From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [PATCH] gpio: lynxpoint: lock IRQs when starting them Date: Tue, 26 Nov 2013 15:18:58 +0200 Message-ID: <52949FC2.6010702@ti.com> References: <1384958549-23722-1-git-send-email-linus.walleij@linaro.org> <528CFF78.9080703@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:37519 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751088Ab3KZNWi (ORCPT ); Tue, 26 Nov 2013 08:22:38 -0500 In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij Cc: "linux-gpio@vger.kernel.org" , Mathias Nyman , Mika Westerberg , Alexandre Courbot On 11/26/2013 11:52 AM, Linus Walleij wrote: > On Wed, Nov 20, 2013 at 7:29 PM, Grygorii Strashko > wrote: >> On 11/20/2013 04:42 PM, Linus Walleij wrote: >>> >>> This uses the new API for tagging GPIO lines as in use by >>> IRQs. This enforces a few semantic checks on how the underlying >>> GPIO line is used. > (...) >>> +static unsigned int lp_irq_startup(struct irq_data *d) >>> +{ >>> + struct lp_gpio *lg = irq_data_get_irq_chip_data(d); >>> + >>> + if (gpio_lock_as_irq(&lg->chip, irqd_to_hwirq(d))) >>> + dev_err(lg->chip.dev, >>> + "unable to lock HW IRQ %lu for IRQ\n", >>> + irqd_to_hwirq(d)); >>> + return 0; >>> +} >>> + >>> +static void lp_irq_shutdown(struct irq_data *d) >>> +{ >>> + struct lp_gpio *lg = irq_data_get_irq_chip_data(d); >>> + >>> + gpio_unlock_as_irq(&lg->chip, irqd_to_hwirq(d)); >>> +} >> >> Seems, such changes may be risky, because .irq_startup() >> and irq_enable()/irq_umask() are mutually exclusive, at least at IRQ request time. >> request_threaded_irq()->__setup_irq()->irq_startup() >> >> More over, IRQ core assumes that IRQ is enabled, unmasked and ready for use after >> .irq_startup() call. You can check functions irq/chip.c->irq_startup() for more info. >> >> So, .irq_enable() functionality need to be duplicated in .irq_startup() at least. >> >> if you agree - above comment is valid for most of similar recent patches ;) > > Yep. I just showcase what a worthless IRQ core user I am... Yeah. That's the Gray hole in Linux's universe :) > > Now what would be the best way to call this? > > Should I just move this into the .enable callback, and if there is no > such callback, create it and call the .unmask explicitly > at the end of it? It would seem a bit counter-intuitive to do this > in the .mask/.unmask callback, as that should only do exactly > that - mask/unmask. > > I'll try this approach... I'm glad to help. Seems you've made it work. Regards, -grygorii