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authorLinus Walleij <linus.walleij@linaro.org>2021-03-26 09:15:35 +0100
committerBartosz Golaszewski <bgolaszewski@baylibre.com>2021-03-26 14:56:19 +0100
commit4a5c9da4ec29bc2a4fff00c2c36ce38826123d68 (patch)
tree3b0a9802fcab2247f7e6688fc440592d47094c64 /Documentation
parent81dd500b1c8612a42979ee3ea788d2d9f19aa9f9 (diff)
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-api/gpio/drivers-on-gpio.rst6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/driver-api/gpio/drivers-on-gpio.rst b/Documentation/driver-api/gpio/drivers-on-gpio.rst
index 41ec3cc72d32..af632d764ac6 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