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283 lines
8.1 KiB
283 lines
8.1 KiB
From eda15425bcd2703ea1cfeebd65847305c17e5f0a Mon Sep 17 00:00:00 2001
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From: John Crispin <blogic@openwrt.org>
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Date: Wed, 27 Mar 2013 18:38:48 +0100
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Subject: [PATCH] owrt: GPIO: add gpio_export_with_name
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http://lists.infradead.org/pipermail/linux-arm-kernel/2012-November/133856.html
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Signed-off-by: John Crispin <blogic@openwrt.org>
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---
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Documentation/devicetree/bindings/gpio/gpio.txt | 60 ++++++++++++++++++++++
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drivers/gpio/gpiolib-of.c | 61 +++++++++++++++++++++++
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drivers/gpio/gpiolib.c | 18 +++++--
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include/asm-generic/gpio.h | 6 ++-
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include/linux/gpio.h | 23 ++++++++-
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5 files changed, 160 insertions(+), 8 deletions(-)
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--- a/Documentation/devicetree/bindings/gpio/gpio.txt
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+++ b/Documentation/devicetree/bindings/gpio/gpio.txt
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@@ -112,3 +112,63 @@ where,
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The pinctrl node must have "#gpio-range-cells" property to show number of
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arguments to pass with phandle from gpio controllers node.
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+
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+3) gpio-export
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+--------------
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+
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+gpio-export will allow you to automatically export gpio
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+
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+required properties:
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+- compatible: Should be "gpio-export"
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+
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+in each child node will reprensent a gpio or if no name is specified
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+a list of gpio to export
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+
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+required properties:
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+- gpios: gpio to export
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+
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+optional properties:
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+ - gpio-export,name: export name
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+ - gpio-export,output: to set the as output with default value
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+ if no present gpio as input
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+ - pio-export,direction_may_change: boolean to allow the direction to be controllable
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+
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+Example:
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+
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+
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+gpio_export {
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+ compatible = "gpio-export";
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+ #size-cells = <0>;
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+
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+ in {
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+ gpio-export,name = "in";
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+ gpios = <&pioC 20 0>;
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+ };
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+
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+ out {
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+ gpio-export,name = "out";
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+ gpio-export,output = <1>;
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+ gpio-export,direction_may_change;
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+ gpios = <&pioC 21 0>;
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+ };
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+
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+ in_out {
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+ gpio-export,name = "in_out";
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+ gpio-export,direction_may_change;
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+ gpios = <&pioC 21 0>;
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+ };
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+
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+ gpios_in {
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+ gpios = <&pioB 0 0
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+ &pioB 3 0
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+ &pioC 4 0>;
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+ gpio-export,direction_may_change;
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+ };
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+
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+ gpios_out {
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+ gpios = <&pioB 1 0
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+ &pioB 2 0
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+ &pioC 3 0>;
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+ gpio-export,output = <1>;
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+ };
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+};
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--- a/drivers/gpio/gpiolib-of.c
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+++ b/drivers/gpio/gpiolib-of.c
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@@ -21,6 +21,8 @@
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#include <linux/of_gpio.h>
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#include <linux/pinctrl/pinctrl.h>
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#include <linux/slab.h>
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+#include <linux/init.h>
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+#include <linux/platform_device.h>
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/* Private data structure for of_gpiochip_find_and_xlate */
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struct gg_data {
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@@ -288,3 +290,69 @@ void of_gpiochip_remove(struct gpio_chip
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if (chip->of_node)
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of_node_put(chip->of_node);
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}
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+
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+static struct of_device_id gpio_export_ids[] = {
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+ { .compatible = "gpio-export" },
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+ { /* sentinel */ }
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+};
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+
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+static int __init of_gpio_export_probe(struct platform_device *pdev)
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+{
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+ struct device_node *np = pdev->dev.of_node;
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+ struct device_node *cnp;
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+ u32 val;
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+ int nb = 0;
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+
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+ for_each_child_of_node(np, cnp) {
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+ const char *name = NULL;
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+ int gpio;
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+ bool dmc;
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+ int max_gpio = 1;
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+ int i;
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+
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+ of_property_read_string(cnp, "gpio-export,name", &name);
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+
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+ if (!name)
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+ max_gpio = of_gpio_count(cnp);
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+
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+ for (i = 0; i < max_gpio; i++) {
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+ unsigned flags = 0;
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+ enum of_gpio_flags of_flags;
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+
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+ gpio = of_get_gpio_flags(cnp, i, &of_flags);
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+
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+ if (of_flags == OF_GPIO_ACTIVE_LOW)
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+ flags |= GPIOF_ACTIVE_LOW;
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+
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+ if (!of_property_read_u32(cnp, "gpio-export,output", &val))
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+ flags |= val ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
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+ else
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+ flags |= GPIOF_IN;
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+
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+ if (devm_gpio_request_one(&pdev->dev, gpio, flags, name ? name : of_node_full_name(np)))
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+ continue;
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+
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+ dmc = of_property_read_bool(cnp, "gpio-export,direction_may_change");
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+ gpio_export_with_name(gpio, dmc, name);
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+ nb++;
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+ }
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+ }
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+
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+ dev_info(&pdev->dev, "%d gpio(s) exported\n", nb);
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+
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+ return 0;
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+}
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+
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+static struct platform_driver gpio_export_driver = {
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+ .driver = {
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+ .name = "gpio-export",
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+ .owner = THIS_MODULE,
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+ .of_match_table = of_match_ptr(gpio_export_ids),
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+ },
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+};
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+
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+static int __init of_gpio_export_init(void)
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+{
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+ return platform_driver_probe(&gpio_export_driver, of_gpio_export_probe);
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+}
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+device_initcall(of_gpio_export_init);
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--- a/drivers/gpio/gpiolib.c
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+++ b/drivers/gpio/gpiolib.c
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@@ -714,9 +714,10 @@ static struct class gpio_class = {
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/**
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- * gpio_export - export a GPIO through sysfs
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+ * gpio_export_with_name - export a GPIO through sysfs
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* @gpio: gpio to make available, already requested
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* @direction_may_change: true if userspace may change gpio direction
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+ * @name: gpio name
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* Context: arch_initcall or later
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*
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* When drivers want to make a GPIO accessible to userspace after they
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@@ -728,7 +729,7 @@ static struct class gpio_class = {
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*
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* Returns zero on success, else an error.
