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[92.34.203.20]) by smtp.gmail.com with ESMTPSA id f9sm787100lft.242.2021.03.26.01.15.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Mar 2021 01:15:37 -0700 (PDT) From: Linus Walleij To: linux-gpio@vger.kernel.org Cc: Bartosz Golaszewski , Linus Walleij Subject: [PATCH] gpio: Mention GPIO MUX in docs Date: Fri, 26 Mar 2021 09:15:35 +0100 Message-Id: <20210326081535.1679507-1-linus.walleij@linaro.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org There is now a GPIO multiplexer, so mention this in the document about drivers using GPIO as backend. Signed-off-by: Linus Walleij --- Documentation/driver-api/gpio/drivers-on-gpio.rst | 6 ++++++ 1 file changed, 6 insertions(+) -- 2.29.2 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