Re: [PATCH v4 04/11] tty: serdev: Add method to enable break flags

From: Christoph Fritz <christoph.fritz@hexdev.de>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Jiri Slaby <jirislaby@kernel.org>,
	Simon Horman <horms@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Vincent Mailhol <mailhol.vincent@wanadoo.fr>,
	 "David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Rob Herring <robh@kernel.org>,
	 Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Jiri Kosina <jikos@kernel.org>,
	Benjamin Tissoires <bentiss@kernel.org>,
	Sebastian Reichel <sre@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Andreas Lauser <andreas.lauser@mercedes-benz.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Pavel Pisa <pisa@cmp.felk.cvut.cz>,
	linux-can@vger.kernel.org, Netdev <netdev@vger.kernel.org>,
	 devicetree@vger.kernel.org, linux-input@vger.kernel.org,
	linux-serial <linux-serial@vger.kernel.org>
Subject: Re: [PATCH v4 04/11] tty: serdev: Add method to enable break flags
Date: Sun, 12 May 2024 15:08:08 +0200	[thread overview]
Message-ID: <3070ec70b2477560f205cc4c34dd84b320831365.camel@hexdev.de> (raw)
In-Reply-To: <36b0d460-1d96-89d8-db4a-76d735f7ee6b@linux.intel.com>

On Fri, 2024-05-10 at 17:21 +0300, Ilpo Järvinen wrote:
> On Thu, 9 May 2024, Christoph Fritz wrote:
...
> > diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
> > index 613cb356b918d..23a1e76cb553b 100644
> > --- a/drivers/tty/serdev/core.c
> > +++ b/drivers/tty/serdev/core.c
> > @@ -339,6 +339,17 @@ unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned i
> >  }
> >  EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
> >  
> > +void serdev_device_set_break_detection(struct serdev_device *serdev, bool enable)
> > +{
> > +	struct serdev_controller *ctrl = serdev->ctrl;
> > +
> > +	if (!ctrl || !ctrl->ops->set_break_detection)
> > +		return;
> 
> Why you need to test for !ctrl?

In our case we don't, it's an extra check like all the other functions
here:

https://elixir.bootlin.com/linux/v6.9-rc7/source/drivers/tty/serdev/core.c#L330

> 
> > +	ctrl->ops->set_break_detection(ctrl, enable);
> 
> I'd use positive logic here:
> 
> 	if (ctrl->ops->set_break_detection)
> 		ctrl->ops->set_break_detection(ctrl, enable);