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54 lines
1.9 KiB
C++
54 lines
1.9 KiB
C++
#pragma once
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#include <array>
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#include <cstdint>
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#include "esphome/core/hal.h"
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namespace esphome {
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namespace gpio_expander {
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/// @brief A class to cache the read state of a GPIO expander.
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/// This class caches reads between GPIO Pins which are on the same bank.
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/// This means that for reading whole Port (ex. 8 pins) component needs only one
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/// I2C/SPI read per main loop call. It assumes, that one bit in byte identifies one GPIO pin
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/// Template parameters:
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/// T - Type which represents internal register. Could be uint8_t or uint16_t. Adjust to
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/// match size of your internal GPIO bank register.
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/// N - Number of pins
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template<typename T, T N> class CachedGpioExpander {
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public:
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bool digital_read(T pin) {
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uint8_t bank = pin / (sizeof(T) * BITS_PER_BYTE);
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if (this->read_cache_invalidated_[bank]) {
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this->read_cache_invalidated_[bank] = false;
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if (!this->digital_read_hw(pin))
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return false;
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}
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return this->digital_read_cache(pin);
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}
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void digital_write(T pin, bool value) { this->digital_write_hw(pin, value); }
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protected:
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/// @brief Call component low level function to read GPIO state from device
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virtual bool digital_read_hw(T pin) = 0;
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/// @brief Call component read function from internal cache.
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virtual bool digital_read_cache(T pin) = 0;
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/// @brief Call component low level function to write GPIO state to device
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virtual void digital_write_hw(T pin, bool value) = 0;
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const uint8_t cache_byte_size_ = N / (sizeof(T) * BITS_PER_BYTE);
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/// @brief Invalidate cache. This function should be called in component loop().
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void reset_pin_cache_() {
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for (T i = 0; i < this->cache_byte_size_; i++) {
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this->read_cache_invalidated_[i] = true;
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}
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}
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static const uint8_t BITS_PER_BYTE = 8;
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std::array<bool, N / (sizeof(T) * BITS_PER_BYTE)> read_cache_invalidated_{};
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};
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} // namespace gpio_expander
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} // namespace esphome
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