On Fri, Jan 09, 2015 at 10:11:10AM +0100, Hans de Goede wrote: > Hi, > > On 09-01-15 09:51, Maxime Ripard wrote: > >On Fri, Jan 09, 2015 at 09:36:28AM +0100, Hans de Goede wrote: > >>Hi, > >> > >>On 09-01-15 09:30, Maxime Ripard wrote: > >>>On Tue, Jan 06, 2015 at 12:56:37AM +0800, wens Tsai wrote: > >> > >><snip> > >> > >>>>For sun6i it is somewhat harder. > >>> > >>>Yep, that version D thing is going to cause us a bit of trouble, but > >>>since we don't have any hardware available, I'd say we should ignore > >>>it for now. > >> > >>Version D ? I more or less completely missed that, care to explain ? > >> > >>I guess this is going to impact u-boot too ? > > > >I don't think it will, or at least, not for this issue. > > > > From what we saw in the Allwinner BSPs, the A31 rev D might need > >different operating points for cpufreq. > > Ah, what about the max-speed operating point ? That is being set by > u-boot early on, specifically for sun6i / sun8i it sets VDD-CPU to 1.2V > and the CPU-clock to 1008MHz.
Based on the two samples here: https://github.com/linux-sunxi/sunxi-boards/blob/master/sys_config/a31/hummingbird_a31.fex#L919 and here: https://github.com/linux-sunxi/sunxi-boards/blob/master/sys_config/a31/mele_i7.fex#L1436 The voltage always seem lower for each OPP. So I guess if you use the voltages from the pre-rev-D OPPs, you'd be fine. > >It's not really an issue per-se, but supporting both pre-rev-D and > >post-rev-D will need to have a bit of thoughts. > > Hmm, tricky. What if we add a second, soc-specific, compatible to the > cpu nodes which contains the cpu-revision, and then have 2 nodes > for each cpu, with either one (or both) with status = "disabled"; and > then on early board init detect the revision and enable the right cpu > nodes ? I was more thinking to feed the OPPs directly from the code in mach-sunxi if we detect a rev-D. I don't really know what would be the side effects of playing with the CPU nodes like that. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
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