MmapGpio.hxx

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#ifndef _OS_MMAPGPIO_HXX_
#define _OS_MMAPGPIO_HXX_
 
#include "os/Gpio.hxx"
 
template<typename STORAGE>
class MmapGpioTemplate : public Gpio
{
public:
    constexpr MmapGpioTemplate(
        STORAGE *const ptr, const unsigned bit_ofs, const bool is_output)
        : ptr_(ptr + (bit_ofs >> 5))
        , bit_(bit_ofs & 31)
        , isOutput_(is_output ? 1 : 0)
    {
    }
 
    void write(Value new_state) const OVERRIDE
    {
        if (new_state == Value::SET) {
            *ptr_ |= (1<<bit_);
        } else {
            *ptr_ &= ~(1<<bit_);
        }
    }
 
    void set() const OVERRIDE
    {
        *ptr_ |= (1<<bit_);
    }
 
    void clr() const OVERRIDE
    {
        *ptr_ &= ~(1<<bit_);
    }
 
    Value read() const OVERRIDE
    {
        return ((*ptr_) & (1<<bit_)) != 0 ? Value::SET : Value::CLR;
    }
 
    void set_direction(Direction dir) const OVERRIDE
    {
        // Mmapped GPIO cannot change direction.
        HASSERT(dir == direction());
    }
 
    Direction direction() const OVERRIDE
    {
        return isOutput_ ? Direction::DOUTPUT : Direction::DINPUT;
    }
 
private:
    STORAGE * const ptr_;
    const unsigned bit_ : 5;
    const unsigned isOutput_ : 1;
};
 
using MmapGpio = MmapGpioTemplate<uint32_t>;
using MmapGpio8 = MmapGpioTemplate<uint8_t>;
 
#endif // _OS_MMAPGPIO_HXX_