ((drv_data->pins_cfg.configured_as_outputs & value) != value) {
LOG_ERR("Pin(s) is/are configured as input which should be output.");
return -EOPNOTSUPP;
}
tx_buf = (drv_data->pins_cfg.outputs_state & ~mask);
tx_buf |= (value & mask);
tx_buf ^= toggle;
rc = i2c_write_dt(&drv_cfg->i2c, &tx_buf, sizeof(tx_buf));
if (rc != 0) {
LOG_ERR("%s: failed to write output port: %d", dev->name, rc);
return -EIO;
}
k_sem_take(&drv_data->lock, K_FOREVER);
drv_data->pins_cfg.outputs_state = tx_buf;
k_sem_give(&drv_data->lock);
return 0;
}
/**
* @brief This function fills a dummy because the pfc8574 has no pins to configure.
* You can use it to set some pins permanent to HIGH or LOW until reset. It uses the port_set_raw
* function to set the pins of pcf8574 directly.
*
* @param dev Pointer to the device structure for the driver instance.
* @param pin The bit in the io register which is set to high
* @param flags Flags like the GPIO direction or the state
*
* @retval 0 If successful.
* @retval Negative value for error.
*/
static int pcf8574_pin_configure(const struct device *dev, gpio_pin_t pin, gpio_flags_t flags)
{
struct pcf8574_drv_data *drv_data = dev->data;
int ret = 0;
uint8_t temp_pins = drv_data->pins_cfg.outputs_state;
uint8_t temp_outputs = drv_data->pins_cfg.configured_as_outputs;
if (flags & (GPIO_PULL_UP | GPIO_PULL_DOWN | GPIO_DISCONNECTED | GPIO_SINGLE_ENDED)) {
return -ENOTSUP;
}
if (flags & GPIO_INPUT) {
temp_outputs &= ~BIT(pin);
temp_pins &= ~(1 << pin);
} else if (flags & GPIO_OUTPUT) {
drv_data->pins_cfg.configured_as_outputs |= BIT(pin);
temp_outputs = drv_data->pins_cfg.configured_as_outputs;
}
if (flags & GPIO_OUTPUT_INIT_HIGH) {
temp_pins |= (1 << pin);
}
if (flags & GPIO_OUTPUT_INIT_LOW) {
temp_pins &= ~(1 << pin);
}
ret = pcf8574_port_set_raw(dev, drv_data->pins_cfg.configured_as_outputs, temp_pins, 0);
if (ret == 0) {
k_sem_take(&drv_data->lock, K_FOREVER);
drv_data->pins_cfg.outputs_state = temp_pins;
drv_data->pins_cfg.configured_as_outputs = temp_outputs;
k_sem_give(&drv_data->lock);
}
return ret;
}
/**
* @brief Sets a value to the pins of pcf8574
*
* @param dev Pointer to the device structure for the driver instance.
* @param mask The bit mask which bits should be set
* @param value The value which should be set
*
* @retval 0 If successful.
* @retval Negative value for error.
*/
static int pcf8574_port_set_masked_raw(const struct device *dev, gpio_port_pins_t mask,
gpio_port_value_t value)
{
return pcf8574_port_set_raw(dev, (uint8_t)mask, (uint8_t)value, 0);
}
/**
* @brief Sets some output pins of the pcf8574
*
* @param dev Pointer to the device structure for the driver instance.
* @param pins The pin(s) which will be set in a range from 0 to 7
*
* @retval 0 If successful.
* @retval Negative value for error.
*/
static int pcf8574_port_set_bits_raw(const struct device *dev, gpio_port_pins_t pins)
{
return pcf8574_port_set_raw(dev, (uint8_t)pins, (uint8_t)pins, 0);
}
/**
* @brief clear some bits
*
* @param dev Pointer to the device structure for the driver instance.
* @param pins Pins which will be cleared
*
* @retval 0 If successful.
* @retval Negative value for error.
*/
static int pcf8574_port_clear_bits_raw(const struct device *dev, gpio_port_pins_t pins)
{
return pcf8574_port_set_raw(dev, (uint8_t)pins, 0, 0);
}
/**
* @brief Toggle some bits
*
* @param dev Pointer to the device structure for the driver instance.
* @param pins Pins which will be toggled
*
* @retval 0 If successful.
* @retval Negative value for error.
