From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sylwester Nawrocki Subject: Re: [PATCH v3 2/2] ARM: EXYNOS: Add Gscaler device from DT Date: Fri, 03 Aug 2012 01:40:51 +0200 Message-ID: <501B1003.1090003@gmail.com> References: <1342789723-3949-1-git-send-email-shaik.ameer@samsung.com> <1342789723-3949-3-git-send-email-shaik.ameer@samsung.com> <033301cd6fb0$7ac4af90$704e0eb0$%kim@samsung.com> <5018E656.3070803@samsung.com> <036f01cd6fc4$120a9910$361fcb30$%kim@samsung.com> <50197D66.1050108@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-samsung-soc-owner@vger.kernel.org To: Olof Johansson Cc: Kukjin Kim , Sylwester Nawrocki , Thomas Abraham , Shaik Ameer Basha , linux-samsung-soc@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, sy0816.kang@samsung.com, olofj@google.com, thomas.ab@samsung.com, sachin.kamat@linaro.org, joshi@samsung.com, shaik.samsung@gmail.com, sungchun.kang@samsung.com, Rob Herring List-Id: devicetree@vger.kernel.org On 08/02/2012 06:33 PM, Olof Johansson wrote: > On Wed, Aug 1, 2012 at 12:03 PM, Sylwester Nawrocki > wrote: > >> It wouldn't be clear what specific SoCs the "samsung,exynos5-gsc" compatible >> string applies to, would it ? I believe there are already minor differences >> in GScaler parameters on currently available exynos5 SoC. The variant data >> structures are used to handle this and the compatible string determines which >> variant data structure is selected during driver's initialization. >> If you use a wildcard 'compatible' string this won't be possible any more. >> >> Also it would look odd IMO to have two compatible strings like: >> compatible = "samsung,exynos5-gsc", "samsung,exynos5400-gsc"; > > In this particular case, since you're saying that there are subtle > differences between different part numbers, I'm guessing there's good > reason to go specific, but in general there's no need to avoid > exynos5-gsc. > > Your example is also false, since the strings would be in reverse > order (from specific to generic). That would look perfectly normal. You're right, but my intention was more to say that there would have been two entries in the driver's of_match_table, where "samsung,exynos5-gsc" wouldn't have obvious meaning. Devices within these SoCs tend to differ across part numbers and usually there is one common driver handling them. I can't tell for sure now there are differences, but I would have been surprised if there wouldn't. > So, bottom line: I agree in this particular instance, but I disagree > that it's a hard generic rule. Thanks, sorry if it sounded like I'm advocating it as a general rule. I'm no DT expert whatsoever, but in this particular case it just sounded messy to use only exynos5-gsc. -- Regards, Sylwester