linux-kernel - Re: [PATCH v7 3/3] tty: 8250_omap: Use software emulated RS485 direction control

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Date:	Sat, 23 Jan 2016 17:20:27 +0200
From:	Andy Shevchenko <andy.shevchenko@...il.com>
To:	"Matwey V. Kornilov" <matwey@....msu.ru>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>,
	Peter Hurley <peter@...leysoftware.com>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>
Subject: Re: [PATCH v7 3/3] tty: 8250_omap: Use software emulated RS485
 direction control

On Tue, Jan 19, 2016 at 10:33 PM, Matwey V. Kornilov <matwey@....msu.ru> wrote:
> Use software emulated RS485 direction control to provide RS485 API existed in
> omap_serial driver. Note that 8250_omap issues interrupt on shift register
> empty which is single prerequesite for using software emulated RS485.


> +static int omap_8250_rs485_config(struct uart_port *port, struct serial_rs485 *rs485)
> +{
> +       struct uart_8250_port *up = up_to_u8250p(port);
> +
> +       /* Clamp the delays to [0, 100ms] */

It's not exactly clamping but rather cutting extra as I can see below.

> +       rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
> +       rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);

> +       /* Both serial8250_em485_* functions are idempotent */

Better to decode what functions do you mean here.

> +       if (rs485->flags & SER_RS485_ENABLED) {
> +               int ret = serial8250_em485_init(up);
> +               if (ret) {
> +                       rs485->flags &= ~SER_RS485_ENABLED;
> +                       port->rs485.flags &= ~SER_RS485_ENABLED;
> +               }

> +               return ret;
> +       } else

You have to do } else { in multi-line branches, but luckily there is
redundant else keyword.

And checkpatch.pl doesn't tell you anything?

> +               serial8250_em485_destroy(up);
> +
> +       return 0;
> +}

-- 
With Best Regards,
Andy Shevchenko