--- /dev/null
+#include <linux/idr.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/kdev_t.h>
+
+#include "gpiolib.h"
+
+static DEFINE_IDR(dirent_idr);
+
+
+/* lock protects against unexport_gpio() being called while
+ * sysfs files are active.
+ */
+static DEFINE_MUTEX(sysfs_lock);
+
+/*
+ * /sys/class/gpio/gpioN... only for GPIOs that are exported
+ * /direction
+ * * MAY BE OMITTED if kernel won't allow direction changes
+ * * is read/write as "in" or "out"
+ * * may also be written as "high" or "low", initializing
+ * output value as specified ("out" implies "low")
+ * /value
+ * * always readable, subject to hardware behavior
+ * * may be writable, as zero/nonzero
+ * /edge
+ * * configures behavior of poll(2) on /value
+ * * available only if pin can generate IRQs on input
+ * * is read/write as "none", "falling", "rising", or "both"
+ * /active_low
+ * * configures polarity of /value
+ * * is read/write as zero/nonzero
+ * * also affects existing and subsequent "falling" and "rising"
+ * /edge configuration
+ */
+
+static ssize_t gpio_direction_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ status = -EIO;
+ } else {
+ gpiod_get_direction(desc);
+ status = sprintf(buf, "%s\n",
+ test_bit(FLAG_IS_OUT, &desc->flags)
+ ? "out" : "in");
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static ssize_t gpio_direction_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else if (sysfs_streq(buf, "high"))
+ status = gpiod_direction_output_raw(desc, 1);
+ else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
+ status = gpiod_direction_output_raw(desc, 0);
+ else if (sysfs_streq(buf, "in"))
+ status = gpiod_direction_input(desc);
+ else
+ status = -EINVAL;
+
+ mutex_unlock(&sysfs_lock);
+ return status ? : size;
+}
+
+static /* const */ DEVICE_ATTR(direction, 0644,
+ gpio_direction_show, gpio_direction_store);
+
+static ssize_t gpio_value_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else
+ status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static ssize_t gpio_value_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else if (!test_bit(FLAG_IS_OUT, &desc->flags))
+ status = -EPERM;
+ else {
+ long value;
+
+ status = kstrtol(buf, 0, &value);
+ if (status == 0) {
+ gpiod_set_value_cansleep(desc, value);
+ status = size;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static const DEVICE_ATTR(value, 0644,
+ gpio_value_show, gpio_value_store);
+
+static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
+{
+ struct kernfs_node *value_sd = priv;
+
+ sysfs_notify_dirent(value_sd);
+ return IRQ_HANDLED;
+}
+
+static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
+ unsigned long gpio_flags)
+{
+ struct kernfs_node *value_sd;
+ unsigned long irq_flags;
+ int ret, irq, id;
+
+ if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
+ return 0;
+
+ irq = gpiod_to_irq(desc);
+ if (irq < 0)
+ return -EIO;
+
+ id = desc->flags >> ID_SHIFT;
+ value_sd = idr_find(&dirent_idr, id);
+ if (value_sd)
+ free_irq(irq, value_sd);
+
+ desc->flags &= ~GPIO_TRIGGER_MASK;
+
+ if (!gpio_flags) {
+ gpiod_unlock_as_irq(desc);
+ ret = 0;
+ goto free_id;
+ }
+
+ irq_flags = IRQF_SHARED;
+ if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
+ irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+ IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+ if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
+ irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+ IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+
+ if (!value_sd) {
+ value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
+ if (!value_sd) {
+ ret = -ENODEV;
+ goto err_out;
+ }
+
+ ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
+ if (ret < 0)
+ goto free_sd;
+ id = ret;
+
+ desc->flags &= GPIO_FLAGS_MASK;
+ desc->flags |= (unsigned long)id << ID_SHIFT;
+
+ if (desc->flags >> ID_SHIFT != id) {
+ ret = -ERANGE;
+ goto free_id;
+ }
+ }
+
+ ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
+ "gpiolib", value_sd);
+ if (ret < 0)
+ goto free_id;
+
+ ret = gpiod_lock_as_irq(desc);
+ if (ret < 0) {
+ gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
+ goto free_id;
+ }
+
+ desc->flags |= gpio_flags;
+ return 0;
+
+free_id:
+ idr_remove(&dirent_idr, id);
+ desc->flags &= GPIO_FLAGS_MASK;
+free_sd:
+ if (value_sd)
+ sysfs_put(value_sd);
+err_out:
+ return ret;
+}
+
+static const struct {
+ const char *name;
+ unsigned long flags;
+} trigger_types[] = {
+ { "none", 0 },
+ { "falling", BIT(FLAG_TRIG_FALL) },
+ { "rising", BIT(FLAG_TRIG_RISE) },
+ { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
+};
+
+static ssize_t gpio_edge_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else {
+ int i;
+
+ status = 0;
+ for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
+ if ((desc->flags & GPIO_TRIGGER_MASK)
+ == trigger_types[i].flags) {
+ status = sprintf(buf, "%s\n",
+ trigger_types[i].name);
+ break;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static ssize_t gpio_edge_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
+ if (sysfs_streq(trigger_types[i].name, buf))
+ goto found;
+ return -EINVAL;
+
+found:
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else {
+ status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
