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Date: Wed, 3 Apr 2013 13:56:54 +0300
From: Mika Westerberg <mika.westerberg@...ux.intel.com>
To: linux-kernel@...r.kernel.org
Cc: Grant Likely <grant.likely@...retlab.ca>,
Linus Walleij <linus.walleij@...aro.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Mathias Nyman <mathias.nyman@...ux.intel.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
linux-acpi@...r.kernel.org
Subject: [PATCH] gpiolib-acpi: introduce acpi_get_gpio_by_index() helper
Instead of open-coding ACPI GPIO resource lookup in each driver, we provide
a helper function analogous to Device Tree version that allows drivers to
specify which GPIO resource they are interested (using an index to the GPIO
resources). The function then finds out the correct resource, translates
the ACPI GPIO number to the corresponding Linux GPIO number and returns
that.
Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
---
Documentation/acpi/enumeration.txt | 32 ++++++++++++++-
drivers/gpio/gpiolib-acpi.c | 77 ++++++++++++++++++++++++++++++++++++
include/linux/acpi_gpio.h | 17 ++++++++
3 files changed, 125 insertions(+), 1 deletion(-)
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 a063eb0..b66df3b 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -54,6 +54,83 @@ int acpi_get_gpio(char *path, int pin)
}
EXPORT_SYMBOL_GPL(acpi_get_gpio);
+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);
static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
{
diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
index b76ebd0..598ea41 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);
#else /* CONFIG_GPIO_ACPI */
@@ -16,6 +27,12 @@ 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) { }
#endif /* CONFIG_GPIO_ACPI */
--
1.7.10.4
--
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