Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752882AbbGBPiw (ORCPT ); Thu, 2 Jul 2015 11:38:52 -0400 Received: from mail-yk0-f172.google.com ([209.85.160.172]:33196 "EHLO mail-yk0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753037AbbGBPil (ORCPT ); Thu, 2 Jul 2015 11:38:41 -0400 MIME-Version: 1.0 In-Reply-To: References: <1435754753-31307-1-git-send-email-tomeu.vizoso@collabora.com> <1435754753-31307-2-git-send-email-tomeu.vizoso@collabora.com> From: Rob Herring Date: Thu, 2 Jul 2015 10:38:21 -0500 Message-ID: Subject: Re: [PATCH v1 1/3] gpio: defer probe if pinctrl cannot be found To: Geert Uytterhoeven Cc: Tomeu Vizoso , "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 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1974 Lines: 47 On Thu, Jul 2, 2015 at 3:59 AM, Geert Uytterhoeven wrote: > Hi Rob, > > On Wed, Jul 1, 2015 at 7:36 PM, 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. > > Isn't that already the case? > If I change the compatible value of a pinctrl node to an invalid value, I get: > > sh-sci e6c50000.serial: could not find pctldev for node > /pfc@e6050000/serial1, deferring probe I guess so. >> We could address this by simply marking the pin controller node >> disabled. However, ... > > Doesn't seem to make any difference. No doubt. I'm proposing that it should, not that it does already. Of course, the callers will also have to test for -ENODEV and ignore those errors. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/