Re: [PATCH v4 2/2] spi: spi-cadence-quadspi: Fix division by zero warning

[Pratyush Yadav <p.yadav@xxxxxx>]

On 16/07/21 03:08AM, Yoshitaka Ikeda wrote:
> Fix below division by zero warning:
> - The reason for dividing by zero is because the dummy bus width is zero,
>   but if the dummy n bytes is zero, it indicates that there is no data transfer,
>   so we can just return zero without doing any calculations.
> 
> [    0.795337] Division by zero in kernel.
>    :
> [    0.834051] [<807fd40c>] (__div0) from [<804e1acc>] (Ldiv0+0x8/0x10)
> [    0.839097] [<805f0710>] (cqspi_exec_mem_op) from [<805edb4c>] (spi_mem_exec_op+0x3b0/0x3f8)
> 
> Fixes: 7512eaf54190 ("spi: cadence-quadspi: Fix dummy cycle calculation when buswidth > 1")
> Signed-off-by: Yoshitaka Ikeda <ikeda@xxxxxxxxxxxx>

Thanks.

Reviewed-by: Pratyush Yadav <p.yadav@xxxxxx>

> ---
>  drivers/spi/spi-cadence-quadspi.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
> index 7a00346ff9b9..d62d69dd72b9 100644
> --- a/drivers/spi/spi-cadence-quadspi.c
> +++ b/drivers/spi/spi-cadence-quadspi.c
> @@ -309,6 +309,9 @@ static unsigned int cqspi_calc_dummy(const struct spi_mem_op *op, bool dtr)
>  {
>  	unsigned int dummy_clk;
>  
> +	if (!op->dummy.nbytes)
> +		return 0;
> +
>  	dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
>  	if (dtr)
>  		dummy_clk /= 2;
> -- 
> 2.32.0

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.