From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: Re: [PATCH] spi: pxa2xx: Add CS control clock quirk Date: Thu, 13 Feb 2020 19:18:36 +0200 Message-ID: <20200213171836.GD10400@smile.fi.intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Jarkko Nikula , Rajat Jain , Daniel Mack , Haojian Zhuang , Robert Jarzmik , Mark Brown , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Evan Green , "rajatxjain-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" , "evgreen-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org" , "Muthukrishnan, Porselvan" To: "Srivastava, Shobhit" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: 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