Re: [PATCH 2/8] clk: berlin: add clock binding docs for Marvell Berlin2 SoCs
From: Sebastian Hesselbarth
Date: Tue May 13 2014 - 04:39:21 EST
On 05/11/2014 10:24 PM, Sebastian Hesselbarth wrote:
This adds mandatory device tree binding documentation for the clock related
IP found on Marvell Berlin2 (BG2, BG2CD, and BG2Q) SoCs.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
---
Cc: Mike Turquette <mturquette@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Pawel Moll <pawel.moll@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Cc: Antoine Tenart <antoine.tenart@xxxxxxxxxxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
.../devicetree/bindings/clock/berlin2-clock.txt | 169 +++++++++++++++++++++
1 file changed, 169 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/berlin2-clock.txt
diff --git a/Documentation/devicetree/bindings/clock/berlin2-clock.txt b/Documentation/devicetree/bindings/clock/berlin2-clock.txt
new file mode 100644
index 000000000000..3da87a488402
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/berlin2-clock.txt
@@ -0,0 +1,169 @@
+* Marvell Berlin2 clock bindings
+
+Marvell Berlin2 (BG2, BG2CD, BG2Q) share the same IP for PLLs and clocks,
+with some minor differences in features and register layout. The below
+describes the individual clock related IP:
+
+* Audio/Video PLL
+
+The Audio/Video PLL (AVPLL) is a dual-VCO PLL with 8 channels each. Each
+of the VCOs can sythesize a single VCO frequency based on a single input
+reference clock. Each of the 8 channels then, can derive an output clock
+from that VCO frequency by various dividers/multipliers.
+
+Required properties:
+- compatible: shall be "marvell,berlin2-avpll"
+- reg: address and length of the corresponding AVPLL registers
+- #clock-cells: shall be set to 2
+- clocks: single clock specifier referencing the AVPLL input clock
+
+To ease match-up with the desired AVPLL output clock, clock specifiers
+referencing AVPLL clocks shall contain two cells. The first refers to
+the VCO (0=AVPLL_A, 1=AVPLL_B) while the second refers to the corresponding
+channel starting with 1. For example, to reference AVPLL_B3 the clock
+specifier shall be: <&avpll 1 3>.
+
+Example:
+
+avpll: pll@ea0040 {
+ compatible = "marvell,berlin2-avpll";
+ #clock-cells = <2>;
+ reg = <0xea0050 0x100>;
+ clocks = <&refclk>;
+};
+
+* Simple PLLs
+
+Simple PLLs are memory mapped PLLs that can sythesize a single output clock
+based on a single input reference clock.
+
+Required properties:
+- compatible: shall be one of the following:
+ "marvell,berlin2-pll" for Berlin BG2/BG2CD PLLs
+ "marvell,berlin2q-pll" for Berlin BG2Q PLLs
+- reg: address and length of the corresponding PLL registers
+- #clock-cells: shall be set to 0
+- clocks: single clock specifier referencing the PLL input clock
+
+Example:
+
+cpupll: pll@ea003c {
+ compatible = "marvell,berlin2-pll";
+ #clock-cells = <0>;
+ reg = <0xea003c 0x14>;
+ clocks = <&refclk>;
+};
+
+* Single-register clock dividers
+
+Single-register clock dividers are complex divider cells, allowing
+to divide a reference clock with a set of fixed dividers. Also they
+comprise and input clock mux with bypass and an ouput clock gate.
+
+Required properties:
+- compatible: shall be "marvell,berlin2-clk-div"
+- reg: address and length of the corresponding DIV registers
+- #clock-cells: shall be set to 0
+- clocks: clock specifiers referencing the DIV input clocks
+- clock-names: array of strings describing the clock specifiers above.
+ Allowed clock-names are "mux_bypass" for the clock mux bypass selection
+ and "muxN" (N=0..7) for each of the 8 possible clock mux inputs.
+
+Example:
+
+gfx3dcore_clk: clock@ea022c {
+ compatible = "marvell,berlin2-clk-div";
Actually using the clock driver for SDHCI IP revealed some issues
already. Above compatible should have been "marvell,berlin2-div".
