spi/spi-fsl-spi: Add support for setting a maximum number of bits per word

Acked-by: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 8 insertions, 1 deletions

diff --git a/drivers/spi/spi-fsl-lib.h b/drivers/spi/spi-fsl-lib.h
index 5a9c36c7cb68..d5c788b584df 100644
--- a/drivers/spi/spi-fsl-lib.h
+++ b/drivers/spi/spi-fsl-lib.h
@@ -71,6 +71,7 @@ struct mpc8xxx_spi {
 
 #ifdef CONFIG_SPI_FSL_SPI
         int type;
+        u8 max_bits_per_word;
 
         void (*set_shifts)(u32 *rx_shift, u32 *tx_shift,
                            int bits_per_word, int msb_first);
diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index b9064434e0f7..7eff63a284ff 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -213,7 +213,8 @@ static int fsl_spi_setup_transfer(struct spi_device *spi,
 
         /* 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 > 16) && (bits_per_word != 32))
+            || (bits_per_word > mpc8xxx_spi->max_bits_per_word))
                 return -EINVAL;
 
         if (!hz)
@@ -520,6 +521,7 @@ static struct spi_master * fsl_spi_probe(struct device *dev,
         mpc8xxx_spi = spi_master_get_devdata(master);
         mpc8xxx_spi->spi_do_one_msg = fsl_spi_do_one_msg;
         mpc8xxx_spi->spi_remove = fsl_spi_remove;
+        mpc8xxx_spi->max_bits_per_word = 32;
         mpc8xxx_spi->type = fsl_spi_get_type(dev);
 
         ret = fsl_spi_cpm_init(mpc8xxx_spi);
@@ -557,6 +559,10 @@ static struct spi_master * fsl_spi_probe(struct device *dev,
 
         /* Enable SPI interface */
         regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
+        if (mpc8xxx_spi->max_bits_per_word < 8) {
+                regval &= ~SPMODE_LEN(0xF);
+                regval |= SPMODE_LEN(mpc8xxx_spi->max_bits_per_word - 1);
+        }
         if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE)
                 regval |= SPMODE_OP;