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Subject: Re: [PATCH 1/9] serial: core: move RS485 configuration tasks from
 drivers into core
To:     =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>
Cc:     gregkh@linuxfoundation.org, jirislaby@kernel.org,
        linux-arm-kernel@lists.infradead.org,
        alexandre.belloni@bootlin.com, mcoquelin.stm32@gmail.com,
        richard.genoud@gmail.com, festevam@gmail.com,
        s.hauer@pengutronix.de, linux@armlinux.org.uk,
        nicolas.ferre@microchip.com, alexandre.torgue@foss.st.com,
        ludovic.desroches@microchip.com, lukas@wunner.de,
        linux-imx@nxp.com, kernel@pengutronix.de,
        linux-serial@vger.kernel.org, shawnguo@kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-kernel@vger.kernel.org
References: <20220213222737.15709-1-LinoSanfilippo@gmx.de>
 <20220213222737.15709-2-LinoSanfilippo@gmx.de>
 <20220214070622.rz5cv6yy3aarvrjv@pengutronix.de>
From:   Lino Sanfilippo <LinoSanfilippo@gmx.de>
Message-ID: <edbb9e1d-bed4-0850-08f4-029c4fcbfd5c@gmx.de>
Date:   Mon, 14 Feb 2022 16:09:53 +0100
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Hi,

On 14.02.22 at 08:06, Uwe Kleine-K=F6nig wrote:
> On Sun, Feb 13, 2022 at 11:27:29PM +0100, Lino Sanfilippo wrote:
>> Several drivers that support setting the RS485 configuration via usersp=
ace
>> implement on or more of the following tasks:
>
> s/on/one/

Ok

>
>>
>> - in case of an invalid RTS configuration (both RTS after send and RTS =
on
>>   send set or both unset) fall back to enable RTS on send and disable R=
TS
>>   after send
>>
>> - nullify the padding field of the returned serial_rs485 struct
>>
>> - copy the configuration into the uart port struct
>>
>> - limit RTS delays to 100 ms
>>
>> Move these tasks into the serial core to make them generic and to provi=
de
>> a consistent beheviour among all drivers.
>
> s/beheviour/behaviour/
>

Ok

>> Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
>> ---
>>  drivers/tty/serial/serial_core.c | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/seri=
al_core.c
>> index 846192a7b4bf..3fab4070359c 100644
>> --- a/drivers/tty/serial/serial_core.c
>> +++ b/drivers/tty/serial/serial_core.c
>> @@ -1282,8 +1282,21 @@ static int uart_set_rs485_config(struct uart_por=
t *port,
>>  	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
>>  		return -EFAULT;
>>
>> +	/* pick sane settings if the user hasn't */
>> +	if (!(rs485.flags & SER_RS485_RTS_ON_SEND) =3D=3D
>> +	    !(rs485.flags & SER_RS485_RTS_AFTER_SEND)) {
>> +		rs485.flags |=3D SER_RS485_RTS_ON_SEND;
>> +		rs485.flags &=3D ~SER_RS485_RTS_AFTER_SEND;
>> +	}
>> +	/* clamp the delays to [0, 100ms] */
>> +	rs485.delay_rts_before_send =3D min(rs485.delay_rts_before_send, 100U=
);
>> +	rs485.delay_rts_after_send =3D min(rs485.delay_rts_after_send, 100U);
>> +	memset(rs485.padding, 0, sizeof(rs485.padding));
>> +
>>  	spin_lock_irqsave(&port->lock, flags);
>>  	ret =3D port->rs485_config(port, &rs485);
>> +	if (!ret)
>> +		port->rs485 =3D rs485;
>
> I was only Cc:d for the imx patch (patch #7) and tried to verify the
> claim there that "the serial core already assigns the passed
> configuration to the uart port". That failed when I looked at my kernel
> tree.
>
> So it would be great, if you sent dependencies (or at least a cover
> letter) to all recipients of a given patch to ease review. Also I want
> to suggest to mention uart_set_rs485_config() in the commit log of the
> imx patch (and probably the others) to simplify verifying the claim
> there.
>

Thanks for the review, I will correct the typos in the next version.
I will also cc you directly for the next version if you dont mind.
get_maintainers only spit out "Pengutronix Kernel Team" so I used that
address for the whole series (including the cover letter).


Regards,
Lino