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Subject: Re: [PATCH 7/8] serial: ar933x: Remove redundant assignment in
 rs485_config
To:     =?UTF-8?Q?Ilpo_J=c3=a4rvinen?= <ilpo.jarvinen@linux.intel.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        vz@mleia.com, linux-arm-kernel@lists.infradead.org,
        devicetree@vger.kernel.org,
        linux-serial <linux-serial@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, lukas@wunner.de,
        p.rosenberger@kunbus.com, Lino Sanfilippo <l.sanfilippo@kunbus.com>
References: <20220622154659.8710-1-LinoSanfilippo@gmx.de>
 <20220622154659.8710-8-LinoSanfilippo@gmx.de>
 <f7beef4-c422-cae3-8e22-8652b407434@linux.intel.com>
From:   Lino Sanfilippo <LinoSanfilippo@gmx.de>
Message-ID: <df19d91d-371b-f0e9-e37c-2bde00d2b840@gmx.de>
Date:   Sun, 26 Jun 2022 16:09:48 +0200
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On 25.06.22 at 12:14, Ilpo J=C3=A4rvinen wrote:
> On Wed, 22 Jun 2022, Lino Sanfilippo wrote:
>
>> From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
>>
>> In uart_set_rs485_config() the serial core already assigns the passed
>> serial_rs485 struct to the uart port.
>>
>> So remove the assignment in the drivers rs485_config() function to avoi=
d
>> redundancy.
>>
>> Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
>> ---
>>  drivers/tty/serial/ar933x_uart.c | 1 -
>>  1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar93=
3x_uart.c
>> index ab2c5b2a1ce8..857e010d01dc 100644
>> --- a/drivers/tty/serial/ar933x_uart.c
>> +++ b/drivers/tty/serial/ar933x_uart.c
>> @@ -591,7 +591,6 @@ static int ar933x_config_rs485(struct uart_port *po=
rt,
>>  		dev_err(port->dev, "RS485 needs rts-gpio\n");
>>  		return 1;
>>  	}
>> -	port->rs485 =3D *rs485conf;
>>  	return 0;
>>  }
>
> Hmm, I realize that for some reason I missed cleaning up this particular
> driver after introducing the serial_rs485 sanitization. It shouldn't nee=
d
> that preceeding if block either because ar933x_no_rs485 gets applied if
> there's no rts_gpiod so the core clears SER_RS485_ENABLED.
>

I think we still need that "if" in case that RS485 was not enabled at driv=
er
startup (no rs485-enabled-at-boot-time) and no RTS GPIO was defined but th=
en
RS485 is enabled via TIOCSRS485.

Maybe in ar933x_uart_probe()

	if ((port->rs485.flags & SER_RS485_ENABLED) &&
	    !up->rts_gpiod) {
		dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n");
		port->rs485.flags &=3D ~SER_RS485_ENABLED;
		port->rs485_supported =3D &ar933x_no_rs485;
	}

should rather be

	if (!up->rts_gpiod) {
		dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n");
		port->rs485.flags &=3D ~SER_RS485_ENABLED;
		port->rs485_supported =3D &ar933x_no_rs485;
	}


Regards,
Lino