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SubjectRe: Re: [PATCH] spi: pxa2xx: Add CS control clock quirk
On Thu, Feb 13, 2020 at 04:57:24PM +0000, Srivastava, Shobhit wrote:
> > On 2/12/20 12:34 AM, Rajat Jain wrote:


> > I wonder is it enough to have this quick toggling only or is time or actually
> > number of clock cycles dependent? Now there is no delay between but I'm
> > thinking if it needs certain number cycles does this still work when using low
> > ssp_clk rates similar than in commit d0283eb2dbc1 ("spi:
> > pxa2xx: Add output control for multiple Intel LPSS chip selects").
> >
> > I'm thinking can this be done only once after resume and may other LPSS
> > blocks need the same? I.e. should this be done in drivers/mfd/intel-lpss.c?

> This behavior is seen after S0ix resume, but it is not seen after S3 resume.

I already commented in the other thread about this.

Have you checked what's going on in intel_lpss_suspend() and
intel_lpss_resume() for your case?

Is intel_lpss_prepare() called during S0ix exit?

> I am thinking that it happens because we are not enabling the SSP after resume.
> It is deferred until we need to send data. By enabling the SSP in resume, I don’t see the issue.
> For S3, I think BIOS re-enables the SSP in resume flow.

With Best Regards,
Andy Shevchenko

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