zephyr/drivers/gpio/gpio_mmio32.c

176 lines
4.6 KiB
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.
*/
#include <drivers/gpio/gpio_mmio32.h>
#include <errno.h>
static int gpio_mmio32_config(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->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 ((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->mask & ~(1 << pin)));
}
irq_unlock(key);
}
return 0;
}
static int gpio_mmio32_port_get_raw(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->mask;
return 0;
}
static int gpio_mmio32_port_set_masked_raw(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->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(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->mask;
/* Update pin state atomically */
key = irq_lock();
*reg = (*reg | mask);
irq_unlock(key);
return 0;
}
static int gpio_mmio32_port_clear_bits_raw(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->mask;
/* Update pin state atomically */
key = irq_lock();
*reg = (*reg & ~mask);
irq_unlock(key);
return 0;
}
static int gpio_mmio32_port_toggle_bits(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->mask;
/* Update pin state atomically */
key = irq_lock();
*reg = (*reg ^ mask);
irq_unlock(key);
return 0;
}
static int gpio_mmio32_pin_interrupt_configure(struct device *dev,
gpio_pin_t pin, enum gpio_int_mode mode,
enum gpio_int_trig trig)
{
if (mode != GPIO_INT_MODE_DISABLED) {
return -ENOTSUP;
}
return 0;
}
static const struct gpio_driver_api 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(struct device *dev)
{
struct gpio_mmio32_context *context = dev->data;
const struct gpio_mmio32_config *config = dev->config;
context->config = config;
dev->api = &gpio_mmio32_api;
return 0;
}