From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Wed, 04 Apr 2012 12:32:04 -0600 Subject: [PATCH v5 09/16] pwm: tegra: Add device tree support In-Reply-To: <20120404050054.GA30807@avionic-0098.adnet.avionic-design.de> References: <1332945238-14897-1-git-send-email-thierry.reding@avionic-design.de> <1332945238-14897-10-git-send-email-thierry.reding@avionic-design.de> <4F7602CD.2010808@wwwdotorg.org> <20120402083749.GA6576@avionic-0098.adnet.avionic-design.de> <4F79C8D4.2000306@wwwdotorg.org> <20120403175511.GA26399@avionic-0098.mockup.avionic-design.de> <20120403234249.E292E3E03F3@localhost> <20120404050054.GA30807@avionic-0098.adnet.avionic-design.de> Message-ID: <4F7C93A4.5000906@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/03/2012 11:00 PM, Thierry Reding wrote: > * Grant Likely wrote: >> On Tue, 3 Apr 2012 19:55:11 +0200, Thierry Reding wrote: >>> * Stephen Warren wrote: >>>> On 04/02/2012 02:37 AM, Thierry Reding wrote: >>>>> * Stephen Warren wrote: >>>>>> On 03/28/2012 08:33 AM, Thierry Reding wrote: >>>>>>> Add auxdata to instantiate the PWFM controller from a device tree, >>>>>>> include the corresponding nodes in the dtsi files for Tegra 20 and >>>>>>> Tegra 30 and add binding documentation. >>>>>>> >>>>>>> Signed-off-by: Thierry Reding >>>>>>> Acked-by: Stephen Warren >>>>>> >>>>>>> diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c >>>>>> ... >>>>>>> +#ifdef CONFIG_OF >>>>>>> +static struct of_device_id tegra_pwm_of_match[] = { >>>>>>> + { .compatible = "nvidia,tegra20-pwm" }, >>>>>>> + { .compatible = "nvidia,tegra30-pwm" }, >>>>>> >>>>>> Could you swap those two lines, so that tegra30-pwm matches first. It >>>>>> makes no difference at present, but might in the future if the driver >>>>>> actually has to differentiate the two SoCs. >>>>> >>>>> I thought the matching order was determined by the compatible property in the >>>>> device tree, not the OF match table of the driver. >>>> >>>> At least logically, yes. However, of_match_device() appears to iterate >>>> over each match table entry, checking whether it matches any string in >>>> the compatible flag. Perhaps this could be considered a bug? >>> >>> It certainly is counter-intuitive. Maybe Grant or Rob can comment? >> >> Yes, it is a bug. The order of of_device_id should be entirely >> irrelevant, and the order in the DT compatible property should >> determine which match entry is returned. > > I've had a look at the code and it looks like a fix will not be entirely > trivial. I think moving out the compatible check out of the while loop in > of_match_node() and separately iterate over all strings in the compatible > property would be the easiest. That will also prioritize the compatible > match over matches by name and type but I think that's exactly what we > want. From a quick look it certainly seems like the large majority of > drivers match by compatible anyway. > > Do you want me to prepare a patch or can you take care of it? > > Stephen: Can I assume that you're fine with this Tegra PWM patch if such > a change to the matching function is committed? Yes.