mirror of
https://github.com/esphome/esphome.git
synced 2024-06-27 10:45:33 +02:00
113 lines
5.1 KiB
C++
113 lines
5.1 KiB
C++
#pragma once
|
|
#include <cstdint>
|
|
#include <cstddef>
|
|
#include <utility>
|
|
#include <vector>
|
|
|
|
namespace esphome {
|
|
namespace i2c {
|
|
|
|
/// @brief Error codes returned by I2CBus and I2CDevice methods
|
|
enum ErrorCode {
|
|
NO_ERROR = 0, ///< No error found during execution of method
|
|
ERROR_OK = 0, ///< No error found during execution of method
|
|
ERROR_INVALID_ARGUMENT = 1, ///< method called invalid argument(s)
|
|
ERROR_NOT_ACKNOWLEDGED = 2, ///< I2C bus acknowledgment not received
|
|
ERROR_TIMEOUT = 3, ///< timeout while waiting to receive bytes
|
|
ERROR_NOT_INITIALIZED = 4, ///< call method to a not initialized bus
|
|
ERROR_TOO_LARGE = 5, ///< requested a transfer larger than buffers can hold
|
|
ERROR_UNKNOWN = 6, ///< miscellaneous I2C error during execution
|
|
ERROR_CRC = 7, ///< bytes received with a CRC error
|
|
};
|
|
|
|
/// @brief the ReadBuffer structure stores a pointer to a read buffer and its length
|
|
struct ReadBuffer {
|
|
uint8_t *data; ///< pointer to the read buffer
|
|
size_t len; ///< length of the buffer
|
|
};
|
|
|
|
/// @brief the WriteBuffer structure stores a pointer to a write buffer and its length
|
|
struct WriteBuffer {
|
|
const uint8_t *data; ///< pointer to the write buffer
|
|
size_t len; ///< length of the buffer
|
|
};
|
|
|
|
/// @brief This Class provides the methods to read and write bytes from an I2CBus.
|
|
/// @note The I2CBus virtual class follows a *Factory design pattern* that provides all the interfaces methods required
|
|
/// by clients while deferring the actual implementation of these methods to a subclasses. I2C-bus specification and
|
|
/// user manual can be found here https://www.nxp.com/docs/en/user-guide/UM10204.pdf and an interesting I²C Application
|
|
/// note https://www.nxp.com/docs/en/application-note/AN10216.pdf
|
|
class I2CBus {
|
|
public:
|
|
/// @brief Creates a ReadBuffer and calls the virtual readv() method to read bytes into this buffer
|
|
/// @param address address of the I²C component on the i2c bus
|
|
/// @param buffer pointer to an array of bytes that will be used to store the data received
|
|
/// @param len length of the buffer = number of bytes to read
|
|
/// @return an i2c::ErrorCode
|
|
virtual ErrorCode read(uint8_t address, uint8_t *buffer, size_t len) {
|
|
ReadBuffer buf;
|
|
buf.data = buffer;
|
|
buf.len = len;
|
|
return readv(address, &buf, 1);
|
|
}
|
|
|
|
/// @brief This virtual method reads bytes from an I2CBus into an array of ReadBuffer.
|
|
/// @param address address of the I²C component on the i2c bus
|
|
/// @param buffers pointer to an array of ReadBuffer
|
|
/// @param count number of ReadBuffer to read
|
|
/// @return an i2c::ErrorCode
|
|
/// @details This is a pure virtual method that must be implemented in a subclass.
|
|
virtual ErrorCode readv(uint8_t address, ReadBuffer *buffers, size_t count) = 0;
|
|
|
|
virtual ErrorCode write(uint8_t address, const uint8_t *buffer, size_t len) {
|
|
return write(address, buffer, len, true);
|
|
}
|
|
|
|
/// @brief Creates a WriteBuffer and calls the writev() method to send the bytes from this buffer
|
|
/// @param address address of the I²C component on the i2c bus
|
|
/// @param buffer pointer to an array of bytes that contains the data to be sent
|
|
/// @param len length of the buffer = number of bytes to write
|
|
/// @param stop true or false: True will send a stop message, releasing the bus after
|
|
/// transmission. False will send a restart, keeping the connection active.
|
|
/// @return an i2c::ErrorCode
|
|
virtual ErrorCode write(uint8_t address, const uint8_t *buffer, size_t len, bool stop) {
|
|
WriteBuffer buf;
|
|
buf.data = buffer;
|
|
buf.len = len;
|
|
return writev(address, &buf, 1, stop);
|
|
}
|
|
|
|
virtual ErrorCode writev(uint8_t address, WriteBuffer *buffers, size_t cnt) {
|
|
return writev(address, buffers, cnt, true);
|
|
}
|
|
|
|
/// @brief This virtual method writes bytes to an I2CBus from an array of WriteBuffer.
|
|
/// @param address address of the I²C component on the i2c bus
|
|
/// @param buffers pointer to an array of WriteBuffer
|
|
/// @param count number of WriteBuffer to write
|
|
/// @param stop true or false: True will send a stop message, releasing the bus after
|
|
/// transmission. False will send a restart, keeping the connection active.
|
|
/// @return an i2c::ErrorCode
|
|
/// @details This is a pure virtual method that must be implemented in the subclass.
|
|
virtual ErrorCode writev(uint8_t address, WriteBuffer *buffers, size_t count, bool stop) = 0;
|
|
|
|
protected:
|
|
/// @brief Scans the I2C bus for devices. Devices presence is kept in an array of std::pair
|
|
/// that contains the address and the corresponding bool presence flag.
|
|
void i2c_scan_() {
|
|
for (uint8_t address = 8; address < 120; address++) {
|
|
auto err = writev(address, nullptr, 0);
|
|
if (err == ERROR_OK) {
|
|
scan_results_.emplace_back(address, true);
|
|
} else if (err == ERROR_UNKNOWN) {
|
|
scan_results_.emplace_back(address, false);
|
|
}
|
|
}
|
|
}
|
|
std::vector<std::pair<uint8_t, bool>> scan_results_; ///< array containing scan results
|
|
bool scan_{false}; ///< Should we scan ? Can be set in the yaml
|
|
};
|
|
|
|
} // namespace i2c
|
|
} // namespace esphome
|