Bad check of the parameter of the SPI_IOC_RD_LSB_FIRST ioctl call

[ostor1960]

I’am using the
linux: 5.4.0-xilinx-v2020.2
spi-tools: a3f1f68

I have an issue with using the SPI_IOC_RD_LSB_FIRST and SPI_IOC_WR_LSB_FIRST ioctl calls.
With the spi-config –l 1 command I could set this parameter in the kernel spi driver.
But –q query command returns always lsb=0.

I see an unconsistency in the usage of the parameter of these calls in the spi-tools and spidev kernel.

In the spio-tools/spiconfig.c the parameter valid values are : 0, SPI_LSB_FIRST
if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, & byte) < 0) {
perror("SPI_IOC_RD_LSB_FIRST");
exit(EXIT_FAILURE);
}
config.lsb = (byte == SPI_LSB_FIRST ? 1 : 0);

 if ((config.lsb != new_config.lsb) && (new_config.lsb != -1)) {
       byte = (new_config.lsb ? SPI_LSB_FIRST : 0);
       if (ioctl(fd, SPI_IOC_WR_LSB_FIRST, & byte) < 0) {
            perror("SPI_IOC_WR_LSB_FIRST");
            exit(EXIT_FAILURE);
       }
 }

In the spidev.c the valid parameter values are: 0, 1
case SPI_IOC_RD_LSB_FIRST:
retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,
(__u8 __user *)arg);
break;

 case SPI_IOC_WR_LSB_FIRST:
       retval = get_user(tmp, (__u8 __user *)arg);
       if (retval == 0) {
            u32  save = spi->mode;

            if (tmp)
                  spi->mode |= SPI_LSB_FIRST;
            else
                  spi->mode &= ~SPI_LSB_FIRST;
            retval = spi_setup(spi);
            if (retval < 0)
                  spi->mode = save;
            else
                  dev_dbg(&spi->dev, "%csb first\n",
                             tmp ? 'l' : 'm');
       }
       break;

I read on the page https://www.kernel.org/doc/Documentation/spi/spidev
"SPI_IOC_RD_LSB_FIRST, SPI_IOC_WR_LSB_FIRST ... pass a pointer to a byte
which will return (RD) or assign (WR) the bit justification used to
transfer SPI words. Zero indicates MSB-first; other values indicate
the less common LSB-first encoding. In both cases the specified value
is right-justified in each word, so that unused (TX) or undefined (RX)
bits are in the MSBs."

I think that modifying the spi-tools SPI_IOC_RD_BITS_PER_WORD not checking against the SPI_LSB_FIRST value, but non zero, we can resolve the issue :
if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, & byte) < 0) {
perror("SPI_IOC_RD_LSB_FIRST");
exit(EXIT_FAILURE);
}
config.lsb = (byte ? 1 : 0);