Magnus Lilja wrote:
> Commit f9b6a1575d9f1ca192e4cb60e547aa66f08baa3f, "i.MX31: fix SPI
> driver for shorter than 32 bit" broke 32 bit transfers. This patch
> makes single 32 bit transfer work again.
>
> Transfer lengths that are known not to work will abort and print
> an error message.
>
> Tested on i.MX31 Litekit and i.MX31 PDK using 32 bit transfers to
> the MC13783/ATLAS chip (using the 'date' command).
>
> Signed-off-by: Magnus Lilja <lilja.mag...@gmail.com>
> ---
>
> As discussed on the mailing list, Guennadi Liakhovetski thinks that
> all transfers > 16 bits are broken. This patch fixes the 32 bit case
> and makes sure the user is notified if a broken bitlength is used.
>
> drivers/spi/mxc_spi.c | 9 +++++++++
> 1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
> index fad9840..93c2bd7 100644
> --- a/drivers/spi/mxc_spi.c
> +++ b/drivers/spi/mxc_spi.c
> @@ -131,6 +131,13 @@ int spi_xfer(struct spi_slave *slave, unsigned int
> bitlen, const void *dout,
> return 1;
> }
>
> + /* This driver is currently partly broken, alert the user */
> + if (bitlen > 16 && bitlen != 32) {
I believe this check can be improved
The transfer loops over 32 bit blks.
so bitlen that are multiples of 32 should work.
so
bitlen != 32
can change to
(bitlen % 32)
Tom
> + printf("Error: SPI transfer with bitlen=%d is broken.\n",
> + bitlen);
> + return 1;
> + }
> +
> for (i = 0, in_l = (u32 *)din, out_l = (u32 *)dout;
> i < n_blks;
> i++, in_l++, out_l++, bitlen -= 32) {
> @@ -142,6 +149,8 @@ int spi_xfer(struct spi_slave *slave, unsigned int
> bitlen, const void *dout,
> *(u8 *)din = data;
> else if (bitlen < 17)
> *(u16 *)din = data;
> + else
> + *in_l = data;
> }
> }
>
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