From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerlando Falauto Subject: Re: [PATCH v3] gpio: interrupt consistency check for OF GPIO IRQs Date: Mon, 11 Nov 2013 19:28:37 +0100 Message-ID: <528121D5.40403@keymile.com> References: <1377526030-32024-1-git-send-email-larsi@wh2.tu-dresden.de> <1521079.WSLhhfqBXl@lem-wkst-02> <52261BF0.4090106@wwwdotorg.org> <3144247.j2q6H0KWZx@lem-wkst-02> <52279524.8090006@wwwdotorg.org> <20130909161924.GT29403@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130909161924.GT29403-GFdadSzt00ze9xe1eoZjHA@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mark Brown Cc: Stephen Warren , Lars Poeschel , Javier Martinez Canillas , Linus Walleij , Lars Poeschel , Grant Likely , "linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Mark Rutland , Ian Campbell , Kumar Gala , Pawel Moll , Tomasz Figa , Enric Balletbo i Serra , Jean-Christophe PLAGNIOL-VILLARD , Santosh Shilimkar , Kevin Hilman , Balaji T K , Tony Lindgren , Jon List-Id: devicetree@vger.kernel.org Hi everyone, [jumping in on an old discussion] On 09/09/2013 06:19 PM, Mark Brown wrote: > On Wed, Sep 04, 2013 at 02:16:36PM -0600, Stephen Warren wrote: >> On 09/04/2013 03:05 AM, Lars Poeschel wrote: > >>> The driver that tries to use the GPIO requested by this patch before HAS to >>> fail. This is exactly the intention of this patch. We don't want the GPIO to >>> be requested any more, if it is used as an interrupt pin. > >> That will break existing drivers. There are drivers that request the >> same GPIO and IRQ. IIRC, the SDHCI CD (Card Detect) GPIO is requested >> that way. > > Yes, plus input devices and audio jack detection among others. This > pattern is very common if the GPIO is actually being used as a GPIO, an > edge triggered interrupt is used to flag when something happens and the > state is determined by reading the GPIO state (often with some > debounce). I actually came across this thread while looking for an answer to the following (apparently trivial) question: If you were to write a new driver & binding, what would be, in general, the recommended DT binding for a cascade interrupt controller (or any other peripheral, for that matter), which is connected through a GPIO (to be used as IRQ)? a) Through gpios = <&gpio0 N> b) through interrupt-parent = <&gpio0> & interrupts , or c) both? Thanks! Gerlando -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html