From 9ee0a0558819e63d189426c953668fe1ce7cb637 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Mon, 28 Aug 2017 09:59:20 -0700 Subject: Input: PS/2 gpio bit banging driver for serio bus This driver provides PS/2 serio bus support by implementing bit banging with the GPIO API. The GPIO pins, data and clock, can be configured with a node in the device tree or by generic device properties (GDP). Writing to a device is supported as well, though it is possible timings can not be halt as they are tough and difficult to reach with bit banging. Therefore it can be configured (also in DT and GDP) whether the serio write function should be available for clients. This driver is for development purposes and not recommended for productive use. However, this driver can be useful e.g. when no USB port is available or using old peripherals is desired as PS/2 controller chips getting rare. This driver was tested on bcm2825 and on Kirin 960 and it worked well together with the atkbd and psmouse driver. Signed-off-by: Danilo Krummrich Reviewed-by: Linus Walleij Acked-by: Rob Herring Signed-off-by: Dmitry Torokhov --- Documentation/gpio/drivers-on-gpio.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/gpio') diff --git a/Documentation/gpio/drivers-on-gpio.txt b/Documentation/gpio/drivers-on-gpio.txt index 306513251713..9a78d385b92e 100644 --- a/Documentation/gpio/drivers-on-gpio.txt +++ b/Documentation/gpio/drivers-on-gpio.txt @@ -84,6 +84,11 @@ hardware descriptions such as device tree or ACPI: NAND flash MTD subsystem and provides chip access and partition parsing like any other NAND driving hardware. +- ps2-gpio: drivers/input/serio/ps2-gpio.c is used to drive a PS/2 (IBM) serio + bus, data and clock line, by bit banging two GPIO lines. It will appear as + any other serio bus to the system and makes it possible to connect drivers + for e.g. keyboards and other PS/2 protocol based devices. + 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 -- cgit 1.4.1