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This version (08 Apr 2022 15:17) was approved by Antoniu Miclaus.The Previously approved version (18 Mar 2021 16:52) is available.Diff

Table of Contents

ADI JESD204B/C Receive Peripheral Linux Driver

Supported Devices

Description

The AXI JESD204B RX peripheral driver is a simple driver that supports the ADI JESD204B Receive Peripheral. The driver reads JESD204B link configuration data from the devicetree and configures the peripheral accordingly. After configuration has completed the JESD204B link is enabled. Link state can be monitored through sysfs files.

This driver also work in conjunction with the JESD204 (FSM) Interface Linux Kernel Framework, in this case JESD204B link configuration is provided by the JESD204-FSM framework.

Source Code

Status

Source Mainlined?
drivers/iio/jesd204/axi_jesd204_rx.c No

Files

Function File
driver drivers/iio/jesd204/axi_jesd204_rx.c

Example platform device / device tree initialization

The AXI JESD204B driver is a platform driver and can currently only be instantiated via device tree.

Deprecated Non-jesd204-fsm mode

Required devicetree properties:

  • compatible: Must always be “adi,axi-jesd204-rx-1.00.a”
  • reg: Base address and register area size. This parameter expects a register range.
  • interrupts: Property with a value describing the interrupt number.
  • clock-names: List of input clock names - “s_axi_aclk”, “device_clk”
  • clocks: Clock phandles and specifiers (See clock bindings for details on clock-names and clocks).
  • adi,frames-per-multiframe: Number of frames per multi-frame (K)
  • adi,octets-per-frame: Number of octets per frame (F)

Optional devicetree properties:

  • adi,high-density: If specified the JESD204B link is configured for high density (HD) operation.
  • adi,subclass: The JESD204B subclass.

Example: 

		jesd204b-rx@77b00000 {
			compatible = "adi,axi-jesd204-rx-1.00.a";
			reg = <0x77b00000 0x10000>;
			interrupts = <0 56 4>;

			clock-names = "s_axi_aclk", "device_clk";
			clocks = <&clkc 14>, <&ad9528 13>;

			adi,octets-per-frame = <32>;
			adi,frames-per-multiframe = <4>;
		};

jesd204-fsm mode

When using the JESD204 (FSM) Interface Linux Kernel Framework the JESD link parameters are broadcasted by the framework to all link components.

Required devicetree properties:

  • compatible: Must always be “adi,axi-jesd204-rx-1.00.a”
  • reg: Base address and register area size. This parameter expects a register range.
  • interrupts: Property with a value describing the interrupt number.
  • clock-names: List of input clock names - “s_axi_aclk”, “device_clk”, “lane_clk”
  • clocks: Clock phandles and specifiers (See clock bindings for details on clock-names and clocks).
  • jesd204-device: Adds device to the jesd204-fsm kernel framework
  • jesd204-inputs: jesd204-fsm devices phandles and specifiers (used to build the link topology)

Optional devicetree clock-names:

  • link_clk: When using the link layer gearbox in order to support NP=12 modes, device_clk and link_clock need to be different. This is typical the case in case SYNTH_DATA_PATH_WIDTH and TPL_DATA_PATH_WIDTH differs. Then device_clk becomes link_clk times SYNTH_DATA_PATH_WIDTH / TPL_DATA_PATH_WIDTH. link_clk still needs to be lane_clk / 40 for JESD204B/8B10B encoding and lane_clk / 66 for JESD204C/64B66B encoding.
  • conv2: Optional SERDES (CPLL/QPLL) REFCLK from a difference source which rate and state must be in sync with the main conv clk.

