Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752840AbbGNCaI (ORCPT ); Mon, 13 Jul 2015 22:30:08 -0400 Received: from mail-yk0-f169.google.com ([209.85.160.169]:33179 "EHLO mail-yk0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751929AbbGNCaE (ORCPT ); Mon, 13 Jul 2015 22:30:04 -0400 MIME-Version: 1.0 In-Reply-To: References: <1434589243-502-1-git-send-email-gregory.0xf0@gmail.com> <1434589243-502-4-git-send-email-gregory.0xf0@gmail.com> From: Gregory Fong Date: Mon, 13 Jul 2015 19:29:33 -0700 Message-ID: Subject: Re: [PATCH v3 3/4] gpio: brcmstb: Add interrupt and wakeup source support To: Linus Walleij Cc: "linux-gpio@vger.kernel.org" , Alexandre Courbot , bcm-kernel-feedback-list , Brian Norris , "devicetree@vger.kernel.org" , Florian Fainelli , Ian Campbell , Kumar Gala , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Mark Rutland , Pawel Moll , Rob Herring , Russell King 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: 3677 Lines: 94 On Mon, Jul 13, 2015 at 5:58 AM, Linus Walleij wrote: > On Thu, Jun 18, 2015 at 3:00 AM, Gregory Fong wrote: > >> Uses the gpiolib irqchip helpers. For this to work, the irq setup >> function is called once per bank instead of once per device. Note >> that all known uses of this block have a BCM7120 L2 interrupt >> controller as a parent. Supports interrupts for all GPIOs. >> >> In the IRQ handler, we check for raised IRQs for invalid GPIOs and >> warn (ratelimited) if they're encountered. >> >> Also, several drivers (e.g. gpio-keys) allow for GPIOs to be >> configured as wakeup sources, and this GPIO controller supports that >> through a separate interrupt path. >> >> The de-facto standard DT property "wakeup-source" is checked, since >> that indicates whether the GPIO controller hardware can wake. Uses >> the IRQCHIP_MASK_ON_SUSPEND irq_chip flag because UPG GIO doesn't have >> any of its own wakeup source configuration. >> >> Aside regarding gpiolib irqchip helpers: It wasn't obvious (to me) >> that you can have multiple chained irqchips and associated IRQ domains >> for a single parent IRQ, and as long as the xlate function is written >> correctly, a GPIO IRQ request end up checking the correct domain and >> will get associated with the correct IRQ. What helps make this clear >> is to read >> drivers/gpio/gpiolib-of.c: >> - of_gpiochip_find_and_xlate() >> - of_get_named_gpiod_flags() >> drivers/gpio/gpiolib.c: >> - gpiochip_find() > > Sorry for the unclarities, this is a bit hairy. Suggestions as to > how we can make it easier and/or bring code for this into gpiolib > are welcome. Right now I have a hard time seeing any way to > make this more generic and helpful :/ I'll see about putting together an update to the documentation discussing more about the case where you have one IRQ shared by multiple GPIO banks. > > Overall this patch looks real nice. Some nitpicks below. > >> @@ -164,6 +398,16 @@ static int brcmstb_gpio_probe(struct platform_device *pdev) >> priv->reg_base = reg_base; >> priv->pdev = pdev; >> >> + if (of_property_read_bool(np, "interrupt-controller")) { >> + priv->parent_irq = platform_get_irq(pdev, 0); >> + if (priv->parent_irq < 0) { > > This should be <= 0 since 0 is NO_IRQ Will fix. > >> + dev_err(dev, "Couldn't get IRQ"); >> + return -ENOENT; >> + } >> + } else { >> + priv->parent_irq = -ENOENT; >> + } > > Why should this code only execute if the node is marked > "interrupt-controller"? It makes it seem like IRQs cannot arrive > to it unless it is intended to serve other consumers. > > Maybe in practice this is true, but... If the node does not contain the "interrupt-controller" property, the hardware does not support GPIO interrupts, and I designed the driver specifically to allow that to work. If the node does contain that property, then being unable to complete IRQ setup is a fatal error, because something is badly misconfigured. > >> + if (priv->parent_irq >= 0) { >> + err = brcmstb_gpio_irq_setup(pdev, bank); >> + if (err) >> + goto fail; >> + } > > Again 0 is NO_IRQ so this should be > 0 not >= 0. OK, will change. Thanks, Gregory -- 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/