Hi, On 23 February 2013 03:07, Sylwester Nawrocki <sylvester.nawrocki@xxxxxxxxx> wrote: > Hi Vikas, > > On 02/22/2013 08:06 AM, Vikas Sajjan wrote: >>>>>>> >>>>>>> +++ b/Documentation/devicetree/bindings/drm/exynos/fimd.txt > > [...] > >>>>>>> @@ -0,0 +1,37 @@ >>>>>>> +Device-Tree bindings for fimd driver > > > Perhaps something like: > > Exynos SoC display controller (FIMD) > > would do ? Even though bindings are to be used by some driver we should > be focusing on describing the actual hardware. > OK. will change. > >>>>>>> +FIMD stands for Fully Interactive Mobile Display, is the Display >>>>>>> Controller for >>>>>>> +the Exynos series of SoCs which transfers the image data from a >>>>>>> video >>>>>>> buffer >>>>>>> +located in the system memory to an external LCD interface. >>>>>>> + >>>>>>> +Required properties: >>>>>>> +- compatible := value should be "samsung,exynos5-fimd" or >>>>>>> "samsung,exynos4-fimd" >>>>>> >>>>>> >>>>>> >>>>>> What about older SoCs like S5Pv210 ? There is the FIMD IP block in >>>>>> those >>>>>> SoCs >>>>>> as well. There are also differences in the FIMD IP block across >>>>>> various >>>>>> SoC >>>>>> version, so either you need to list the quirks in the bindings or use >>>>>> an >>>>>> appropriate compatible properties if there are significant differences >>>>>> across >>>>>> FIMDs that make them not really compatible. >>>>>> >>>>> as of now, I was working on Exynos4 and Exynos5 SoC. have to really >>>>> see the differences in the previous SoC and how to handle all those >>>>> FIMD IPs in the driver. >>>>> if you know the differences between these FIMD IPs, please let me know. >>>> >>>> >>>> >>>> Please have a look at drivers/video/s3c-fb.c and all driver_data >>>> structures >>>> defined for various SoCs. >>>> >>>> [...] >>>> >>> I went through the driver_data structures define for s5p64x0,s3c2443, >>> s5pv210, s5pc100 ad 64xx SoCs. >>> there are some differences w.r.t number of windows, osd_stride length >>> and regsiter offsets. >>> but I dont have access to all the above mentioned Boards and so that >>> I can modify and test on each one of them. > > > I don't ask you to add support for all existing FIMD variants. Please just > make sure the bindings you're documenting here, with focus on the Exynos > SoCs, are also usable for older SoC series. > > >> as far as i know this file exynos_drm_fimd.c is meant only for exynos4 >> onwards SoCs, > > > Yes, but the bindings are for FIMD IP block and should possibly be > consistent > across all SoC series. I think we should bear in mind that eventually all > these SoCs get device tree support. Actually I've seen already patches for > s3c24xx and s3c64xx SoC series. > > >> ( I think Mr. Inki Dae can throw more light on this ) >> and also the previous boards based on s5p64x0,s3c2443,s5pv210, >> s5pc100 and 64xx, dont have DT support. > > > We can't tell for sure the SoC series listed above won't get device tree > support sooner or later, as this is an open source project. > > >> also in the function drm_fimd_get_driver_data(), there is provision to >> get the NON-DT "driver data" as well. So somebody who wants to use >> this driver for the above mentioned SoCs can add the driver-data. > > > I'm not concerned about this particular driver, only about the DT bindings > that are not supposed to change over time. So some care needs to be taken > when designing the bindings. > > >> so wanted to know how you want me to go about it. > > > My concern was that you use "samsung,exynos4-fimd" for FIMD IP found on all > Exynos4 SoC, whereas there could be some differences for Exynos4210 and > Exynos4212/4412. It looks like both are shipped with FIMD rev. 6.0 though. > Anyway, still there are some details that may need to be handled, e.g. > maximum > VCLK frequency is 80 MHz for Exynos4210 FIMD0 and Exynos4412 FIMD (there is > only one there in Exynos4412 as opposed to two in Exynos4210), while for > Exynos4210 FIMD1 it is only 50 MHz. When there are differences we really > care about (and support for FIMD1 is added) I guess things like this could > be handled through optional properties. > > I thought about something like: > > compatible = "samsung,exynos4210-fimd"; for Exynos4210 and > compatible = "samsung,exynos4212-fimd", "samsung,exynos4210-fimd"; for > Exynos4212 and Exynos412, > > but "samsung,exynos4-fimd" seems good enough, since the FIMD IP block > appears nearly identical across Exynos4210...Exynos4412. > ok thanks. Will modify the documentation as below. compatible = "samsung, exynos4-fimd"; for Exynos4 SoCs compatible = "samsung, exynos5-fimd" ; for Exynos5 SoCs compatible = "samsung, s3c64xx-fimd" ; for S3C64XX SoCs compatible = "samsung, s3c24xx-fimd" ; for S3C24XX SoCs compatible = "samsung, s5p64x0-fimd" ; for S5P64X0 SoCs compatible = "samsung, s5pc100-fimd" ; for S5PC100 SoCs compatible = "samsung, s5pv210-fimd" ; for S5PV210 SoCs > -- > > Thanks, > Sylwester -- Thanks and Regards Vikas Sajjan -- 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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