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);