From 7d8a8b0e46a970fba505d967e93123e9729d97b5 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Sun, 23 Jun 2013 00:16:22 +0200
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 | 68 +++++++++++++++++++++++
drivers/gpio/gpiolib.c | 24 +++++---
include/asm-generic/gpio.h | 6 +-
include/linux/gpio.h | 26 ++++++++-
5 files changed, 172 insertions(+), 12 deletions(-)
diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
index a336287..c2a9024 100644
--- 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>;
+ };
+};
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 5150df6..195491b 100644
--- 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 {
@@ -253,3 +255,69 @@ void of_gpiochip_remove(struct gpio_chip *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++) {
+ unsigned flags = 0;
+ enum of_gpio_flags of_flags;
+
+ gpio = of_get_gpio_flags(cnp, i, &of_flags);
+
+ if (of_flags == OF_GPIO_ACTIVE_LOW)
+ flags |= GPIOF_ACTIVE_LOW;
+
+ if (!of_property_read_u32(cnp, "gpio-export,output", &val))
+ flags |= val ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+ else
+ flags |= GPIOF_IN;
+
+ if (devm_gpio_request_one(&pdev->dev, gpio, flags, name ? name : of_node_full_name(np)))
+ continue;
+
+ dmc = of_property_read_bool(cnp, "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);
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c2534d6..8697c82 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -96,7 +96,7 @@ static int gpiod_get_value(const struct gpio_desc *desc);
static void gpiod_set_value(struct gpio_desc *desc, int value);
static int gpiod_cansleep(const struct gpio_desc *desc);
static int gpiod_to_irq(const struct gpio_desc *desc);
-static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
+static int gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name);
static int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc);
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
@@ -674,7 +674,7 @@ static ssize_t export_store(struct class *class,
status = -ENODEV;
goto done;
}
- status = gpiod_export(desc, true);
+ status = gpiod_export(desc, true, NULL);
if (status < 0)
gpiod_free(desc);
else
@@ -736,9 +736,10 @@ 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
@@ -750,7 +751,7 @@ static struct class gpio_class = {
*
* Returns zero on success, else an error.
*/
-static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
+static int gpiod_export(struct gpio_desc *desc, bool direction_may_change, const char *name)
{
unsigned long flags;
int status;
@@ -783,6 +784,8 @@ static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
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);
@@ -829,11 +832,11 @@ fail_unlock:
return status;
}
-int gpio_export(unsigned gpio, bool direction_may_change)
+int gpio_export_with_name(unsigned gpio, bool direction_may_change, const char *name)
{
- return gpiod_export(gpio_to_desc(gpio), direction_may_change);
+ return gpiod_export(gpio_to_desc(gpio), direction_may_change, name);
}
-EXPORT_SYMBOL_GPL(gpio_export);
+EXPORT_SYMBOL_GPL(gpio_export_with_name);
static int match_export(struct device *dev, const void *data)
{
@@ -1092,7 +1095,7 @@ static inline void gpiochip_unexport(struct gpio_chip *chip)
}
static inline int gpiod_export(struct gpio_desc *desc,
- bool direction_may_change)
+ bool direction_may_change, const char *name)
{
return -ENOSYS;
}
@@ -1521,6 +1524,9 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
if (flags & GPIOF_OPEN_SOURCE)
set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+ if (flags & GPIOF_ACTIVE_LOW)
+ set_bit(FLAG_ACTIVE_LOW, &gpio_desc[gpio].flags);
+
if (flags & GPIOF_DIR_IN)
err = gpiod_direction_input(desc);
else
@@ -1531,7 +1537,7 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
goto free_gpio;
if (flags & GPIOF_EXPORT) {
- err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
+ err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE, NULL);
if (err)
goto free_gpio;
}
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index bde6469..3290572 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -202,7 +202,8 @@ extern void gpio_free_array(const struct gpio *array, size_t num);
* 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);
@@ -284,7 +285,8 @@ 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;
}
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index f6c7ae3..80a574a 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -27,6 +27,9 @@
#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
+#define GPIOF_ACTIVE_LOW (1 << 6)
+
+
/**
* struct gpio - a structure describing a GPIO with configuration
* @gpio: the GPIO number
@@ -169,7 +172,8 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
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);
@@ -236,4 +240,24 @@ int devm_gpio_request_one(struct device *dev, unsigned gpio,
unsigned long flags, const char *label);
void devm_gpio_free(struct device *dev, unsigned int 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 */
--
1.7.10.4