This mirrors the conventions used in other SPI drivers (kirkwood,
davinci, atmel, et al) where the din/dout buffer can be NULL when the
received/transmitted data isn't important. This reduces the need for
allocating additional buffers when write-only/read-only functionality is
needed.
In the din == NULL case, the received data is simply not stored. In the
dout == NULL case, zeroes are transmitted.
Signed-off-by: Andrew Ruder <andrew.ru...@elecsyscorp.com>
---
drivers/spi/soft_spi.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/soft_spi.c b/drivers/spi/soft_spi.c
index 5d22351..5fdd091 100644
--- a/drivers/spi/soft_spi.c
+++ b/drivers/spi/soft_spi.c
@@ -137,9 +137,15 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
* Check if it is time to work on a new byte.
*/
if((j % 8) == 0) {
- tmpdout = *txd++;
+ if (txd) {
+ tmpdout = *txd++;
+ } else {
+ tmpdout = 0;
+ }
if(j != 0) {
- *rxd++ = tmpdin;
+ if (rxd) {
+ *rxd++ = tmpdin;
+ }
}
tmpdin = 0;
}
@@ -164,9 +170,11 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
* bits over to left-justify them. Then store the last byte
* read in.
*/
- if((bitlen % 8) != 0)
- tmpdin <<= 8 - (bitlen % 8);
- *rxd++ = tmpdin;
+ if (rxd) {
+ if((bitlen % 8) != 0)
+ tmpdin <<= 8 - (bitlen % 8);
+ *rxd++ = tmpdin;
+ }
if (flags & SPI_XFER_END)
spi_cs_deactivate(slave);
--
1.8.4.rc3
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
