SPI.hxx

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#ifndef _FREERTOS_DRIVERS_COMMON_SPI_HXX_
#define _FREERTOS_DRIVERS_COMMON_SPI_HXX_
 
#include <unistd.h>
#include <compiler.h>
 
#include "BlockOrWakeUp.hxx"
#include "SimpleLog.hxx"
#include "Devtab.hxx"
#include "nmranet_config.h"
#include "os/OS.hxx"
#include "spi/spidev.h"
 
class SPI : public Node
{
public:
    typedef void (*ChipSelectMethod)();
 
    __attribute__((optimize("-O3")))
    int transfer_with_cs_assert(struct spi_ioc_transfer *msg)
    {
        csAssert();
        int result = transfer(msg);
        csDeassert();
        return result;
    }
 
    __attribute__((optimize("-O3")))
    int transfer_with_cs_assert_polled(struct spi_ioc_transfer *msgs,
                                       int num = 1)
    {
        int count = 0;
        int result;
 
        csAssert();
        for (int i = 0; i < num; ++i, ++msgs)
        {
            result = transfer_polled(msgs);
            if (UNLIKELY(result < 0))
            {
                // something bad happened, reset the bus and bail
                csDeassert();
                return result;
            }
            count += msgs->len;
        }
        csDeassert();
        return count;
    }
 
    __attribute__((optimize("-O3")))
    int transfer_messages(struct spi_ioc_transfer *msgs, int num);
 
protected:
    SPI(const char *name, ChipSelectMethod cs_assert,
        ChipSelectMethod cs_deassert, OSMutex *bus_lock = nullptr)
        : Node(name)
        , csAssert(cs_assert)
        , csDeassert(cs_deassert)
        , speedHz(1000000)
        , bitsPerWord(8)
        , mode(SPI_MODE_0)
        , lsbFirst(false)
        , busLock(bus_lock)
    {
    }
 
    ~SPI()
    {
        HASSERT(0);
    }
 
    void bus_lock()
    {
        if (busLock)
        {
            busLock->lock();
        }
    }
 
    void bus_unlock()
    {
        if (busLock)
        {
            busLock->unlock();
        }
    }
 
    virtual int transfer(struct spi_ioc_transfer *msg) = 0;
 
    virtual int transfer_polled(struct spi_ioc_transfer *msg) = 0;
 
    virtual int update_configuration() = 0;
 
    int ioctl(File *file, unsigned long int key, unsigned long data) override;
 
    ChipSelectMethod csAssert;
 
    ChipSelectMethod csDeassert;
 
    uint32_t speedHz;
 
    uint8_t bitsPerWord;
 
    uint8_t mode;
 
    bool lsbFirst;
 
private:
    ssize_t read(File *file, void *buf, size_t count) override;
 
    ssize_t write(File *file, const void *buf, size_t count) override;
 
    void flush_buffers() override {}
 
    OSMutex *busLock;
 
    SPI();
 
    DISALLOW_COPY_AND_ASSIGN(SPI);
};
 
#endif /* _FREERTOS_DRIVERS_COMMON_SPI_HXX_ */