Hello Geert,

On Mon, Mar 06, 2017 at 09:49:39AM +0100, Geert Uytterhoeven wrote:

quoted

Given that mctrl-gpio can be useful on legacy platforms, a device could
silently run without cts-gpio even there.

On platforms were CONFIG_GPIOLIB=n, this is not true, so the issue is moot.

All serial drivers using (optional) mctrl-gpio have this in Kconfig:

    select SERIAL_MCTRL_GPIO if GPIOLIB

So they will use mctrl-gpio when GPIOLIB is enabled.
If GPIOPLIB is disabled, no flow control GPIOs are expected, and the
driver should not break that case.

So it all boils down to the question: Is GPIOLIB=n enough to assume no
gpio is needed?

I'd say it is not.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |