Atmosphere/fusee/fusee-secondary/src/gpio.c

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C
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#include <string.h>
#include <stdint.h>
#include <errno.h>
#include "gpio.h"
#include "lib/printk.h"
enum tegra_gpio_shifts {
GPIO_BANK_SHIFT = 5,
GPIO_PORT_SHIFT = 3,
};
enum tegra_gpio_masks {
GPIO_PORT_MASK = 0x3,
GPIO_PIN_MASK = 0x7,
};
/**
* Returns a GPIO bank object that corresponds to the given GPIO pin,
* which can be created using the TEGRA_GPIO macro or passed from the name macro.
*
* @param pin The GPIO to get the bank for.
* @return The GPIO bank object to use for working with the given bank.
*/
static volatile struct tegra_gpio_bank *gpio_get_bank(enum tegra_named_gpio pin)
{
volatile struct tegra_gpio *gpio = gpio_get_regs();
int bank_number = pin >> GPIO_BANK_SHIFT;
return &gpio->bank[bank_number];
}
/**
* @return the port number for working with the given GPIO.
*/
static volatile int gpio_get_port(enum tegra_named_gpio pin)
{
return (pin >> GPIO_PORT_SHIFT) & GPIO_PORT_MASK;
}
/**
* @return a mask to be used to work with the given GPIO
*/
static volatile uint32_t gpio_get_mask(enum tegra_named_gpio pin)
{
uint32_t pin_number = pin & GPIO_PIN_MASK;
return (1 << pin_number);
}
/**
* Performs a simple GPIO configuration operation.
*
* @param pin The GPIO pin to work with, as created with TEGRA_GPIO, or a named GPIO.
* @param should_be_set True iff the relevant bit should be set; or false if it should be cleared.
* @param offset The offset into a gpio_bank structure
*/
static void gpio_simple_register_set(enum tegra_named_gpio pin, bool should_be_set, size_t offset)
{
// Retrieve the register set that corresponds to the given pin and offset.
uintptr_t cluster_addr = (uintptr_t)gpio_get_bank(pin) + offset;
uint32_t *cluster = (uint32_t *)cluster_addr;
// Figure out the offset into the cluster,
// and the mask to be used.
int port = gpio_get_port(pin);
uint32_t mask = gpio_get_mask(pin);
// Set or clear the bit, as appropriate.
if (should_be_set)
cluster[port] |= mask;
else
cluster[port] &= ~mask;
}
/**
* Performs a simple GPIO configuration operation.
*
* @param pin The GPIO pin to work with, as created with TEGRA_GPIO, or a named GPIO.
* @param should_be_set True iff the relevant bit should be set; or false if it should be cleared.
* @param offset The offset into a gpio_bank structure
*/
static bool gpio_simple_register_get(enum tegra_named_gpio pin, size_t offset)
{
// Retrieve the register set that corresponds to the given pin and offset.
uintptr_t cluster_addr = (uintptr_t)gpio_get_bank(pin) + offset;
uint32_t *cluster = (uint32_t *)cluster_addr;
// Figure out the offset into the cluster,
// and the mask to be used.
int port = gpio_get_port(pin);
uint32_t mask = gpio_get_mask(pin);
// Convert the given value to a boolean.
return !!(cluster[port] & mask);
}
/**
* Configures a given pin as either GPIO or SFIO.
*
* @param pin The GPIO pin to work with, as created with TEGRA_GPIO, or a named GPIO.
* @param mode The relevant mode.
*/
void gpio_configure_mode(enum tegra_named_gpio pin, enum tegra_gpio_mode mode)
{
gpio_simple_register_set(pin, mode == GPIO_MODE_GPIO, offsetof(struct tegra_gpio_bank, config));
}
/**
* Configures a given pin as either INPUT or OUPUT.
*
* @param pin The GPIO pin to work with, as created with TEGRA_GPIO, or a named GPIO.
* @param direction The relevant direction.
*/
void gpio_configure_direction(enum tegra_named_gpio pin, enum tegra_gpio_direction dir)
{
gpio_simple_register_set(pin, dir == GPIO_DIRECTION_OUTPUT, offsetof(struct tegra_gpio_bank, direction));
}
/**
* Drives a relevant GPIO pin as either HIGH or LOW.
*
* @param pin The GPIO pin to work with, as created with TEGRA_GPIO, or a named GPIO.
* @param mode The relevant mode.
*/
void gpio_write(enum tegra_named_gpio pin, enum tegra_gpio_value value)
{
gpio_simple_register_set(pin, value == GPIO_LEVEL_HIGH, offsetof(struct tegra_gpio_bank, out));
}
/**
* Drives a relevant GPIO pin as either HIGH or LOW.
*
* @param pin The GPIO pin to work with, as created with TEGRA_GPIO, or a named GPIO.
* @param mode The relevant mode.
*/
enum tegra_gpio_value gpio_read(enum tegra_named_gpio pin)
{
return gpio_simple_register_get(pin, offsetof(struct tegra_gpio_bank, in));
}