drivers/gpio/gpio_sn74hc595.c

/*
 * Copyright (c) 2022 Matthias Freese
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT ti_sn74hc595

/**
 * @file Driver for 74 HC shift register
 */

#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/spi.h>
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/kernel.h>

#include <zephyr/drivers/gpio/gpio_utils.h>

#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(gpio_sn74hc595, CONFIG_GPIO_LOG_LEVEL);

#if CONFIG_SPI_INIT_PRIORITY >= CONFIG_GPIO_SN74HC595_INIT_PRIORITY
#error SPI_INIT_PRIORITY must be lower than SN74HC595_INIT_PRIORITY
#endif

struct gpio_sn74hc595_config {
	/* gpio_driver_config needs to be first */
	struct gpio_driver_config config;

	struct spi_dt_spec bus;
	struct gpio_dt_spec reset_gpio;
};

struct gpio_sn74hc595_drv_data {
	/* gpio_driver_data needs to be first */
	struct gpio_driver_data data;

	struct k_mutex lock;
	uint8_t output;
};

static int sn74hc595_spi_write(const struct device *dev, void *buf, size_t len_bytes)
{
	const struct gpio_sn74hc595_config *config = dev->config;

	__ASSERT(((buf != NULL) || (len_bytes == 0)), "no valid buffer given");
	__ASSERT(!k_is_in_isr(), "attempt to access SPI from ISR");

	struct spi_buf tx_buf[] = { { .buf = buf, .len = len_bytes } };
	const struct spi_buf_set tx = { .buffers = tx_buf, .count = 1 };

	return spi_write_dt(&config->bus, &tx);
}

static int gpio_sn74hc595_config(const struct device *dev, gpio_pin_t pin, gpio_flags_t flags)
{
	ARG_UNUSED(dev);
	ARG_UNUSED(pin);
	ARG_UNUSED(flags);
	return 0;
}

static int gpio_sn74hc595_port_get_raw(const struct device *dev, uint32_t *value)
{
	struct gpio_sn74hc595_drv_data *drv_data = dev->data;

	k_mutex_lock(&drv_data->lock, K_FOREVER);

	*value = drv_data->output;

	k_mutex_unlock(&drv_data->lock);

	return 0;
}

static int gpio_sn74hc595_port_set_masked_raw(const struct device *dev, uint32_t mask,
					      uint32_t value)
{
	struct gpio_sn74hc595_drv_data *drv_data = dev->data;
	int ret = 0;
	uint8_t output;

	k_mutex_lock(&drv_data->lock, K_FOREVER);

	/* check if we need to do something at all      */
	/* current output differs from new masked value */
	if ((drv_data->output & mask) != (mask & value)) {
		output = (drv_data->output & ~mask) | (mask & value);

		ret = sn74hc595_spi_write(dev, &output, 1U);
		if (ret < 0) {
			goto unlock;
		}

		drv_data->output = output;
	}

unlock:
	k_mutex_unlock(&drv_data->lock);
	return ret;
}

static int gpio_sn74hc595_port_set_bits_raw(const struct device *dev, uint32_t mask)
{
	return gpio_sn74hc595_port_set_masked_raw(dev, mask, mask);
}

static int gpio_sn74hc595_port_clear_bits_raw(const struct device *dev, uint32_t mask)
{
	return gpio_sn74hc595_port_set_masked_raw(dev, mask, 0U);
}

static int gpio_sn74hc595_port_toggle_bits(const struct device *dev, uint32_t mask)
{
	struct gpio_sn74hc595_drv_data *drv_data = dev->data;
	int ret;
	uint8_t toggled_output;

	k_mutex_lock(&drv_data->lock, K_FOREVER);

	toggled_output = drv_data->output ^ mask;

	ret = sn74hc595_spi_write(dev, &toggled_output, 1U);
	if (ret < 0) {
		goto unlock;
	}

	drv_data->output ^= mask;

unlock:
	k_mutex_unlock(&drv_data->lock);
	return ret;
}

static const struct gpio_driver_api gpio_sn74hc595_drv_api_funcs = {
	.pin_configure = gpio_sn74hc595_config,
	.port_get_raw = gpio_sn74hc595_port_get_raw,
	.port_set_masked_raw = gpio_sn74hc595_port_set_masked_raw,
	.port_set_bits_raw = gpio_sn74hc595_port_set_bits_raw,
	.port_clear_bits_raw = gpio_sn74hc595_port_clear_bits_raw,
	.port_toggle_bits = gpio_sn74hc595_port_toggle_bits,
};

/**
 * @brief Initialization function of sn74hc595
 *
 * @param dev Device struct
 * @return 0 if successful, failed otherwise.
 */
static int gpio_sn74hc595_init(const struct device *dev)
{
	const struct gpio_sn74hc595_config *config = dev->config;
	struct gpio_sn74hc595_drv_data *drv_data = dev->data;

	if (!spi_is_ready_dt(&config->bus)) {
		LOG_ERR("SPI bus %s not ready", config->bus.bus->name);
		return -ENODEV;
	}

	if (!gpio_is_ready_dt(&config->reset_gpio)) {
		LOG_ERR("GPIO port %s not ready", config->reset_gpio.port->name);
		return -ENODEV;
	}

	if (gpio_pin_configure_dt(&config->reset_gpio, GPIO_OUTPUT_ACTIVE) < 0) {
		LOG_ERR("Unable to configure RST GPIO pin %u", config->reset_gpio.pin);
		return -EINVAL;
	}

	gpio_pin_set(config->reset_gpio.port, config->reset_gpio.pin, 0);

	drv_data->output = 0U;
	return 0;
}

#define SN74HC595_SPI_OPERATION									\
	((uint16_t)(SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8)))

#define SN74HC595_INIT(n)									\
	static struct gpio_sn74hc595_drv_data sn74hc595_data_##n = {				\
		.output = 0,									\
		.lock = Z_MUTEX_INITIALIZER(sn74hc595_data_##n.lock),				\
	};											\
												\
	static const struct gpio_sn74hc595_config sn74hc595_config_##n = {			\
		.config = {									\
			.port_pin_mask =							\
				GPIO_PORT_PIN_MASK_FROM_DT_INST(n),				\
		},										\
		.bus = SPI_DT_SPEC_INST_GET(n, SN74HC595_SPI_OPERATION, 0),			\
		.reset_gpio = GPIO_DT_SPEC_INST_GET(n, reset_gpios),				\
	};											\
												\
	DEVICE_DT_DEFINE(DT_DRV_INST(n), &gpio_sn74hc595_init, NULL,				\
			 &sn74hc595_data_##n, &sn74hc595_config_##n, POST_KERNEL,		\
			 CONFIG_GPIO_SN74HC595_INIT_PRIORITY, &gpio_sn74hc595_drv_api_funcs);

DT_INST_FOREACH_STATUS_OKAY(SN74HC595_INIT)