[PATCH 2/3] dt-bindings: clock: Add bindings for ZynqMP clock driver

Rob Herring robh at kernel.org
Wed Mar 7 17:20:00 PST 2018


On Wed, Mar 7, 2018 at 4:47 PM, Jolly Shah <JOLLYS at xilinx.com> wrote:
> Hi Rob,
>
>
>> -----Original Message-----
>> From: Rob Herring [mailto:robh at kernel.org]
>> Sent: Monday, March 05, 2018 5:46 PM
>> To: Jolly Shah <JOLLYS at xilinx.com>
>> Cc: mturquette at baylibre.com; sboyd at codeaurora.org;
>> michal.simek at xilinx.com; mark.rutland at arm.com; linux-clk at vger.kernel.org;
>> devicetree at vger.kernel.org; Shubhrajyoti Datta <shubhraj at xilinx.com>; linux-
>> kernel at vger.kernel.org; Jolly Shah <JOLLYS at xilinx.com>; Rajan Vaja
>> <RAJANV at xilinx.com>; linux-arm-kernel at lists.infradead.org
>> Subject: Re: [PATCH 2/3] dt-bindings: clock: Add bindings for ZynqMP clock
>> driver
>>
>> On Wed, Feb 28, 2018 at 02:27:40PM -0800, Jolly Shah wrote:
>> > Add documentation to describe Xilinx ZynqMP clock driver bindings.
>> >
>> > Signed-off-by: Jolly Shah <jollys at xilinx.com>
>> > Signed-off-by: Rajan Vaja <rajanv at xilinx.com>
>> > Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta at xilinx.com>
>> > ---

>> > +95         dpll_post_src
>> > +96         vpll_int
>> > +97         vpll_pre_src
>> > +98         vpll_half
>> > +99         vpll_int_mux
>> > +100                vpll_post_src
>> > +101                can0_mio
>> > +102                can1_mio
>> > +
>> > +Example:
>> > +
>> > +clk: clk {
>> > +   #clock-cells = <1>;
>> > +   compatible = "xlnx,zynqmp-clk";
>>
>> How do you control the clocks?
>
> Clocks are controlled by a dedicated platform management controller. Above clock ids are used to identify clocks between master and PMU.

What is the interface to the "platform management controller"? Because
you have no registers, I'm guessing a firmware interface? If so, then
just define the firmware node as a clock provider.

Rob



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