Bug 243201 - Zynq/Zybo uart reference clock speed is wrong in device tree file.
Summary: Zynq/Zybo uart reference clock speed is wrong in device tree file.
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: arm (show other bugs)
Version: CURRENT
Hardware: arm Any
: --- Affects Only Me
Assignee: freebsd-arm mailing list
URL:
Keywords: patch
Depends on:
Blocks:
 
Reported: 2020-01-09 00:36 UTC by Thomas Skibo
Modified: 2020-01-09 13:22 UTC (History)
0 users

See Also:


Attachments
fix uart reference clock in zynq device tree files (892 bytes, text/plain)
2020-01-09 00:36 UTC, Thomas Skibo
no flags Details

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Description Thomas Skibo 2020-01-09 00:36:15 UTC
Created attachment 210549 [details]
fix uart reference clock in zynq device tree files

The Zybo board uses a 100Mhz reference clock for its uarts but the device tree file indicates it's 50Mhz.  Zybo boots up using whatever speed is set by u-boot but this problem becomes apparent when you attempt to change the uart speed.

The Zedboard uses a 50Mhz clock so it works properly.  But, it seems most Zynq boards use 100Mhz and only the Zedboard uses 50Mhz so my proposed fix is to change the "default" reference clock in zynq-7000.dtsi to 100Mhz and then set Zedboard's ref clock to 50Mhz in zedboard.dts.

Thanks to Milan Obuch for discovering this and pointing it out to me.