diff options
author | Mika Westerberg <mika.westerberg@linux.intel.com> | 2016-10-21 16:21:30 +0200 |
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committer | Linus Walleij <linus.walleij@linaro.org> | 2016-10-24 16:33:11 +0200 |
commit | c80f1ba75df25837fb76044e06686b6587d33f6a (patch) | |
tree | f39b7fd7795bf25d0d6f19df7a86b57b667c0f06 /drivers/gpio/gpiolib-acpi.c | |
parent | ACPI / gpio: Allow holes in list of GPIOs for a device (diff) | |
download | linux-c80f1ba75df25837fb76044e06686b6587d33f6a.tar.xz linux-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>
Diffstat (limited to 'drivers/gpio/gpiolib-acpi.c')
-rw-r--r-- | drivers/gpio/gpiolib-acpi.c | 71 |
1 files changed, 71 insertions, 0 deletions
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); } |