gpio: Add use guidance documentation

The text in this new document is a response to recurring questions
about the GPIO in-kernel API vs the userspace ABI. When do you use
one or the other? It can be a bit intuitive, but I tried to sum it
all up.

Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20200108001712.47500-1-linus.walleij@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/Documentation/driver-api/gpio/drivers-on-gpio.rst b/Documentation/driver-api/gpio/drivers-on-gpio.rst
index f3a189320e11..820b403d50f6 100644
--- a/Documentation/driver-api/gpio/drivers-on-gpio.rst
+++ b/Documentation/driver-api/gpio/drivers-on-gpio.rst
@@ -95,7 +95,7 @@ to emulate MCTRL (modem control) signals CTS/RTS by using two GPIO lines. The
 MTD NOR flash has add-ons for extra GPIO lines too, though the address bus is
 usually connected directly to the flash.
 
-Use those instead of talking directly to the GPIOs using sysfs; they integrate
-with kernel frameworks better than your userspace code could. Needless to say,
-just using the appropriate kernel drivers will simplify and speed up your
-embedded hacking in particular by providing ready-made components.
+Use those instead of talking directly to the GPIOs from userspace; they
+integrate with kernel frameworks better than your userspace code could.
+Needless to say, just using the appropriate kernel drivers will simplify and
+speed up your embedded hacking in particular by providing ready-made components.