From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH 4/4 v4] iio: st_sensors: support open drain mode Date: Thu, 14 Apr 2016 08:30:34 -0500 Message-ID: <20160414133034.GA10104@rob-hp-laptop> References: <1460466079-15392-1-git-send-email-linus.walleij@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Walleij Cc: Jonathan Cameron , "linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Giuseppe Barba , Denis Ciocca List-Id: devicetree@vger.kernel.org On Thu, Apr 14, 2016 at 10:36:53AM +0200, Linus Walleij wrote: > On Wed, Apr 13, 2016 at 10:52 PM, Rob Herring wrote: > > On Tue, Apr 12, 2016 at 8:01 AM, Linus Walleij wrote: > >> Some types of ST Sensors can be connected to the same IRQ line > >> as other peripherals using open drain. Add a device tree binding > >> and a sensor data property to flip the right bit in the interrupt > >> control register to enable open drain mode on the INT line. > >> > >> If the line is set to be open drain, also tag on IRQF_SHARED > >> to the IRQ flags when requesting the interrupt, as the whole > >> point of using open drain interrupt lines is to share them with > >> more than one peripheral (wire-or). > >> > >> Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > >> Cc: Giuseppe Barba > >> Cc: Denis Ciocca > >> Cc: Rob Herring > >> Signed-off-by: Linus Walleij > >> --- > >> ChangeLog v3->v4: > >> - Rename DT bool property st,int-pin-open-drain to int-pin-open-drain > >> - Rob Herring ACKed st,int-pin-open-drain but not including his ACK > >> on this even though it's close > > > > We already have st,irq-open-drain, gpio-open-drain, linux,open-drain > > and drive-open-drain (from pinctrl). > > > > If we want something common, then it should probably be part of > > interrupt bindings, not something common to IIO. > > I could agree to use the pin control drive-open-drain; > > It has very little to do with the interrupt bindings, there are > so many interrupt lines in the world, the fact that some of them > go over open drain rails doesn't matter to the interrupt-controller > devices, it needs to be below them. Yes, but it is open drain because the interrupt is shared. That fact is enough to determine how to configure the pin. Unfortunately, it is a bit hard to determine an interrupt is shared based on how the interrupt bindings work. Adding a flag doesn't work because the cell contents are specific to the interrupt controller (though we have standardized them to some extent). > I will resubmit using the pin control binding. Given I don't have a better suggestion, that sounds fine. Rob From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:53698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753659AbcDNNaj (ORCPT ); Thu, 14 Apr 2016 09:30:39 -0400 Date: Thu, 14 Apr 2016 08:30:34 -0500 From: Rob Herring To: Linus Walleij Cc: Jonathan Cameron , "linux-iio@vger.kernel.org" , "devicetree@vger.kernel.org" , Giuseppe Barba , Denis Ciocca Subject: Re: [PATCH 4/4 v4] iio: st_sensors: support open drain mode Message-ID: <20160414133034.GA10104@rob-hp-laptop> References: <1460466079-15392-1-git-send-email-linus.walleij@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On Thu, Apr 14, 2016 at 10:36:53AM +0200, Linus Walleij wrote: > On Wed, Apr 13, 2016 at 10:52 PM, Rob Herring wrote: > > On Tue, Apr 12, 2016 at 8:01 AM, Linus Walleij wrote: > >> Some types of ST Sensors can be connected to the same IRQ line > >> as other peripherals using open drain. Add a device tree binding > >> and a sensor data property to flip the right bit in the interrupt > >> control register to enable open drain mode on the INT line. > >> > >> If the line is set to be open drain, also tag on IRQF_SHARED > >> to the IRQ flags when requesting the interrupt, as the whole > >> point of using open drain interrupt lines is to share them with > >> more than one peripheral (wire-or). > >> > >> Cc: devicetree@vger.kernel.org > >> Cc: Giuseppe Barba > >> Cc: Denis Ciocca > >> Cc: Rob Herring > >> Signed-off-by: Linus Walleij > >> --- > >> ChangeLog v3->v4: > >> - Rename DT bool property st,int-pin-open-drain to int-pin-open-drain > >> - Rob Herring ACKed st,int-pin-open-drain but not including his ACK > >> on this even though it's close > > > > We already have st,irq-open-drain, gpio-open-drain, linux,open-drain > > and drive-open-drain (from pinctrl). > > > > If we want something common, then it should probably be part of > > interrupt bindings, not something common to IIO. > > I could agree to use the pin control drive-open-drain; > > It has very little to do with the interrupt bindings, there are > so many interrupt lines in the world, the fact that some of them > go over open drain rails doesn't matter to the interrupt-controller > devices, it needs to be below them. Yes, but it is open drain because the interrupt is shared. That fact is enough to determine how to configure the pin. Unfortunately, it is a bit hard to determine an interrupt is shared based on how the interrupt bindings work. Adding a flag doesn't work because the cell contents are specific to the interrupt controller (though we have standardized them to some extent). > I will resubmit using the pin control binding. Given I don't have a better suggestion, that sounds fine. Rob