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From eda15425bcd2703ea1cfeebd65847305c17e5f0a Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Wed, 27 Mar 2013 18:38:48 +0100
Subject: [PATCH] owrt: GPIO: add gpio_export_with_name
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-November/133856.html
Signed-off-by: John Crispin <blogic@openwrt.org>
---
Documentation/devicetree/bindings/gpio/gpio.txt | 60 ++++++++++++++++++++++
drivers/gpio/gpiolib-of.c | 61 +++++++++++++++++++++++
drivers/gpio/gpiolib.c | 18 +++++--
include/asm-generic/gpio.h | 6 ++-
include/linux/gpio.h | 23 ++++++++-
5 files changed, 160 insertions(+), 8 deletions(-)
--- a/Documentation/devicetree/bindings/gpio/gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio.txt
@@ -112,3 +112,63 @@ where,
The pinctrl node must have "#gpio-range-cells" property to show number of
arguments to pass with phandle from gpio controllers node.
+
+3) gpio-export
+--------------
+
+gpio-export will allow you to automatically export gpio
+
+required properties:
+- compatible: Should be "gpio-export"
+
+in each child node will reprensent a gpio or if no name is specified
+a list of gpio to export
+
+required properties:
+- gpios: gpio to export
+
+optional properties:
+ - gpio-export,name: export name
+ - gpio-export,output: to set the as output with default value
+ if no present gpio as input
+ - pio-export,direction_may_change: boolean to allow the direction to be controllable
+
+Example:
+
+
+gpio_export {
+ compatible = "gpio-export";
+ #size-cells = <0>;
+
+ in {
+ gpio-export,name = "in";
+ gpios = <&pioC 20 0>;
+ };
+
+ out {
+ gpio-export,name = "out";
+ gpio-export,output = <1>;
+ gpio-export,direction_may_change;
+ gpios = <&pioC 21 0>;
+ };
+
+ in_out {
+ gpio-export,name = "in_out";
+ gpio-export,direction_may_change;
+ gpios = <&pioC 21 0>;
+ };
+
+ gpios_in {
+ gpios = <&pioB 0 0
+ &pioB 3 0
+ &pioC 4 0>;
+ gpio-export,direction_may_change;
+ };
+
+ gpios_out {
+ gpios = <&pioB 1 0
+ &pioB 2 0
+ &pioC 3 0>;
+ gpio-export,output = <1>;
+ };
+};
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -21,6 +21,8 @@
#include <linux/of_gpio.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
/* Private data structure for of_gpiochip_find_and_xlate */
struct gg_data {
@@ -288,3 +290,62 @@ void of_gpiochip_remove(struct gpio_chip
if (chip->of_node)
of_node_put(chip->of_node);
}
+
+static struct of_device_id gpio_export_ids[] = {
+ { .compatible = "gpio-export" },
+ { /* sentinel */ }
+};
+
+static int __init of_gpio_export_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device_node *cnp;
+ u32 val;
+ int nb = 0;
+
+ for_each_child_of_node(np, cnp) {
+ const char *name = NULL;
+ int gpio;
+ bool dmc;
+ int max_gpio = 1;
+ int i;
+
+ of_property_read_string(cnp, "gpio-export,name", &name);
+
+ if (!name)
+ max_gpio = of_gpio_count(cnp);
+
+ for (i = 0; i < max_gpio; i++) {
+ gpio = of_get_gpio(cnp, i);
+ if (devm_gpio_request(&pdev->dev, gpio, name ? name : of_node_full_name(np)))
+ continue;
+
+ if (!of_property_read_u32(cnp, "gpio-export,output", &val))
+ gpio_direction_output(gpio, val);
+ else
+ gpio_direction_input(gpio);
+
+ dmc = of_property_read_bool(np, "gpio-export,direction_may_change");
+ gpio_export_with_name(gpio, dmc, name);
+ nb++;
+ }
+ }
+
+ dev_info(&pdev->dev, "%d gpio(s) exported\n", nb);
+
+ return 0;
+}
+
+static struct platform_driver gpio_export_driver = {
+ .driver = {
+ .name = "gpio-export",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(gpio_export_ids),
+ },
+};
+
+static int __init of_gpio_export_init(void)
+{
+ return platform_driver_probe(&gpio_export_driver, of_gpio_export_probe);
+}
+device_initcall(of_gpio_export_init);
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -714,9 +714,10 @@ static struct class gpio_class = {
/**
- * gpio_export - export a GPIO through sysfs
+ * gpio_export_with_name - export a GPIO through sysfs
* @gpio: gpio to make available, already requested
* @direction_may_change: true if userspace may change gpio direction
+ * @name: gpio name
* Context: arch_initcall or later
*
* When drivers want to make a GPIO accessible to userspace after they
@@ -728,7 +729,7 @@ static struct class gpio_class = {
*
* Returns zero on success, else an error.
*/
-int gpio_export(unsigned gpio, bool direction_may_change)
+int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
{
unsigned long flags;
struct gpio_desc *desc;
@@ -762,6 +763,8 @@ int gpio_export(unsigned gpio, bool dire
goto fail_unlock;
}
+ if (name)
+ ioname = name;
if (!desc->chip->direction_input || !desc->chip->direction_output)
direction_may_change = false;
spin_unlock_irqrestore(&gpio_lock, flags);
@@ -804,7 +807,7 @@ fail_unlock:
pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
return status;
}
-EXPORT_SYMBOL_GPL(gpio_export);
+EXPORT_SYMBOL_GPL(gpio_export_with_name);
static int match_export(struct device *dev, void *data)
{
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -204,7 +204,8 @@ void devm_gpio_free(struct device *dev,
* A sysfs interface can be exported by individual drivers if they want,
* but more typically is configured entirely from userspace.
*/
-extern int gpio_export(unsigned gpio, bool direction_may_change);
+extern int gpio_export_with_name(unsigned gpio, bool direction_may_change,
+ const char *name);
extern int gpio_export_link(struct device *dev, const char *name,
unsigned gpio);
extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
@@ -249,7 +250,8 @@ struct device;
/* sysfs support is only available with gpiolib, where it's optional */
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
+static inline int gpio_export_with_name(unsigned gpio,
+ bool direction_may_change, const char *name)
{
return -ENOSYS;
}
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -189,7 +189,8 @@ static inline void gpio_set_value_cansle
WARN_ON(1);
}
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
+static inline int gpio_export_with_name(unsigned gpio,
+ bool direction_may_change, const char *name)
{
/* GPIO can never have been requested or set as {in,out}put */
WARN_ON(1);
@@ -248,4 +249,24 @@ gpiochip_remove_pin_ranges(struct gpio_c
#endif /* ! CONFIG_GENERIC_GPIO */
+/**
+ * gpio_export - export a GPIO through sysfs
+ * @gpio: gpio to make available, already requested
+ * @direction_may_change: true if userspace may change gpio direction
+ * Context: arch_initcall or later
+ *
+ * When drivers want to make a GPIO accessible to userspace after they
+ * have requested it -- perhaps while debugging, or as part of their
+ * public interface -- they may use this routine. If the GPIO can
+ * change direction (some can't) and the caller allows it, userspace
+ * will see "direction" sysfs attribute which may be used to change
+ * the gpio's direction. A "value" attribute will always be provided.
+ *
+ * Returns zero on success, else an error.
+ */
+static inline int gpio_export(unsigned gpio,bool direction_may_change)
+{
+ return gpio_export_with_name(gpio, direction_may_change, NULL);
+}
+
#endif /* __LINUX_GPIO_H */
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