[lkml]   [2023]   [Jan]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 07/16] spi: bcm63xx-hsspi: Add polling mode support

On 01/06/2023 01:47 PM, Mark Brown wrote:
> On Fri, Jan 06, 2023 at 12:07:59PM -0800, William Zhang wrote:
>> Polling mode provides better throughput in general by avoiding the
>> interrupt overhead as the maximum data size one interrupt can handle is
>> only 512 bytes.
>> When interrupt is not defined in the HSSPI dts node, driver switches to
>> polling mode for controller SPI message processing. Also add driver
>> banner message when the driver is loaded successfully.
> This should not be something the user selects via the DT, if the polling
> mode is better then the driver should just use it regardless of there
> being an interrupt wired up. Generally there's some point at which the
> benefits of polling become minimal (and the costs more impactful) but if
> the DMA setup is as bad as it sounds then the driver should just ignore
> the interrupt.
I agree but this is more for backward compatibility as the original
driver uses interrupt to work with MIPS based SoC and I do not want to
change that behavior. For newer devices I added, they work in polling
mode by default with the dts I supplied. IMHO it is also good to have
this fallback option to use interrupt in case user is sensitive to cpu
[unhandled content-type:application/pkcs7-signature]
 \ /
  Last update: 2023-03-26 23:31    [W:0.081 / U:0.728 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site