lkml.org 
[lkml]   [2012]   [Feb]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: pch_uart and pch_phub clock selection
    From
    Hi

    2012年2月17日16:28 Feng Tang <feng.tang@intel.com>:
    > I see that the the CM-iTC board is special-cased to set a 192MHz uart_clock.
    > This is done in pch_uart.c code, but there is some register manipulation done in
    > the pch_phub.c driver and I don't understand the connection. How are the two
    > related?
    According to your use, need to configure clock registers which are in pch_phub .
    Upstreamed version, UART_CLK can be used directly(neither multiple nor
    division) as UART clock.

    You can get clock configuration information from SourceForge.
    (http://sourceforge.net/projects/ml7213/files/Kernel%202.6.37/Release/Ver1.2.0/EG20TPCH_ML7213_ML7223_ML7831_linux-2.6.37_v120_20110930.tar.bz2/
    and extract pch_phub. you can find readme.)
    I extract it and show below.

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    <Configuration>
    =======================

    1. Over 115K baud rate UART settings
    By default, UART can communicate less than 115Kbps.
    In case you want UART to work more than 115Kbps, the following
    clock configuration is necessary.
    - Clock setting
    Set BAUDSEL = usb_48mhz
    Set PLL2VCO = "x 8" the clock
    Set BAUDDIV = "x 1/6" the clock
    Set UARTCLKSEL = PLL2 output
    For details, please refer to ML7213/ML7223 EDS "5 Chip Configuration"
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    In case we want UART to work high baud rate(e.g.4Mbps), we set like above.
    and execute "setserial /dev/ttyPCH0 baud_base 4000000".
    I can see PCH_UART with 4Mbps works well.

    Darren, is this answer for your question ?

    > Tomoya, do you know if we can also set it to 192MHz for ML7223 IOH Bus-m/n?
    Yes, you can.

    --
    ROHM Co., Ltd.
    tomoya


    \
     
     \ /
      Last update: 2012-02-17 10:53    [W:0.023 / U:0.388 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site