Documentation: gpio: Move drivers-on-gpio.txt to driver-api

Move gpio/drivers-on-gpio.txt to driver-api/gpio/drivers-on-gpio.rst and
make sure it builds cleanly as ReST.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 0 insertions, 96 deletions

diff --git a/Documentation/gpio/drivers-on-gpio.txt b/Documentation/gpio/drivers-on-gpio.txt
deleted file mode 100644
index a2ccbab12eb7..000000000000
--- a/Documentation/gpio/drivers-on-gpio.txt
+++ /dev/null
@@ -1,96 +0,0 @@
-Subsystem drivers using GPIO
-============================
-
-Note that standard kernel drivers exist for common GPIO tasks and will provide
-the right in-kernel and userspace APIs/ABIs for the job, and that these
-drivers can quite easily interconnect with other kernel subsystems using
-hardware descriptions such as device tree or ACPI:
-
-- leds-gpio: drivers/leds/leds-gpio.c will handle LEDs connected to  GPIO
-  lines, giving you the LED sysfs interface
-
-- ledtrig-gpio: drivers/leds/trigger/ledtrig-gpio.c will provide a LED trigger,
-  i.e. a LED will turn on/off in response to a GPIO line going high or low
-  (and that LED may in turn use the leds-gpio as per above).
-
-- gpio-keys: drivers/input/keyboard/gpio_keys.c is used when your GPIO line
-  can generate interrupts in response to a key press. Also supports debounce.
-
-- gpio-keys-polled: drivers/input/keyboard/gpio_keys_polled.c is used when your
-  GPIO line cannot generate interrupts, so it needs to be periodically polled
-  by a timer.
-
-- gpio_mouse: drivers/input/mouse/gpio_mouse.c is used to provide a mouse with
-  up to three buttons by simply using GPIOs and no mouse port. You can cut the
-  mouse cable and connect the wires to GPIO lines or solder a mouse connector
-  to the lines for a more permanent solution of this type.
-
-- gpio-beeper: drivers/input/misc/gpio-beeper.c is used to provide a beep from
-  an external speaker connected to a GPIO line.
-
-- extcon-gpio: drivers/extcon/extcon-gpio.c is used when you need to read an
-  external connector status, such as a headset line for an audio driver or an
-  HDMI connector. It will provide a better userspace sysfs interface than GPIO.
-
-- restart-gpio: drivers/power/reset/gpio-restart.c is used to restart/reboot
-  the system by pulling a GPIO line and will register a restart handler so
-  userspace can issue the right system call to restart the system.
-
-- poweroff-gpio: drivers/power/reset/gpio-poweroff.c is used to power the
-  system down by pulling a GPIO line and will register a pm_power_off()
-  callback so that userspace can issue the right system call to power down the
-  system.
-
-- gpio-gate-clock: drivers/clk/clk-gpio.c is used to control a gated clock
-  (off/on) that uses a GPIO, and integrated with the clock subsystem.
-
-- i2c-gpio: drivers/i2c/busses/i2c-gpio.c is used to drive an I2C bus
-  (two wires, SDA and SCL lines) by hammering (bitbang) two GPIO lines. It will
-  appear as any other I2C bus to the system and makes it possible to connect
-  drivers for the I2C devices on the bus like any other I2C bus driver.
-
-- spi_gpio: drivers/spi/spi-gpio.c is used to drive an SPI bus (variable number
-  of wires, at least SCK and optionally MISO, MOSI and chip select lines) using
-  GPIO hammering (bitbang). It will appear as any other SPI bus on the system
-  and makes it possible to connect drivers for SPI devices on the bus like
-  any other SPI bus driver. For example any MMC/SD card can then be connected
-  to this SPI by using the mmc_spi host from the MMC/SD card subsystem.
-
-- w1-gpio: drivers/w1/masters/w1-gpio.c is used to drive a one-wire bus using
-  a GPIO line, integrating with the W1 subsystem and handling devices on
-  the bus like any other W1 device.
-
-- gpio-fan: drivers/hwmon/gpio-fan.c is used to control a fan for cooling the
-  system, connected to a GPIO line (and optionally a GPIO alarm line),
-  presenting all the right in-kernel and sysfs interfaces to make your system
-  not overheat.
-
-- gpio-regulator: drivers/regulator/gpio-regulator.c is used to control a
-  regulator providing a certain voltage by pulling a GPIO line, integrating
-  with the regulator subsystem and giving you all the right interfaces.
-
-- gpio-wdt: drivers/watchdog/gpio_wdt.c is used to provide a watchdog timer
-  that will periodically "ping" a hardware connected to a GPIO line by toggling
-  it from 1-to-0-to-1. If that hardware does not receive its "ping"
-  periodically, it will reset the system.
-
-- gpio-nand: drivers/mtd/nand/gpio.c is used to connect a NAND flash chip to
-  a set of simple GPIO lines: RDY, NCE, ALE, CLE, NWP. It interacts with the
-  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
-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.