Re: [PATCH v2] dt-bindings: clock: brcm,kona-ccu: convert to YAML

Conor Dooley
2023-10-30T11:41:57Z

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On Sun, Oct 29, 2023 at 10:16:14PM +0100, Artur Weber wrote:
>
> On 28/10/2023 13:30, Stanislav Jakubek wrote:
> > On Fri, Oct 27, 2023 at 03:47:48PM +0100, Conor Dooley wrote:
> > > On Tue, Oct 24, 2023 at 06:45:21PM +0200, Stanislav Jakubek wrote:
> > > > Convert Broadcom Kona family clock controller unit (CCU) bindings
> > > > to DT schema.
> > >
> > > I didn't cross-check the clock-output-names, but this conversion mostly
> > > looks good to me.
> > >
> > > > Changes during conversion:
> > > > - remove "dmac" from clock-output-names for brcm,bcm11351-master-ccu,
> > > > it is not used in DT nor the dt-bindings
> > > > - remove "uartb4" from clock-output-names for brcm,bcm21664-slave-ccu,
> > > > it is not used in DT nor the dt-bindings
> > >
> > > This I'm not sure about - they _were_ documented in the text-form
> > > dt-binding, even if they weren't used in the dts. If the clock
> > > controller does actually produce these clocks, removing them doesn't
> > > make sense to me.
> >
> > Hi Conor. Looking at downstream, I was not able to find these clocks, though
> > I admit that I'm not familiar enough with the downstream mess to be 100%
> > confident.
> >
> > From what I can tell, the BCM21664 arch/arm/mach-hawaii/clock.c (e.g. [1])
> > doesn't contain any mention of uartb4, only uartb, uartb2 and uartb3.
> > And similarly, for the BCM281XX arch/arm/mach-capri/clock_capri.c (e.g. [2])
> > I wasn't able to find any mention of dmac, only dmac_mux_apb and dma_axi
> > (though these two don't seem to be supported on mainline yet).
>
> I've done some digging in the downstream kernel; for the BCM21664, I'm
> almost certain that the uartb4 clock doesn't exist. Broadcom helpfully
> left in "RDB" files containing the entire register layout of all of the
> components; and even in the RDB for the slave clock manager[1] (used by
> the other uart clocks), there is no uartb4, nor is it mentioned
> anywhere else in the kernel (judging by a quick grep in the kernel
> sources).
>
> As for the BCM281XX clocks, there indeed doesn't seem to be an exact
> "dmac" clock but there is a "dmac" clock gate register[2], which is
> used for the dma_axi clock, so perhaps that's what this is referring
> to? Also not 100% certain.

I'm 99% sure I was happy with this otherwise, so thanks for doing the
investigation guys :)

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Cheers,
Conor.

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