Re: [PATCH 0/2] Add rs485 support to uartps driver

Michal Simek
2023-05-11T07:34:14Z

On 5/10/23 18:26, Guntupalli, Manikanta wrote:
> Hi Maarten,
>
>> -----Original Message-----
>> From: m.brock@vanmierlo.com <m.brock@vanmierlo.com>
>> Sent: Thursday, May 4, 2023 5:52 PM
>> To: Guntupalli, Manikanta <manikanta.guntupalli@amd.com>
>> Cc: gregkh@linuxfoundation.org; robh+dt@kernel.org;
>> krzysztof.kozlowski+dt@linaro.org; michal.simek@xilinx.com; linux-
>> serial@vger.kernel.org; devicetree@vger.kernel.org; linux-
>> kernel@vger.kernel.org; jirislaby@kernel.org; linux-arm-
>> kernel@lists.infradead.org; Simek, Michal <michal.simek@amd.com>; git
>> (AMD-Xilinx) <git@amd.com>; Pandey, Radhey Shyam
>> <radhey.shyam.pandey@amd.com>; Datta, Shubhrajyoti
>> <shubhrajyoti.datta@amd.com>; Goud, Srinivas <srinivas.goud@amd.com>;
>> manion05gk@gmail.com
>> Subject: Re: [PATCH 0/2] Add rs485 support to uartps driver
>>
>> Manikanta Guntupalli wrote 2023-04-26 14:29:
>>> Add optional gpio property to uartps node to support rs485 Add rs485
>>> support to uartps driver
>>>
>>> Manikanta Guntupalli (2):
>>> dt-bindings: Add optional gpio property to uartps node to support
>>> rs485
>>> tty: serial: uartps: Add rs485 support to uartps driver
>>>
>>> .../devicetree/bindings/serial/cdns,uart.yaml | 5 +
>>> drivers/tty/serial/xilinx_uartps.c | 96 ++++++++++++++++++-
>>> 2 files changed, 100 insertions(+), 1 deletion(-)
>>
>> Why would you want to use a GPIO and not RTS for choosing the direction as
>> is more common in this case?
> In ZynqMp platform Cadence UART Controller RTS signal routed to external through the PL(Programmable Logic) design not through Multiplexed IO.

Just to extend this a little bit. Cadence IP has modem signals but they are not
available over MIOs only over EMIO via PL logic. But board which this feature
targets can't have connection to PL pins to be able to use any modem signal for
this logic.

Thanks,
Michal