From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [PATCH v4] gpio: lib-sysfs: Add 'wakeup' attribute Date: Fri, 16 Jan 2015 12:11:08 +0100 Message-ID: <20150116111108.GG30960@localhost> References: <1421351389-11660-1-git-send-email-soren.brinkmann@xilinx.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1421351389-11660-1-git-send-email-soren.brinkmann@xilinx.com> Sender: linux-doc-owner@vger.kernel.org To: Soren Brinkmann Cc: Linus Walleij , Johan Hovold , Alexandre Courbot , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org List-Id: linux-api@vger.kernel.org On Thu, Jan 15, 2015 at 11:49:49AM -0800, Soren Brinkmann wrote: > Add an attribute 'wakeup' to the GPIO sysfs interface which allows > marking/unmarking a GPIO as wake IRQ. > The file 'wakeup' is created in each exported GPIOs directory, if an IRQ > is associated with that GPIO and the irqchip implements set_wake(). > Writing 'enabled' to that file will enable wake for that GPIO, while > writing 'disabled' will disable wake. > Reading that file will return either 'disabled' or 'enabled' depening on > the currently set flag for the GPIO's IRQ. > > Signed-off-by: Soren Brinkmann > Reviewed-by: Alexandre Courbot > --- > Hi Linus, Johan, > > I rebased my patch. And things look good. I took at closer look at this patch now and I really don't think it should be merged at all. We have a mechanism for handling wake-up sources (documented in Documentation/power/devices.txt) as well as an ABI to enable/disable them using the power/wakeup device attribute from userspace. Implementing proper wakeup support for unclaimed GPIOs would take some work (if at all desired), but that is not a reason to be adding custom implementations that violates the kernel's power policies and new ABIs that would need to be maintained forever. [ And we really shouldn't be adding anything to the broken gpio sysfs interface until it's been redesigned. ] Meanwhile you can (should) use gpio-keys if you need to wake your system on gpio events. > But the 'is_visible' things does not behave the way I expected it to. > It seems to be only triggered on an export but not when attributes > change. Hence, in my case, everything was visiible since the inital > state matches that, but even when changing the direction or things > like that, attributes don't disappear. Is that something still worked > on? Expected That's expected. We generally don't want attributes to appear or disappear after the device has been registered (although there is a mechanism for cases were it makes sense). This is no different from how your v3 patch worked either. Johan