linux-kernel - Re: GPIO-driven RTS on TI hardware with 8250

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Date:	Mon, 8 Feb 2016 10:35:55 +0300
From:	Ильяс Гасанов 
	<torso.nafi@...il.com>
To:	Peter Hurley <peter@...leysoftware.com>
Cc:	"Matwey V. Kornilov" <matwey@....msu.ru>,
	Andy Shevchenko <andy.shevchenko@...il.com>,
	Russell King <linux@....linux.org.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: GPIO-driven RTS on TI hardware with 8250_omap driver

Hello,

2016-01-16 2:55 GMT+03:00 Peter Hurley <peter@...leysoftware.com>:
> Please use the helpers in serial_mctrl_gpio.c if you try this.
>
> And please build on top of Matwey's patches, as those will likely be
> the rs485 implementation for the 8250_omap driver soon.

As far as I understand, since em485 callbacks are invoked by timers,
the code is to be executed in atomic context. However certain GPIO
controllers (particularly the OMAP-based one which is used on our
AM335x) require the use of the gpio_*_cansleep() functions, and cannot
work with the atomic-friendly non-cansleep ones. Do the aforementioned
helpers in serial_mctrl_gpio.c address this issue?

Regards,
Ilyas G.