On Fri, Apr 25, 2014 at 12:09 AM, Andrew Ruder
<andrew.ru...@elecsyscorp.com> wrote:
> 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>
> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagn...@jcrosoft.com>
> Cc: Jagan Teki <jagannadh.t...@gmail.com>
> ---
> Cleaned up errors/warnings from checkpatch.pl. I'm surprised they were
> flagged
> by the script since the actual ERRORs were all on lines I didn't change but
> were
> only included in the context.
>
> scripts/checkpatch.pl 0001-spi-soft_spi-Support-NULL-din-dout-buffers.patch
> total: 0 errors, 0 warnings, 0 checks, 31 lines checked
>
> drivers/spi/soft_spi.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/spi/soft_spi.c b/drivers/spi/soft_spi.c
> index 5d22351..c969be3 100644
> --- a/drivers/spi/soft_spi.c
> +++ b/drivers/spi/soft_spi.c
> @@ -136,10 +136,14 @@ 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 ((j % 8) == 0) {
> + if (txd)
> + tmpdout = *txd++;
> + else
> + tmpdout = 0;
> if(j != 0) {
> - *rxd++ = tmpdin;
> + if (rxd)
> + *rxd++ = tmpdin;
> }
> tmpdin = 0;
> }
> @@ -164,9 +168,11 @@ 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);
> --
> 1.9.0.rc3.12.gbc97e2d
>
Applied to u-boot-spi/master
thanks!
--
Jagan.
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