+ if (!status)
+ status = size;
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ return status;
+}
+
+static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
+
+static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
+ int value)
+{
+ int status = 0;
+
+ if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
+ return 0;
+
+ if (value)
+ set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+ else
+ clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
+ /* reconfigure poll(2) support if enabled on one edge only */
+ if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
+ !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
+ unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
+
+ gpio_setup_irq(desc, dev, 0);
+ status = gpio_setup_irq(desc, dev, trigger_flags);
+ }
+
+ return status;
+}
+
+static ssize_t gpio_active_low_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else
+ status = sprintf(buf, "%d\n",
+ !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
+
+ mutex_unlock(&sysfs_lock);
+
+ return status;
+}
+
+static ssize_t gpio_active_low_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ ssize_t status;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ status = -EIO;
+ } else {
+ long value;
+
+ status = kstrtol(buf, 0, &value);
+ if (status == 0)
+ status = sysfs_set_active_low(desc, dev, value != 0);
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ return status ? : size;
+}
+
+static const DEVICE_ATTR(active_low, 0644,
+ gpio_active_low_show, gpio_active_low_store);
+
+static const struct attribute *gpio_attrs[] = {
+ &dev_attr_value.attr,
+ &dev_attr_active_low.attr,
+ NULL,
+};
+
+static const struct attribute_group gpio_attr_group = {
+ .attrs = (struct attribute **) gpio_attrs,
+};
+
+/*
+ * /sys/class/gpio/gpiochipN/
+ * /base ... matching gpio_chip.base (N)
+ * /label ... matching gpio_chip.label
+ * /ngpio ... matching gpio_chip.ngpio
+ */
+
+static ssize_t chip_base_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_chip *chip = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", chip->base);
+}
+static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
+
+static ssize_t chip_label_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_chip *chip = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%s\n", chip->label ? : "");
+}
+static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
+
+static ssize_t chip_ngpio_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ const struct gpio_chip *chip = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", chip->ngpio);
+}
+static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
+
+static const struct attribute *gpiochip_attrs[] = {
+ &dev_attr_base.attr,
+ &dev_attr_label.attr,
+ &dev_attr_ngpio.attr,
+ NULL,
+};
+
+static const struct attribute_group gpiochip_attr_group = {
+ .attrs = (struct attribute **) gpiochip_attrs,
+};
+
+/*
+ * /sys/class/gpio/export ... write-only
+ * integer N ... number of GPIO to export (full access)
+ * /sys/class/gpio/unexport ... write-only
+ * integer N ... number of GPIO to unexport
+ */
+static ssize_t export_store(struct class *class,
+ struct class_attribute *attr,
+ const char *buf, size_t len)
+{
+ long gpio;
+ struct gpio_desc *desc;
+ int status;
+
+ status = kstrtol(buf, 0, &gpio);
+ if (status < 0)
+ goto done;
+
+ desc = gpio_to_desc(gpio);
+ /* reject invalid GPIOs */
+ if (!desc) {
+ pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+ return -EINVAL;
+ }
+
+ /* No extra locking here; FLAG_SYSFS just signifies that the
+ * request and export were done by on behalf of userspace, so
+ * they may be undone on its behalf too.
+ */
+
+ status = gpiod_request(desc, "sysfs");
+ if (status < 0) {
+ if (status == -EPROBE_DEFER)
+ status = -ENODEV;
+ goto done;
+ }
+ status = gpiod_export(desc, true);
+ if (status < 0)
+ gpiod_free(desc);
+ else
+ set_bit(FLAG_SYSFS, &desc->flags);
+
+done:
+ if (status)
+ pr_debug("%s: status %d\n", __func__, status);
+ return status ? : len;
+}
+
+static ssize_t unexport_store(struct class *class,
+ struct class_attribute *attr,
+ const char *buf, size_t len)
+{
+ long gpio;
+ struct gpio_desc *desc;
+ int status;
+
+ status = kstrtol(buf, 0, &gpio);
+ if (status < 0)
+ goto done;
+
+ desc = gpio_to_desc(gpio);
+ /* reject bogus commands (gpio_unexport ignores them) */
+ if (!desc) {
+ pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+ return -EINVAL;
+ }
+
+ status = -EINVAL;
+
+ /* No extra locking here; FLAG_SYSFS just signifies that the
+ * request and export were done by on behalf of userspace, so
+ * they may be undone on its behalf too.
+ */
+ if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
+ status = 0;
+ gpiod_free(desc);
+ }
+done:
+ if (status)
+ pr_debug("%s: status %d\n", __func__, status);
+ return status ? : len;
+}
+
+static struct class_attribute gpio_class_attrs[] = {
+ __ATTR(export, 0200, NULL, export_store),
+ __ATTR(unexport, 0200, NULL, unexport_store),
+ __ATTR_NULL,
+};
+
+static struct class gpio_class = {
+ .name = "gpio",
+ .owner = THIS_MODULE,
+
+ .class_attrs = gpio_class_attrs,
+};
+
+
+/**
+ * gpiod_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.
