Messages in this thread |  | | | Date | Mon, 28 May 2012 18:27:20 +0200 | | From | Roland Stigge <> | | Subject | Re: [PATCH] serial/of-serial: Add 16654 chip to compatible string list |
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On 28/05/12 17:03, Russell King - ARM Linux wrote: >> Initially, with my RFC patch, there was an #ifdef for bigger FIFO in >> case of LPC32xx where we have a 16550A variant with 64 byte fifos. > > What are all the differences? Is it just a larger FIFO?
Yes, this is how it's summarized in the manual (LPC32xx SoC).
>> So maybe 16750 is the better choice for me, anyway. Already supported in >> of-serial. Works for now, but need more testing. Another hint is that >> 16750 is advertised as "IP core for Soc" which matches the case of LPC32xx. > > 16750 also has automatic hardware flow control support, selectable through > bit 5 in the MCR register. If your UART has that, then it's probably a > 16750 derivative rather than a 16550 or 16650 derivative. > > 16650s have an EFR register at offset 2, selectable by writing 0xBF into > the LCR register, which the 16750 doesn't have. 16650 also has automatic > hardware flow control, bit this is selected through a couple of bits in > the EFR.
The 4 LPC32xx's "Standard" UARTs have neither of those.
Is it ok to use "ns16650", i.e. PORT_16650, or do I need to introduce a FIFO depth configuration?
Thanks in advance,
Roland
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