[U-Boot] [PATCH 13/17] aspeed: Add support for Clocks needed by MACs

[Tom Rini]

On Mon, Mar 20, 2017 at 10:52:12AM -0700, Maxim Sloyko wrote:
> On Mon, Mar 20, 2017 at 10:30 AM, Tom Rini <trini at konsulko.com> wrote:
> 
> > On Mon, Mar 20, 2017 at 10:24:20AM -0700, Maxim Sloyko wrote:
> > > On Sun, Mar 19, 2017 at 9:42 AM, Tom Rini <trini at konsulko.com> wrote:
> > >
> > > > On Thu, Mar 16, 2017 at 02:36:20PM -0700, Maxim Sloyko wrote:
> > > > > Add support for clocks needed by MACs to ast2500 clock driver.
> > > > > The clocks are D2-PLL, which is used by both MACs and PCLK_MAC1 and
> > > > > PCLK_MAC2 for MAC1 and MAC2 respectively.
> > > > >
> > > > > The rate of D2-PLL is hardcoded to 250MHz -- the value used in Aspeed
> > > > > SDK. It is not entirely clear from the datasheet how this clock is
> > used
> > > > > by MACs, so not clear if the rate would ever need to be different.
> > So,
> > > > > for now, hardcoding it is probably safer.
> > > > >
> > > > > The rate of PCLK_MAC{1,2} is chosen based on MAC speed selected
> > through
> > > > > hardware strapping.
> > > > >
> > > > > So, the network driver would only need to enable these clocks, no
> > need
> > > > > to configure the rate.
> > > > >
> > > > > Signed-off-by: Maxim Sloyko <maxims at google.com>
> > > > > ---
> > > > >
> > > > >  arch/arm/dts/ast2500-u-boot.dtsi               |   8 +
> > > > >  arch/arm/include/asm/arch-aspeed/scu_ast2500.h |  62 +++++-
> > > > >  drivers/clk/aspeed/clk_ast2500.c               | 265
> > > > ++++++++++++++++++++++---
> > > > >  include/dt-bindings/clock/ast2500-scu.h        |   2 +
> > > > >  4 files changed, 304 insertions(+), 33 deletions(-)
> > > > >
> > > > > diff --git a/arch/arm/dts/ast2500-u-boot.dtsi
> > > > b/arch/arm/dts/ast2500-u-boot.dtsi
> > > > > index faeeec1be4..f826646095 100644
> > > > > --- a/arch/arm/dts/ast2500-u-boot.dtsi
> > > > > +++ b/arch/arm/dts/ast2500-u-boot.dtsi
> > > > > @@ -61,3 +61,11 @@
> > > > >               };
> > > > >       };
> > > > >  };
> > > > > +
> > > > > +&mac0 {
> > > > > +     clocks = <&scu PCLK_MAC1>, <&scu PLL_D2PLL>;
> > > > > +};
> > > > > +
> > > > > +&mac1 {
> > > > > +     clocks = <&scu PCLK_MAC2>, <&scu PLL_D2PLL>;
> > > > > +};
> > > >
> > > > Why is this here and not in the main dts file?  The -u-boot.dtsi is for
> > > > stuff that's not appropriate in the upstream dts file.  Thanks!
> > >
> > > There is no clock driver for this part in mainline Linux Kernel yet and I
> > > don't know how it will end up being configured. I suspect that they might
> > > not use the same bindings though.
> > >
> > > Should I put this into board specific dts?
> >
> > So this applies to a lot of parts of the series here.  What we don't
> > want to do is have places where the DTS here diverges from the Linux
> > kernel DTS and we don't reconcile them.  If the relevant Linux drivers
> > are not in mainline, are they at least in linux-next or otherwise
> > submitted to the relevant subtrees?
> >
> 
> No, as far as I know, maybe Rick (cc'ed) knows what is the plan there.
> 
> I'm not really working on the linux driver and it's outside of my control.
> 
> I can change network driver, so that it does not use this DT configuration
> and either hard code clock config into it, or configure it's clocks in
> board specific file -- would that be more acceptable?

For all the cases where you don't have the DT portion itself upstream
yet, go with platdata instead for now.  Unless I'm mis-recalling things
that is.

-- 
Tom
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