I'll fix it up for v2.
Also, the commit msg should start with 'dt-binding: clk:' I guess.
Sebastian
+ #clock-cells = <0>;
+ reg = <0xea0022c 0x4>;
+ clocks = <&syspll>,
+ <&avpll AVPLL_B 4>, <&avpll AVPLL_B 5>,
+ <&avpll AVPLL_B 6>, <&avpll AVPLL_B 7>;
+ clock-names = "mux_bypass",
+ "mux0", "mux1", "mux2", "mux3";
+};
+
+* SoC-specific core clocks
+
+In addition to the above, there is a register set dealing with SoC
+specific clock dividers, muxes, and gates. There is also the complex
+divider cell used above, but instead of independent registers, they
+share a common set of registers. The core clocks are represented by
+a single DT node providing access to the remaining clocks.
+
+Required properties:
+- compatible: shall be one of
+ "marvell,berlin2-core-clocks" for BG2/BG2CD SoCs
+ "marvell,berlin2q-core-clocks" for BG2Q SoCs
+- reg: address and length of the corresponding clock registers
+- #clock-cells: shall be set to 1
+- clocks: clock specifiers referencing the core clock input clocks
+- clock-names: array of strings describing the clock specifiers above.
+ Allowed clock-names for the reference clocks are
+ "refclk", "syspll", "mempll", "cpupll"
+ also Audio/Video PLL clocks shall be named with
+ "avpll_VN" (V=0...1 for AVPLL_A and AVPLL_B, N=1..8 for the
+ corresponding reference input from AVPLL).
+
+Optional properties for BG2/BG2CD SoCs:
+- clocks/clock-names: in addition to the allowed clock names above,
+ there is an external video clock input that shall be named "video_ext0".
+
+Clocks provided by core clocks shall be referenced by a clock specifier
+indexing one of the provided clocks. A SoC-specific list of available clocks
+is below the example.
+
+Example:
+coreclk: clock@ea0150 {
+ compatible = "marvell,berlin2-core-clocks";
+ #clock-cells = <1>;
+ reg = <0xea0150 0x1c>;
+ clocks = <&refclk>, <&syspll>, <&mempll>, <&cpupll>,
+ <&avpll 0 1>, <&avpll 0 2>,
+ <&avpll 0 3>, <&avpll 0 4>,
+ <&avpll 0 5>, <&avpll 0 6>,
+ <&avpll 0 7>, <&avpll 0 8>,
+ <&avpll 1 1>, <&avpll 1 2>,
+ <&avpll 1 3>, <&avpll 1 4>,
+ <&avpll 1 5>, <&avpll 1 6>,
+ <&avpll 1 7>, <&avpll 1 8>,
+ <&externalvideoclk>;
+ clock-names = "refclk", "syspll", "mempll", "cpupll",
+ "avpll_a1", "avpll_a2", "avpll_a3", "avpll_a4",
+ "avpll_a5", "avpll_a6", "avpll_a7", "avpll_a8",
+ "avpll_b1", "avpll_b2", "avpll_b3", "avpll_b4",
+ "avpll_b5", "avpll_b6", "avpll_b7", "avpll_b8",
+ "video_ext0";
+};
+
+* BG2/BG2CD core clock indicies:
+0 - SYS
+1 - CPU
+2 - DRMFIGO
+3 - CFG
+4 - GFX
+5 - ZSP
+6 - PERIF
+7 - PCUBE
+8 - VSCOPE
+9 - NFC_ECC
+10 - VPP
+11 - APP
+12 - AUDIO0
+23 - AUDIO2
+14 - AUDIO3
+15 - AUDIO1
+16 - GETH0
+17 - GETH1
+18 - SATA
+19 - AHBAPB
+20 - USB0
+21 - USB1
+22 - PBRIDGE
+23 - SDIO0
+24 - SDIO1
+25 - NFC
+26 - SMEMC
+27 - AUDIOHD
+28 - VIDEO0
+29 - VIDEO1
+30 - VIDEO2
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