Re: [PATCH v3 5/5] serial: 8250_dw: add em485 support

Giulio Benetti
2021-02-05T18:55:14Z

Il 02/02/2021 12:22, Andy Shevchenko ha scritto:
> On Tue, Feb 02, 2021 at 01:31:17AM +0100, Giulio Benetti wrote:
>> Il 18/05/2020 17:21, Andy Shevchenko ha scritto:
>>> On Sun, May 17, 2020 at 11:56:10PM +0200, Heiko Stuebner wrote:
>>>> From: Giulio Benetti <giulio.benetti@micronovasrl.com>
>>>>
>>>> Need to use rs485 transceiver so let's use existing em485 485 emulation
>>>> layer on top of 8250.
>>>>
>>>> Add rs485_config callback to port and uses the standard em485 start and
>>>> stop helpers.
>>>
>>> Would it prevent to use native RS485 support?
>>
>> 8250_dw doesn't have a native RS485 support, do you mean using hardware
>> RTS assertion? Anyway at the moment it's not present. This would be the
>> first rs485 support added to 8250_dw.
>
> DW v4.0+ has it.

I have access to datasheet of DW v3, and I don't have access to hardware
with DW v4.0v Uart.
But I could add rs485emu for only UART version < 4.0 and I can find Uart
version by reading UCV register, would it be acceptable?

Best regards
--
Giulio Benetti
CTO

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