On Thu, Oct 30, 2014 at 1:42 AM, Pantelis Antoniou <pantelis.antoniou@xxxxxxxxx> wrote: > Hi Benoit, > >> On Oct 29, 2014, at 18:34 , Benoit Parrot <bparrot@xxxxxx> wrote: >> >> Pantelis, >> >> Thanks for the feedback. >> >> Pantelis Antoniou <pantelis.antoniou@xxxxxxxxx> wrote on Wed [2014-Oct-29 10:53:44 +0200]: >>> Hi Benoit, >>> >>>> On Oct 21, 2014, at 23:09 , Benoit Parrot <bparrot@xxxxxx> wrote: >>>> >>>> Based on Boris Brezillion work this is a reworked patch >>>> of his initial GPIO hogging mechanism. >>>> This patch provides a way to initally configure specific GPIO >>>> when the gpio controller is probe. >>>> >>>> The actual DT scanning to collect the GPIO specific data is performed >>>> as part of the gpiochip_add(). >>>> >>>> The purpose of this is to allows specific GPIOs to be configured >>>> without any driver specific code. >>>> This particularly usueful because board design are getting >>>> increassingly complex and given SoC pins can now have upward >>>> of 10 mux values a lot of connections are now dependent on >>>> external IO muxes to switch various modes and combination. >>>> >>>> Specific drivers should not necessarily need to be aware of >>>> what accounts to a specific board implementation. This board level >>>> "description" should be best kept as part of the dts file. >>>> >>> >>> This look like it’s going to the right direction. I have a few general >>> comments at first. >>> >>> 1) It relies on dubious DT binding of having sub-nodes of the >>> gpio device implicitly defining hogs. >> >> I think in this instance the nodes are explicitly defining hogs. >> Please clarify. What would you like to see here? >>> > > Any subnodes are implicitly taken as hog definitions. This is not right because > gpio controllers might have subnodes that they use for another purpose. > >>> 2) There is no way for having hogs inserted dynamically as far as I can tell, and >>> no way to remove a hog either. >> >> The original patch was allowing that but, Linus's review comment suggested this feature be >> part of the gpio-controller's gpiochip_add() hook only. >> > > If it’s not possible to remove a hog, then it’s no good for my use case in which > the gpios get exported and then removed. Why would you want to remove a GPIO hog at runtime, and what is the point of having it set in the DT in that case? -- 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
