From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 3554FB6F31 for ; Tue, 11 Aug 2009 23:44:54 +1000 (EST) Received: from buildserver.ru.mvista.com (unknown [213.79.90.228]) by ozlabs.org (Postfix) with ESMTP id C24FCDDD04 for ; Tue, 11 Aug 2009 23:44:52 +1000 (EST) Date: Tue, 11 Aug 2009 17:44:50 +0400 From: Anton Vorontsov To: Felix Radensky Subject: Re: [PATCH] powerpc/85xx: Workaround MPC8536 GPIO 1 errata. Message-ID: <20090811134450.GA9820@oksana.dev.rtsoft.ru> References: <> <1249981458-16102-1-git-send-email-felix@embedded-sol.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <1249981458-16102-1-git-send-email-felix@embedded-sol.com> Cc: linuxppc-dev@ozlabs.org Reply-To: avorontsov@ru.mvista.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Aug 11, 2009 at 12:04:18PM +0300, Felix Radensky wrote: > On MPC8536 Rev 1.0 the status of GPIO pins configured > as output cannot be determined by reading GPDAT register. > Workaround by reading the status of input pins from GPDAT > and the status of output pins from a shadow register. > > Signed-off-by: Felix Radensky > --- > arch/powerpc/sysdev/mpc8xxx_gpio.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletions(-) > > diff --git a/arch/powerpc/sysdev/mpc8xxx_gpio.c b/arch/powerpc/sysdev/mpc8xxx_gpio.c > index 103eace..0b996f3 100644 > --- a/arch/powerpc/sysdev/mpc8xxx_gpio.c > +++ b/arch/powerpc/sysdev/mpc8xxx_gpio.c > @@ -56,9 +56,13 @@ static void mpc8xxx_gpio_save_regs(struct of_mm_gpio_chip *mm) > > static int mpc8xxx_gpio_get(struct gpio_chip *gc, unsigned int gpio) > { > + u32 val; > struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc); > + struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm); > + > + val = in_be32(mm->regs + GPIO_DAT) && ~in_be32(mm->regs + GPIO_DIR); Are you sure about &&? Plus, this are two reads instead of just one. I think it'll be better to implement mpc8536_gpio_get(), and then do if (of_device_is_compatible(np, ... 8536-gpio-bank ...)) gc->get = mpc8536_gpio_get; else gc->get = mpc8xxx_gpio_get; > - return in_be32(mm->regs + GPIO_DAT) & mpc8xxx_gpio2mask(gpio); > + return (val | mpc8xxx_gc->data) & mpc8xxx_gpio2mask(gpio); > } > > static void mpc8xxx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) Thanks, -- Anton Vorontsov email: cbouatmailru@gmail.com irc://irc.freenode.net/bd2