From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Add support for translating ACPI GPIO pin numbers to Linux GPIO API pins.
Needs a gpio controller driver with the acpi handler hook set.
Drivers can use acpi_get_gpio() to translate ACPI5 GpioIO and GpioInt
resources to Linux GPIO's.
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/gpio/Kconfig | 4 ++++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpiolib-acpi.c | 56 +++++++++++++++++++++++++++++++++++++++++++
include/linux/acpi_gpio.h | 19 +++++++++++++++
4 files changed, 80 insertions(+)
create mode 100644 drivers/gpio/gpiolib-acpi.c
create mode 100644 include/linux/acpi_gpio.h
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f11d8e3..5c9b384 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -49,6 +49,10 @@ config OF_GPIO
def_bool y
depends on OF
+config GPIO_ACPI
+ def_bool y
+ depends on ACPI
+
config DEBUG_GPIO
bool "Debug GPIO calls"
depends on DEBUG_KERNEL
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 9aeed67..420dbac 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -4,6 +4,7 @@ ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
obj-$(CONFIG_GPIOLIB) += gpiolib.o devres.o
obj-$(CONFIG_OF_GPIO) += gpiolib-of.o
+obj-$(CONFIG_GPIO_ACPI) += gpiolib-acpi.o
# Device drivers. Generally keep list sorted alphabetically
obj-$(CONFIG_GPIO_GENERIC) += gpio-generic.o
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
new file mode 100644
index 0000000..8ef9831
--- /dev/null
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -0,0 +1,56 @@
+/*
+ * ACPI helpers for GPIO API
+ *
+ * Copyright (C) 2012, Intel Corporation
+ * Authors: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
+ * Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/errno.h>
+#include <linux/gpio.h>
+#include <linux/export.h>
+#include <linux/acpi_gpio.h>
+#include <linux/acpi.h>
+
+static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
+{
+ acpi_handle handle = data;
+
+ if (!gc->dev)
+ return false;
+
+ return gc->dev->acpi_handle == handle;
+}
+
+/**
+ * acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API
+ * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
+ * @pin: ACPI GPIO pin number (0-based, controller-relative)
+ *
+ * Returns GPIO number to use with Linux generic GPIO API, or errno error value
+ */
+
+int acpi_get_gpio(char *path, int pin)
+{
+ struct gpio_chip *chip;
+ acpi_handle handle;
+ acpi_status status;
+
+ status = acpi_get_handle(NULL, path, &handle);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ chip = gpiochip_find(handle, acpi_gpiochip_find);
+ if (!chip)
+ return -ENODEV;
+
+ if (!gpio_is_valid(chip->base + pin))
+ return -EINVAL;
+
+ return chip->base + pin;
+}
+EXPORT_SYMBOL_GPL(acpi_get_gpio);
diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
new file mode 100644
index 0000000..91615a3
--- /dev/null
+++ b/include/linux/acpi_gpio.h
@@ -0,0 +1,19 @@
+#ifndef _LINUX_ACPI_GPIO_H_
+#define _LINUX_ACPI_GPIO_H_
+
+#include <linux/errno.h>
+
+#ifdef CONFIG_GPIO_ACPI
+
+int acpi_get_gpio(char *path, int pin);
+
+#else /* CONFIG_GPIO_ACPI */
+
+static inline int acpi_get_gpio(char *path, int pin)
+{
+ return -ENODEV;
+}
+
+#endif /* CONFIG_GPIO_ACPI */
+
+#endif /* _LINUX_ACPI_GPIO_H_ */
--
1.7.10.4
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