Messages in this thread | | | Date | Mon, 28 Oct 2019 08:54:57 -0700 | From | Olof Johansson <> | Subject | Re: [PATCH v3] mfd: db8500-prcmu: Support U8420-sysclk firmware |
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On Sat, Oct 26, 2019 at 11:47:32PM +0200, Linus Walleij wrote: > There is a distinct version of the Ux500 U8420 variant > with "sysclk", as can be seen from the vendor code that > didn't make it upstream, this firmware lacks the > ULPPLL (ultra-low power phase locked loop) which in > effect means that the timer clock is instead wired to > the 32768 Hz always-on clock. > > This has some repercussions when enabling the timer > clock as the code as it stands will disable the timer > clock on these platforms (lacking the so-called > "doze mode") and obtaining the wrong rate of the timer > clock. > > The timer frequency is of course needed very early in > the boot, and as a consequence, we need to shuffle > around the early PRCMU init code: whereas in the past > we did not need to look up the PRCMU firmware version > in the early init, but now we need to know the version > before the core system timers are registered so we > restructure the platform callbacks to the PRCMU so as > not to take any arguments and instead look up the > resources it needs directly from the device tree > when initializing. > > As we do not yet support any platforms using this > firmware it is not a regression, but as PostmarketOS > is starting to support products with this firmware we > need to fix this up. > > The low rate of 32kHz also makes the MTU timer unsuitable > as delay timer but this needs to be fixed in a separate > patch. > > Cc: arm@kernel.org > Cc: Lee Jones <lee.jones@linaro.org> > Cc: Stephan Gerhold <stephan@gerhold.net> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Fine with me to go through MTD, so:
Acked-by: Olof Johansson <olof@lixom.net>
-Olof
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