134 lines
4 KiB
Diff
134 lines
4 KiB
Diff
From 282f1ca84b35f3be68abc4fd8b52e229f3cb6bb7 Mon Sep 17 00:00:00 2001
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From: John Crispin <blogic@openwrt.org>
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Date: Thu, 8 Mar 2012 13:23:53 +0100
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Subject: [PATCH 01/70] GPIO: add bindings for managed devices
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This patch adds 2 functions that allow managed devices to request GPIOs.
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These GPIOs will then be managed by drivers/base/devres.c.
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Signed-off-by: John Crispin <blogic@openwrt.org>
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Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
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---
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drivers/gpio/Makefile | 2 +-
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drivers/gpio/devres.c | 90 ++++++++++++++++++++++++++++++++++++++++++++
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include/asm-generic/gpio.h | 4 ++
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3 files changed, 95 insertions(+), 1 deletions(-)
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create mode 100644 drivers/gpio/devres.c
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--- a/drivers/gpio/Makefile
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+++ b/drivers/gpio/Makefile
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@@ -2,7 +2,7 @@
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ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
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-obj-$(CONFIG_GPIOLIB) += gpiolib.o
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+obj-$(CONFIG_GPIOLIB) += gpiolib.o devres.o
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# Device drivers. Generally keep list sorted alphabetically
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obj-$(CONFIG_GPIO_GENERIC) += gpio-generic.o
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--- /dev/null
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+++ b/drivers/gpio/devres.c
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@@ -0,0 +1,90 @@
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+/*
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+ * drivers/gpio/devres.c - managed gpio resources
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2
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+ * as published by the Free Software Foundation.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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+ *
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+ * This file is based on kernel/irq/devres.c
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+ *
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+ * Copyright (c) 2011 John Crispin <blogic@openwrt.org>
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+ */
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+
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+#include <linux/module.h>
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+#include <linux/gpio.h>
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+#include <linux/device.h>
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+#include <linux/gfp.h>
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+
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+static void devm_gpio_release(struct device *dev, void *res)
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+{
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+ unsigned *gpio = res;
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+
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+ gpio_free(*gpio);
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+}
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+
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+static int devm_gpio_match(struct device *dev, void *res, void *data)
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+{
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+ unsigned *this = res, *gpio = data;
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+
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+ return *this == *gpio;
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+}
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+
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+/**
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+ * devm_gpio_request - request a gpio for a managed device
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+ * @dev: device to request the gpio for
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+ * @gpio: gpio to allocate
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+ * @label: the name of the requested gpio
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+ *
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+ * Except for the extra @dev argument, this function takes the
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+ * same arguments and performs the same function as
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+ * gpio_request(). GPIOs requested with this function will be
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+ * automatically freed on driver detach.
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+ *
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+ * If an GPIO allocated with this function needs to be freed
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+ * separately, devm_gpio_free() must be used.
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+ */
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+
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+int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
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+{
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+ unsigned *dr;
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+ int rc;
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+
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+ dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
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+ if (!dr)
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+ return -ENOMEM;
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+
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+ rc = gpio_request(gpio, label);
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+ if (rc) {
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+ devres_free(dr);
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+ return rc;
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+ }
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+
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+ *dr = gpio;
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+ devres_add(dev, dr);
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+
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+ return 0;
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+}
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+EXPORT_SYMBOL(devm_gpio_request);
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+
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+/**
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+ * devm_gpio_free - free an interrupt
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+ * @dev: device to free gpio for
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+ * @gpio: gpio to free
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+ *
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+ * Except for the extra @dev argument, this function takes the
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+ * same arguments and performs the same function as gpio_free().
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+ * This function instead of gpio_free() should be used to manually
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+ * free GPIOs allocated with devm_gpio_request().
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+ */
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+void devm_gpio_free(struct device *dev, unsigned int gpio)
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+{
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+
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+ WARN_ON(devres_destroy(dev, devm_gpio_release, devm_gpio_match,
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+ &gpio));
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+ gpio_free(gpio);
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+}
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+EXPORT_SYMBOL(devm_gpio_free);
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--- a/include/asm-generic/gpio.h
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+++ b/include/asm-generic/gpio.h
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@@ -175,6 +175,10 @@ extern int gpio_request_one(unsigned gpi
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extern int gpio_request_array(const struct gpio *array, size_t num);
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extern void gpio_free_array(const struct gpio *array, size_t num);
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+/* bindings for managed devices that want to request gpios */
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+int devm_gpio_request(struct device *dev, unsigned gpio, const char *label);
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+void devm_gpio_free(struct device *dev, unsigned int gpio);
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+
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#ifdef CONFIG_GPIO_SYSFS
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/*
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