Hi Mark,

Hi,

quoted

quoted

I think that given that we know the UART is not quite a PL011 we should
add an additional compatible string just in case some difference crops
up later that is problematic.

So we'd have something like:

	compatible = "hisilicon,hi6220-uart", "arm,pl011", "arm,primecell";

That way we can add any optimisations or workarounds later as required.

I understand and thanks for your suggestion.

Can I do not do this work in this patch set? Because I got the
information UART0 is PL011 compatible. Hisilicon uart engineer can do
this work in the future, maybe for UART1/UART2.

I am not asking you to do any driver work for this -- the current driver
should ignore the "hisilicon,hi6220-uart" string and recognise
"arm,pl011".

I am only asking you to add the additional string to the DTS, and to
update the binding document to list the new string. That way if and when
we need the kernel to distinguish between a regular PL011 and the
hi6220-specific variant, the DTB does not need to be updated in order to
do so.

How about add the following binding rule to the 2/5 patch:
---------------------------
*Hisilicon Enhanced ARM AMBA Primecell PL011 serial UART

Required properties:
- compatible: must be "hisilicon,hi6220-uart", "arm,primecell", "arm,pl011"
- reg: exactly one register range with length 0x1000
- interrupts: exactly one interrupt specifier

See also bindings/serial/pl011.txt

Example:

uart0: uart at f8015000 { 
        compatible = "hisilicon,hi6220-uart", "arm,pl011", "arm,primecell";
        reg = <0x0 0xf8015000 0x0 0x1000>;
        interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>;
        clocks = <&ao_ctrl HI6220_UART0_PCLK>, <&ao_ctrl HI6220_UART0_PCLK>;
        clock-names = "uartclk", "apb_pclk";
};
---------------------------
 

Is UART 0 different from UART1 and UART2?

Yes,  but my patch just includes UART0, we do some changements for UART1/2
to improve performance.  

Thanks,

Bintian

Thanks,
Mark.

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