On 2016/6/14 10:13, Doug Anderson wrote: > Shawn, > > On Mon, Jun 13, 2016 at 5:59 PM, Shawn Lin <shawn.lin at rock-chips.com> wrote: >>> Even in the case that an SoC designer didn't put a value into >>> corecfg_baseclkfreq that matched register[15:8], it seems very likely >>> that the rate returned from the clk_get_rate() would match. >>> >>> I guess what I'm saying is that, to me, it seems like my patch isn't >>> broken in any real systems. If we ever find a system that needs this >>> behavior in the future, we can add it. Until then, it seems like my >>> patch would be fine. Do you agree? >> >> >> I agree. But from the code itself, we should still use >> SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN to see if we could get >> it from internal register in case of some platforms don't >> provide the clk stuff.. Sounds sane? :) > > Could we wait until there exists a SoC that needs to provide > baseclkfreq in its sdhci_arasan_soc_ctl_map table and that needs this > value copied from register[15:8]? yes, I think the base clk got from clk framework shouldn't make any difference with that from register[15:8] if implemented. And we now decide how to get base clk in a certain variant driver which menas we know that this variant would never implement register[15:8], so it looks fine for your patch with only a nit that we should make sure we toggle up the COMMON_CLK. I saw your v2.1 to deal with it, so I think it's okay now to add Reviewed-by: Shawn Lin <shawn.lin at rock-chips.com> > > AKA: > > A) If you have a SoC where clk_get_rate() is right and software needs > to set baseclkfreq manualy, then you should include "baseclkfreq" in > your sdhci_arasan_soc_ctl_map table. This is like rk3399. Note that > if _both_ clk_get_rate() and register[15:8] are right, that's fine. > We can still use clk_get_rate() since it will be exactly the same as > register[15:8]. > > B) If you have a SoC that doesn't even expose corecfg_baseclkfreq to > software control, just don't include "baseclkfreq" in your > sdhci_arasan_soc_ctl_map table. Easy. This is how my patch treats > anyone using the current "generic" bindings, but you could easily just > specify an offset of "-1" for baseclkfreq if you didn't want to use > the generic bindings but couldn't control baseclkfreq. > > C) If you have a SoC that provides a valid value in register[15:8] and > clk_get_rate() is wrong and software is required to copy the value > from register[15:8] to baseclkfreq, technically we should fix > clk_get_rate() anyway. It's good when common clock framework provides > correct values. NOTE: It seems very unlikely to me that > register[15:8] would be right AND that software would be required to > copy this value to baseclkfreq, but I suppose there are some pretty > crazy hardware designs out there. > > D) If you have a SoC that provides a valid value in register[15:8] and > clk_get_rate() is wrong and can't be fixed (REALLY?) and software is > required to copy the value from register[15:8] to baseclkfreq, we will > need to add new code. My assertion is that such a SoC doesn't exist > and is unlikely to ever exist, so I am hesitant to add extra code to > support this SoC. > > > With my patch, A) and B) are certainly handled. I think C) is > unlikely to exist, but if it did exist then I'd say we should fix > clk_get_rate(). I think D) is VERY unlikely to exist. If I'm shown > proof of D) existing, I'm happy to submit a patch for it. Until we > see proof of D)'s existence, I don't think we should clutter the code > with support for it. > > > -Doug > > > -- Best Regards Shawn Lin
