Messages in this thread | | | Date | Fri, 17 Feb 2012 18:50:33 +0900 | Subject | Re: pch_uart and pch_phub clock selection | From | Tomoya MORINAGA <> |
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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
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