Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758783Ab3DDJeK (ORCPT ); Thu, 4 Apr 2013 05:34:10 -0400 Received: from mga01.intel.com ([192.55.52.88]:1364 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758753Ab3DDJeJ (ORCPT ); Thu, 4 Apr 2013 05:34:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,407,1363158000"; d="scan'208";a="316777092" Date: Thu, 4 Apr 2013 12:38:20 +0300 From: Mika Westerberg To: Benjamin Tissoires Cc: linux-kernel@vger.kernel.org, Grant Likely , Linus Walleij , "Rafael J. Wysocki" , Mathias Nyman , linux-acpi@vger.kernel.org Subject: Re: [PATCH] gpiolib-acpi: introduce acpi_get_gpio_by_index() helper Message-ID: <20130404093820.GI21804@intel.com> References: <1364986614-15711-1-git-send-email-mika.westerberg@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3130 Lines: 66 On Thu, Apr 04, 2013 at 11:19:53AM +0200, Benjamin Tissoires wrote: > Hi Mika, > > On Wed, Apr 3, 2013 at 12:56 PM, Mika Westerberg > wrote: > > Instead of open-coding ACPI GPIO resource lookup in each driver, we provide > > a helper function analogous to Device Tree version that allows drivers to > > specify which GPIO resource they are interested (using an index to the GPIO > > resources). The function then finds out the correct resource, translates > > the ACPI GPIO number to the corresponding Linux GPIO number and returns > > that. > > > > Signed-off-by: Mika Westerberg > > --- > > Documentation/acpi/enumeration.txt | 32 ++++++++++++++- > > drivers/gpio/gpiolib-acpi.c | 77 ++++++++++++++++++++++++++++++++++++ > > include/linux/acpi_gpio.h | 17 ++++++++ > > 3 files changed, 125 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt > > index 94a6561..b0d5410 100644 > > --- a/Documentation/acpi/enumeration.txt > > +++ b/Documentation/acpi/enumeration.txt > > @@ -199,6 +199,8 @@ the device to the driver. For example: > > { > > Name (SBUF, ResourceTemplate() > > { > > + ... > > + // Used to power on/off the device > > GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, > > IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0", > > 0x00, ResourceConsumer,,) > > @@ -206,10 +208,20 @@ the device to the driver. For example: > > // Pin List > > 0x0055 > > } > > + > > + // Interrupt for the device > > + GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullNone, > > + 0x0000, "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer,,) > > Sorry for coming late in the GPIO ACPI discussion, but when I see this > documentation, I wonder: > wouldn't it be feasible to find the correct GPIO by its type? Here, we > have a GpioIo and a GpioInt, and I bet this would be sometime more > useful to request the first GpioInt without knowing the correct order > of declarations. Why not. But then again you can always check the type returned in the acpi_gpio_info structure and pick the first GpioInt (if you have multiple GPIO resources). > It may be feasible by walking the tree, but a helper would be of great > help (thinking at i2c-hid here, which can not rely on indexes in the > DSDT). Well, index is the only thing we can rely on unfortunately. There's nothing like names or anything like that. What I've seen from ACPI enumerated i2c-hid devices there is only one GPIO resource (GpioInt) declared. -- 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/