*/
static int pcf8574_port_toggle_bits(const struct device *dev, gpio_port_pins_t pins)
{
return pcf8574_port_set_raw(dev, 0, 0, (uint8_t)pins);
}
/* Each pin gives an interrupt at pcf8574. In this function the configuration is checked. */
static int pcf8574_pin_interrupt_configure(const struct device *dev, gpio_pin_t pin,
enum gpio_int_mode mode, enum gpio_int_trig trig)
{
const struct pcf8574_drv_cfg *drv_cfg = dev->config;
if (!drv_cfg->gpio_int.port) {
return -ENOTSUP;
}
/* This device supports only edge-triggered interrupts. */
if (mode == GPIO_INT_MODE_LEVEL) {
return -ENOTSUP;
}
return 0;
}
/** Register the callback in the callback list */
static int pcf8574_manage_callback(const struct device *dev, struct gpio_callback *callback,
bool set)
{
struct pcf8574_drv_data *drv_data = dev->data;
return gpio_manage_callback(&drv_data->callbacks, callback, set);
}
/** Initialize the pcf8574 */
static int pcf8574_init(const struct device *dev)
{
const struct pcf8574_drv_cfg *drv_cfg = dev->config;
struct pcf8574_drv_data *drv_data = dev->data;
int rc;
if (!device_is_ready(drv_cfg->i2c.bus)) {
LOG_ERR("%s is not ready", drv_cfg->i2c.bus->name);
return -ENODEV;
}
/* If the INT line is available, configure the callback for it. */
if (drv_cfg->gpio_int.port) {
if (!device_is_ready(drv_cfg->gpio_int.port)) {
LOG_ERR("Port is not ready");
return -ENODEV;
}
rc = gpio_pin_configure_dt(&drv_cfg->gpio_int, GPIO_INPUT);
if (rc != 0) {
LOG_ERR("%s: failed to configure INT line: %d", dev->name, rc);
return -EIO;
}
rc = gpio_pin_interrupt_configure_dt(&drv_cfg->gpio_int, GPIO_INT_EDGE_TO_ACTIVE);
if (rc != 0) {
LOG_ERR("%s: failed to configure INT interrupt: %d", dev->name, rc);
return -EIO;
}
gpio_init_callback(&drv_data->int_gpio_cb, pcf8574_int_gpio_handler,
BIT(drv_cfg->gpio_int.pin));
rc = gpio_add_callback(drv_cfg->gpio_int.port, &drv_data->int_gpio_cb);
if (rc != 0) {
LOG_ERR("%s: failed to add INT callback: %d", dev->name, rc);
return -EIO;
}
}
return 0;
}
/** Realizes the functions of gpio.h for pcf8574*/
static const struct gpio_driver_api pcf8574_drv_api = {
.pin_configure = pcf8574_pin_configure,
.port_get_raw = pcf8574_port_get_raw,
.port_set_masked_raw = pcf8574_port_set_masked_raw,
.port_set_bits_raw = pcf8574_port_set_bits_raw,
.port_clear_bits_raw = pcf8574_port_clear_bits_raw,
.port_toggle_bits = pcf8574_port_toggle_bits,
.pin_interrupt_configure = pcf8574_pin_interrupt_configure,
.manage_callback = pcf8574_manage_callback,
};
#define GPIO_PCF8574_INST(idx) \
static const struct pcf8574_drv_cfg pcf8574_cfg##idx = { \
.common = \
{ \
.port_pin_mask = GPIO_PORT_PIN_MASK_FROM_DT_INST(idx), \
}, \
.gpio_int = GPIO_DT_SPEC_INST_GET_OR(idx, int_gpios, {0}), \
.i2c = I2C_DT_SPEC_INST_GET(idx), \
}; \
static struct pcf8574_drv_data pcf8574_data##idx = { \
.lock = Z_SEM_INITIALIZER(pcf8574_data##idx.lock, 1, 1), \
.work = Z_WORK_INITIALIZER(pcf8574_work_handler), \
.dev = DEVICE_DT_INST_GET(idx), \
}; \
DEVICE_DT_INST_DEFINE(idx, pcf8574_init, NULL, &pcf8574_data##idx, &pcf8574_cfg##idx, \
POST_KERNEL, CONFIG_GPIO_PCF8574_INIT_PRIORITY, &pcf8574_drv_api);
DT_INST_FOREACH_STATUS_OKAY(GPIO_PCF8574_INST);