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Diffstat (limited to 'Documentation/devicetree/bindings/clock/qoriq-clock.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/clock/qoriq-clock.txt | 61 |
1 files changed, 50 insertions, 11 deletions
diff --git a/Documentation/devicetree/bindings/clock/qoriq-clock.txt b/Documentation/devicetree/bindings/clock/qoriq-clock.txt index df4a259a6898..16a3ec433119 100644 --- a/Documentation/devicetree/bindings/clock/qoriq-clock.txt +++ b/Documentation/devicetree/bindings/clock/qoriq-clock.txt @@ -1,6 +1,6 @@ * Clock Block on Freescale QorIQ Platforms -Freescale qoriq chips take primary clocking input from the external +Freescale QorIQ chips take primary clocking input from the external SYSCLK signal. The SYSCLK input (frequency) is multiplied using multiple phase locked loops (PLL) to create a variety of frequencies which can then be passed to a variety of internal logic, including @@ -13,14 +13,16 @@ which the chip complies. Chassis Version Example Chips --------------- ------------- 1.0 p4080, p5020, p5040 -2.0 t4240, b4860, t1040 +2.0 t4240, b4860 1. Clock Block Binding Required properties: -- compatible: Should contain a specific clock block compatible string - and a single chassis clock compatible string. - Clock block strings include, but not limited to, one of the: +- compatible: Should contain a chip-specific clock block compatible + string and (if applicable) may contain a chassis-version clock + compatible string. + + Chip-specific strings are of the form "fsl,<chip>-clockgen", such as: * "fsl,p2041-clockgen" * "fsl,p3041-clockgen" * "fsl,p4080-clockgen" @@ -30,15 +32,14 @@ Required properties: * "fsl,b4420-clockgen" * "fsl,b4860-clockgen" * "fsl,ls1021a-clockgen" - Chassis clock strings include: + Chassis-version clock strings include: * "fsl,qoriq-clockgen-1.0": for chassis 1.0 clocks * "fsl,qoriq-clockgen-2.0": for chassis 2.0 clocks - reg: Describes the address of the device's resources within the address space defined by its parent bus, and resource zero represents the clock register set -- clock-frequency: Input system clock frequency -Recommended properties: +Optional properties: - ranges: Allows valid translation between child's address space and parent's. Must be present if the device has sub-nodes. - #address-cells: Specifies the number of cells used to represent @@ -47,8 +48,46 @@ Recommended properties: - #size-cells: Specifies the number of cells used to represent the size of an address. Must be present if the device has sub-nodes and set to 1 if present +- clock-frequency: Input system clock frequency (SYSCLK) +- clocks: If clock-frequency is not specified, sysclk may be provided + as an input clock. Either clock-frequency or clocks must be + provided. + +2. Clock Provider + +The clockgen node should act as a clock provider, though in older device +trees the children of the clockgen node are the clock providers. + +When the clockgen node is a clock provider, #clock-cells = <2>. +The first cell of the clock specifier is the clock type, and the +second cell is the clock index for the specified type. + + Type# Name Index Cell + 0 sysclk must be 0 + 1 cmux index (n in CLKCnCSR) + 2 hwaccel index (n in CLKCGnHWACSR) + 3 fman 0 for fm1, 1 for fm2 + 4 platform pll 0=pll, 1=pll/2, 2=pll/3, 3=pll/4 + +3. Example + + clockgen: global-utilities@e1000 { + compatible = "fsl,p5020-clockgen", "fsl,qoriq-clockgen-1.0"; + clock-frequency = <133333333>; + reg = <0xe1000 0x1000>; + #clock-cells = <2>; + }; + + fman@400000 { + ... + clocks = <&clockgen 3 0>; + ... + }; +} +4. Legacy Child Nodes -2. Clock Provider/Consumer Binding +NOTE: These nodes are deprecated. Kernels should continue to support +device trees with these nodes, but new device trees should not use them. Most of the bindings are from the common clock binding[1]. [1] Documentation/devicetree/bindings/clock/clock-bindings.txt @@ -82,7 +121,7 @@ Recommended properties: - reg: Should be the offset and length of clock block base address. The length should be 4. -Example for clock block and clock provider: +Legacy Example: / { clockgen: global-utilities@e1000 { compatible = "fsl,p5020-clockgen", "fsl,qoriq-clockgen-1.0"; @@ -142,7 +181,7 @@ Example for clock block and clock provider: }; }; -Example for clock consumer: +Example for legacy clock consumer: / { cpu0: PowerPC,e5500@0 { |