linux-kernel - Re: [PATCH v3 3/5] serial: 8250: Support separate rs485 rx-enable GPIO

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Message-ID: <20200518171646.GO1634618@smile.fi.intel.com>
Date:   Mon, 18 May 2020 20:16:46 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Maarten Brock <m.brock@...mierlo.com>
Cc:     Lukas Wunner <lukas@...ner.de>, Heiko Stuebner <heiko@...ech.de>,
        gregkh@...uxfoundation.org, jslaby@...e.com,
        matwey.kornilov@...il.com, giulio.benetti@...ronovasrl.com,
        linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        christoph.muellner@...obroma-systems.com,
        Heiko Stuebner <heiko.stuebner@...obroma-systems.com>,
        linux-serial-owner@...r.kernel.org
Subject: Re: [PATCH v3 3/5] serial: 8250: Support separate rs485 rx-enable
 GPIO

On Mon, May 18, 2020 at 07:05:11PM +0200, Maarten Brock wrote:
> On 2020-05-18 18:35, Andy Shevchenko wrote:
> > On Mon, May 18, 2020 at 06:13:16PM +0200, Maarten Brock wrote:
> > > On 2020-05-18 17:22, Lukas Wunner wrote:
> > > > On Mon, May 18, 2020 at 06:12:41PM +0300, Andy Shevchenko wrote:
> > > > > On Sun, May 17, 2020 at 11:56:08PM +0200, Heiko Stuebner wrote:

...

> > > But "High" on a gpio would disable the receiver when connected to !RE.
> > 
> > No, that's exactly the point of the terminology (asserted means active
> > whatever
> > polarity it is). You need to define active-low in GPIO description.
> 
> Is there anything wrong with defining GPIOD_OUT_ACTIVE or GPIOD_OUT_ASSERTED
> for this very purpose? May I suggest to deprecate GPIOD_OUT_HIGH and replace
> it?

Please, ask GPIO maintainers, I'm not one.

-- 
With Best Regards,
Andy Shevchenko