- Clock Block on Freescale QorIQ Platforms
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
cores and peripheral IP blocks.
Please refer to the Reference Manual for details.
All references to “1.0” and “2.0” refer to the QorIQ chassis version to
which the chip complies.
Chassis Version Example Chips
1.0 p4080, p5020, p5040
2.0 t4240, b4860
- Clock Block Binding
Required properties:
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,
-clockgen”, such as: - “fsl,p2041-clockgen”
- “fsl,p3041-clockgen”
- “fsl,p4080-clockgen”
- “fsl,p5020-clockgen”
- “fsl,p5040-clockgen”
- “fsl,t4240-clockgen”
- “fsl,b4420-clockgen”
- “fsl,b4860-clockgen”
- “fsl,ls1012a-clockgen”
- “fsl,ls1021a-clockgen”
- “fsl,ls1043a-clockgen”
- “fsl,ls1046a-clockgen”
- “fsl,ls1088a-clockgen”
- “fsl,ls2080a-clockgen”
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
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
physical base addresses. Must be present if the device has
sub-nodes and set to 1 if present - #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.
A second input clock, called “coreclk”, may be provided if
core PLLs are based on a different input clock from the
platform PLL. - clock-names: Required if a coreclk is present. Valid names are
“sysclk” and “coreclk”.
- 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
4=pll/5, 5=pll/6, 6=pll/7, 7=pll/8
5 coreclk must be 0
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>; ...};
}Legacy Child Nodes
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
Required properties:
- compatible : Should include one of the following:
- “fsl,qoriq-core-pll-1.0” for core PLL clocks (v1.0)
- “fsl,qoriq-core-pll-2.0” for core PLL clocks (v2.0)
- “fsl,qoriq-core-mux-1.0” for core mux clocks (v1.0)
- “fsl,qoriq-core-mux-2.0” for core mux clocks (v2.0)
- “fsl,qoriq-sysclk-1.0”: for input system clock (v1.0).
It takes parent’s clock-frequency as its clock. - “fsl,qoriq-sysclk-2.0”: for input system clock (v2.0).
It takes parent’s clock-frequency as its clock. - “fsl,qoriq-platform-pll-1.0” for the platform PLL clock (v1.0)
- “fsl,qoriq-platform-pll-2.0” for the platform PLL clock (v2.0)
- #clock-cells: From common clock binding. The number of cells in a
clock-specifier. Should be <0> for “fsl,qoriq-sysclk-[1,2].0”
clocks, or <1> for “fsl,qoriq-core-pll-[1,2].0” clocks.
For “fsl,qoriq-core-pll-[1,2].0” clocks, the single
clock-specifier cell may take the following values:- 0 - equal to the PLL frequency
- 1 - equal to the PLL frequency divided by 2
- 2 - equal to the PLL frequency divided by 4
Recommended properties:
- clocks: Should be the phandle of input parent clock
- clock-names: From common clock binding, indicates the clock name
- clock-output-names: From common clock binding, indicates the names of
output clocks - reg: Should be the offset and length of clock block base address.
The length should be 4.
Legacy Example:
/ {
clockgen: global-utilities@e1000 {
compatible = “fsl,p5020-clockgen”, “fsl,qoriq-clockgen-1.0”;
ranges = <0x0 0xe1000 0x1000>;
clock-frequency = <133333333>;
reg = <0xe1000 0x1000>;
#address-cells = <1>;
#size-cells = <1>;
sysclk: sysclk {
#clock-cells = <0>;
compatible = "fsl,qoriq-sysclk-1.0";
clock-output-names = "sysclk";
};
pll0: pll0@800 {
#clock-cells = <1>;
reg = <0x800 0x4>;
compatible = "fsl,qoriq-core-pll-1.0";
clocks = <&sysclk>;
clock-output-names = "pll0", "pll0-div2";
};
pll1: pll1@820 {
#clock-cells = <1>;
reg = <0x820 0x4>;
compatible = "fsl,qoriq-core-pll-1.0";
clocks = <&sysclk>;
clock-output-names = "pll1", "pll1-div2";
};
mux0: mux0@0 {
#clock-cells = <0>;
reg = <0x0 0x4>;
compatible = "fsl,qoriq-core-mux-1.0";
clocks = <&pll0 0>, <&pll0 1>, <&pll1 0>, <&pll1 1>;
clock-names = "pll0", "pll0-div2", "pll1", "pll1-div2";
clock-output-names = "cmux0";
};
mux1: mux1@20 {
#clock-cells = <0>;
reg = <0x20 0x4>;
compatible = "fsl,qoriq-core-mux-1.0";
clocks = <&pll0 0>, <&pll0 1>, <&pll1 0>, <&pll1 1>;
clock-names = "pll0", "pll0-div2", "pll1", "pll1-div2";
clock-output-names = "cmux1";
};
platform-pll: platform-pll@c00 {
#clock-cells = <1>;
reg = <0xc00 0x4>;
compatible = "fsl,qoriq-platform-pll-1.0";
clocks = <&sysclk>;
clock-output-names = "platform-pll", "platform-pll-div2";
};
};
};
Example for legacy clock consumer:
/ {
cpu0: PowerPC,e5500@0 {
…
clocks = <&mux0>;
…
};
};
