Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 4 Aug 2016 15:05:16 +0200 | Subject | Re: [PATCH v4 2/2] spi: add driver for J-Core SPI controller |
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Hi Rich,
On Sat, Jul 30, 2016 at 5:34 AM, Rich Felker <dalias@libc.org> wrote: > On Thu, Jul 28, 2016 at 08:51:25PM +0100, Mark Brown wrote: >> On Thu, Jul 28, 2016 at 03:40:45PM -0400, Rich Felker wrote: >> > On Thu, Jul 28, 2016 at 08:11:53PM +0100, Mark Brown wrote: >> > > Why are you not using the clock API for this? Just require a clock and >> > > use clk_get_rate() to find out what rate it is. >> >> > I thought about that but I'm not familiar with it. I can try to figure >> > it out quickly and test that approach; don't see any reason it >> > shouldn't work. Would you insist on having full support for >> > enabling/disabling the clk when it's in use, or would you be happy >> > with treating it as a fixed clock that's always-on for now and >> > possibly extending it with more functionality later if there's ever >> > hardware where that's relevant/helpful? >> >> It's fine to just enable it at startup and leave it on, though the >> runtime PM ops are trivial and you can set auto_runtime_pm to have the >> core do the gets and puts. > > I was able to get it working via the clk api and I'll include support > for this in the next version of the patch, but to actually use it > depends on changing arch/sh to use the common clk framework; otherwise > there's no way to provide a suitable clk in the DT and have > [devm_]clk_get actually pick it up. Should I keep around the option of > using clock-frequency too? That would be most convenient. > > I do have a pending patch from Sato-san to switch arch/sh over to CCF > but it's part of a series and I don't think it's ready to merge. I may > be able to merge just a minimal, safe subset that won't break legacy > non-DT configurations, though.
I think you can use non-CCF clocks with DT, if you register them first. Cfr. the clk_names[] array and shmobile_clk_workaround() function in v3.18:arch/arm/mach-shmobile/board-koelsch-reference.c and v3.18:arch/arm/mach-shmobile/clock.c
Or was that the other way around?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
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
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