On 08/06/2013 05:45 PM, Hanumant Singh wrote: > On 7/31/2013 5:17 PM, Hanumant Singh wrote: >> On 7/31/2013 2:06 PM, Stephen Warren wrote: >>> On 07/31/2013 01:46 PM, Hanumant Singh wrote: >>>> On 7/30/2013 8:59 PM, Stephen Warren wrote: >>>>> On 07/30/2013 06:13 PM, Hanumant Singh wrote: >>>>>> On 7/30/2013 5:08 PM, Stephen Warren wrote: >>>>>>> On 07/30/2013 06:01 PM, Hanumant Singh wrote: >>>>>>>> On 7/30/2013 2:22 PM, Stephen Warren wrote: >>>>>>>>> On 07/30/2013 03:10 PM, hanumant wrote: >>>>>>>>> ... >>>>>>>>>> We actually have the same TLMM pinmux used by several socs of a >>>>>>>>>> family. >>>>>>>>>> The number of pins on each soc may vary. >>>>>>>>>> Also a given soc gets used in a number of boards. >>>>>>>>>> The device tree for a given soc is split into the different >>>>>>>>>> boards >>>>>>>>>> that >>>>>>>>>> its in ie the boards inherit a common soc.dtsi but have separate >>>>>>>>>> dts. >>>>>>>>>> The boards for the same soc may use different pin groups for >>>>>>>>>> accomplishing a function, since we have multiple i2c, spi uart >>>>>>>>>> etc >>>>>>>>>> peripheral instances on a soc. A different instance of each of >>>>>>>>>> the >>>>>>>>>> above >>>>>>>>>> peripherals, can be used in different boards, utilizing different >>>>>>>>>> or subset of same pin groups. >>>>>>>>>> Thus I would need to have multiple C files for one soc, based >>>>>>>>>> on the >>>>>>>>>> boards that it goes into. >>>>>>>>> >>>>>>>>> The pinctrl driver should be exposing the raw capabilities of >>>>>>>>> the HW. >>>>>>>>> All the board-specific configuration should be expressed in DT. >>>>>>>>> So, the >>>>>>>>> driver shouldn't have to know anything about different boards at >>>>>>>>> compile-time. >>>>>>>>> >>>>>>>> I agree, so I wanted to keep the pin grouping information in DT, we >>>>>>>> already have a board based differentiation of dts files in DT, >>>>>>>> for the >>>>>>>> same soc. >>>>>>> >>>>>>> That's the opposite of what I was saying. Pin groups are a >>>>>>> feature of >>>>>>> the SoC design, not the board. >>>>>>> >>>>>> Sorry I guess I wasn't clear. >>>>>> Right now I have a soc-pinctrl.dtsi containing pin groupings. >>>>>> This will be "inherited" by soc-boardtype.dts. >>>>>> The pinctrl client device nodes in soc-boardtype.dts will point to >>>>>> pin >>>>>> groupings in soc-pinctrl.dtsi that are valid for that particular >>>>>> boardtype. >>>>>> Is this a valid design? >>>>> >>>>> OK, so you have two types of child node inside the pinctrl DT node; >>>>> some >>>>> define the pin groups the SoC has (in soc.dtsi) and some define >>>>> pinctrl >>>>> states that reference the pin group nodes and are referenced by the >>>>> client nodes. >>>>> >>>>> That's probably fine. However, I'd still question putting the pin >>>>> group >>>>> nodes in DT at all; I'm not convinced it's better than just putting >>>>> those into the driver itself. You end up with the same data tables >>>>> after >>>>> parsing the DT anyway. >>>>> >>>> >>>> Any feedback for the rest of the patch? >>> >>> I'm certainly waiting for this aspect of the patch to be resolved; I >>> think it will impact the rest of the patch so much that it's not worth >>> reviewing until we decide on where to represent the pin groups (some DT >>> parsing could would be removed if we put the pin group definitions into >>> the driver, hence wouldn't need to be reviewed, and likewise there's be >>> some new tables to review). >>> >> >> I am trying to look at examples of what you are suggesting. >> I was looking at the exynos implementation, and just from a brief glance >> it seems like there too the pin grouping is being specified in the >> device tree, using what looks like labels of the pins. >> The labels are matched to group structures in soc specific files? >> >> By having the pin groupings in DT I am able to reuse the driver without >> any SOC based code bloat. >> As I mentioned earlier, we have entire families of SOCs using the same >> TLMM hardware. >> Its not a guarantee that for a given TLMM version, >> the pin groupings on that hardware are the same for every SOC that its >> in. Its infact most likely that I wont be able to use the pin groupings >> from one SOC to the next even if they both use the same TLMM. >> It will very quickly lead to a bloat of >> pinctrl-<msm_soc>.c (containing the pin groupings replicated for each >> soc) >> which use TLMM version specific register programming implementation >> pinctrl-tlmm-<version>.c >> and the DT parsing and interface to framework (which remains unchanged). >> pinctrl-msm.c. >> >> Thanks >> Hanumant >> > > Any comments on this? No. As I said, I personally want to see all the pingroups defined in the pinctrl driver. But, if someone else acks/... the patches without it, I probably won't nack it. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
