docs: w1: convert to ReST and add to the kAPI group of docs

The 1wire documentation was written with w1 developers in
mind, so, it makes sense to add it together with the driver-api
set.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 47 insertions, 0 deletions

diff --git a/Documentation/w1/masters/w1-gpio.rst b/Documentation/w1/masters/w1-gpio.rst
new file mode 100644
index 000000000000..18fdb7366372
--- /dev/null
+++ b/Documentation/w1/masters/w1-gpio.rst
@@ -0,0 +1,47 @@
+=====================
+Kernel driver w1-gpio
+=====================
+
+Author: Ville Syrjala <syrjala@sci.fi>
+
+
+Description
+-----------
+
+GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
+wire and the GPIO pin can be specified using GPIO machine descriptor tables.
+It is also possible to define the master using device tree, see
+Documentation/devicetree/bindings/w1/w1-gpio.txt
+
+
+Example (mach-at91)
+-------------------
+
+::
+
+  #include <linux/gpio/machine.h>
+  #include <linux/w1-gpio.h>
+
+  static struct gpiod_lookup_table foo_w1_gpiod_table = {
+	.dev_id = "w1-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("at91-gpio", AT91_PIN_PB20, NULL, 0,
+			GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN),
+	},
+  };
+
+  static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
+	.ext_pullup_enable_pin	= -EINVAL,
+  };
+
+  static struct platform_device foo_w1_device = {
+	.name			= "w1-gpio",
+	.id			= -1,
+	.dev.platform_data	= &foo_w1_gpio_pdata,
+  };
+
+  ...
+	at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
+	at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
+	gpiod_add_lookup_table(&foo_w1_gpiod_table);
+	platform_device_register(&foo_w1_device);