Example: 

		axi_ad9081_rx_jesd: axi-jesd204-rx@84a90000 {
			compatible = "adi,axi-jesd204-rx-1.0";
			reg = <0x84a90000 0x1000>;

			interrupts = <0 107 IRQ_TYPE_LEVEL_HIGH>;

			clocks = <&zynqmp_clk 71>, <&hmc7044 10>, <&axi_ad9081_adxcvr_rx 0>;
			clock-names = "s_axi_aclk", "device_clk", "lane_clk";

			jesd204-device;
			#jesd204-cells = <2>;
			jesd204-inputs = <&axi_ad9081_adxcvr_rx 0 FRAMER_LINK0_RX>;
		};

Enabling Linux driver support

Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”) 

Linux Kernel Configuration
	Device Drivers  --->
	<*>     Industrial I/O support --->
	    --- Industrial I/O support
	    -*-   Enable ring buffer support within IIO
	    -*-     Industrial I/O lock free software ring
	    -*-   Enable triggered sampling support

            <*>   JESD204 High-Speed Serial Interface Support  --->
	        [--snip--]
		<*>   Analog Devices AXI JESD204B RX Support
	        [--snip--]

Sysfs Interface

This driver provides advanced diagnostics, status and via sysfs. A brief summary is with examples are provided below.

This specifies any shell prompt running on the target 

root@analog:/sys/bus/platform/devices/84a90000.axi-jesd204-rx# ls -al
total 0
drwxr-xr-x  4 root root    0 Feb  6 13:41 .
drwxr-xr-x 12 root root    0 Feb  6 13:41 ..
lrwxrwxrwx  1 root root    0 Feb  6 13:41 driver -> ../../../../bus/platform/drivers/axi-jesd204-rx
-rw-r--r--  1 root root 4096 Feb  6 16:27 driver_override
-r--r--r--  1 root root 4096 Feb  6 16:27 encoder
drwxr-xr-x  3 root root    0 Feb  6 13:41 jesd204:4
-r--------  1 root root 4096 Feb  6 16:27 lane0_info
-r--------  1 root root 4096 Feb  6 16:27 lane1_info
-r--------  1 root root 4096 Feb  6 16:27 lane2_info
-r--------  1 root root 4096 Feb  6 16:27 lane3_info
-r--------  1 root root 4096 Feb  6 16:27 lane4_info
-r--------  1 root root 4096 Feb  6 16:27 lane5_info
-r--------  1 root root 4096 Feb  6 16:27 lane6_info
-r--------  1 root root 4096 Feb  6 16:27 lane7_info
-r--r--r--  1 root root 4096 Feb  6 16:27 modalias
lrwxrwxrwx  1 root root    0 Feb  6 16:27 of_node -> ../../../../firmware/devicetree/base/fpga-axi@0/axi-jesd204-rx@84a90000
drwxr-xr-x  2 root root    0 Feb  6 16:27 power
-r--r--r--  1 root root 4096 Feb  6 16:27 status
lrwxrwxrwx  1 root root    0 Feb  6 13:41 subsystem -> ../../../../bus/platform
-rw-r--r--  1 root root 4096 Feb  6 13:41 uevent

Reading the device/link status:

This specifies any shell prompt running on the target 

root@analog:/sys/bus/platform/devices/84a90000.axi-jesd204-rx# cat status
Link is enabled
Measured Link Clock: 375.034 MHz
Reported Link Clock: 375.000 MHz
Measured Device Clock: 375.034 MHz
Reported Device Clock: 375.000 MHz
Desired Device Clock: 375.000 MHz
Lane rate: 15000.000 MHz
Lane rate / 40: 375.000 MHz
LMFC rate: 46.875 MHz
Link status: DATA
SYSREF captured: Yes
SYSREF alignment error: No

Reading the Encoder used:

This specifies any shell prompt running on the target 

root@analog:/sys/bus/platform/devices/84a90000.axi-jesd204-rx# cat encoder 
8b10b

Reading the Lane Status:

This specifies any shell prompt running on the target 

root@analog:/sys/bus/platform/devices/84a90000.axi-jesd204-rx# cat lane0_info 
Errors: 0
CGS state: DATA
Initial Frame Synchronization: Yes
Lane Latency: 3 Multi-frames and 13 Octets
Initial Lane Alignment Sequence: Yes
DID: 0, BID: 0, LID: 2, L: 8, SCR: 1, F: 1
K: 32, M: 4, N: 16, CS: 0, N': 16, S: 1, HD: 0
FCHK: 0x9, CF: 0
ADJCNT: 0, PHADJ: 0, ADJDIR: 0, JESDV: 1, SUBCLASS: 1
FC: 15000000

More Information

resources/tools-software/linux-drivers/jesd204/axi_jesd204_rx.txt · Last modified: 08 Apr 2022 15:17 by Antoniu Miclaus

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