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*/
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-int gpio_export(unsigned gpio, bool direction_may_change)
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+int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
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{
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unsigned long flags;
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struct gpio_desc *desc;
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@@ -762,6 +763,8 @@ int gpio_export(unsigned gpio, bool dire
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goto fail_unlock;
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}
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+ if (name)
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+ ioname = name;
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if (!desc->chip->direction_input || !desc->chip->direction_output)
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direction_may_change = false;
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spin_unlock_irqrestore(&gpio_lock, flags);
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@@ -804,7 +807,7 @@ fail_unlock:
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pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
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return status;
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}
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-EXPORT_SYMBOL_GPL(gpio_export);
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+EXPORT_SYMBOL_GPL(gpio_export_with_name);
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static int match_export(struct device *dev, void *data)
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{
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@@ -1418,6 +1421,9 @@ int gpio_request_one(unsigned gpio, unsi
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if (flags & GPIOF_OPEN_SOURCE)
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set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);
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+ if (flags & GPIOF_ACTIVE_LOW)
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+ set_bit(FLAG_ACTIVE_LOW, &gpio_desc[gpio].flags);
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+
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if (flags & GPIOF_DIR_IN)
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err = gpio_direction_input(gpio);
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else
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--- a/include/asm-generic/gpio.h
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+++ b/include/asm-generic/gpio.h
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@@ -204,7 +204,8 @@ void devm_gpio_free(struct device *dev,
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* A sysfs interface can be exported by individual drivers if they want,
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* but more typically is configured entirely from userspace.
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*/
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-extern int gpio_export(unsigned gpio, bool direction_may_change);
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+extern int gpio_export_with_name(unsigned gpio, bool direction_may_change,
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+ const char *name);
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extern int gpio_export_link(struct device *dev, const char *name,
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unsigned gpio);
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extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
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@@ -249,7 +250,8 @@ struct device;
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/* sysfs support is only available with gpiolib, where it's optional */
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-static inline int gpio_export(unsigned gpio, bool direction_may_change)
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+static inline int gpio_export_with_name(unsigned gpio,
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+ bool direction_may_change, const char *name)
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{
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return -ENOSYS;
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}
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--- a/include/linux/gpio.h
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+++ b/include/linux/gpio.h
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@@ -27,6 +27,9 @@
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#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
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#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
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+#define GPIOF_ACTIVE_LOW (1 << 6)
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+
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+
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/**
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* struct gpio - a structure describing a GPIO with configuration
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* @gpio: the GPIO number
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@@ -189,7 +192,8 @@ static inline void gpio_set_value_cansle
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WARN_ON(1);
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}
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-static inline int gpio_export(unsigned gpio, bool direction_may_change)
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+static inline int gpio_export_with_name(unsigned gpio,
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+ bool direction_may_change, const char *name)
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{
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/* GPIO can never have been requested or set as {in,out}put */
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WARN_ON(1);
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@@ -248,4 +252,24 @@ gpiochip_remove_pin_ranges(struct gpio_c
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#endif /* ! CONFIG_GENERIC_GPIO */
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+/**
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+ * gpio_export - export a GPIO through sysfs
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+ * @gpio: gpio to make available, already requested
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+ * @direction_may_change: true if userspace may change gpio direction
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+ * Context: arch_initcall or later
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+ *
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+ * When drivers want to make a GPIO accessible to userspace after they
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+ * have requested it -- perhaps while debugging, or as part of their
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+ * public interface -- they may use this routine. If the GPIO can
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+ * change direction (some can't) and the caller allows it, userspace
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+ * will see "direction" sysfs attribute which may be used to change
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+ * the gpio's direction. A "value" attribute will always be provided.
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+ *
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+ * Returns zero on success, else an error.
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+ */
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+static inline int gpio_export(unsigned gpio,bool direction_may_change)
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+{
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+ return gpio_export_with_name(gpio, direction_may_change, NULL);
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+}
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+
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#endif /* __LINUX_GPIO_H */
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