Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757185Ab2E3JWW (ORCPT ); Wed, 30 May 2012 05:22:22 -0400 Received: from mail-vc0-f174.google.com ([209.85.220.174]:51108 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973Ab2E3JWU (ORCPT ); Wed, 30 May 2012 05:22:20 -0400 Message-ID: <4FC5F2FA.4050606@gmail.com> Date: Wed, 30 May 2012 18:14:18 +0800 From: Xiao Jiang User-Agent: Thunderbird 2.0.0.24 (X11/20101027) MIME-Version: 1.0 To: "Cousson, Benoit" CC: Jon Hunter , linux@arm.linux.org.uk, rob.herring@calxeda.com, grant.likely@secretlab.ca, rnayak@ti.com, tony@atomide.com, wim@iguana.be, devicetree-discuss@lists.ozlabs.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-watchdog@vger.kernel.org Subject: Re: [PATCH 3/3] watchdog: omap_wdt: add device tree support References: <1337942552-28218-1-git-send-email-jgq516@gmail.com> <1337942552-28218-4-git-send-email-jgq516@gmail.com> <4FC51008.1050004@ti.com> <4FC59171.8040009@gmail.com> <4FC5D21F.2030702@ti.com> In-Reply-To: <4FC5D21F.2030702@ti.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2858 Lines: 82 Cousson, Benoit wrote: > On 5/30/2012 5:18 AM, Xiao Jiang wrote: >> Jon Hunter wrote: >>> On 05/25/2012 05:42 AM, jgq516@gmail.com wrote: >>>> From: Xiao Jiang >>>> >>>> Add device table for omap_wdt to support dt. >>>> >>>> Signed-off-by: Xiao Jiang >>>> --- >>>> drivers/watchdog/omap_wdt.c | 8 ++++++++ >>>> 1 files changed, 8 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c >>>> index 8285d65..d98c615 100644 >>>> --- a/drivers/watchdog/omap_wdt.c >>>> +++ b/drivers/watchdog/omap_wdt.c >>>> @@ -430,6 +430,13 @@ static int omap_wdt_resume(struct >>>> platform_device *pdev) >>>> #define omap_wdt_resume NULL >>>> #endif >>>> >>>> +static const struct of_device_id omap_wdt_of_match[] = { >>>> + { .compatible = "ti,omap3-wdt", }, >>>> + { .compatible = "ti,omap4-wdt", }, > > If there is no difference between the OMAP3 and the OMAP4 WDT IP, just > add one entry "ti,omap3-wdt". And then in the OMAP4 DTS you will just > put : compatible = "ti,omap3-wdt"; or compatible = "ti,omap4-wdt", > "ti,omap3-wdt"; > I'm still a little bit confused about the real need for the > "ti,omap4-wdt: entry, but it seems to be the way to do it in PPC. I believe OMAP2, OMAP3 and OMAP4 share the same IP, so how about use "ti, omap2-wdt"? and other dts files put compatible like "ti,omap4-wdt", "ti,omap2-wdt" and "ti,omap4-wdt", "ti,omap2-wdt". > >>>> + {}, >>>> +}; >>>> +MODULE_DEVICE_TABLE(of, omap_wdt_of_match); >>>> + >>>> static struct platform_driver omap_wdt_driver = { >>>> .probe = omap_wdt_probe, >>>> .remove = __devexit_p(omap_wdt_remove), >>>> @@ -439,6 +446,7 @@ static struct platform_driver omap_wdt_driver = { >>>> .driver = { >>>> .owner = THIS_MODULE, >>>> .name = "omap_wdt", >>>> + .of_match_table = omap_wdt_of_match, >>>> }, >>>> }; >>>> >>> >>> I think we need to add some code to the probe function that calls >>> of_match_device() and ensures we find a match. For example ... >>> >>> if (of_have_populated_dt()) >>> if (!of_match_device(omap_wdt_of_match, &pdev->dev)) >>> return -EINVAL; >>> >> Will add it in v2, thanks for suggestion. > > No, in fact this is not needed. We need that mainly when several > instances can match the same driver and thus we select the proper one > using the of_match_device. Otherwise, just check is the device_node is > there. > > In that case, the driver does not even care about any DT node so there > is no need to add extra code for that. Keep it simple. > Thanks for elaborating, simple is good for this one. Regards, Xiao > Regards, > Benoit -- 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/