diff options
author | Tero Kristo <t-kristo@ti.com> | 2013-09-13 13:02:15 +0400 |
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committer | Mike Turquette <mturquette@linaro.org> | 2014-01-18 00:35:04 +0400 |
commit | b4761198bfaf29649dc58a48e8b123ea4174ba95 (patch) | |
tree | 7c350ec98d991e2e6035a6e0098002d28ea3223c /Documentation/devicetree/bindings/clock/ti | |
parent | 975e15487d5abfd5f33fea9c1ba0b987604f0d0f (diff) | |
download | linux-b4761198bfaf29649dc58a48e8b123ea4174ba95.tar.xz |
CLK: ti: add support for ti divider-clock
This patch adds support for TI divider clock binding, which simply uses
the basic clock divider to provide the features needed.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Diffstat (limited to 'Documentation/devicetree/bindings/clock/ti')
-rw-r--r-- | Documentation/devicetree/bindings/clock/ti/divider.txt | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/clock/ti/divider.txt b/Documentation/devicetree/bindings/clock/ti/divider.txt new file mode 100644 index 000000000000..35a6f5c7e5c2 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/ti/divider.txt @@ -0,0 +1,114 @@ +Binding for TI divider 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 adjustable clock rate divider that does not gate and has +only one input clock or parent. By default the value programmed into +the register is one less than the actual divisor value. E.g: + +register value actual divisor value +0 1 +1 2 +2 3 + +This assumption may be modified by the following optional properties: + +ti,index-starts-at-one - valid divisor values start at 1, not the default +of 0. E.g: +register value actual divisor value +1 1 +2 2 +3 3 + +ti,index-power-of-two - valid divisor values are powers of two. E.g: +register value actual divisor value +0 1 +1 2 +2 4 + +Additionally an array of valid dividers may be supplied like so: + + ti,dividers = <4>, <8>, <0>, <16>; + +Which will map the resulting values to a divisor table by their index: +register value actual divisor value +0 4 +1 8 +2 <invalid divisor, skipped> +3 16 + +Any zero value in this array means the corresponding bit-value is invalid +and must not be used. + +The binding must also provide the register to control the divider and +unless the divider array is provided, min and max dividers. Optionally +the number of bits to shift that mask, if necessary. If the shift value +is missing it is the same as supplying a zero shift. + +This binding can also optionally provide support to the hardware autoidle +feature, see [2]. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt +[2] Documentation/devicetree/bindings/clock/ti/autoidle.txt + +Required properties: +- compatible : shall be "ti,divider-clock" or "ti,composite-divider-clock". +- #clock-cells : from common clock binding; shall be set to 0. +- clocks : link to phandle of parent clock +- reg : offset for register controlling adjustable divider + +Optional properties: +- clock-output-names : from common clock binding. +- ti,dividers : array of integers defining divisors +- ti,bit-shift : number of bits to shift the divider value, defaults to 0 +- ti,min-div : min divisor for dividing the input clock rate, only + needed if the first divisor is offset from the default value (1) +- ti,max-div : max divisor for dividing the input clock rate, only needed + if ti,dividers is not defined. +- ti,index-starts-at-one : valid divisor programming starts at 1, not zero, + only valid if ti,dividers is not defined. +- ti,index-power-of-two : valid divisor programming must be a power of two, + only valid if ti,dividers is not defined. +- ti,autoidle-shift : bit shift of the autoidle enable bit for the clock, + see [2] +- ti,invert-autoidle-bit : autoidle is enabled by setting the bit to 0, + see [2] +- ti,set-rate-parent : clk_set_rate is propagated to parent + +Examples: +dpll_usb_m2_ck: dpll_usb_m2_ck@4a008190 { + #clock-cells = <0>; + compatible = "ti,divider-clock"; + clocks = <&dpll_usb_ck>; + ti,max-div = <127>; + reg = <0x190>; + ti,index-starts-at-one; +}; + +aess_fclk: aess_fclk@4a004528 { + #clock-cells = <0>; + compatible = "ti,divider-clock"; + clocks = <&abe_clk>; + ti,bit-shift = <24>; + reg = <0x528>; + ti,max-div = <2>; +}; + +dpll_core_m3x2_div_ck: dpll_core_m3x2_div_ck { + #clock-cells = <0>; + compatible = "ti,composite-divider-clock"; + clocks = <&dpll_core_x2_ck>; + ti,max-div = <31>; + reg = <0x0134>; + ti,index-starts-at-one; +}; + +ssi_ssr_div_fck_3430es2: ssi_ssr_div_fck_3430es2 { + #clock-cells = <0>; + compatible = "ti,composite-divider-clock"; + clocks = <&corex2_fck>; + ti,bit-shift = <8>; + reg = <0x0a40>; + ti,dividers = <0>, <1>, <2>, <3>, <4>, <0>, <6>, <0>, <8>; +}; |