From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH] powerpc/gpio: Fix the wrong GPIO input data on MPC8572/MPC8536 Date: Tue, 19 Nov 2013 16:51:34 -0600 Message-ID: <1384901494.1403.383.camel@snotra.buserror.net> References: <1384499789-3631-1-git-send-email-Gang.Liu@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-db8lp0184.outbound.messaging.microsoft.com ([213.199.154.184]:12998 "EHLO db8outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752707Ab3KSWvk (ORCPT ); Tue, 19 Nov 2013 17:51:40 -0500 In-Reply-To: <1384499789-3631-1-git-send-email-Gang.Liu@freescale.com> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Liu Gang Cc: linuxppc-dev@lists.ozlabs.org, linux-gpio@vger.kernel.org, linus.walleij@linaro.org, b07421@freescale.com, r61911@freescale.com On Fri, 2013-11-15 at 15:16 +0800, Liu Gang wrote: > For MPC8572/MPC8536, the status of GPIOs defined as output > cannot be determined by reading GPDAT register, so the code > use shadow data register instead. But if the input pins are > asserted high, they will always read high due to the shadow > data, even if the pins are set to low. > > So the input pins should be read directly from GPDAT, not > the shadow data. > > Signed-off-by: Liu Gang > --- > drivers/gpio/gpio-mpc8xxx.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c > index 9ae29cc..1d4ac75 100644 > --- a/drivers/gpio/gpio-mpc8xxx.c > +++ b/drivers/gpio/gpio-mpc8xxx.c > @@ -71,6 +71,7 @@ static int mpc8572_gpio_get(struct gpio_chip *gc, unsigned int gpio) > struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm); > > val = in_be32(mm->regs + GPIO_DAT) & ~in_be32(mm->regs + GPIO_DIR); > + mpc8xxx_gc->data &= in_be32(mm->regs + GPIO_DIR); > > return (val | mpc8xxx_gc->data) & mpc8xxx_gpio2mask(gpio); > } It seems odd to update ->data in a function that's supposed to be reading things... Perhaps it would be better to keep ->data in a good state from the beginning. -Scott