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Explorer
Explorer
763 Views
Registered: ‎04-21-2017

How to change si570 clocks on ZCU106 dev-kit using Petalinux .DTSI files

Dear Forum,

 

I'm building a Petalinux project for the ZCU106 dev-kit, and in the zcu106-reva.dtsi file I can find specific reference to the si570 chip that is setup to drive the User_MGT clock pin. In the zcu106-reva.dtsi file, this si570 is setup as follows.

 

i2c@3 { /* i2c mw 74 0 8 */
#address-cells = <1>;
#size-cells = <0>;
reg = <3>;
si570_2: clock-generator3@5d { /* USER MGT SI570 - u56 */
#clock-cells = <0>;
compatible = "silabs,si570";
reg = <0x5d>;
temperature-stability = <50>; /* copy from zc702 */
factory-fout = <156250000>;
clock-frequency = <148500000>;
};
};

 

For my design I want the output of this clock to remain at 156.25Mhz.

 

 

1) Should I edit the zcu106-reva.dtsi file directly?

If so how Delete or Edit the clock-frequency value..?

 

2) Should I add the above text to my system-user.dtsi file, with appropriate edits to get 156.25MHz..?

Will settings in the system-user.dtsi file overwrite those in other .dtsi files?

 

TTFN.

 

DJE666

 

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5 Replies
Moderator
Moderator
737 Views
Registered: ‎02-07-2018

Re: How to change si570 clocks on ZCU106 dev-kit using Petalinux .DTSI files

Hi ,

You can add node details with required clock value in system-user.dtsi. This will overwrite required value.

 

You can check wether taht value is reflected or not  by converting  output (system.dtb) to system.dts using below command.

  • dtc -I dtb -O dts -o  system.dts system.dtb

 

 

Thanks & Regards

Aravind

 

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Explorer
Explorer
674 Views
Registered: ‎04-21-2017

Re: How to change si570 clocks on ZCU106 dev-kit using Petalinux .DTSI files

Hi Aravind,

 

Thanks for this data.

 

Can you please clarify what constitutes the full details of any given NODE in the system? If we take the example that I initially posted, should I put all this text in the system-user.dtsi, a sub-section of it or something else? Here is the original text..

 

i2c@3 { /* i2c mw 74 0 8 */
#address-cells = <1>;
#size-cells = <0>;
reg = <3>;
si570_2: clock-generator3@5d { /* USER MGT SI570 - u56 */
#clock-cells = <0>;
compatible = "silabs,si570";
reg = <0x5d>;
temperature-stability = <50>; /* copy from zc702 */
factory-fout = <156250000>;
clock-frequency = <148500000>;
};
};

 

Would the following simple edit to the last line be correct in the system-user.dtsi?

 

i2c@3 { /* i2c mw 74 0 8 */
#address-cells = <1>;
#size-cells = <0>;
reg = <3>;
si570_2: clock-generator3@5d { /* USER MGT SI570 - u56 */
#clock-cells = <0>;
compatible = "silabs,si570";
reg = <0x5d>;
temperature-stability = <50>; /* copy from zc702 */
factory-fout = <156250000>;
clock-frequency = <156250000>;
};
};

 

Regards,

 

DJE666

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Moderator
Moderator
660 Views
Registered: ‎04-24-2017

Re: How to change si570 clocks on ZCU106 dev-kit using Petalinux .DTSI files

Hi @dje666,

 

In system-user.dtsi you can override the clocks as shown below.

 

/include/ "system-conf.dtsi"
/ {
};

&i2c1 {
    i2cswitch@74 {
        i2c@3 {
            si570_2: clock-generator@5d { /* USER MGT SI570 - u56 */
                clock-frequency = <156250000>;
            };
        };
    };
};

Thanks,
Sandeep
PetaLinux Yocto | Embedded SW Support

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Visitor rougravitas
Visitor
127 Views
Registered: ‎07-30-2019

Re: How to change si570 clocks on ZCU106 dev-kit using Petalinux .DTSI files - 2019.1

This is how the device tree is described on my system as the i2c buss on the ZCU106 is connected to a multiplexer
 
&i2c1 {
    i2c-mux@74 {
        i2c@3 {
            si570_2: clock-generator@5d { /* USER MGT SI570 - u56 */
                clock-frequency = <125000000>;
            };
        };
    };
};

 

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Moderator
Moderator
110 Views
Registered: ‎09-12-2007

Re: How to change si570 clocks on ZCU106 dev-kit using Petalinux .DTSI files - 2019.1

If you want to manually build the DTB outside petalinux, you will need to precompile the include folders. This is shown in the wiki below:

https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/136904764/Creating+Devicetree+from+Devicetree+Generator+for+Zynq+Ultrascale+and+Zynq+7000

gcc -I my_dts -E -nostdinc -undef -D__DTS__ -x assembler-with-cpp -o my_dts/system-top.dts.tmp my_dts/system-top.dts
dtc -I dts -O dtb -o my_dts/system-top.dtb my_dts/system-top.dts.tmp

 

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