From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752024AbaJBHql (ORCPT ); Thu, 2 Oct 2014 03:46:41 -0400 Received: from mout.kundenserver.de ([212.227.17.24]:65487 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751958AbaJBHqh (ORCPT ); Thu, 2 Oct 2014 03:46:37 -0400 From: Arnd Bergmann To: "Rafael J. Wysocki" Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Mika Westerberg , linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, Linus Walleij , Alexandre Courbot , Dmitry Torokhov , Bryan Wu , Lee Jones , Grant Likely , Aaron Lu , Darren Hart Subject: Re: [PATCH v3 02/15] Driver core: Unified device properties interface for platform firmware Date: Thu, 02 Oct 2014 09:46:29 +0200 Message-ID: <6092163.dWXI6rWTCu@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <4390403.PNxQqnBDGX@vostro.rjw.lan> References: <1410868367-11056-1-git-send-email-mika.westerberg@linux.intel.com> <7365448.TlsV4zB2It@wuerfel> <4390403.PNxQqnBDGX@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V02:K0:uDam0uwOAQZJEu63idmbs+B8VMwAYkMe1ht7L4e1lkU 0zw3Tphj004dqfj/QOwi8jSndOnf+feVv0EW2zJ4YFAQahSxCO Pn2nSAy2NU59wNVYFMF5xXDJwmCscWRY83wSHkbfaFla2laNm4 WdU4f/YjoqcsR8DcgIWWQK/JO3nEj/jrKRO3ZH/mpBzD0wBK0s GTwN7Xcpfd9+G2jB0DhhwlkEbGek6hNxDS4GRNs9crwWfBLAkN PZGmOJKVqwNvseA4sQjKSaPXfFxDCgcUkkE8VyJ/fgmuJntoHJ ArtuEwpcHQohBMN5YfBCJF8b+lCCg45IWzUHvYXCaYiWolGeGo ufTc+b0W9MCLoZEnAdCc= X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 02 October 2014 00:09:44 Rafael J. Wysocki wrote: > On Wednesday, October 01, 2014 09:47:40 AM Arnd Bergmann wrote: > > On Wednesday 01 October 2014 04:10:03 Rafael J. Wysocki wrote: > > I still have my reservations against the child accessors, and would > > like to hear what other people think. Passing a void pointer rather > > than struct fw_dev_node has both advantages and disadvantages, and > > I won't complain about either one if enough other people on the DT > > side would like to see the addition of the child functions. > > I actually would rather like to know if the people on the DT side have any > problems with the child functions. Sure, any kind of feedback would be helpful really. > Because, suppose that they wouldn't like those functions at all. What are we > supposed to do, then, honestly? Add the whole DT vs ACPI logic to the leds-gpio > and gpio_keys_polled drivers? But these drivers have no reason whatsoever > to include that. Zero. > > So suggestions welcome. > > [BTW, In principle we also could use something like > > typedef union dev_node { > struct acpi_device *acpi_node; > struct device_node *of_node; > } dev_node_t; > > instead of the (void *) for more type safety. It still is useful to pass the > parent pointer along with that, though.] Yes, I'm not worried about the implementation details. > > > Finally, device_for_each_child_node() is added for iterating over > > > the children of the device description object associated with a > > > given device. > > > > > > The interface covers both ACPI and Device Trees. > > > > > > This change set includes material from Mika Westerberg and Aaron Lu. > > > > > > > Regarding device_for_each_child_node(), the syntax is inconsistent > > with what we normally use, which can probably be changed. All of the > > DT for_each_* helpers are macros that are used like > > > > struct device *dev = ...; > > void *child; /* iterator */ > > > > device_for_each_child_node(dev, child) { > > u32 something; > > device_child_property_read_u32(dev, child, "propname", &something); > > > > do_something(dev, something); > > } > > > > If we get a consensus on having the child interfaces, I'd rather see > > them done this way than with a callback pointer, for consistency > > reasons. > > That certainly is doable, although the resulting macro would generate a rather > large chunk of code each time it is used. #define device_for_each_child_node(dev, child) \ for (child = device_get_next_child_node(dev, NULL), child, \ child = device_get_next_child_node(dev, child)) void *device_get_next_child_node(struct device *dev, void *child) { if (IS_ENABLED(CONFIG_OF) && dev->of_node) return of_get_next_child(dev->of_node, child); else if (IS_ENABLED(CONFIG_ACPI) && ...) return acpi_get_next_child(dev, child); return NULL; } Not any more code than what we have today for the DT-only case, and it's really just a function call in a loop. Arnd