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Subject: Re: [PATCH V2 3/4] ARM64 LPC: support serial based on low-pin-count
To: Arnd Bergmann <arnd@arndb.de>, zhichang <zhichang.yuan02@gmail.com>
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From: "zhichang.yuan" <yuanzhichang@hisilicon.com>
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Date: Wed, 14 Sep 2016 19:48:49 +0800
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On 2016/9/8 17:58, Arnd Bergmann wrote:
> On Thursday, September 8, 2016 5:51:25 PM CEST zhichang wrote:
>> On 2016年09月07日 22:50, Arnd Bergmann wrote:
>>> On Wednesday, September 7, 2016 9:33:52 PM CEST Zhichang Yuan wrote:
>>>> From: "zhichang.yuan" <yuanzhichang@hisilicon.com>
>>>>
>>>> On Hip06 platform, a 16550 compatible UART is connected to low-pin-count and
>>>> controlled through the LPC I/O cycles. This patch drives the UART port with
>>>> the specific serial in/out function pair based on the indirect-IO mechanism
>>>> introduced by Hip06 LPC driver.
>>>>
>>>> Signed-off-by: zhichang.yuan <yuanzhichang@hisilicon.com>
>>>
>>> Any reason this cannot just use the regular drivers/tty/serial/8250/8250_of.c
>>> driver?
>> I think two reasons for that:
>> 1. 8250_of.c is only for devicetree, but we need to support ACPI device too;
> 
> ACPI has its own way of describing serial ports, use that instead.
Could you give me some info about ACPI serial ports?
I found there is _CRS specific for serial, but it seems no serial driver use that.

Thanks!
Zhichang

> 
>> 2. It seems UPIO_PORT is not supported there.
> 
> Should be easy enough to add.
> 
> 	Arnd
> 
> .
>