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

[Maxim Sloyko]

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?


>
> --
> Tom
>



-- 
*M*axim *S*loyko