From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [PATCH v3 10/15] leds: leds-gpio: Add ACPI probing support Date: Thu, 2 Oct 2014 12:55:36 +0300 Message-ID: <20141002095536.GI1786@lahna.fi.intel.com> References: <1410868367-11056-1-git-send-email-mika.westerberg@linux.intel.com> <2043842.LxdgdYRbIF@wuerfel> <20141001140441.GF1786@lahna.fi.intel.com> <6852466.Q5TXcWChqW@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <6852466.Q5TXcWChqW@wuerfel> Sender: linux-acpi-owner@vger.kernel.org To: Arnd Bergmann Cc: "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, Greg Kroah-Hartman , Linus Walleij , Alexandre Courbot , Dmitry Torokhov , Bryan Wu , Lee Jones , Grant Likely , Aaron Lu , Darren Hart List-Id: devicetree@vger.kernel.org On Wed, Oct 01, 2014 at 04:14:20PM +0200, Arnd Bergmann wrote: > On Wednesday 01 October 2014 17:04:41 Mika Westerberg wrote: > > > > > On the question what to put into the name and type fields, that is > > > unrelated. The type is supposed to be for the 'device_type' property > > > in DT, which we should never rely on in a driver that supports both > > > APCI and DT. In Linux we only use that for "pci", "cpu" and "memory", > > > all of which have their own way of getting probed in ACPI. > > > The "name" is normally ignored in DT as well, except for backwards > > > compatibility with old bindings, but I would argue that you should not > > > just put "prp0001" in there. Either leave it empty like type, or use > > > the name of the device as it appears in the ACPI tables, such as "DEV0" > > > or "PWM". > > > > OK, I think it makes sense to leave them empty. I remember I tried that > > at some point but it didn't work without N and T fields. Is there some > > example what to put there in case of empty? > > > > Something like "of:N*T*Cgpio-leds" perhaps? > > Sorry, don't know. If I read the code right, the type field in DT ends > up being "" for any device that doesn't set the device_type > property, but that seems a bit silly and probably isn't worth copying. OK, I checked and udev wants to have both N and T but they can be left empty. If there are no objections the modalias will look like this: [root@mnw01 ~]# cat /sys/bus/spi/devices/spi-PRP0001\:00/modalias of:Nat25TCatmel,at25 In other words name is the ACPI device name (AT25) in lower case, T is left empty and C is the compatible property.