On 11/02/16 09:57, Ulf Hansson wrote: > On 11 February 2016 at 10:13, Jon Hunter <jonathanh@xxxxxxxxxx> wrote: >> >> On 10/02/16 18:25, Ulf Hansson wrote: >> >> [snip] >> >>>>> Perhaps there's a way to allow the generic PM domain to control this >>>>> by itself. If we for example used the struct device corresponding to >>>>> the powergate driver, genpd could use it to distinguish between >>>>> various instances of genpd structs..!? Maybe it would simplify the way >>>>> to deal with removing domains? >>>> >>>> Yes, that would be ideal. However, would have require changing >>>> genpd_init()? I am not sure how genpd would be able to access the device >>>> struct for the powergate driver because we don't provide this via any >>>> API I am aware of? And I am guessing that you don't wish to expose the >>>> gpd_list to the world either. >>>> >>>> If there is an easy way, I am open to it, but looking at it today, I am >>>> not sure I see a simple way in which we could add a new API to do this. >>>> However, may be I am missing something! >>> >>> If we add a new __pm_genpd_init() API, that could require a struct >>> device to be provided. That API will thus invoke the existing >>> pm_genpd_init() but also deal with the extra things needed here. >>> >>> I would also allow such an API to return an error code. >>> >>> Correspondingly, pm_genpd_remove() could be required to be provided >>> with a struct device. >>> >>> Existing users of pm_genpd_init() can then convert to >>> __pm_genpd_init() whenever suitable. >>> >>> Of course, another option is just to add new member in the genpd >>> struct for the struct *device. The caller of pm_genpd_init() could >>> check it, but allow it to be NULL. Although, the pm_genpd_remove() API >>> would require that pointer to the struct device to be set... >>> >>> What do you think? >> >> Yes, sounds good. May be it is simpler just to add a new member and let >> the platform genpd driver handle it. >> >> I am wondering if in addition to pm_genpd_remove(), we then just have a >> function called pm_genpd_remove_tail(), which allows you to pass the >> struct device pointer and will remove the last pm-domain from the >> gpd_list and return the genpd pointer if successful. Internally, it will >> call pm_genpd_remove(). It seems to me that if there are nested >> pm-domains, then we probably want to remove them starting from the tail >> as opposed to the head. >> >> How does that sound? > > Why not make pm_genpd_remove() to behave as you describe for > pm_genpd_remove_tail()? > That's probably the only sane way to remove genpds anyhow!? Simply to offer flexibility. I could see that for some devices that have no dependencies between pm-domains and have a static list of pm-domains, they can simply call pm_genpd_remove() for a given pm-domain. However, that said, I can envision a case where a single pm-domain would be removed by itself and so may be there is no benefit? Cheers Jon -- 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