+ */
+int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
+{
+ unsigned long flags;
+ int status;
+ const char *ioname = NULL;
+ struct device *dev;
+ int offset;
+
+ /* can't export until sysfs is available ... */
+ if (!gpio_class.p) {
+ pr_debug("%s: called too early!\n", __func__);
+ return -ENOENT;
+ }
+
+ if (!desc) {
+ pr_debug("%s: invalid gpio descriptor\n", __func__);
+ return -EINVAL;
+ }
+
+ mutex_lock(&sysfs_lock);
+
+ spin_lock_irqsave(&gpio_lock, flags);
+ if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
+ test_bit(FLAG_EXPORT, &desc->flags)) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n",
+ __func__,
+ test_bit(FLAG_REQUESTED, &desc->flags),
+ test_bit(FLAG_EXPORT, &desc->flags));
+ status = -EPERM;
+ goto fail_unlock;
+ }
+
+ if (!desc->chip->direction_input || !desc->chip->direction_output)
+ direction_may_change = false;
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ offset = gpio_chip_hwgpio(desc);
+ if (desc->chip->names && desc->chip->names[offset])
+ ioname = desc->chip->names[offset];
+
+ dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
+ desc, ioname ? ioname : "gpio%u",
+ desc_to_gpio(desc));
+ if (IS_ERR(dev)) {
+ status = PTR_ERR(dev);
+ goto fail_unlock;
+ }
+
+ status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
+ if (status)
+ goto fail_unregister_device;
+
+ if (direction_may_change) {
+ status = device_create_file(dev, &dev_attr_direction);
+ if (status)
+ goto fail_unregister_device;
+ }
+
+ if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
+ !test_bit(FLAG_IS_OUT, &desc->flags))) {
+ status = device_create_file(dev, &dev_attr_edge);
+ if (status)
+ goto fail_unregister_device;
+ }
+
+ set_bit(FLAG_EXPORT, &desc->flags);
+ mutex_unlock(&sysfs_lock);
+ return 0;
+
+fail_unregister_device:
+ device_unregister(dev);
+fail_unlock:
+ mutex_unlock(&sysfs_lock);
+ gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpiod_export);
+
+static int match_export(struct device *dev, const void *data)
+{
+ return dev_get_drvdata(dev) == data;
+}
+
+/**
+ * gpiod_export_link - create a sysfs link to an exported GPIO node
+ * @dev: device under which to create symlink
+ * @name: name of the symlink
+ * @gpio: gpio to create symlink to, already exported
+ *
+ * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
+ * node. Caller is responsible for unlinking.
+ *
+ * Returns zero on success, else an error.
+ */
+int gpiod_export_link(struct device *dev, const char *name,
+ struct gpio_desc *desc)
+{
+ int status = -EINVAL;
+
+ if (!desc) {
+ pr_warn("%s: invalid GPIO\n", __func__);
+ return -EINVAL;
+ }
+
+ mutex_lock(&sysfs_lock);
+
+ if (test_bit(FLAG_EXPORT, &desc->flags)) {
+ struct device *tdev;
+
+ tdev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (tdev != NULL) {
+ status = sysfs_create_link(&dev->kobj, &tdev->kobj,
+ name);
+ } else {
+ status = -ENODEV;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ if (status)
+ gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpiod_export_link);
+
+/**
+ * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value
+ * @gpio: gpio to change
+ * @value: non-zero to use active low, i.e. inverted values
+ *
+ * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
+ * The GPIO does not have to be exported yet. If poll(2) support has
+ * been enabled for either rising or falling edge, it will be
+ * reconfigured to follow the new polarity.
+ *
+ * Returns zero on success, else an error.
+ */
+int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
+{
+ struct device *dev = NULL;
+ int status = -EINVAL;
+
+ if (!desc) {
+ pr_warn("%s: invalid GPIO\n", __func__);
+ return -EINVAL;
+ }
+
+ mutex_lock(&sysfs_lock);
+
+ if (test_bit(FLAG_EXPORT, &desc->flags)) {
+ dev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (dev == NULL) {
+ status = -ENODEV;
+ goto unlock;
+ }
+ }
+
+ status = sysfs_set_active_low(desc, dev, value);
+
+unlock:
+ mutex_unlock(&sysfs_lock);
+
+ if (status)
+ gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);
+
+/**
+ * gpiod_unexport - reverse effect of gpio_export()
+ * @gpio: gpio to make unavailable
+ *
+ * This is implicit on gpio_free().
+ */
+void gpiod_unexport(struct gpio_desc *desc)
+{
+ int status = 0;
+ struct device *dev = NULL;
+
+ if (!desc) {
+ pr_warn("%s: invalid GPIO\n", __func__);
+ return;
+ }
+
+ mutex_lock(&sysfs_lock);
+
+ if (test_bit(FLAG_EXPORT, &desc->flags)) {
+
+ dev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (dev) {
+ gpio_setup_irq(desc, dev, 0);
+ clear_bit(FLAG_EXPORT, &desc->flags);
+ } else
+ status = -ENODEV;
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ if (dev) {
+ device_unregister(dev);
+ put_device(dev);
+ }
+
+ if (status)
+ gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+}
+EXPORT_SYMBOL_GPL(gpiod_unexport);
+
+int gpiochip_export(struct gpio_chip *chip)
+{
+ int status;
+ struct device *dev;
+
+ /* Many systems register gpio chips for SOC support very early,
+ * before driver model support is available. In those cases we
+ * export this later, in gpiolib_sysfs_init() ... here we just
+ * verify that _some_ field of gpio_class got initialized.
