Subject: [PATCHv9 08/43] clk: ti: add composite clock support

From: [email-masked] (Nishanth Menon)
Date: Thu, 31 Oct 2013 11:32:30 -0500

On 10/31/2013 11:27 AM, Nishanth Menon wrote:
> On 10/25/2013 10:57 AM, Tero Kristo wrote:
>> 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 <[email-masked]>
>> ---
>>  .../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.c
>>
>> diff --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