Re: [PATCH v2 3/5] fpga manager: xilinx-spi: rework write_complete loop implementation

[Tom Rix]

On 8/27/20 7:32 AM, Luca Ceresoli wrote:
> In preparation to add error checking for gpiod_get_value(), rework
> the loop to avoid the duplication of these lines:
>
>       if (gpiod_get_value(conf->done))
>               return xilinx_spi_apply_cclk_cycles(conf);
>
> There is little advantage in this rework with current code. However
> error checking will expand these two lines to five, making code
> duplication more annoying.
>
> Signed-off-by: Luca Ceresoli <l...@lucaceresoli.net>
>
> ---
>
> This patch is new in v2
> ---
>  drivers/fpga/xilinx-spi.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
> index 01f494172379..cfc933d70f52 100644
> --- a/drivers/fpga/xilinx-spi.c
> +++ b/drivers/fpga/xilinx-spi.c
> @@ -151,22 +151,19 @@ static int xilinx_spi_write_complete(struct 
> fpga_manager *mgr,
>                                    struct fpga_image_info *info)
>  {
>       struct xilinx_spi_conf *conf = mgr->priv;
> -     unsigned long timeout;
> +     unsigned long timeout = jiffies + 
> usecs_to_jiffies(info->config_complete_timeout_us);
>       int ret;
>  
> -     if (gpiod_get_value(conf->done))
> -             return xilinx_spi_apply_cclk_cycles(conf);
> -
> -     timeout = jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
> +     while (true) {
> +             if (gpiod_get_value(conf->done))
> +                     return xilinx_spi_apply_cclk_cycles(conf);
>  
> -     while (time_before(jiffies, timeout)) {
> +             if (time_after(jiffies, timeout))
> +                     break;
>  
>               ret = xilinx_spi_apply_cclk_cycles(conf);
>               if (ret)
>                       return ret;
> -
> -             if (gpiod_get_value(conf->done))
> -                     return xilinx_spi_apply_cclk_cycles(conf);
>       } 

Do you need another

        if (gpiod_get_value(conf->done))
                return xilinx_spi_apply_cclk_cycles(conf);

here to cover the chance of sleeping in the loop ?

Tom

>  
>       dev_err(&mgr->dev, "Timeout after config data transfer\n");