From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH v1 1/3] gpio: defer probe if pinctrl cannot be found Date: Fri, 10 Jul 2015 09:27:45 -0600 Message-ID: <559FE471.1030408@wwwdotorg.org> References: <1435754753-31307-1-git-send-email-tomeu.vizoso@collabora.com> <1435754753-31307-2-git-send-email-tomeu.vizoso@collabora.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from avon.wwwdotorg.org ([70.85.31.133]:38715 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754837AbbGJP1u (ORCPT ); Fri, 10 Jul 2015 11:27:50 -0400 In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Tomeu Vizoso , Rob Herring Cc: "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-tegra@vger.kernel.org" , Linus Walleij , Grant Likely , Rob Herring , Alexandre Courbot On 07/10/2015 03:29 AM, Tomeu Vizoso wrote: > On 1 July 2015 at 19:36, Rob Herring wrote: >> On Wed, Jul 1, 2015 at 7:45 AM, Tomeu Vizoso wrote: >>> When an OF node has a pin range for its GPIOs, return -EPROBE_DEFER if >>> the pin controller isn't available. >>> >>> Otherwise, the GPIO range wouldn't be set at all unless the pin >>> controller probed always before the GPIO chip. >>> >>> With this change, the probe of the GPIO chip will be deferred and will >>> be retried at a later point, hopefully once the pin controller has been >>> registered and probed already. >> >> This will break cases where the pinctrl driver does not exist, but the >> DT contains pinctrl bindings. We can have similar problems already >> with clocks though. However, IMO this problem is a bit different in >> that pinctrl is more likely entirely optional while clocks are often >> required. You may do all pin setup in bootloader/firmware on some >> boards and not others. Of course then why put pinctrl in the DT in >> that case? They could be present just due to how chip vs. board dts >> files are structured. > > I see. My instinct tells me that it would be better if the gpio-ranges > property was set in the board dts, but I don't really know what each > mach does with its DTSs. That doesn't make sense; the mapping between GPIO controller pins and pin controller pins is a property of the SoC not the board.