ardupilot/libraries/AP_HAL_Linux/GPIO_RPI.h

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#pragma once
#include <stdint.h>
#include "AP_HAL_Linux.h"
/**
* @brief Check for valid Raspberry Pi pin range
*
* @tparam pin
* @return uint8_t
*/
template <uint8_t pin> constexpr uint8_t RPI_GPIO_()
{
static_assert(pin > 1 && pin < 32, "Invalid pin value.");
return pin;
}
namespace Linux {
/**
* @brief Class for Raspberry PI GPIO control
*
* For more information: https://elinux.org/RPi_BCM2835_GPIOs
*
*/
class GPIO_RPI : public AP_HAL::GPIO {
public:
GPIO_RPI();
void init() override;
void pinMode(uint8_t pin, uint8_t output) override;
void pinMode(uint8_t pin, uint8_t output, uint8_t alt) override;
uint8_t read(uint8_t pin) override;
void write(uint8_t pin, uint8_t value) override;
void toggle(uint8_t pin) override;
/* Alternative interface: */
AP_HAL::DigitalSource* channel(uint16_t n) override;
/* return true if USB cable is connected */
bool usb_connected(void) override;
private:
// Raspberry Pi BASE memory address
enum class Address : uint32_t {
BCM2708_PERIPHERAL_BASE = 0x20000000, // Raspberry Pi 0/1
BCM2709_PERIPHERAL_BASE = 0x3F000000, // Raspberry Pi 2/3
BCM2711_PERIPHERAL_BASE = 0xFE000000, // Raspberry Pi 4
};
// Offset between peripheral base address
enum class PeripheralOffset : uint32_t {
GPIO = 0x200000,
};
/**
* @brief Open memory device to allow gpio address access
* Should be used before get_memory_pointer calls in the initialization
*
* @return true
* @return false
*/
bool openMemoryDevice();
/**
* @brief Close open memory device
*
*/
void closeMemoryDevice();
/**
* @brief Return pointer to memory location with specific range access
*
* @param address
* @param range
* @return volatile uint32_t*
*/
volatile uint32_t* get_memory_pointer(uint32_t address, uint32_t range) const;
/**
* @brief Get memory address based in base address and peripheral offset
*
* @param address
* @param offset
* @return uint32_t
*/
uint32_t get_address(GPIO_RPI::Address address, GPIO_RPI::PeripheralOffset offset) const;
/**
* @brief Change functionality of GPIO Function Select Registers (GPFSELn) to any alternative function.
* Each GPIO pin is mapped to 3 bits inside a 32 bits register, E.g:
*
* 0b00...'010'101
* GPIO Pin N, 1st bit, LSBit
* GPIO Pin N, 2nd bit
* GPIO Pin N, 3rd bit, MSBit
* GPIO Pin N+1, 1st bit, LSBit
* GPIO Pin N+1, 2nd bit,
* GPIO Pin N+1, 3rd bit, MSBit
* ...
* Reserved
* Reserved
*
* And the value of this 3 bits selects the functionality of the GPIO pin, E.g:
* 000 = GPIO Pin N is an input
* 001 = GPIO Pin N is an output
* 100 = GPIO Pin N takes alternate function 0
* 101 = GPIO Pin N takes alternate function 1
* 110 = GPIO Pin N takes alternate function 2
* 111 = GPIO Pin N takes alternate function 3
* 011 = GPIO Pin N takes alternate function 4
* 010 = GPIO Pin N takes alternate function 5
*
* The alternative functions are defined in the BCM datasheet under "Alternative Function"
* section for each pin.
*
* This information is also valid for:
* - Linux::GPIO_RPI::set_gpio_mode_in
* - Linux::GPIO_RPI::set_gpio_mode_out
*
* @param pin
*/
void set_gpio_mode_alt(int pin, int alternative);
/**
* @brief Set a specific GPIO as input
* Check Linux::GPIO_RPI::set_gpio_mode_alt for more information.
*
* @param pin
*/
void set_gpio_mode_in(int pin);
/**
* @brief Set a specific GPIO as output
* Check Linux::GPIO_RPI::set_gpio_mode_alt for more information.
*
* @param pin
*/
void set_gpio_mode_out(int pin);
/**
* @brief Modify GPSET0 (GPIO Pin Output Set 0) register to set pin as high
* Writing zero to this register has no effect, please use Linux::GPIO_RPI::set_gpio_low
* to set pin as low.
*
* GPSET0 is a 32bits register that each bit points to a respective GPIO pin:
* 0b...101
* GPIO Pin 1, 1st bit, LSBit, defined as High
* GPIO Pin 2, 2nd bit, No effect
* GPIO Pin 3, 3rd bit, defined as High
* ...
*
* @param pin
*/
void set_gpio_high(int pin);
/**
* @brief Modify GPCLR0 (GPIO Pin Output Clear 0) register to set pin as low
* Writing zero to this register has no effect, please use Linux::GPIO_RPI::set_gpio_high
* to set pin as high.
*
* GPCLR0 is a 32bits register that each bit points to a respective GPIO pin:
* 0b...101
* GPIO Pin 1, 1st bit, LSBit, defined as Low
* GPIO Pin 2, 2nd bit, No effect
* GPIO Pin 3, 3rd bit, defined as Low
*
* @param pin
*/
void set_gpio_low(int pin);
/**
* @brief Read GPLEV0 (GPIO Pin Level 0) register check the logic state of a specific pin
*
* GPLEV0 is a 32bits register that each bit points to a respective GPIO pin:
* 0b...101
* GPIO Pin 1, 1st bit, LSBit, Pin is in High state
* GPIO Pin 2, 2nd bit, Pin is in Low state
* GPIO Pin 3, 3rd bit, Pin is in High state
*
* @param pin
* @return true
* @return false
*/
bool get_gpio_logic_state(int pin);
// Memory pointer to gpio registers
volatile uint32_t* _gpio;
// Memory range for the gpio registers
static const uint8_t _gpio_registers_memory_range;
// Path to memory device (E.g: /dev/mem)
static const char* _system_memory_device_path;
// File descriptor for the memory device file
// If it's negative, then there was an error opening the file.
int _system_memory_device;
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// store GPIO output status.
uint32_t _gpio_output_port_status = 0x00;
};
}