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Fix SPI mode setting #25

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Fix SPI mode setting #25

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16 changes: 11 additions & 5 deletions spi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ static PyObject* openSPI(PyObject *self, PyObject *args, PyObject *kwargs) {
uint8_t bits = 8;
uint32_t speed = 500000;
uint16_t delay=0;
uint8_t temp;

int ret = 0;
int fd;
Expand Down Expand Up @@ -93,14 +94,19 @@ static PyObject* openSPI(PyObject *self, PyObject *args, PyObject *kwargs) {
}

// Set mode of SPI device
ret = ioctl(fd, SPI_IOC_WR_MODE, &spi_mode);
ret = ioctl(fd, SPI_IOC_RD_MODE, &temp);
if (ret == -1) {
pabort("can't set spi mode");
pabort("can't get spi mode");
}

ret = ioctl(fd, SPI_IOC_RD_MODE, &spi_mode);
temp &= ~(SPI_CPHA | SPI_CPOL);
temp |= spi_mode;
ret = ioctl(fd, SPI_IOC_WR_MODE, &temp);
if (ret == -1) {
pabort("can't get spi mode");
pabort("can't set spi mode");
}
ret = ioctl(fd, SPI_IOC_RD_MODE, &temp);
if (ret == -1 || ((temp & (SPI_CPHA|SPI_CPOL)) != spi_mode)) {
pabort("can't modify spi mode");
}

/*
Expand Down