dt-bindings: clock: Add bindings for ZynqMP clock driver

Add documentation to describe Xilinx ZynqMP clock driver
bindings.

Signed-off-by: Rajan Vaja <[e-mail]>
Signed-off-by: Jolly Shah <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Reviewed-by: Stephen Boyd <[e-mail]>
Signed-off-by: Michal Simek <[e-mail]>

Documentation/devicetree/bindings/firmware/xilinx/xlnx,zynqmp-firmware.txt

···
 		  - "smc" : SMC #0, following the SMCCC
 		  - "hvc" : HVC #0, following the SMCCC
 
+--------------------------------------------------------------------------
+Device Tree Clock bindings for the Zynq Ultrascale+ MPSoC controlled using
+Zynq MPSoC firmware interface
+--------------------------------------------------------------------------
+The clock controller is a h/w block of Zynq Ultrascale+ MPSoC clock
+tree. It reads required input clock frequencies from the devicetree and acts
+as clock provider for all clock consumers of PS clocks.
+
+See clock_bindings.txt for more information on the generic clock bindings.
+
+Required properties:
+ - #clock-cells:	Must be 1
+ - compatible:		Must contain:	"xlnx,zynqmp-clk"
+ - clocks:		List of clock specifiers which are external input
+			clocks to the given clock controller. Please refer
+			the next section to find the input clocks for a
+			given controller.
+ - clock-names:		List of clock names which are exteral input clocks
+			to the given clock controller. Please refer to the
+			clock bindings for more details.
+
+Input clocks for zynqmp Ultrascale+ clock controller:
+
+The Zynq UltraScale+ MPSoC has one primary and four alternative reference clock
+inputs. These required clock inputs are:
+ - pss_ref_clk (PS reference clock)
+ - video_clk (reference clock for video system )
+ - pss_alt_ref_clk (alternative PS reference clock)
+ - aux_ref_clk
+ - gt_crx_ref_clk (transceiver reference clock)
+
+The following strings are optional parameters to the 'clock-names' property in
+order to provide an optional (E)MIO clock source:
+ - swdt0_ext_clk
+ - swdt1_ext_clk
+ - gem0_emio_clk
+ - gem1_emio_clk
+ - gem2_emio_clk
+ - gem3_emio_clk
+ - mio_clk_XX		# with XX = 00..77
+ - mio_clk_50_or_51	#for the mux clock to gem tsu from 50 or 51
+
+
+Output clocks are registered based on clock information received
+from firmware. Output clocks indexes are mentioned in
+include/dt-bindings/clock/xlnx,zynqmp-clk.h.
+
 -------
 Example
 -------
···
 	zynqmp_firmware: zynqmp-firmware {
 		compatible = "xlnx,zynqmp-firmware";
 		method = "smc";
+		zynqmp_clk: clock-controller {
+			#clock-cells = <1>;
+			compatible = "xlnx,zynqmp-clk";
+			clocks = <&pss_ref_clk>, <&video_clk>, <&pss_alt_ref_clk>, <&aux_ref_clk>, <&gt_crx_ref_clk>;
+			clock-names = "pss_ref_clk", "video_clk", "pss_alt_ref_clk","aux_ref_clk", "gt_crx_ref_clk";
+		};
 	};
 };

include/dt-bindings/clock/xlnx,zynqmp-clk.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Xilinx Zynq MPSoC Firmware layer
+ *
+ *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *
+ */
+
+#ifndef _DT_BINDINGS_CLK_ZYNQMP_H
+#define _DT_BINDINGS_CLK_ZYNQMP_H
+
+#define IOPLL			0
+#define RPLL			1
+#define APLL			2
+#define DPLL			3
+#define VPLL			4
+#define IOPLL_TO_FPD		5
+#define RPLL_TO_FPD		6
+#define APLL_TO_LPD		7
+#define DPLL_TO_LPD		8
+#define VPLL_TO_LPD		9
+#define ACPU			10
+#define ACPU_HALF		11
+#define DBF_FPD			12
+#define DBF_LPD			13
+#define DBG_TRACE		14
+#define DBG_TSTMP		15
+#define DP_VIDEO_REF		16
+#define DP_AUDIO_REF		17
+#define DP_STC_REF		18
+#define GDMA_REF		19
+#define DPDMA_REF		20
+#define DDR_REF			21
+#define SATA_REF		22
+#define PCIE_REF		23
+#define GPU_REF			24
+#define GPU_PP0_REF		25
+#define GPU_PP1_REF		26
+#define TOPSW_MAIN		27
+#define TOPSW_LSBUS		28
+#define GTGREF0_REF		29
+#define LPD_SWITCH		30
+#define LPD_LSBUS		31
+#define USB0_BUS_REF		32
+#define USB1_BUS_REF		33
+#define USB3_DUAL_REF		34
+#define USB0			35
+#define USB1			36
+#define CPU_R5			37
+#define CPU_R5_CORE		38
+#define CSU_SPB			39
+#define CSU_PLL			40
+#define PCAP			41
+#define IOU_SWITCH		42
+#define GEM_TSU_REF		43
+#define GEM_TSU			44
+#define GEM0_REF		45
+#define GEM1_REF		46
+#define GEM2_REF		47
+#define GEM3_REF		48
+#define GEM0_TX			49
+#define GEM1_TX			50
+#define GEM2_TX			51
+#define GEM3_TX			52
+#define QSPI_REF		53
+#define SDIO0_REF		54
+#define SDIO1_REF		55
+#define UART0_REF		56
+#define UART1_REF		57
+#define SPI0_REF		58
+#define SPI1_REF		59
+#define NAND_REF		60
+#define I2C0_REF		61
+#define I2C1_REF		62
+#define CAN0_REF		63
+#define CAN1_REF		64
+#define CAN0			65
+#define CAN1			66
+#define DLL_REF			67
+#define ADMA_REF		68
+#define TIMESTAMP_REF		69
+#define AMS_REF			70
+#define PL0_REF			71
+#define PL1_REF			72
+#define PL2_REF			73
+#define PL3_REF			74
+#define WDT			75
+#define IOPLL_INT		76
+#define IOPLL_PRE_SRC		77
+#define IOPLL_HALF		78
+#define IOPLL_INT_MUX		79
+#define IOPLL_POST_SRC		80
+#define RPLL_INT		81
+#define RPLL_PRE_SRC		82
+#define RPLL_HALF		83
+#define RPLL_INT_MUX		84
+#define RPLL_POST_SRC		85
+#define APLL_INT		86
+#define APLL_PRE_SRC		87
+#define APLL_HALF		88
+#define APLL_INT_MUX		89
+#define APLL_POST_SRC		90
+#define DPLL_INT		91
+#define DPLL_PRE_SRC		92
+#define DPLL_HALF		93
+#define DPLL_INT_MUX		94
+#define DPLL_POST_SRC		95
+#define VPLL_INT		96
+#define VPLL_PRE_SRC		97
+#define VPLL_HALF		98
+#define VPLL_INT_MUX		99
+#define VPLL_POST_SRC		100
+#define CAN0_MIO		101
+#define CAN1_MIO		102
+
+#endif