Return-path: Received: from avon.wwwdotorg.org ([70.85.31.133]:55797 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649AbaCGEW1 (ORCPT ); Thu, 6 Mar 2014 23:22:27 -0500 Message-ID: <5319497F.9080003@wwwdotorg.org> (sfid-20140307_052250_486806_5C9A12B3) Date: Thu, 06 Mar 2014 21:22:23 -0700 From: Stephen Warren MIME-Version: 1.0 To: Chen-Yu Tsai , Linus Walleij CC: Heikki Krogerus , Johannes Berg , "David S. Miller" , Rhyland Klein , Marc Dietrich , Arnd Bergmann , Alexandre Courbot , linux-wireless , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-tegra@vger.kernel.org" Subject: Re: [PATCHv2 3/5] net: rfkill: gpio: remove gpio names References: <1393330950-7283-1-git-send-email-heikki.krogerus@linux.intel.com> <1393330950-7283-4-git-send-email-heikki.krogerus@linux.intel.com> <530D218E.9010007@wwwdotorg.org> <53168976.7000008@wwwdotorg.org> <53169304.9080002@wwwdotorg.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 03/06/2014 08:43 PM, Chen-Yu Tsai wrote: > On Fri, Mar 7, 2014 at 11:41 AM, Linus Walleij wrote: >> On Wed, Mar 5, 2014 at 10:59 AM, Stephen Warren wrote: >>> On 03/04/2014 07:37 PM, Linus Walleij wrote: >>>> On Wed, Mar 5, 2014 at 10:18 AM, Stephen Warren wrote: >>>>> On 03/04/2014 06:43 PM, Linus Walleij wrote: >>>> >>>>>> If I understand the situation correctly it's like ACPI does not have named >>>>>> GPIOs so keeping specifying this in DT GPIO bindings is counter-productive >>>>>> to the work of abstracting the access to GPIO handlers so that drivers >>>>>> need not know whether ACPI or DT is used for describing the hardware. >>>>> >>>>> For devices that already have both ACPI and DT bindings, we can't >>>>> pretend they can be the same; they are already potentially different. We >>>>> simply need to parse DT and ACPI differently, since that's the sway >>>>> their bindings are defined. >>>>> >>>>> For any devices that don't have both ACPI and DT bindings, I agree we >>>>> should certainly strive to make any new bindings aligned so we don't >>>>> have to deal with this for them. >>>>> >>>>> However, we can't change the past. >>>> >>>> Yeah, right, so for this very driver there are no bindings defined (yet) >>>> and the only device tree I can find referencing it is the Tegra20-paz00 >>>> and it just use gpios = <>; >>>> >>>> So in this case I think this patch is the right way forward, but I admit >>>> I'm really uncertain in the general case. >>> >>> If there are no bindings defined at all yet, then we can define both DT >>> and ACPI bindings to use name-based GPIOs. Index-based lookups aren't a >>> good way forward. >> >> After Mark clarifying that ACPI is going to have named GPIOs I'm >> totally aligned on this, so OK! > > Glad to hear this, but is it possible to get rid of the index in current > drivers? Or change the behavior to name-based OR index-based lookups. > This might break any DTs that have multiple GPIOs defined under one > property though. For any bindings that are already defined to use index-based lookups, I think we have to continue using them, for backwards-compatibility with old DTs (and I assume old ACPI databases need the same thing).