+ */
+ if (!gpio_class.p)
+ return 0;
+
+ /* use chip->base for the ID; it's already known to be unique */
+ mutex_lock(&sysfs_lock);
+ dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
+ "gpiochip%d", chip->base);
+ if (!IS_ERR(dev)) {
+ status = sysfs_create_group(&dev->kobj,
+ &gpiochip_attr_group);
+ } else
+ status = PTR_ERR(dev);
+ chip->exported = (status == 0);
+ mutex_unlock(&sysfs_lock);
+
+ if (status) {
+ unsigned long flags;
+ unsigned gpio;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+ gpio = 0;
+ while (gpio < chip->ngpio)
+ chip->desc[gpio++].chip = NULL;
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ chip_dbg(chip, "%s: status %d\n", __func__, status);
+ }
+
+ return status;
+}
+
+void gpiochip_unexport(struct gpio_chip *chip)
+{
+ int status;
+ struct device *dev;
+
+ mutex_lock(&sysfs_lock);
+ dev = class_find_device(&gpio_class, NULL, chip, match_export);
+ if (dev) {
+ put_device(dev);
+ device_unregister(dev);
+ chip->exported = false;
+ status = 0;
+ } else
+ status = -ENODEV;
+ mutex_unlock(&sysfs_lock);
+
+ if (status)
+ chip_dbg(chip, "%s: status %d\n", __func__, status);
+}
+
+static int __init gpiolib_sysfs_init(void)
+{
+ int status;
+ unsigned long flags;
+ struct gpio_chip *chip;
+
+ status = class_register(&gpio_class);
+ if (status < 0)
+ return status;
+
+ /* Scan and register the gpio_chips which registered very
+ * early (e.g. before the class_register above was called).
+ *
+ * We run before arch_initcall() so chip->dev nodes can have
+ * registered, and so arch_initcall() can always gpio_export().
+ */
+ spin_lock_irqsave(&gpio_lock, flags);
+ list_for_each_entry(chip, &gpio_chips, list) {
+ if (!chip || chip->exported)
+ continue;
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ status = gpiochip_export(chip);
+ spin_lock_irqsave(&gpio_lock, flags);
+ }
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+
+ return status;
+}
+postcore_initcall(gpiolib_sysfs_init);
* While any GPIO is requested, its gpio_chip is not removable;
* each GPIO's "requested" flag serves as a lock and refcount.
*/
-static DEFINE_SPINLOCK(gpio_lock);
+DEFINE_SPINLOCK(gpio_lock);
-struct gpio_desc {
- struct gpio_chip *chip;
- unsigned long flags;
-/* flag symbols are bit numbers */
-#define FLAG_REQUESTED 0
-#define FLAG_IS_OUT 1
-#define FLAG_EXPORT 2 /* protected by sysfs_lock */
-#define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */
-#define FLAG_TRIG_FALL 4 /* trigger on falling edge */
-#define FLAG_TRIG_RISE 5 /* trigger on rising edge */
-#define FLAG_ACTIVE_LOW 6 /* value has active low */
-#define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */
-#define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */
-#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
-
-#define ID_SHIFT 16 /* add new flags before this one */
-
-#define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1)
-#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
-
- const char *label;
-};
static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
static DEFINE_MUTEX(gpio_lookup_lock);
static LIST_HEAD(gpio_lookup_list);
-static LIST_HEAD(gpio_chips);
-
-#ifdef CONFIG_GPIO_SYSFS
-static DEFINE_IDR(dirent_idr);
-#endif
-
-static int gpiod_request(struct gpio_desc *desc, const char *label);
-static void gpiod_free(struct gpio_desc *desc);
-
-/* With descriptor prefix */
-
-#define gpiod_emerg(desc, fmt, ...) \
- pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\
- ##__VA_ARGS__)
-#define gpiod_crit(desc, fmt, ...) \
- pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
- ##__VA_ARGS__)
-#define gpiod_err(desc, fmt, ...) \
- pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
- ##__VA_ARGS__)
-#define gpiod_warn(desc, fmt, ...) \
- pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
- ##__VA_ARGS__)
-#define gpiod_info(desc, fmt, ...) \
- pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
- ##__VA_ARGS__)
-#define gpiod_dbg(desc, fmt, ...) \
- pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\
- ##__VA_ARGS__)
-
-/* With chip prefix */
-
-#define chip_emerg(chip, fmt, ...) \
- pr_emerg("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
-#define chip_crit(chip, fmt, ...) \
- pr_crit("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
-#define chip_err(chip, fmt, ...) \
- pr_err("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
-#define chip_warn(chip, fmt, ...) \
- pr_warn("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
-#define chip_info(chip, fmt, ...) \
- pr_info("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
-#define chip_dbg(chip, fmt, ...) \
- pr_debug("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
+LIST_HEAD(gpio_chips);
static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
d->label = label;
}
-/*
- * Return the GPIO number of the passed descriptor relative to its chip
- */
-static int gpio_chip_hwgpio(const struct gpio_desc *desc)
-{
- return desc - &desc->chip->desc[0];
-}
-
/**
* Convert a GPIO number to its descriptor
*/
}
EXPORT_SYMBOL_GPL(gpiod_get_direction);
-#ifdef CONFIG_GPIO_SYSFS
-
-/* lock protects against unexport_gpio() being called while
- * sysfs files are active.
