From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH] gpio/omap: fix off-mode bug: clear debounce clock enable mask on disable Date: Tue, 23 Oct 2012 15:00:09 -0700 Message-ID: <87k3ug7st2.fsf@deeprootsystems.com> References: <1351015771-6308-1-git-send-email-khilman@deeprootsystems.com> <20121023190914.GA853@arwen.pp.htv.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-da0-f46.google.com ([209.85.210.46]:35839 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752631Ab2JWV7m (ORCPT ); Tue, 23 Oct 2012 17:59:42 -0400 Received: by mail-da0-f46.google.com with SMTP id n41so2122815dak.19 for ; Tue, 23 Oct 2012 14:59:41 -0700 (PDT) In-Reply-To: <20121023190914.GA853@arwen.pp.htv.fi> (Felipe Balbi's message of "Tue, 23 Oct 2012 22:09:14 +0300") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: balbi@ti.com Cc: Linus Walleij , linux-omap@vger.kernel.org, Paul Walmsley , linux-arm-kernel@lists.infradead.org, Igor Grinberg Felipe Balbi writes: > Hi, > > On Tue, Oct 23, 2012 at 11:09:31AM -0700, Kevin Hilman wrote: >> From: Kevin Hilman >> >> When debounce clocks are disabled, ensure that the banks >> dbck_enable_mask is cleared also. Otherwise, context restore on >> subsequent off-mode transition will restore previous value from the >> shadow copies (bank->context.debounce*) leading to mismatch state >> between driver state and hardware state. >> >> This was discovered when board code was doing >> >> gpio_request_one() >> gpio_set_debounce() >> gpio_free() >> >> which was leaving the GPIO debounce settings in a confused state. >> Then, enabling off mode causing bogus state to be restored, leaving >> GPIO debounce enabled which then prevented the CORE powerdomain from >> transitioning. >> >> Reported-by: Paul Walmsley >> Cc: Igor Grinberg >> Signed-off-by: Kevin Hilman > > looks like this deserves a Cc: stable@vger.kernel.org tag. > Agreed. I think this goes all the way back to v3.5, but would've only been seen on boards using a request/gpio_set_debounce/free sequence combined with off-mode. Linus, feel free to add the Cc: stable when commiting. Thanks. >> --- >> Applies on v3.7-rc2, targetted for v3.7. >> >> drivers/gpio/gpio-omap.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c >> index 94cbc84..dee2856 100644 >> --- a/drivers/gpio/gpio-omap.c >> +++ b/drivers/gpio/gpio-omap.c >> @@ -187,6 +187,7 @@ static inline void _gpio_dbck_disable(struct gpio_bank *bank) >> * to detect events and generate interrupts at least on OMAP3. >> */ >> __raw_writel(0, bank->base + bank->regs->debounce_en); >> + bank->dbck_enable_mask = 0; > > shouldn't omap_gpio_restore_context() check for dbck_enabled instead of > the mask ? I mean: > > diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c > index 94cbc84..b3a39a7 100644 > --- a/drivers/gpio/gpio-omap.c > +++ b/drivers/gpio/gpio-omap.c > @@ -1371,7 +1371,7 @@ static void omap_gpio_restore_context(struct gpio_bank *bank) > bank->base + bank->regs->dataout); > __raw_writel(bank->context.oe, bank->base + bank->regs->direction); > > - if (bank->dbck_enable_mask) { > + if (bank->dbck_enabled) { > __raw_writel(bank->context.debounce, bank->base + > bank->regs->debounce); > __raw_writel(bank->context.debounce_en, > > the outcome would be the same, so it doesn't really matter. Just that, > at least to me, it would look better. I tried your version, and unfortunately, the outcome is not the same, but don't plan to look into why. $SUBJECT version is targetted and tested. If you want to cleanup the cosmetics here, please do in a subsequent patch. This driver could certainly benefit from more readability cleanups. > No strong feelings though. Good. I'll take that as an Ack. :) Kevin