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Date:   Thu, 30 Jun 2022 02:33:23 +0200
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Subject: Re: [PATCH 7/8] serial: ar933x: Remove redundant assignment in
 rs485_config
Content-Language: en-US
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>
 <df19d91d-371b-f0e9-e37c-2bde00d2b840@gmx.de>
 <033c8d2-3f2e-afe6-2e98-14a61c872b4b@linux.intel.com>
From:   Lino Sanfilippo <LinoSanfilippo@gmx.de>
In-Reply-To: <033c8d2-3f2e-afe6-2e98-14a61c872b4b@linux.intel.com>
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Precedence: bulk


On 27.06.22 10:14, Ilpo J=C3=A4rvinen wrote:
> On Sun, 26 Jun 2022, Lino Sanfilippo wrote:
>
>> 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 av=
oid
>>>> 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/ar=
933x_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 *=
port,
>>>>  		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 particul=
ar
>>> driver after introducing the serial_rs485 sanitization. It shouldn't n=
eed
>>> that preceeding if block either because ar933x_no_rs485 gets applied i=
f
>>> 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 d=
river
>> startup (no rs485-enabled-at-boot-time) and no RTS GPIO was defined but=
 then
>> 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
>
> I think it would be better (and what I should have done while moving the
> check there in the first place but I missed it). In addition, however, i=
t
> would be useful to not print unnecessarily:
>
>> 	if (!up->rts_gpiod) {
>
> if (port->rs485.flags & SER_RS485_ENABLED) {
>
>> 		dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n");
>> 		port->rs485.flags &=3D ~SER_RS485_ENABLED;
>
> }


Right. I will send a fix for this with the new version of my series.

Regards,
Lino