- */
-static DEFINE_MUTEX(sysfs_lock);
-
-/*
- * /sys/class/gpio/gpioN... only for GPIOs that are exported
- * /direction
- * * MAY BE OMITTED if kernel won't allow direction changes
- * * is read/write as "in" or "out"
- * * may also be written as "high" or "low", initializing
- * output value as specified ("out" implies "low")
- * /value
- * * always readable, subject to hardware behavior
- * * may be writable, as zero/nonzero
- * /edge
- * * configures behavior of poll(2) on /value
- * * available only if pin can generate IRQs on input
- * * is read/write as "none", "falling", "rising", or "both"
- * /active_low
- * * configures polarity of /value
- * * is read/write as zero/nonzero
- * * also affects existing and subsequent "falling" and "rising"
- * /edge configuration
- */
-
-static ssize_t gpio_direction_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- const struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags)) {
- status = -EIO;
- } else {
- gpiod_get_direction(desc);
- status = sprintf(buf, "%s\n",
- test_bit(FLAG_IS_OUT, &desc->flags)
- ? "out" : "in");
- }
-
- mutex_unlock(&sysfs_lock);
- return status;
-}
-
-static ssize_t gpio_direction_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
-{
- struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- status = -EIO;
- else if (sysfs_streq(buf, "high"))
- status = gpiod_direction_output_raw(desc, 1);
- else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
- status = gpiod_direction_output_raw(desc, 0);
- else if (sysfs_streq(buf, "in"))
- status = gpiod_direction_input(desc);
- else
- status = -EINVAL;
-
- mutex_unlock(&sysfs_lock);
- return status ? : size;
-}
-
-static /* const */ DEVICE_ATTR(direction, 0644,
- gpio_direction_show, gpio_direction_store);
-
-static ssize_t gpio_value_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- status = -EIO;
- else
- status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
-
- mutex_unlock(&sysfs_lock);
- return status;
-}
-
-static ssize_t gpio_value_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
-{
- struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- status = -EIO;
- else if (!test_bit(FLAG_IS_OUT, &desc->flags))
- status = -EPERM;
- else {
- long value;
-
- status = kstrtol(buf, 0, &value);
- if (status == 0) {
- gpiod_set_value_cansleep(desc, value);
- status = size;
- }
- }
-
- mutex_unlock(&sysfs_lock);
- return status;
-}
-
-static const DEVICE_ATTR(value, 0644,
- gpio_value_show, gpio_value_store);
-
-static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
-{
- struct kernfs_node *value_sd = priv;
-
- sysfs_notify_dirent(value_sd);
- return IRQ_HANDLED;
-}
-
-static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
- unsigned long gpio_flags)
-{
- struct kernfs_node *value_sd;
- unsigned long irq_flags;
- int ret, irq, id;
-
- if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
- return 0;
-
- irq = gpiod_to_irq(desc);
- if (irq < 0)
- return -EIO;
-
- id = desc->flags >> ID_SHIFT;
- value_sd = idr_find(&dirent_idr, id);
- if (value_sd)
- free_irq(irq, value_sd);
-
- desc->flags &= ~GPIO_TRIGGER_MASK;
-
- if (!gpio_flags) {
- gpiod_unlock_as_irq(desc);
- ret = 0;
- goto free_id;
- }
-
- irq_flags = IRQF_SHARED;
- if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
- irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
- IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
- if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
- irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
- IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
-
- if (!value_sd) {
- value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
- if (!value_sd) {
- ret = -ENODEV;
- goto err_out;
- }
-
- ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
- if (ret < 0)
- goto free_sd;
- id = ret;
-
- desc->flags &= GPIO_FLAGS_MASK;
- desc->flags |= (unsigned long)id << ID_SHIFT;
-
- if (desc->flags >> ID_SHIFT != id) {
- ret = -ERANGE;
- goto free_id;
- }
- }
-
- ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
- "gpiolib", value_sd);
- if (ret < 0)
- goto free_id;
-
- ret = gpiod_lock_as_irq(desc);
- if (ret < 0) {
- gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
- goto free_id;
- }
-
- desc->flags |= gpio_flags;
- return 0;
-
-free_id:
- idr_remove(&dirent_idr, id);
- desc->flags &= GPIO_FLAGS_MASK;
-free_sd:
- if (value_sd)
- sysfs_put(value_sd);
-err_out:
- return ret;
-}
-
-static const struct {
- const char *name;
- unsigned long flags;
-} trigger_types[] = {
- { "none", 0 },
- { "falling", BIT(FLAG_TRIG_FALL) },
- { "rising", BIT(FLAG_TRIG_RISE) },
- { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
-};
-
