Commit c80f1ba7 authored by Mika Westerberg's avatar Mika Westerberg Committed by Linus Walleij

ACPI / gpio: Add hogging support

GPIO hogging means that the GPIO controller can "hog" and configure certain
GPIOs without need for a driver or userspace to do that. This is useful in
open-connected boards where BIOS cannot possibly know beforehand which
devices will be connected to the board.

This adds GPIO hogging mechanism to ACPI analogous to Device Tree.
Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 6f7194a1
...@@ -66,6 +66,41 @@ native: ...@@ -66,6 +66,41 @@ native:
} }
} }
Other supported properties
--------------------------
Following Device Tree compatible device properties are also supported by
_DSD device properties for GPIO controllers:
- gpio-hog
- output-high
- output-low
- input
- line-name
Example:
Name (_DSD, Package () {
// _DSD Hierarchical Properties Extension UUID
ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
Package () {
Package () {"hog-gpio8", "G8PU"}
}
})
Name (G8PU, Package () {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () {"gpio-hog", 1},
Package () {"gpios", Package () {8, 0}},
Package () {"output-high", 1},
Package () {"line-name", "gpio8-pullup"},
}
})
See Documentation/devicetree/bindings/gpio/gpio.txt for more information
about these properties.
ACPI GPIO Mappings Provided by Drivers ACPI GPIO Mappings Provided by Drivers
-------------------------------------- --------------------------------------
......
...@@ -857,6 +857,76 @@ static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip) ...@@ -857,6 +857,76 @@ static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
} }
} }
struct gpio_desc *acpi_gpiochip_parse_own_gpio(struct acpi_gpio_chip *achip,
struct fwnode_handle *fwnode, const char **name, unsigned int *lflags,
unsigned int *dflags)
{
struct gpio_chip *chip = achip->chip;
struct gpio_desc *desc;
u32 gpios[2];
int ret;
ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios,
ARRAY_SIZE(gpios));
if (ret < 0)
return ERR_PTR(ret);
ret = acpi_gpiochip_pin_to_gpio_offset(chip->gpiodev, gpios[0]);
if (ret < 0)
return ERR_PTR(ret);
desc = gpiochip_get_desc(chip, ret);
if (IS_ERR(desc))
return desc;
*lflags = 0;
*dflags = 0;
*name = NULL;
if (gpios[1])
*lflags |= GPIO_ACTIVE_LOW;
if (fwnode_property_present(fwnode, "input"))
*dflags |= GPIOD_IN;
else if (fwnode_property_present(fwnode, "output-low"))
*dflags |= GPIOD_OUT_LOW;
else if (fwnode_property_present(fwnode, "output-high"))
*dflags |= GPIOD_OUT_HIGH;
else
return ERR_PTR(-EINVAL);
fwnode_property_read_string(fwnode, "line-name", name);
return desc;
}
static void acpi_gpiochip_scan_gpios(struct acpi_gpio_chip *achip)
{
struct gpio_chip *chip = achip->chip;
struct fwnode_handle *fwnode;
device_for_each_child_node(chip->parent, fwnode) {
unsigned int lflags, dflags;
struct gpio_desc *desc;
const char *name;
int ret;
if (!fwnode_property_present(fwnode, "gpio-hog"))
continue;
desc = acpi_gpiochip_parse_own_gpio(achip, fwnode, &name,
&lflags, &dflags);
if (IS_ERR(desc))
continue;
ret = gpiod_hog(desc, name, lflags, dflags);
if (ret) {
dev_err(chip->parent, "Failed to hog GPIO\n");
return;
}
}
}
void acpi_gpiochip_add(struct gpio_chip *chip) void acpi_gpiochip_add(struct gpio_chip *chip)
{ {
struct acpi_gpio_chip *acpi_gpio; struct acpi_gpio_chip *acpi_gpio;
...@@ -888,6 +958,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip) ...@@ -888,6 +958,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
} }
acpi_gpiochip_request_regions(acpi_gpio); acpi_gpiochip_request_regions(acpi_gpio);
acpi_gpiochip_scan_gpios(acpi_gpio);
acpi_walk_dep_device_list(handle); acpi_walk_dep_device_list(handle);
} }
......
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