From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Jeffery Date: Fri, 20 Oct 2017 18:54:15 +1030 Subject: [RFC PATCH 1/5] gpio: gpiolib: Add core support for maintaining GPIO values on reset In-Reply-To: References: <20171020033727.21557-1-andrew@aj.id.au> <20171020033727.21557-2-andrew@aj.id.au> Message-ID: <1508487855.24322.49.camel@aj.id.au> List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit On Fri, 2017-10-20 at 09:17 +0200, Linus Walleij wrote: > > On Fri, Oct 20, 2017 at 5:37 AM, Andrew Jeffery wrote: >  > > GPIO state reset tolerance is implemented in gpiolib through the > > addition of a new pinconf parameter. With that, some renaming of helpers > > is done to clarify the scope of the already existing > > gpiochip_line_is_persistent(), as it's now ambiguous as to whether that > > means on suspend, reset or both. >  > Isn't it most reasonable to say persistance covers both cases, reset > and/or sleep? This seems a bit like overdefined. I definitely had some internal debate about that. I erred on the side of avoiding potential change in expectations for the arizona. If you consider that overdefined then I'm happy to go the other way. >  > So can we say that is this flag is set, the hardware and driver should > do its best to preserve the value across any system disruptions. >  > We can change the wording of course, patches welcome for that. Yep. >  > But do we really need to distinguish the cases of disruption and > whether we cover up for them or not? >  > I would say we can deal with that the day we have a system with > two register bits (or similar) where you can select to preserve across > sleep, reset, one or the other, AND there is also a usecase such that > a user wants to preserve the value across reset but not suspend or > vice versa. >  > I suspect that will not happen. A very reasonable approach. Cheers for the feedback. Andrew -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: This is a digitally signed message part URL: