| Message ID | 1431773333-23567-3-git-send-email-carlo@caione.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/16, Carlo Caione wrote: > From: Carlo Caione <carlo@endlessm.com> > > Add documentation for the clock controller. > > Signed-off-by: Carlo Caione <carlo@endlessm.com> > --- > .../bindings/clock/amlogic,meson8b-clkc.txt | 40 ++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > create mode 100644 Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt > > diff --git a/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt b/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt > new file mode 100644 > index 0000000..2b7b3fa > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt > @@ -0,0 +1,40 @@ > +* Amlogic Meson8b Clock and Reset Unit > + > +The Amlogic Meson8b clock controller generates and supplies clock to various > +controllers within the SoC. > + > +Required Properties: > + > +- compatible: should be "amlogic,meson8b-clkc" > +- reg: it must be composed by two tuples: > + 0) physical base address of the xtal register and length of memory > + mapped region. > + 1) physical base address of the clock controller and length of memory > + mapped region. > + > +- #clock-cells: should be 1. > + > +Each clock is assigned an identifier and client nodes can use this identifier > +to specify the clock which they consume. All available clocks are defined as > +preprocessor macros in the dt-bindings/clock/meson8b-clkc.h header and can be > +used in device tree sources. > + > +Example: Clock controller node: > + > + clkc: clock-controller@c1104000 { The address after the '@' should be the first reg property. > + #clock-cells = <1>; > + compatible = "amlogic,meson8b-clkc"; > + reg = <0xc1108000 0x4>, <0xc1104000 0x460>; And a reg property of length 0x4 looks like it may be part of some other "device". Should the xtal register be part of a syscon that this node has a phandle to?
On Thu, May 28, 2015 at 11:57 PM, Stephen Boyd <sboyd@codeaurora.org> wrote: >> + >> +Example: Clock controller node: >> + >> + clkc: clock-controller@c1104000 { > > The address after the '@' should be the first reg property. > >> + #clock-cells = <1>; >> + compatible = "amlogic,meson8b-clkc"; >> + reg = <0xc1108000 0x4>, <0xc1104000 0x460>; > > And a reg property of length 0x4 looks like it may be part of > some other "device". Should the xtal register be part of a syscon > that this node has a phandle to? Probably it does. But I don't have any documentation about this device. Also the registers mapped before and after this specific register in the same memory region seem to not be used at all by the code in the Amlogic SDK. So I guess I can safely map that specific register for XTAL.
diff --git a/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt b/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt new file mode 100644 index 0000000..2b7b3fa --- /dev/null +++ b/Documentation/devicetree/bindings/clock/amlogic,meson8b-clkc.txt @@ -0,0 +1,40 @@ +* Amlogic Meson8b Clock and Reset Unit + +The Amlogic Meson8b clock controller generates and supplies clock to various +controllers within the SoC. + +Required Properties: + +- compatible: should be "amlogic,meson8b-clkc" +- reg: it must be composed by two tuples: + 0) physical base address of the xtal register and length of memory + mapped region. + 1) physical base address of the clock controller and length of memory + mapped region. + +- #clock-cells: should be 1. + +Each clock is assigned an identifier and client nodes can use this identifier +to specify the clock which they consume. All available clocks are defined as +preprocessor macros in the dt-bindings/clock/meson8b-clkc.h header and can be +used in device tree sources. + +Example: Clock controller node: + + clkc: clock-controller@c1104000 { + #clock-cells = <1>; + compatible = "amlogic,meson8b-clkc"; + reg = <0xc1108000 0x4>, <0xc1104000 0x460>; + }; + + +Example: UART controller node that consumes the clock generated by the clock + controller: + + uart_AO: serial@c81004c0 { + compatible = "amlogic,meson-uart"; + reg = <0xc81004c0 0x14>; + interrupts = <0 90 1>; + clocks = <&clkc CLKID_CLK81>; + status = "disabled"; + };