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-rw-r--r--Documentation/acpi/enumeration.txt32
-rw-r--r--drivers/gpio/gpiolib-acpi.c77
-rw-r--r--include/linux/acpi_gpio.h17
3 files changed, 125 insertions, 1 deletions
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index 94a6561..b0d5410 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -199,6 +199,8 @@ the device to the driver. For example:
{
Name (SBUF, ResourceTemplate()
{
+ ...
+ // Used to power on/off the device
GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0",
0x00, ResourceConsumer,,)
@@ -206,10 +208,20 @@ the device to the driver. For example:
// Pin List
0x0055
}
+
+ // Interrupt for the device
+ GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullNone,
+ 0x0000, "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer,,)
+ {
+ // Pin list
+ 0x0058
+ }
+
...
- Return (SBUF)
}
+
+ Return (SBUF)
}
These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0"
@@ -220,6 +232,24 @@ The driver can do this by including <linux/acpi_gpio.h> and then calling
acpi_get_gpio(path, gpio). This will return the Linux GPIO number or
negative errno if there was no translation found.
+In a simple case of just getting the Linux GPIO number from device
+resources one can use acpi_get_gpio_by_index() helper function. It takes
+pointer to the device and index of the GpioIo/GpioInt descriptor in the
+device resources list. For example:
+
+ int gpio_irq, gpio_power;
+ int ret;
+
+ gpio_irq = acpi_get_gpio_by_index(dev, 1, NULL);
+ if (gpio_irq < 0)
+ /* handle error */
+
+ gpio_power = acpi_get_gpio_by_index(dev, 0, NULL);
+ if (gpio_power < 0)
+ /* handle error */
+
+ /* Now we can use the GPIO numbers */
+
Other GpioIo parameters must be converted first by the driver to be
suitable to the gpiolib before passing them.
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 89336c4..5c1ef2b 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -201,6 +201,83 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
}
EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
+struct acpi_gpio_lookup {
+ struct acpi_gpio_info info;
+ int index;
+ int gpio;
+ int n;
+};
+
+static int acpi_find_gpio(struct acpi_resource *ares, void *data)
+{
+ struct acpi_gpio_lookup *lookup = data;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
+ return 1;
+
+ if (lookup->n++ == lookup->index && lookup->gpio < 0) {
+ const struct acpi_resource_gpio *agpio = &ares->data.gpio;
+
+ lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr,
+ agpio->pin_table[0]);
+ lookup->info.gpioint =
+ agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
+ }
+
+ return 1;
+}
+
+/**
+ * acpi_get_gpio_by_index() - get a GPIO number from device resources
+ * @dev: pointer to a device to get GPIO from
+ * @index: index of GpioIo/GpioInt resource (starting from %0)
+ * @info: info pointer to fill in (optional)
+ *
+ * Function goes through ACPI resources for @dev and based on @index looks
+ * up a GpioIo/GpioInt resource, translates it to the Linux GPIO number,
+ * and returns it. @index matches GpioIo/GpioInt resources only so if there
+ * are total %3 GPIO resources, the index goes from %0 to %2.
+ *
+ * If the GPIO cannot be translated or there is an error, negative errno is
+ * returned.
+ *
+ * Note: if the GPIO resource has multiple entries in the pin list, this
+ * function only returns the first.
+ */
+int acpi_get_gpio_by_index(struct device *dev, int index,
+ struct acpi_gpio_info *info)
+{
+ struct acpi_gpio_lookup lookup;
+ struct list_head resource_list;
+ struct acpi_device *adev;
+ acpi_handle handle;
+ int ret;
+
+ if (!dev)
+ return -EINVAL;
+
+ handle = ACPI_HANDLE(dev);
+ if (!handle || acpi_bus_get_device(handle, &adev))
+ return -ENODEV;
+
+ memset(&lookup, 0, sizeof(lookup));
+ lookup.index = index;
+ lookup.gpio = -ENODEV;
+
+ INIT_LIST_HEAD(&resource_list);
+ ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
+ &lookup);
+ if (ret < 0)
+ return ret;
+
+ acpi_dev_free_resource_list(&resource_list);
+
+ if (lookup.gpio >= 0 && info)
+ *info = lookup.info;
+
+ return lookup.gpio;
+}
+EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index);
/**
* acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
index 213135f..4c120a1 100644
--- a/include/linux/acpi_gpio.h
+++ b/include/linux/acpi_gpio.h
@@ -1,12 +1,23 @@
#ifndef _LINUX_ACPI_GPIO_H_
#define _LINUX_ACPI_GPIO_H_
+#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio.h>
+/**
+ * struct acpi_gpio_info - ACPI GPIO specific information
+ * @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
+ */
+struct acpi_gpio_info {
+ bool gpioint;
+};
+
#ifdef CONFIG_GPIO_ACPI
int acpi_get_gpio(char *path, int pin);
+int acpi_get_gpio_by_index(struct device *dev, int index,
+ struct acpi_gpio_info *info);
void acpi_gpiochip_request_interrupts(struct gpio_chip *chip);
void acpi_gpiochip_free_interrupts(struct gpio_chip *chip);
@@ -17,6 +28,12 @@ static inline int acpi_get_gpio(char *path, int pin)
return -ENODEV;
}
+static inline int acpi_get_gpio_by_index(struct device *dev, int index,
+ struct acpi_gpio_info *info)
+{
+ return -ENODEV;
+}
+
static inline void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) { }
static inline void acpi_gpiochip_free_interrupts(struct gpio_chip *chip) { }