spi: fsl-spi: Convert to let spi core validate xfer->bits_per_word

Set bits_per_word_mask so spi core will reject transfers that attempt to use
an unsupported bits_per_word value.

fsl_spi_grlib_probe() may update mpc8xxx_spi->max_bits_per_word setting.
So set master->bits_per_word_mask after fsl_spi_grlib_probe().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-fsl-spi.c

@@ -239,12 +239,6 @@ static int fsl_spi_setup_transfer(struct spi_device *spi,
 	if (!bits_per_word)
 		bits_per_word = spi->bits_per_word;
 
-	/* Make sure its a bit width we support [4..16, 32] */
-	if ((bits_per_word < 4)
-	    || ((bits_per_word > 16) && (bits_per_word != 32))
-	    || (bits_per_word > mpc8xxx_spi->max_bits_per_word))
-		return -EINVAL;
-
 	if (!hz)
 		hz = spi->max_speed_hz;
 
@@ -651,6 +645,10 @@ static struct spi_master * fsl_spi_probe(struct device *dev,
 	if (mpc8xxx_spi->type == TYPE_GRLIB)
 		fsl_spi_grlib_probe(dev);
 
+	master->bits_per_word_mask =
+		(SPI_BPW_RANGE_MASK(4, 16) | SPI_BPW_MASK(32)) &
+		SPI_BPW_RANGE_MASK(1, mpc8xxx_spi->max_bits_per_word);
+
 	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE)
 		mpc8xxx_spi->set_shifts = fsl_spi_qe_cpu_set_shifts;