On 8/7/12, Thomas Abraham <thomas.abraham@xxxxxxxxxx> wrote: > On 7 August 2012 07:58, Olof Johansson <olof@xxxxxxxxx> wrote: >> Hi, >> >> On Mon, Aug 6, 2012 at 7:05 PM, Dongjin Kim >> <Dongjin.Kim@xxxxxxxxxxxxxxxxxxx> wrote: >>> Hello, >>> >>> I am trying to understand what I have to do for device tree. >>> >>> In order to create dts file for ODROID-X hardware, it seems I may need >>> dts file of EXYNOS4412 SoC. >>> But maybe exynos4412.dtsi is not merged yet or not exist, like >>> exynos4210.dtsi or exynos5250.dtsi. >>> Obviously it seems not easy to create such a file without SoC datasheet, >>> and I do not have it. >>> >>> So do I wait for the file to be merged by Samsung or better to create >>> initial dts file cloned from exynos4210.dtsi and modify to have verified >>> nodes with the source/header files? >> >> Ideally they already have one waiting to be submitted, but that might >> not be the case. Given that the origenboard design with 4412 is not >> yet shipping, I'm guessing the Linaro Samsung engineers might not have >> done much work on 4412 yet. Kukjin? Thomas? >> >>> What's your suggestion? >> >> The alternative is to use the data you have available -- i.e. sources >> and patches, and craft the device tree from there. The design of 4412 >> is a derivative from 4210, so that's a good start. Next step would be >> to describe the board on top of the SoC, peripherals, etc. Take a look >> at how the origen board support was added, and so on. >> >> I ordered an odroid-x several weeks ago but I haven't have a confirmed >> shipping date yet. :( I'm not sure how long it'll be before I can help >> out, unfortunately. >> >> >> -Olof > > Most of the Exynos4210 device tree support can be reused for > Exynos4412 as well. Looking at the hardware differences between the > two, it might be better to create a new exynos4.dtsi file (kind of > creating it out of the existing exynos4210.dtsi) which will have all > the common bits across all SoC's in the Exynos4 family. > > Further, there can be exynos4210.dtsi and exynos4412.dtsi which would > specify SoC specific differences such as the GIC cpu-offset property > and the additional groups available in the interrupt combiner. > > There are differences in the gpio/pinmux controllers as well which > have to be described using device tree. The current gpio/pinmux device > tree support depends entirely on the gpio-samsung driver which handles > both gpio and pinmux but requires listing all the banks available in > Exynos4412. I would prefer not to do that since we are switching over > to using a pin controller driver and I am currently working on this > driver. > > The pin controller driver is important without which the > gpio/pinmux/pinconf setting for devices such as i2c and sdhci > controller cannot be setup. The basic pinctrl driver for Exynos4 has > already been posted and now I am working on adding gpio and wakeup > interrupt support into that driver (hoping to complete it this week). > > So the probable steps in getting started with using device tree for > Exynos4412 would be > > 1. Create a new exynos4.dtsi file with all the Exynos4 common > properties for all dt supported controllers. > 2. Update the exynos4210.dtsi file accordingly and add the new > exynos4412.dtsi file. > 3. With this, it will be possible to boot the kernel and test > peripherals that do not depend on gpio/pinmux (rtc, wdt, etc). > 4. When the Exynos4 pinctrl driver is available, start adding device > nodes for i2c and sdhci controllers. > 5. Incrementally add device tree coverage for the board and other > peripherals on Exynos4412. Nice! Good plan as I thnk. Thank you, Kyungmin Park -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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