On Thu, 17 Sep 2009 20:52:14 -0400
Mike Frysinger <[email protected]> wrote:

> From: Yi Li <[email protected]>
> 
> The MMC/SPI spec does not play well with typical SPI design -- it often
> needs to send out a command in one message, read a response, then do some
> other arbitrary step.  Since we can't let another SPI client use the bus
> during this time, use the new SPI lock/unlock functions to provide the
> required exclusivity.
> 
> Signed-off-by: Yi Li <[email protected]>
> Signed-off-by: Mike Frysinger <[email protected]>
> ---
> v2
>       - drop now unused maybe_count_child as pointed out by H Hartley Sweeten
> 
>  drivers/mmc/host/mmc_spi.c |   41 ++---------------------------------------
>  1 files changed, 2 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
> index a461017..c3563a7 100644
> --- a/drivers/mmc/host/mmc_spi.c
> +++ b/drivers/mmc/host/mmc_spi.c
> @@ -1084,6 +1084,7 @@ static void mmc_spi_request(struct mmc_host *mmc, 
> struct mmc_request *mrq)
>  #endif
>  
>       /* issue command; then optionally data and stop */
> +     spi_lock_bus(host->spi);
>       status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL);
>       if (status == 0 && mrq->data) {
>               mmc_spi_data_do(host, mrq->cmd, mrq->data, mrq->data->blksz);
> @@ -1092,7 +1093,7 @@ static void mmc_spi_request(struct mmc_host *mmc, 
> struct mmc_request *mrq)
>               else
>                       mmc_cs_off(host);
>       }
> -
> +     spi_unlock_bus(host->spi);
>       mmc_request_done(host->mmc, mrq);

I can't find any code anywhere which puts a non-zero value into
spi_master.[un]lock_bus so in my tree at least, neither of these
patches do anything.

This makes it all a bit hard to understand and review.

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