Re: [PATCH linux-next v3 1/1] spi: imx: dynamic burst length adjust for PIO mode

From: Fabio Estevam
Date: Mon May 29 2017 - 07:07:48 EST


Hi Jiada,

On Fri, May 26, 2017 at 2:02 AM, <jiada_wang@xxxxxxxxxx> wrote:
> From: Jiada Wang <jiada_wang@xxxxxxxxxx>
>
> previously burst length (BURST_LENGTH) is always set to equal
> to bits_per_word, causes a 10us gap between each word in
> transfer, which significantly affects performance.
>
> This patch uses 32 bits transfer to simulate lower bits transfer,
> and adjusts burst length runtimely to use biggeest burst length
> as possible to reduce the gaps in transfer for PIO mode.

Just curious: what is the performance gain you observe with this patch?