From 4a5c9da4ec29bc2a4fff00c2c36ce38826123d68 Mon Sep 17 00:00:00 2001 From: Linus Walleij <linus.walleij@linaro.org> Date: Fri, 26 Mar 2021 09:15:35 +0100 Subject: [PATCH] gpio: Mention GPIO MUX in docs There is now a GPIO multiplexer, so mention this in the document about drivers using GPIO as backend. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> --- Documentation/driver-api/gpio/drivers-on-gpio.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/driver-api/gpio/drivers-on-gpio.rst b/Documentation/driver-api/gpio/drivers-on-gpio.rst index 41ec3cc72d327..af632d764ac6a 100644 --- a/Documentation/driver-api/gpio/drivers-on-gpio.rst +++ b/Documentation/driver-api/gpio/drivers-on-gpio.rst @@ -96,6 +96,12 @@ hardware descriptions such as device tree or ACPI: way to pass the charging parameters from hardware descriptions such as the device tree. +- gpio-mux: drivers/mux/gpio.c is used for controlling a multiplexer using + n GPIO lines such that you can mux in 2^n different devices by activating + different GPIO lines. Often the GPIOs are on a SoC and the devices are + some SoC-external entities, such as different components on a PCB that + can be selectively enabled. + Apart from this there are special GPIO drivers in subsystems like MMC/SD to read card detect and write protect GPIO lines, and in the TTY serial subsystem to emulate MCTRL (modem control) signals CTS/RTS by using two GPIO lines. The -- GitLab