Program Si5338 Quad Clock Generator on Arria10 SoC DevKit

Use a Perl script and I2C command line tools to change the Si5338 settings from Linux

The Si5338 "I2C Programmable Any-Frequency, Any-Output Quad CLock Generator", from Silicon Labs, is used on the Arria10 DevKit to drive several board level clocks. The Arria 10 DevKits has three Si5338 devices: U42 @ 0x70, U50 @ 0x71, and U49 @ 0x73. Refer to the board schematics for more information. The devices are programmed with default settings as listed in the board schematics, but the settings can be modified by loading an internal RAM and triggering a reconfiguration. Clock Builder Software from Silicon Labs is available to generate valid device settings. The software is Windows OS only (no Linux version is available at the time of this writing).

Provided here is a Perl script that parses the resulting 'register_map.h' files generated by the Silicon Labs Clock Builder Software and uses the I2C utilities (i2cget, i2cset) provided with the Arria 10 Golden System Reference Design (GSRD) User Manuals Linux build to program a target Si5338 device.

1.) Download the si5338_cfg Perl Script

2.) Download the Silicon Labs Software

3.) Generate a valid 'register_map.h' file using the Silicon Labs Clock Builder Sofware

4.) Add the 'si5338_cfg' Perl Script and 'register_map.h' files to your Golden System Reference Design (GSRD) User Manuals SD Card and boot the DevKit

5.) From the command prompt, as root, run the command './si5338_cfg {0x70 | 0x71 | 0x73} {register_map.h}

NOTE: The default Linux Device Tree for the Arria 10 DevKit adjusts the I2C interface timing to work with the LCD Display. These settings conflict with the interface timing required by the Si5338 devices. Make the following modifications to the default Linux Device Tree to configure correct I2C interface timing for the Si5338 devices. This will prevent the LCD Display I2C interface from functioning.

      arria10_hps_0_i_i2c_1_i2c: i2c@0xffc02300 {
         compatible = "snps,designware-i2c-15.1", "snps,designware-i2c";
         reg = <0xffc02300 0x00000100>;
         interrupt-parent = <&arria10_hps_0_arm_gic_0>;
         interrupts = <0 106 4>;
         clocks = <&l4_sp_clk>;
         emptyfifo_hold_master = <1>;   /* embeddedsw.dts.params.emptyfifo_hold_master type NUMBER */
         status = "okay";   /* embeddedsw.dts.params.status type STRING */
         #address-cells = <1>;
         #size-cells = <0>;
         speed-mode = <0>;   /* appended from boardinfo */
         clock-frequency = <100000>;   /* appended from boardinfo */
--
<<         i2c-sda-falling-time-ns = <6000>;   /* appended from boardinfo */
<<         i2c-sc1-falling-time-ns = <6000>;   /* appended from boardinfo */
--
>>         //i2c-sda-falling-time-ns = <6000>;   /* appended from boardinfo */
>>         //i2c-sc1-falling-time-ns = <6000>;   /* appended from boardinfo */
>>          i2c-sda-hold-time-ns = <160>;
--
         lcd: newhaven,nhd-0216k3z-nsw-bbw@0x28 {
            compatible = "newhaven,nhd-0216k3z-nsw-bbw";
            reg = <0x00000028>;
            height = <2>;   /* appended from boardinfo */
            width = <16>;   /* appended from boardinfo */
            brightness = <8>;   /* appended from boardinfo */
         }; //end newhaven,nhd-0216k3z-nsw-bbw@0x28 (lcd)