drivers/gpio/gpio_mmio32.c

/*
 * Copyright (c) 2016 Linaro Ltd.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @file
 * @brief Driver to provide the GPIO API for a simple 32-bit i/o register
 *
 * This is a driver for accessing a simple, fixed purpose, 32-bit
 * memory-mapped i/o register using the same APIs as GPIO drivers. This is
 * useful when an SoC or board has registers that aren't part of a GPIO IP
 * block and these registers are used to control things that Zephyr normally
 * expects to be specified using a GPIO pin, e.g. for driving an LED, or
 * chip-select line for an SPI device.
 *
 * The implementation expects that all bits of the hardware register are both
 * readable and writable, and that for any bits that act as outputs, the value
 * read will have the value that was last written to it. This requirement
 * stems from the use of a read-modify-write method for all changes.
 *
 * It is possible to specify a restricted mask of bits that are valid for
 * access, and whenever the register is written, the value of bits outside this
 * mask will be preserved, even when the whole port is written to using
 * gpio_port_write.
 */

#define DT_DRV_COMPAT arm_mmio32_gpio

#include <zephyr/irq.h>
#include <errno.h>

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

struct gpio_mmio32_config {
	/* gpio_driver_config needs to be first */
	struct gpio_driver_config common;
	volatile uint32_t *reg;
	bool is_input;
};

struct gpio_mmio32_context {
	/* gpio_driver_data needs to be first */
	struct gpio_driver_data common;
	const struct gpio_mmio32_config *config;
};

int gpio_mmio32_init(const struct device *dev);

static int gpio_mmio32_config(const struct device *dev, gpio_pin_t pin, gpio_flags_t flags)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = context->config;

	if ((config->common.port_pin_mask & (1 << pin)) == 0) {
		return -EINVAL; /* Pin not in our validity mask */
	}

	if (flags & ~(GPIO_INPUT | GPIO_OUTPUT | GPIO_OUTPUT_INIT_LOW | GPIO_OUTPUT_INIT_HIGH |
		      GPIO_ACTIVE_LOW)) {
		/* We ignore direction and fake polarity, rest is unsupported */
		return -ENOTSUP;
	}

	if (config->is_input && ((flags & GPIO_OUTPUT) != 0)) {
		return -ENOTSUP;
	}
	if (!config->is_input && ((flags & GPIO_INPUT) != 0)) {
		return -ENOTSUP;
	}

	if ((flags & GPIO_OUTPUT) != 0) {
		unsigned int key;
		volatile uint32_t *reg = config->reg;

		key = irq_lock();
		if ((flags & GPIO_OUTPUT_INIT_HIGH) != 0) {
			*reg = (*reg | (1 << pin));
		} else if ((flags & GPIO_OUTPUT_INIT_LOW) != 0) {
			*reg = (*reg & (config->common.port_pin_mask & ~(1 << pin)));
		}
		irq_unlock(key);
	}

	return 0;
}

static int gpio_mmio32_port_get_raw(const struct device *dev, uint32_t *value)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = context->config;

	*value = *config->reg & config->common.port_pin_mask;

	return 0;
}

static int gpio_mmio32_port_set_masked_raw(const struct device *dev, uint32_t mask, uint32_t value)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = context->config;
	volatile uint32_t *reg = config->reg;
	unsigned int key;

	mask &= config->common.port_pin_mask;
	value &= mask;

	/* Update pin state atomically */
	key = irq_lock();
	*reg = (*reg & ~mask) | value;
	irq_unlock(key);

	return 0;
}

static int gpio_mmio32_port_set_bits_raw(const struct device *dev, uint32_t mask)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = context->config;
	volatile uint32_t *reg = config->reg;
	unsigned int key;

	mask &= config->common.port_pin_mask;

	/* Update pin state atomically */
	key = irq_lock();
	*reg = (*reg | mask);
	irq_unlock(key);

	return 0;
}

static int gpio_mmio32_port_clear_bits_raw(const struct device *dev, uint32_t mask)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = context->config;
	volatile uint32_t *reg = config->reg;
	unsigned int key;

	mask &= config->common.port_pin_mask;

	/* Update pin state atomically */
	key = irq_lock();
	*reg = (*reg & ~mask);
	irq_unlock(key);

	return 0;
}

static int gpio_mmio32_port_toggle_bits(const struct device *dev, uint32_t mask)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = context->config;
	volatile uint32_t *reg = config->reg;
	unsigned int key;

	mask &= config->common.port_pin_mask;

	/* Update pin state atomically */
	key = irq_lock();
	*reg = (*reg ^ mask);
	irq_unlock(key);

	return 0;
}

int gpio_mmio32_pin_interrupt_configure(const struct device *port,
					gpio_pin_t pin,
					enum gpio_int_mode mode,
					enum gpio_int_trig trig)
{
	return -ENOTSUP;
}

DEVICE_API(gpio, gpio_mmio32_api) = {
	.pin_configure = gpio_mmio32_config,
	.port_get_raw = gpio_mmio32_port_get_raw,
	.port_set_masked_raw = gpio_mmio32_port_set_masked_raw,
	.port_set_bits_raw = gpio_mmio32_port_set_bits_raw,
	.port_clear_bits_raw = gpio_mmio32_port_clear_bits_raw,
	.port_toggle_bits = gpio_mmio32_port_toggle_bits,
	.pin_interrupt_configure = gpio_mmio32_pin_interrupt_configure,
};

int gpio_mmio32_init(const struct device *dev)
{
	struct gpio_mmio32_context *context = dev->data;
	const struct gpio_mmio32_config *config = dev->config;

	context->config = config;

	return 0;
}

#define MMIO32_GPIO_DEVICE(n)                                                                      \
	static struct gpio_mmio32_context gpio_mmio32_##n##_ctx;                                   \
                                                                                                   \
	static const struct gpio_mmio32_config gpio_mmio32_##n##_cfg = {                           \
		.common =                                                                          \
			{                                                                          \
				.port_pin_mask = GPIO_PORT_PIN_MASK_FROM_DT_INST(n),               \
			},                                                                         \
		.reg = (volatile uint32_t *)DT_INST_REG_ADDR(n),                                   \
		.is_input = DT_INST_PROP(n, direction_input),                                      \
	};                                                                                         \
                                                                                                   \
	DEVICE_DT_INST_DEFINE(n, gpio_mmio32_init, NULL, &gpio_mmio32_##n##_ctx,                   \
			      &gpio_mmio32_##n##_cfg, PRE_KERNEL_1,                                \
			      CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &gpio_mmio32_api);

DT_INST_FOREACH_STATUS_OKAY(MMIO32_GPIO_DEVICE)