From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: Can't pinctrl-baytrail be a module? Date: Tue, 2 Aug 2016 10:38:01 +0200 Message-ID: <20160802103801.765b8202@endymion> References: <20160211125645.GU16826@lahna.fi.intel.com> <56BC903C.9000008@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:41889 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751640AbcHBIil (ORCPT ); Tue, 2 Aug 2016 04:38:41 -0400 In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Mathias Nyman Cc: Takashi Iwai , Mika Westerberg , Heikki Krogerus , Linus Walleij , linux-gpio@vger.kernel.org On Fri, 12 Feb 2016 13:59:45 +0100, Takashi Iwai wrote: > On Thu, 11 Feb 2016 14:44:28 +0100, > Mathias Nyman wrote: > > > > On 11.02.2016 15:08, Takashi Iwai wrote: > > > On Thu, 11 Feb 2016 13:56:45 +0100, > > > Mika Westerberg wrote: > > >> > > >> +Jean and Mathias > > >> > > >> On Thu, Feb 11, 2016 at 01:45:16PM +0100, Takashi Iwai wrote: > > >>> Hi, > > >>> > > >>> while discussing whether to enable pinctrl drivers on openSUSE distro > > >>> kernels, I wonder why pinctrl-baytrail is built-in only. Basically > > >>> the forced built-in is the only reason against the enablement in > > >>> distro kernels. > > >>> > > >>> The other Intel pinctrl drivers seem to be tristate. > > >>> Any missing piece there? > > >> > > >> Jean sent a patch against this couple of hours ago. > > > > > > I noticed it right after I send my mail, too, sorry :) > > > > > >> I explained to him > > >> that there is some ACPI GPIO magic happening on Baytrail-T based > > >> machines such as Asus T100 where the GPIO driver is needed early at > > >> boot, or something along those lines. I've CC'd Mathias Nyman the > > >> original author who hopefully remembers this better. > > > > > > I know of pinctrl-cherryview is needed before others like shdci, but > > > for Baytrail-T, it's more than that? > > > > > > > If I remember correctly the reason was that the gpio driver was supposed > > to work with Hardware reduced ACPI events (in ACPI 5). > > Basically ACPI telling operating system it wants an ACPI event handler run > > when a certain gpio interrupt is triggered, and the HW reduced ACPI expects the OS gpio driver to do it. > > OK, so this is an implicit dependency. If this is the only issue, it > sounds like the driver can be a module. > > > I haven't followed up on this at all. Can't say if we have any HW reduced baytrail variants out there. > > > > For Lynxpoint there was also some issue that pnpacpi reserved the IO resources before a modular gpio driver could get it, > > I think it was fixed, might be that baytrail would face same issue. > > Could you give any pointer, if you remember? Mathias, any progress on this? Thanks, -- Jean Delvare SUSE L3 Support