Hi Uli,
On Wed, Feb 26, 2020 at 9:28 PM Ulrich Hecht <uli+renesas@xxxxxxxx> wrote:
> This series adds the option for declaring clocks as "ignore-unused", i.e.
> clocks that will not be turned on if not used, but also not turned off if
> unused. It also enables this option for the RWDT clocks in (almost) all
> SoCs.
Thanks for your series!
> The point of this is to allow a WDT that has been enabled by the bootloader
> to survive these events:
>
> - deferred probing of the WDT device, which can lead the clock driver
> to disable the WDT clock until the WDT is re-probed, giving it a
> blind spot
> - probe failure in the WDT driver
>
> There are a number of SoCs that have the RWDT clock already declared as
> critical (i.e. turn it on even if it is off _and_ unused). I don't know if
> that is because there was no option for ignore-unused before, or if the
> behavior of turning the clock on even if neither the bootloader nor anything
> in the kernel has asked for it is actually desired. If it's the former,
> these SoCs also have to be converted to the new mechanism.
That was done on all of R-Car Gen2 and RZ/G1, as the SMP bringup code
needs to check the watchdog registers, which can happen at any time, cfr.
commit 58adf1ba0d227754 ("ARM: shmobile: Add watchdog support").
Presumable that was fixed on R-Car Gen3 and RZ/G2, so the watchdog registers
don't have to be checked, and the watchdog doesn't have to run all the
time (holding wood, rabbit legs, and whatever ;-)
> Ulrich Hecht (11):
> clk: renesas: cpg-mssr: add support for ignore-unused clocks
> clk: renesas: r8a7796: mark RWDT clock as ignore-unused
> clk: renesas: r8a7795: mark RWDT clock as ignore-unused
> clk: renesas: r8a77970: mark RWDT clock as ignore-unused
> clk: renesas: r8a77980: mark RWDT clock as ignore-unused
> clk: renesas: r8a77995: mark RWDT clock as ignore-unused
> clk: renesas: r8a774a1: mark RWDT clock as ignore-unused
> clk: renesas: r8a774b1: mark RWDT clock as ignore-unused
> clk: renesas: r8a774c0: mark RWDT clock as ignore-unused
> clk: renesas: r8a77965: mark RWDT clock as ignore-unused
> clk: renesas: r8a77990: mark RWDT clock as ignore-unused
I think the SoC-specific parts can be merged safely into two patches,
one for R-Car Gen3, and one for RZ/G2?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
