Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752296Ab1BQLAr (ORCPT ); Thu, 17 Feb 2011 06:00:47 -0500 Received: from metis.ext.pengutronix.de ([92.198.50.35]:43943 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751268Ab1BQLAq convert rfc822-to-8bit (ORCPT ); Thu, 17 Feb 2011 06:00:46 -0500 Date: Thu, 17 Feb 2011 12:00:43 +0100 From: Wolfram Sang To: Peter Tyser Cc: linux-kernel@vger.kernel.org, Alek Du , Samuel Ortiz , David Brownell , Eric Miao , Uwe Kleine-K?nig , Mark Brown , Joe Perches , Alan Cox , Grant Likely Subject: Re: [PATCH v2 2/4] gpiolib: Add ability to get GPIO pin direction Message-ID: <20110217110043.GA30692@pengutronix.de> References: <1297904216-15219-1-git-send-email-ptyser@xes-inc.com> <1297904216-15219-2-git-send-email-ptyser@xes-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <1297904216-15219-2-git-send-email-ptyser@xes-inc.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: wsa@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2572 Lines: 72 On Wed, Feb 16, 2011 at 06:56:54PM -0600, Peter Tyser wrote: > Add a new get_direction() function to the gpio_chip structure. This is > useful so that the direction of a pin can be determined when its > initially exported. Previously, the direction defaulted to "unknown" > regardless of the actual configuration of the GPIO pin. > > If a GPIO driver implements get_direction(), it is called in > gpio_request() to set the initial direction of the pin accurately. > > Cc: Alek Du > Cc: Samuel Ortiz > Cc: David Brownell > Cc: Eric Miao > Cc: Uwe Kleine-K?nig > Cc: Mark Brown > Cc: Joe Perches > Cc: Alan Cox > Cc: Grant Likely > Signed-off-by: Peter Tyser > --- > Changes since v1: > - Add support for "unknown" direction > > drivers/gpio/gpiolib.c | 20 ++++++++++++++++++++ > include/asm-generic/gpio.h | 4 ++++ > 2 files changed, 24 insertions(+), 0 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index 0113c10..7723beb 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -1214,6 +1214,26 @@ int gpio_request(unsigned gpio, const char *label) > } > } > > + if (chip->get_direction) { > + /* chip->get_direction may sleep */ > + spin_unlock_irqrestore(&gpio_lock, flags); > + switch (chip->get_direction(chip, gpio - chip->base)) { > + case -1: Use some #defines instead of hardcoded values? > + clear_bit(FLAG_DIR_OUT, &desc->flags); > + clear_bit(FLAG_DIR_IN, &desc->flags); > + break; > + case 0: > + set_bit(FLAG_DIR_IN, &desc->flags); > + clear_bit(FLAG_DIR_OUT, &desc->flags); > + break; > + case 1: > + set_bit(FLAG_DIR_OUT, &desc->flags); > + clear_bit(FLAG_DIR_IN, &desc->flags); > + break; > + } > + spin_lock_irqsave(&gpio_lock, flags); You are changing the flags without the lock. I think it would be good to copy the locking-pattern of chip->request for now. Regards, Wolfram -- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ | -- 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/