-static ssize_t gpio_edge_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- const struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- status = -EIO;
- else {
- int i;
-
- status = 0;
- for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
- if ((desc->flags & GPIO_TRIGGER_MASK)
- == trigger_types[i].flags) {
- status = sprintf(buf, "%s\n",
- trigger_types[i].name);
- break;
- }
- }
-
- mutex_unlock(&sysfs_lock);
- return status;
-}
-
-static ssize_t gpio_edge_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
-{
- struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
- int i;
-
- for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
- if (sysfs_streq(trigger_types[i].name, buf))
- goto found;
- return -EINVAL;
-
-found:
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- status = -EIO;
- else {
- status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
- if (!status)
- status = size;
- }
-
- mutex_unlock(&sysfs_lock);
-
- return status;
-}
-
-static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
-
-static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
- int value)
-{
- int status = 0;
-
- if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
- return 0;
-
- if (value)
- set_bit(FLAG_ACTIVE_LOW, &desc->flags);
- else
- clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
-
- /* reconfigure poll(2) support if enabled on one edge only */
- if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
- !!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
- unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
-
- gpio_setup_irq(desc, dev, 0);
- status = gpio_setup_irq(desc, dev, trigger_flags);
- }
-
- return status;
-}
-
-static ssize_t gpio_active_low_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- const struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- status = -EIO;
- else
- status = sprintf(buf, "%d\n",
- !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
-
- mutex_unlock(&sysfs_lock);
-
- return status;
-}
-
-static ssize_t gpio_active_low_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
-{
- struct gpio_desc *desc = dev_get_drvdata(dev);
- ssize_t status;
-
- mutex_lock(&sysfs_lock);
-
- if (!test_bit(FLAG_EXPORT, &desc->flags)) {
- status = -EIO;
- } else {
- long value;
-
- status = kstrtol(buf, 0, &value);
- if (status == 0)
- status = sysfs_set_active_low(desc, dev, value != 0);
- }
-
- mutex_unlock(&sysfs_lock);
-
- return status ? : size;
-}
-
-static const DEVICE_ATTR(active_low, 0644,
- gpio_active_low_show, gpio_active_low_store);
-
-static const struct attribute *gpio_attrs[] = {
- &dev_attr_value.attr,
- &dev_attr_active_low.attr,
- NULL,
-};
-
-static const struct attribute_group gpio_attr_group = {
- .attrs = (struct attribute **) gpio_attrs,
-};
-
-/*
- * /sys/class/gpio/gpiochipN/
- * /base ... matching gpio_chip.base (N)
- * /label ... matching gpio_chip.label
- * /ngpio ... matching gpio_chip.ngpio
- */
-
-static ssize_t chip_base_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- const struct gpio_chip *chip = dev_get_drvdata(dev);
-
- return sprintf(buf, "%d\n", chip->base);
-}
-static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
-
-static ssize_t chip_label_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- const struct gpio_chip *chip = dev_get_drvdata(dev);
-
- return sprintf(buf, "%s\n", chip->label ? : "");
-}
-static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
-
-static ssize_t chip_ngpio_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- const struct gpio_chip *chip = dev_get_drvdata(dev);
-
- return sprintf(buf, "%u\n", chip->ngpio);
-}
-static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
-
-static const struct attribute *gpiochip_attrs[] = {
- &dev_attr_base.attr,
- &dev_attr_label.attr,
- &dev_attr_ngpio.attr,
- NULL,
-};
-
-static const struct attribute_group gpiochip_attr_group = {
- .attrs = (struct attribute **) gpiochip_attrs,
-};
-
-/*
- * /sys/class/gpio/export ... write-only
- * integer N ... number of GPIO to export (full access)
- * /sys/class/gpio/unexport ... write-only
- * integer N ... number of GPIO to unexport
- */
-static ssize_t export_store(struct class *class,
- struct class_attribute *attr,
- const char *buf, size_t len)
-{
- long gpio;
- struct gpio_desc *desc;
- int status;
-
- status = kstrtol(buf, 0, &gpio);
- if (status < 0)
- goto done;
-
- desc = gpio_to_desc(gpio);
- /* reject invalid GPIOs */
- if (!desc) {
- pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
- return -EINVAL;
- }
-
- /* No extra locking here; FLAG_SYSFS just signifies that the
- * request and export were done by on behalf of userspace, so
- * they may be undone on its behalf too.
