spi.h

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#pragma once
#include <utils/queue.h>
#include <utils/deadline.h>
 
#include "gpio.h"
#include "registry.h"
namespace SPI {
class Request; //< forward declaration
enum class Mode { M0, M1, M2, M3 }; //< SPI Modes 0 - 3
enum class FirstBit { MSB, LSB }; //< transmission first bit significance
struct Device {
    Sink<Request> &bus;
    DIO cs;
    struct Conf {
        Mode mode; 
        FirstBit fsb; 
        bool operator!=(const Conf &o) {
            return mode != o.mode || fsb != o.fsb;
        }
    } const conf; 
    Device(Sink<Request> &bus, DIO cs, Conf c) : bus(bus), cs(cs), conf(c) {
        select(false);
    }
 
    void select(bool sel) {
        cs.set(!sel);
    }
 
    virtual void callback(const Request req)=0;
};
 
struct Request {
    Device *dev;     
    Buffer<uint8_t> data; 
    enum Direction {
        MOSI = 1, 
        MISO = 2, 
        BOTH = 3, 
    } dir; 
};
 
struct HW : public Sink<Request> {
    inline static Registry<HW, SPI_HandleTypeDef, 4> reg{};
 
    Queue<Request> q;
    Deadline deadline{};
    struct {
        bool xfer;
        Device::Conf conf;
    } active{};
 
    struct Conf {
        SPI_TypeDef *spi; 
        AFIO miso, mosi, sck; 
        uint32_t prescaler; 
    };
    HW(const Conf &conf);
    bool full() override;
    void push(Request &&rq) override;
    using Sink<Request>::push;
    void irqHandler();
    SPI_HandleTypeDef handle{};
};
}