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Date: Tue, 20 Dec 2011 21:40:21 +0100
From: John Crispin <blogic@...nwrt.org>
To: Grant Likely <grant.likely@...retlab.ca>
Cc: linux-kernel@...r.kernel.org, John Crispin <blogic@...nwrt.org>
Subject: [PATCH] GPIO: add bindings for managed devices
This patch adds 2 functions that allow managed devices to request GPIOs.
These GPIOs will then be managed by drivers/base/devres.c.
Signed-off-by: John Crispin <blogic@...nwrt.org>
---
drivers/gpio/Makefile | 2 +-
drivers/gpio/devres.c | 90 ++++++++++++++++++++++++++++++++++++++++++++
include/asm-generic/gpio.h | 4 ++
3 files changed, 95 insertions(+), 1 deletions(-)
create mode 100644 drivers/gpio/devres.c
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index dbcb0bc..da60964 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -2,7 +2,7 @@
ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
-obj-$(CONFIG_GPIOLIB) += gpiolib.o
+obj-$(CONFIG_GPIOLIB) += gpiolib.o devres.o
# Device drivers. Generally keep list sorted alphabetically
obj-$(CONFIG_GPIO_GENERIC) += gpio-generic.o
diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
new file mode 100644
index 0000000..3dd2939
--- /dev/null
+++ b/drivers/gpio/devres.c
@@ -0,0 +1,90 @@
+/*
+ * drivers/gpio/devres.c - managed gpio resources
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * This file is based on kernel/irq/devres.c
+ *
+ * Copyright (c) 2011 John Crispin <blogic@...nwrt.org>
+ */
+
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/device.h>
+#include <linux/gfp.h>
+
+static void devm_gpio_release(struct device *dev, void *res)
+{
+ unsigned *gpio = res;
+
+ gpio_free(*gpio);
+}
+
+static int devm_gpio_match(struct device *dev, void *res, void *data)
+{
+ unsigned *this = res, *gpio = data;
+
+ return *this == *gpio;
+}
+
+/**
+ * devm_gpio_request - request a gpio for a managed device
+ * @dev: device to request the gpio for
+ * @gpio: gpio to allocate
+ * @label: the name of the requested gpio
+ *
+ * Except for the extra @dev argument, this function takes the
+ * same arguments and performs the same function as
+ * gpio_request(). GPIOs requested with this function will be
+ * automatically freed on driver detach.
+ *
+ * If an GPIO allocated with this function needs to be freed
+ * separately, devm_gpio_free() must be used.
+ */
+
+int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
+{
+ unsigned *dr;
+ int rc;
+
+ dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
+ if (!dr)
+ return -ENOMEM;
+
+ rc = gpio_request(gpio, label);
+ if (rc) {
+ devres_free(dr);
+ return rc;
+ }
+
+ *dr = gpio;
+ devres_add(dev, dr);
+
+ return 0;
+}
+EXPORT_SYMBOL(devm_gpio_request);
+
+/**
+ * devm_gpio_free - free an interrupt
+ * @dev: device to free gpio for
+ * @gpio: gpio to free
+ *
+ * Except for the extra @dev argument, this function takes the
+ * same arguments and performs the same function as gpio_free().
+ * This function instead of gpio_free() should be used to manually
+ * free GPIOs allocated with devm_gpio_request().
+ */
+void devm_gpio_free(struct device *dev, unsigned int gpio)
+{
+
+ WARN_ON(devres_destroy(dev, devm_gpio_release, devm_gpio_match,
+ &gpio));
+ gpio_free(gpio);
+}
+EXPORT_SYMBOL(devm_gpio_free);
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 8c86210..8601a02 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -175,6 +175,10 @@ extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *labe
extern int gpio_request_array(const struct gpio *array, size_t num);
extern void gpio_free_array(const struct gpio *array, size_t num);
+/* bindings for managed devices that want to request gpios */
+int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
+void devm_gpio_free(struct device *dev, unsigned int gpio);
+
#ifdef CONFIG_GPIO_SYSFS
/*
--
1.7.7.1
--
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