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author | Mika Westerberg <mika.westerberg@linux.intel.com> | 2016-10-21 17:21:30 +0300 |
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committer | Linus Walleij <linus.walleij@linaro.org> | 2016-10-24 16:33:11 +0200 |
commit | c80f1ba75df25837fb76044e06686b6587d33f6a (patch) | |
tree | f39b7fd7795bf25d0d6f19df7a86b57b667c0f06 | |
parent | 6f7194a10bdba1588357342c6daaaeef98e0004f (diff) | |
download | linux-stable-c80f1ba75df25837fb76044e06686b6587d33f6a.tar.gz linux-stable-c80f1ba75df25837fb76044e06686b6587d33f6a.tar.bz2 linux-stable-c80f1ba75df25837fb76044e06686b6587d33f6a.zip |
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: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
-rw-r--r-- | Documentation/acpi/gpio-properties.txt | 35 | ||||
-rw-r--r-- | drivers/gpio/gpiolib-acpi.c | 71 |
2 files changed, 106 insertions, 0 deletions
diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt index 09cff657b82c..d9076af271f5 100644 --- a/Documentation/acpi/gpio-properties.txt +++ b/Documentation/acpi/gpio-properties.txt @@ -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 -------------------------------------- diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c index 700ea6ad609b..4f46982ce982 100644 --- a/drivers/gpio/gpiolib-acpi.c +++ b/drivers/gpio/gpiolib-acpi.c @@ -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) { struct acpi_gpio_chip *acpi_gpio; @@ -888,6 +958,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip) } acpi_gpiochip_request_regions(acpi_gpio); + acpi_gpiochip_scan_gpios(acpi_gpio); acpi_walk_dep_device_list(handle); } |