- */
-
- status = gpiod_request(desc, "sysfs");
- if (status < 0) {
- if (status == -EPROBE_DEFER)
- status = -ENODEV;
- goto done;
- }
- status = gpiod_export(desc, true);
- if (status < 0)
- gpiod_free(desc);
- else
- set_bit(FLAG_SYSFS, &desc->flags);
-
-done:
- if (status)
- pr_debug("%s: status %d\n", __func__, status);
- return status ? : len;
-}
-
-static ssize_t unexport_store(struct class *class,
- struct class_attribute *attr,
- const char *buf, size_t len)
-{
- long gpio;
- struct gpio_desc *desc;
- int status;
-
- status = kstrtol(buf, 0, &gpio);
- if (status < 0)
- goto done;
-
- desc = gpio_to_desc(gpio);
- /* reject bogus commands (gpio_unexport ignores them) */
- if (!desc) {
- pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
- return -EINVAL;
- }
-
- status = -EINVAL;
-
- /* No extra locking here; FLAG_SYSFS just signifies that the
- * request and export were done by on behalf of userspace, so
- * they may be undone on its behalf too.
- */
- if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
- status = 0;
- gpiod_free(desc);
- }
-done:
- if (status)
- pr_debug("%s: status %d\n", __func__, status);
- return status ? : len;
-}
-
-static struct class_attribute gpio_class_attrs[] = {
- __ATTR(export, 0200, NULL, export_store),
- __ATTR(unexport, 0200, NULL, unexport_store),
- __ATTR_NULL,
-};
-
-static struct class gpio_class = {
- .name = "gpio",
- .owner = THIS_MODULE,
-
- .class_attrs = gpio_class_attrs,
-};
-
-
-/**
- * gpiod_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.
- */
-int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
-{
- unsigned long flags;
- int status;
- const char *ioname = NULL;
- struct device *dev;
- int offset;
-
- /* can't export until sysfs is available ... */
- if (!gpio_class.p) {
- pr_debug("%s: called too early!\n", __func__);
- return -ENOENT;
- }
-
- if (!desc) {
- pr_debug("%s: invalid gpio descriptor\n", __func__);
- return -EINVAL;
- }
-
- mutex_lock(&sysfs_lock);
-
- spin_lock_irqsave(&gpio_lock, flags);
- if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
- test_bit(FLAG_EXPORT, &desc->flags)) {
- spin_unlock_irqrestore(&gpio_lock, flags);
- gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n",
- __func__,
- test_bit(FLAG_REQUESTED, &desc->flags),
- test_bit(FLAG_EXPORT, &desc->flags));
- status = -EPERM;
- goto fail_unlock;
- }
-
- if (!desc->chip->direction_input || !desc->chip->direction_output)
- direction_may_change = false;
- spin_unlock_irqrestore(&gpio_lock, flags);
-
- offset = gpio_chip_hwgpio(desc);
- if (desc->chip->names && desc->chip->names[offset])
- ioname = desc->chip->names[offset];
-
- dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
- desc, ioname ? ioname : "gpio%u",
- desc_to_gpio(desc));
- if (IS_ERR(dev)) {
- status = PTR_ERR(dev);
- goto fail_unlock;
- }
-
- status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
- if (status)
- goto fail_unregister_device;
-
- if (direction_may_change) {
- status = device_create_file(dev, &dev_attr_direction);
- if (status)
- goto fail_unregister_device;
- }
-
- if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
- !test_bit(FLAG_IS_OUT, &desc->flags))) {
- status = device_create_file(dev, &dev_attr_edge);
- if (status)
- goto fail_unregister_device;
- }
-
- set_bit(FLAG_EXPORT, &desc->flags);
- mutex_unlock(&sysfs_lock);
- return 0;
-
-fail_unregister_device:
- device_unregister(dev);
-fail_unlock:
- mutex_unlock(&sysfs_lock);
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
- return status;
-}
-EXPORT_SYMBOL_GPL(gpiod_export);
-
-static int match_export(struct device *dev, const void *data)
-{
- return dev_get_drvdata(dev) == data;
-}
-
-/**
- * gpiod_export_link - create a sysfs link to an exported GPIO node
- * @dev: device under which to create symlink
- * @name: name of the symlink
- * @gpio: gpio to create symlink to, already exported
- *
- * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
- * node. Caller is responsible for unlinking.
- *
- * Returns zero on success, else an error.
- */
-int gpiod_export_link(struct device *dev, const char *name,
- struct gpio_desc *desc)
-{
- int status = -EINVAL;
-
- if (!desc) {
- pr_warn("%s: invalid GPIO\n", __func__);
- return -EINVAL;
- }
-
- mutex_lock(&sysfs_lock);
-
- if (test_bit(FLAG_EXPORT, &desc->flags)) {
- struct device *tdev;
-
- tdev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (tdev != NULL) {
- status = sysfs_create_link(&dev->kobj, &tdev->kobj,
- name);
- } else {
- status = -ENODEV;
- }
- }
-
- mutex_unlock(&sysfs_lock);
-
- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
-
- return status;
-}
-EXPORT_SYMBOL_GPL(gpiod_export_link);
-
-/**
- * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value
- * @gpio: gpio to change
- * @value: non-zero to use active low, i.e. inverted values
- *
- * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
- * The GPIO does not have to be exported yet. If poll(2) support has
- * been enabled for either rising or falling edge, it will be
- * reconfigured to follow the new polarity.
- *
- * Returns zero on success, else an error.
