Re: [PATCHv9 08/43] clk: ti: add composite clock support
From: Nishanth Menon <nm@ti.com>
Date: 2013-10-31 16:32:30
Also in:
linux-arm-kernel, linux-omap
On 10/31/2013 11:27 AM, Nishanth Menon wrote:
On 10/25/2013 10:57 AM, Tero Kristo wrote:quoted
This is a multipurpose clock node, which contains support for multiple sub-clocks. Uses basic composite clock type to implement the actual functionality, and TI specific gate, mux and divider clocks. Signed-off-by: Tero Kristo <redacted> --- .../devicetree/bindings/clock/ti/composite.txt | 54 +++++ drivers/clk/ti/Makefile | 2 +- drivers/clk/ti/composite.c | 222 ++++++++++++++++++++ include/linux/clk/ti.h | 8 + 4 files changed, 285 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/clock/ti/composite.txt create mode 100644 drivers/clk/ti/composite.cdiff --git a/Documentation/devicetree/bindings/clock/ti/composite.txt b/Documentation/devicetree/bindings/clock/ti/composite.txt new file mode 100644 index 0000000..5f43c47 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/ti/composite.txt@@ -0,0 +1,54 @@ +Binding for TI composite clock. + +Binding status: Unstable - ABI compatibility may be broken in the future + +This binding uses the common clock binding[1]. It assumes a +register-mapped composite clock with multiple different sub-types; + +a multiplexer clock with multiple input clock signals or parents, one +of which can be selected as output, this behaves exactly as [2] + +an adjustable clock rate divider, this behaves exactly as [3] + +a gating function which can be used to enable and disable the output +clock, this behaves exactly as [4] + +The binding must provide a list of the component clocks that shall be +merged to this clock. The component clocks shall be of one of the +"ti,*composite*-clock" types. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt +[2] Documentation/devicetree/bindings/clock/ti/mux.txt +[3] Documentation/devicetree/bindings/clock/ti/divider.txt +[4] Documentation/devicetree/bindings/clock/ti/gate.txt + +Required properties: +- compatible : shall be: "ti,composite-clock" +- clocks : link phandles of component clocks +- #clock-cells : from common clock binding; shall be set to 0. + +Examples: + +usb_l4_gate_ick: usb_l4_gate_ick { + #clock-cells = <0>; + compatible = "ti,composite-interface-clock"; + clocks = <&l4_ick>; + ti,bit-shift = <5>; + reg = <0x0a10>; +}; + +usb_l4_div_ick: usb_l4_div_ick { + #clock-cells = <0>; + compatible = "ti,composite-divider-clock"; + clocks = <&l4_ick>; + ti,bit-shift = <4>; + ti,max-div = <1>; + reg = <0x0a40>; + ti,index-starts-at-one; +}; + +usb_l4_ick: usb_l4_ick { + #clock-cells = <0>; + compatible = "ti,composite-clock"; + clocks = <&usb_l4_gate_ick>, <&usb_l4_div_ick>; +};
From Topology perspective, would this be a better approach?
usb_l4_ick: usb_l4_ick {
#clock-cells = <0>;
compatible = "ti,composite-clock";
usb_l4_gate_ick: usb_l4_gate_ick {
#clock-cells = <0>;
compatible = "ti,composite-interface-clock";
clocks = <&l4_ick>;
ti,bit-shift = <5>;
reg = <0x0a10>;
};
usb_l4_div_ick: usb_l4_div_ick {
#clock-cells = <0>;
compatible = "ti,composite-divider-clock";
clocks = <&l4_ick>;
ti,bit-shift = <4>;
ti,max-div = <1>;
reg = <0x0a40>;
ti,index-starts-at-one;
};
};
--
Regards,
Nishanth Menon