- */
-int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
-{
- struct device *dev = NULL;
- int status = -EINVAL;
-
- if (!desc) {
- pr_warn("%s: invalid GPIO\n", __func__);
- return -EINVAL;
- }
-
- mutex_lock(&sysfs_lock);
-
- if (test_bit(FLAG_EXPORT, &desc->flags)) {
- dev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (dev == NULL) {
- status = -ENODEV;
- goto unlock;
- }
- }
-
- status = sysfs_set_active_low(desc, dev, value);
-
-unlock:
- mutex_unlock(&sysfs_lock);
-
- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
-
- return status;
-}
-EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);
-
-/**
- * gpiod_unexport - reverse effect of gpio_export()
- * @gpio: gpio to make unavailable
- *
- * This is implicit on gpio_free().
- */
-void gpiod_unexport(struct gpio_desc *desc)
-{
- int status = 0;
- struct device *dev = NULL;
-
- if (!desc) {
- pr_warn("%s: invalid GPIO\n", __func__);
- return;
- }
-
- mutex_lock(&sysfs_lock);
-
- if (test_bit(FLAG_EXPORT, &desc->flags)) {
-
- dev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (dev) {
- gpio_setup_irq(desc, dev, 0);
- clear_bit(FLAG_EXPORT, &desc->flags);
- } else
- status = -ENODEV;
- }
-
- mutex_unlock(&sysfs_lock);
-
- if (dev) {
- device_unregister(dev);
- put_device(dev);
- }
-
- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
-}
-EXPORT_SYMBOL_GPL(gpiod_unexport);
-
-static int gpiochip_export(struct gpio_chip *chip)
-{
- int status;
- struct device *dev;
-
- /* Many systems register gpio chips for SOC support very early,
- * before driver model support is available. In those cases we
- * export this later, in gpiolib_sysfs_init() ... here we just
- * verify that _some_ field of gpio_class got initialized.
- */
- if (!gpio_class.p)
- return 0;
-
- /* use chip->base for the ID; it's already known to be unique */
- mutex_lock(&sysfs_lock);
- dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
- "gpiochip%d", chip->base);
- if (!IS_ERR(dev)) {
- status = sysfs_create_group(&dev->kobj,
- &gpiochip_attr_group);
- } else
- status = PTR_ERR(dev);
- chip->exported = (status == 0);
- mutex_unlock(&sysfs_lock);
-
- if (status) {
- unsigned long flags;
- unsigned gpio;
-
- spin_lock_irqsave(&gpio_lock, flags);
- gpio = 0;
- while (gpio < chip->ngpio)
- chip->desc[gpio++].chip = NULL;
- spin_unlock_irqrestore(&gpio_lock, flags);
-
- chip_dbg(chip, "%s: status %d\n", __func__, status);
- }
-
- return status;
-}
-
-static void gpiochip_unexport(struct gpio_chip *chip)
-{
- int status;
- struct device *dev;
-
- mutex_lock(&sysfs_lock);
- dev = class_find_device(&gpio_class, NULL, chip, match_export);
- if (dev) {
- put_device(dev);
- device_unregister(dev);
- chip->exported = false;
- status = 0;
- } else
- status = -ENODEV;
- mutex_unlock(&sysfs_lock);
-
- if (status)
- chip_dbg(chip, "%s: status %d\n", __func__, status);
-}
-
-static int __init gpiolib_sysfs_init(void)
-{
- int status;
- unsigned long flags;
- struct gpio_chip *chip;
-
- status = class_register(&gpio_class);
- if (status < 0)
- return status;
-
- /* Scan and register the gpio_chips which registered very
- * early (e.g. before the class_register above was called).
- *
- * We run before arch_initcall() so chip->dev nodes can have
- * registered, and so arch_initcall() can always gpio_export().
- */
- spin_lock_irqsave(&gpio_lock, flags);
- list_for_each_entry(chip, &gpio_chips, list) {
- if (!chip || chip->exported)
- continue;
-
- spin_unlock_irqrestore(&gpio_lock, flags);
- status = gpiochip_export(chip);
- spin_lock_irqsave(&gpio_lock, flags);
- }
- spin_unlock_irqrestore(&gpio_lock, flags);
-
-
- return status;
-}
-postcore_initcall(gpiolib_sysfs_init);
-
-#else
-static inline int gpiochip_export(struct gpio_chip *chip)
-{
- return 0;
-}
-
-static inline void gpiochip_unexport(struct gpio_chip *chip)
-{
-}
-
-#endif /* CONFIG_GPIO_SYSFS */
-
/*
* Add a new chip to the global chips list, keeping the list of chips sorted
* by base order.
return status;
}
-static int gpiod_request(struct gpio_desc *desc, const char *label)
+int gpiod_request(struct gpio_desc *desc, const char *label)
{
int status = -EPROBE_DEFER;
struct gpio_chip *chip;
return ret;
}
-static void gpiod_free(struct gpio_desc *desc)
+void gpiod_free(struct gpio_desc *desc)
{
if (desc && __gpiod_free(desc))
module_put(desc->chip->owner);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff