zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/drivers/gpio/gpiolib.c b/ap/os/linux/linux-3.4.x/drivers/gpio/gpiolib.c
new file mode 100644
index 0000000..0f1190a
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/gpio/gpiolib.c
@@ -0,0 +1,1882 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/gpio.h>
+
+/* Optional implementation infrastructure for GPIO interfaces.
+ *
+ * Platforms may want to use this if they tend to use very many GPIOs
+ * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
+ *
+ * When kernel footprint or instruction count is an issue, simpler
+ * implementations may be preferred. The GPIO programming interface
+ * allows for inlining speed-critical get/set operations for common
+ * cases, so that access to SOC-integrated GPIOs can sometimes cost
+ * only an instruction or two per bit.
+ */
+
+
+/* When debugging, extend minimal trust to callers and platform code.
+ * Also emit diagnostic messages that may help initial bringup, when
+ * board setup or driver bugs are most common.
+ *
+ * Otherwise, minimize overhead in what may be bitbanging codepaths.
+ */
+#ifdef DEBUG
+#define extra_checks 1
+#else
+#define extra_checks 0
+#endif
+
+/* gpio_lock prevents conflicts during gpio_desc[] table updates.
+ * 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);
+
+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_RESERVED 2
+#define FLAG_EXPORT 3 /* protected by sysfs_lock */
+#define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */
+#define FLAG_TRIG_FALL 5 /* trigger on falling edge */
+#define FLAG_TRIG_RISE 6 /* trigger on rising edge */
+#define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */
+#define FLAG_OPEN_DRAIN 8 /* Gpio is open drain type */
+#define FLAG_OPEN_SOURCE 9 /* Gpio is open source type */
+#define FLAG_SYSFS_DIR 10 /* show sysfs direction attribute */
+
+#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))
+
+#ifdef CONFIG_DEBUG_FS
+ const char *label;
+#endif
+};
+static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
+
+#ifdef CONFIG_GPIO_SYSFS
+static DEFINE_IDR(dirent_idr);
+#endif
+
+static inline void desc_set_label(struct gpio_desc *d, const char *label)
+{
+#ifdef CONFIG_DEBUG_FS
+ d->label = label;
+#endif
+}
+
+/* Warn when drivers omit gpio_request() calls -- legal but ill-advised
+ * when setting direction, and otherwise illegal. Until board setup code
+ * and drivers use explicit requests everywhere (which won't happen when
+ * those calls have no teeth) we can't avoid autorequesting. This nag
+ * message should motivate switching to explicit requests... so should
+ * the weaker cleanup after faults, compared to gpio_request().
+ *
+ * NOTE: the autorequest mechanism is going away; at this point it's
+ * only "legal" in the sense that (old) code using it won't break yet,
+ * but instead only triggers a WARN() stack dump.
+ */
+static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
+{
+ const struct gpio_chip *chip = desc->chip;
+ const int gpio = chip->base + offset;
+
+ if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
+ "autorequest GPIO-%d\n", gpio)) {
+ if (!try_module_get(chip->owner)) {
+ pr_err("GPIO-%d: module can't be gotten \n", gpio);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ /* lose */
+ return -EIO;
+ }
+ desc_set_label(desc, "[auto]");
+ /* caller must chip->request() w/o spinlock */
+ if (chip->request)
+ return 1;
+ }
+ return 0;
+}
+
+/* caller holds gpio_lock *OR* gpio is marked as requested */
+struct gpio_chip *gpio_to_chip(unsigned gpio)
+{
+ return gpio_desc[gpio].chip;
+}
+
+/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
+static int gpiochip_find_base(int ngpio)
+{
+ int i;
+ int spare = 0;
+ int base = -ENOSPC;
+
+ for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
+ struct gpio_desc *desc = &gpio_desc[i];
+ struct gpio_chip *chip = desc->chip;
+
+ if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) {
+ spare++;
+ if (spare == ngpio) {
+ base = i;
+ break;
+ }
+ } else {
+ spare = 0;
+ if (chip)
+ i -= chip->ngpio - 1;
+ }
+ }
+
+ if (gpio_is_valid(base))
+ pr_debug("%s: found new base at %d\n", __func__, base);
+ return base;
+}
+
+/**
+ * gpiochip_reserve() - reserve range of gpios to use with platform code only
+ * @start: starting gpio number
+ * @ngpio: number of gpios to reserve
+ * Context: platform init, potentially before irqs or kmalloc will work
+ *
+ * Returns a negative errno if any gpio within the range is already reserved
+ * or registered, else returns zero as a success code. Use this function
+ * to mark a range of gpios as unavailable for dynamic gpio number allocation,
+ * for example because its driver support is not yet loaded.
+ */
+int __init gpiochip_reserve(int start, int ngpio)
+{
+ int ret = 0;
+ unsigned long flags;
+ int i;
+
+ if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1))
+ return -EINVAL;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ for (i = start; i < start + ngpio; i++) {
+ struct gpio_desc *desc = &gpio_desc[i];
+
+ if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) {
+ ret = -EBUSY;
+ goto err;
+ }
+
+ set_bit(FLAG_RESERVED, &desc->flags);
+ }
+
+ pr_debug("%s: reserved gpios from %d to %d\n",
+ __func__, start, start + ngpio - 1);
+err:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ return ret;
+}
+
+#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;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else
+ 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)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ unsigned gpio = desc - gpio_desc;
+ ssize_t status;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
+ status = -EIO;
+ else if (sysfs_streq(buf, "high"))
+ status = gpio_direction_output(gpio, 1);
+ else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
+ status = gpio_direction_output(gpio, 0);
+ else if (sysfs_streq(buf, "in"))
+ status = gpio_direction_input(gpio);
+ 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)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ unsigned gpio = desc - gpio_desc;
+ ssize_t status;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ status = -EIO;
+ } else {
+ int value;
+
+ value = !!gpio_get_value_cansleep(gpio);
+ if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+ value = !value;
+
+ status = sprintf(buf, "%d\n", value);
+ }
+
+ 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)
+{
+ const struct gpio_desc *desc = dev_get_drvdata(dev);
+ unsigned gpio = desc - gpio_desc;
+ ssize_t status;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ 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 = strict_strtol(buf, 0, &value);
+ if (status == 0) {
+ if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+ value = !value;
+ gpio_set_value_cansleep(gpio, value != 0);
+ status = size;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+ return status;
+}
+
+static DEVICE_ATTR(value, 0644,
+ gpio_value_show, gpio_value_store);
+
+static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
+{
+ struct sysfs_dirent *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 sysfs_dirent *value_sd;
+ unsigned long irq_flags;
+ int ret, irq, id;
+
+ if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
+ return 0;
+
+ irq = gpio_to_irq(desc - gpio_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) {
+ 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, NULL, "value");
+ if (!value_sd) {
+ ret = -ENODEV;
+ goto err_out;
+ }
+
+ do {
+ ret = -ENOMEM;
+ if (idr_pre_get(&dirent_idr, GFP_KERNEL))
+ ret = idr_get_new_above(&dirent_idr, value_sd,
+ 1, &id);
+ } while (ret == -EAGAIN);
+
+ if (ret)
+ goto free_sd;
+
+ 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;
+
+ 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;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ 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;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ 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;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ 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;
+
+ if(NULL==desc)
+ return -EINVAL;
+
+ mutex_lock(&sysfs_lock);
+
+ if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ status = -EIO;
+ } else {
+ long value;
+
+ status = strict_strtol(buf, 0, &value);
+ if (status == 0)
+ status = sysfs_set_active_low(desc, dev, value != 0);
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+ return status ? : size;
+}
+
+static DEVICE_ATTR(active_low, 0644,
+ gpio_active_low_show, gpio_active_low_store);
+
+static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
+ int n)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct gpio_desc *desc = dev_get_drvdata(dev);
+ unsigned gpio = desc - gpio_desc;
+ umode_t mode = attr->mode;
+ bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags);
+
+ if (attr == &dev_attr_direction.attr) {
+ if (!show_direction)
+ mode = 0;
+ } else if (attr == &dev_attr_edge.attr) {
+ if (gpio_to_irq(gpio) < 0)
+ mode = 0;
+ if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags))
+ mode = 0;
+ }
+
+ return mode;
+}
+
+static struct attribute *gpio_attrs[] = {
+ &dev_attr_direction.attr,
+ &dev_attr_edge.attr,
+ &dev_attr_value.attr,
+ &dev_attr_active_low.attr,
+ NULL,
+};
+
+static const struct attribute_group gpio_group = {
+ .attrs = gpio_attrs,
+ .is_visible = gpio_is_visible,
+};
+
+static const struct attribute_group *gpio_groups[] = {
+ &gpio_group,
+ NULL
+};
+
+/*
+ * /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);
+ if(NULL==chip)
+ return -EINVAL;
+
+ 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);
+ if(NULL==chip)
+ return -EINVAL;
+
+ 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);
+ if(NULL==chip)
+ return -EINVAL;
+
+ return sprintf(buf, "%u\n", chip->ngpio);
+}
+static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
+
+static struct attribute *gpiochip_attrs[] = {
+ &dev_attr_base.attr,
+ &dev_attr_label.attr,
+ &dev_attr_ngpio.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(gpiochip);
+
+/*
+ * /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;
+ int status;
+
+ status = strict_strtol(buf, 0, &gpio);
+ if (status < 0)
+ goto done;
+
+ /* 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 = gpio_request(gpio, "sysfs");
+ if (status < 0) {
+ if (status == -EPROBE_DEFER)
+ status = -ENODEV;
+ goto done;
+ }
+ status = gpio_export(gpio, true);
+ if (status < 0)
+ gpio_free(gpio);
+ else
+ set_bit(FLAG_SYSFS, &gpio_desc[gpio].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;
+ int status;
+
+ status = strict_strtol(buf, 0, &gpio);
+ if (status < 0)
+ goto done;
+
+ status = -EINVAL;
+
+ /* reject bogus commands (gpio_unexport ignores them) */
+ if (!gpio_is_valid(gpio))
+ goto done;
+
+ /* 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, &gpio_desc[gpio].flags)) {
+ status = 0;
+ gpio_free(gpio);
+ }
+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,
+};
+
+
+/**
+ * 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.
+ */
+int gpio_export(unsigned gpio, bool direction_may_change)
+{
+ unsigned long flags;
+ struct gpio_desc *desc;
+ int status;
+ const char *ioname = NULL;
+ struct device *dev;
+
+ /* can't export until sysfs is available ... */
+ if (!gpio_class.p) {
+ pr_debug("%s: called too early!\n", __func__);
+ return -ENOENT;
+ }
+
+ if (!gpio_is_valid(gpio)) {
+ pr_debug("%s: gpio %d is not valid\n", __func__, gpio);
+ return -EINVAL;
+ }
+
+ mutex_lock(&sysfs_lock);
+
+ spin_lock_irqsave(&gpio_lock, flags);
+ desc = &gpio_desc[gpio];
+ if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
+ test_bit(FLAG_EXPORT, &desc->flags)) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
+ __func__, gpio,
+ test_bit(FLAG_REQUESTED, &desc->flags),
+ test_bit(FLAG_EXPORT, &desc->flags));
+ return -EPERM;
+ }
+
+ if (desc->chip->direction_input && desc->chip->direction_output &&
+ direction_may_change) {
+ set_bit(FLAG_SYSFS_DIR, &desc->flags);
+ }
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
+ ioname = desc->chip->names[gpio - desc->chip->base];
+
+ dev = device_create_with_groups(&gpio_class, desc->chip->dev,
+ MKDEV(0, 0), desc, gpio_groups,
+ ioname ? ioname : "gpio%u", gpio);
+ if (IS_ERR(dev)) {
+ status = PTR_ERR(dev);
+ goto fail_unlock;
+ }
+
+ set_bit(FLAG_EXPORT, &desc->flags);
+ mutex_unlock(&sysfs_lock);
+ return 0;
+
+fail_unlock:
+ mutex_unlock(&sysfs_lock);
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_export);
+
+static int match_export(struct device *dev, void *data)
+{
+ return dev_get_drvdata(dev) == data;
+}
+
+/**
+ * gpio_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 gpio_export_link(struct device *dev, const char *name, unsigned gpio)
+{
+ struct gpio_desc *desc;
+ int status = -EINVAL;
+
+ if (!gpio_is_valid(gpio))
+ goto done;
+
+ mutex_lock(&sysfs_lock);
+
+ desc = &gpio_desc[gpio];
+
+ 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);
+ put_device(tdev);
+ } else {
+ status = -ENODEV;
+ }
+ }
+
+ mutex_unlock(&sysfs_lock);
+
+done:
+ if (status)
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_export_link);
+
+
+/**
+ * gpio_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 gpio_sysfs_set_active_low(unsigned gpio, int value)
+{
+ struct gpio_desc *desc;
+ struct device *dev = NULL;
+ int status = -EINVAL;
+
+ if (!gpio_is_valid(gpio))
+ goto done;
+
+ mutex_lock(&sysfs_lock);
+
+ desc = &gpio_desc[gpio];
+
+ 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);
+ put_device(dev);
+unlock:
+ mutex_unlock(&sysfs_lock);
+
+done:
+ if (status)
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
+
+/**
+ * gpio_unexport - reverse effect of gpio_export()
+ * @gpio: gpio to make unavailable
+ *
+ * This is implicit on gpio_free().
+ */
+void gpio_unexport(unsigned gpio)
+{
+ struct gpio_desc *desc;
+ int status = 0;
+ struct device *dev = NULL;
+
+ if (!gpio_is_valid(gpio)) {
+ status = -EINVAL;
+ goto done;
+ }
+
+ mutex_lock(&sysfs_lock);
+
+ desc = &gpio_desc[gpio];
+
+ 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_SYSFS_DIR, &desc->flags);
+ clear_bit(FLAG_EXPORT, &desc->flags);
+ } else
+ status = -ENODEV;
+ }
+
+ mutex_unlock(&sysfs_lock);
+ if (dev) {
+ device_unregister(dev);
+ put_device(dev);
+ }
+done:
+ if (status)
+ pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+}
+EXPORT_SYMBOL_GPL(gpio_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_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
+ chip, gpiochip_groups,
+ "gpiochip%d", chip->base);
+ if (IS_ERR(dev))
+ status = PTR_ERR(dev);
+ else
+ status = 0;
+ chip->exported = (status == 0);
+ mutex_unlock(&sysfs_lock);
+
+ if (status) {
+ unsigned long flags;
+ unsigned gpio;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+ gpio = chip->base;
+ while (gpio_desc[gpio].chip == chip)
+ gpio_desc[gpio++].chip = NULL;
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ pr_debug("%s: chip %s status %d\n", __func__,
+ chip->label, 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 = 0;
+ status = 0;
+ } else
+ status = -ENODEV;
+ mutex_unlock(&sysfs_lock);
+
+ if (status)
+ pr_debug("%s: chip %s status %d\n", __func__,
+ chip->label, status);
+}
+
+static int __init gpiolib_sysfs_init(void)
+{
+ int status;
+ unsigned long flags;
+ unsigned gpio;
+
+ 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);
+ for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
+ struct gpio_chip *chip;
+
+ chip = gpio_desc[gpio].chip;
+ 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 */
+
+/**
+ * gpiochip_add() - register a gpio_chip
+ * @chip: the chip to register, with chip->base initialized
+ * Context: potentially before irqs or kmalloc will work
+ *
+ * Returns a negative errno if the chip can't be registered, such as
+ * because the chip->base is invalid or already associated with a
+ * different chip. Otherwise it returns zero as a success code.
+ *
+ * When gpiochip_add() is called very early during boot, so that GPIOs
+ * can be freely used, the chip->dev device must be registered before
+ * the gpio framework's arch_initcall(). Otherwise sysfs initialization
+ * for GPIOs will fail rudely.
+ *
+ * If chip->base is negative, this requests dynamic assignment of
+ * a range of valid GPIOs.
+ */
+int gpiochip_add(struct gpio_chip *chip)
+{
+ unsigned long flags;
+ int status = 0;
+ unsigned id;
+ int base = chip->base;
+
+ if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
+ && base >= 0) {
+ status = -EINVAL;
+ goto fail;
+ }
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (base < 0) {
+ base = gpiochip_find_base(chip->ngpio);
+ if (base < 0) {
+ status = base;
+ goto unlock;
+ }
+ chip->base = base;
+ }
+
+ /* these GPIO numbers must not be managed by another gpio_chip */
+ for (id = base; id < base + chip->ngpio; id++) {
+ if (gpio_desc[id].chip != NULL) {
+ status = -EBUSY;
+ break;
+ }
+ }
+ if (status == 0) {
+ for (id = base; id < base + chip->ngpio; id++) {
+ gpio_desc[id].chip = chip;
+
+ /* REVISIT: most hardware initializes GPIOs as
+ * inputs (often with pullups enabled) so power
+ * usage is minimized. Linux code should set the
+ * gpio direction first thing; but until it does,
+ * we may expose the wrong direction in sysfs.
+ */
+ gpio_desc[id].flags = !chip->direction_input
+ ? (1 << FLAG_IS_OUT)
+ : 0;
+ }
+
+ of_gpiochip_add(chip);
+ }
+
+unlock:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ status = gpiochip_export(chip);
+ if (status) {
+ of_gpiochip_remove(chip);
+ goto fail;
+ }
+
+ pr_info("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
+ chip->base, chip->base + chip->ngpio - 1,
+ chip->label ? : "generic");
+
+ return 0;
+fail:
+ /* failures here can mean systems won't boot... */
+ pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
+ chip->base, chip->base + chip->ngpio - 1,
+ chip->label ? : "generic");
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpiochip_add);
+
+/**
+ * gpiochip_remove() - unregister a gpio_chip
+ * @chip: the chip to unregister
+ *
+ * A gpio_chip with any GPIOs still requested may not be removed.
+ */
+int gpiochip_remove(struct gpio_chip *chip)
+{
+ unsigned long flags;
+ int status = 0;
+ unsigned id;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ of_gpiochip_remove(chip);
+
+ for (id = chip->base; id < chip->base + chip->ngpio; id++) {
+ if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
+ status = -EBUSY;
+ break;
+ }
+ }
+ if (status == 0) {
+ for (id = chip->base; id < chip->base + chip->ngpio; id++)
+ gpio_desc[id].chip = NULL;
+ }
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ if (status == 0)
+ gpiochip_unexport(chip);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpiochip_remove);
+
+/**
+ * gpiochip_find() - iterator for locating a specific gpio_chip
+ * @data: data to pass to match function
+ * @callback: Callback function to check gpio_chip
+ *
+ * Similar to bus_find_device. It returns a reference to a gpio_chip as
+ * determined by a user supplied @match callback. The callback should return
+ * 0 if the device doesn't match and non-zero if it does. If the callback is
+ * non-zero, this function will return to the caller and not iterate over any
+ * more gpio_chips.
+ */
+struct gpio_chip *gpiochip_find(const void *data,
+ int (*match)(struct gpio_chip *chip,
+ const void *data))
+{
+ struct gpio_chip *chip = NULL;
+ unsigned long flags;
+ int i;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+ for (i = 0; i < ARCH_NR_GPIOS; i++) {
+ if (!gpio_desc[i].chip)
+ continue;
+
+ if (match(gpio_desc[i].chip, data)) {
+ chip = gpio_desc[i].chip;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ return chip;
+}
+EXPORT_SYMBOL_GPL(gpiochip_find);
+
+/* These "optional" allocation calls help prevent drivers from stomping
+ * on each other, and help provide better diagnostics in debugfs.
+ * They're called even less than the "set direction" calls.
+ */
+int gpio_request(unsigned gpio, const char *label)
+{
+ struct gpio_desc *desc;
+ struct gpio_chip *chip;
+ int status = -EINVAL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (!gpio_is_valid(gpio)) {
+ status = -EINVAL;
+ goto done;
+ }
+ desc = &gpio_desc[gpio];
+ chip = desc->chip;
+ if (chip == NULL)
+ goto done;
+
+ if (!try_module_get(chip->owner))
+ goto done;
+
+ /* NOTE: gpio_request() can be called in early boot,
+ * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
+ */
+
+ if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
+ desc_set_label(desc, label ? : "?");
+ status = 0;
+ } else {
+ status = -EBUSY;
+ module_put(chip->owner);
+ goto done;
+ }
+
+ if (chip->request) {
+ /* chip->request may sleep */
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ status = chip->request(chip, gpio - chip->base);
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (status < 0) {
+ desc_set_label(desc, NULL);
+ module_put(chip->owner);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ }
+ }
+
+done:
+ if (status)
+ pr_debug("gpio_request: gpio-%d (%s) status %d\n",
+ gpio, label ? : "?", status);
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ return status;
+}
+EXPORT_SYMBOL(gpio_request);
+
+void gpio_free(unsigned gpio)
+{
+ unsigned long flags;
+ struct gpio_desc *desc;
+ struct gpio_chip *chip;
+
+ might_sleep();
+
+ if (!gpio_is_valid(gpio)) {
+ WARN_ON(extra_checks);
+ return;
+ }
+
+ gpio_unexport(gpio);
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ desc = &gpio_desc[gpio];
+ chip = desc->chip;
+ if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
+ if (chip->free) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ might_sleep_if(chip->can_sleep);
+ chip->free(chip, gpio - chip->base);
+ spin_lock_irqsave(&gpio_lock, flags);
+ }
+ desc_set_label(desc, NULL);
+ module_put(desc->chip->owner);
+ clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
+ clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
+ } else
+ WARN_ON(extra_checks);
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+}
+EXPORT_SYMBOL(gpio_free);
+
+/**
+ * gpio_request_one - request a single GPIO with initial configuration
+ * @gpio: the GPIO number
+ * @flags: GPIO configuration as specified by GPIOF_*
+ * @label: a literal description string of this GPIO
+ */
+int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
+{
+ int err;
+
+ err = gpio_request(gpio, label);
+ if (err)
+ return err;
+
+ if (flags & GPIOF_OPEN_DRAIN)
+ set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags);
+
+ if (flags & GPIOF_OPEN_SOURCE)
+ set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);
+
+ if (flags & GPIOF_DIR_IN)
+ err = gpio_direction_input(gpio);
+ else
+ err = gpio_direction_output(gpio,
+ (flags & GPIOF_INIT_HIGH) ? 1 : 0);
+
+ if (err)
+ gpio_free(gpio);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(gpio_request_one);
+
+/**
+ * gpio_request_array - request multiple GPIOs in a single call
+ * @array: array of the 'struct gpio'
+ * @num: how many GPIOs in the array
+ */
+int gpio_request_array(const struct gpio *array, size_t num)
+{
+ int i, err;
+
+ for (i = 0; i < num; i++, array++) {
+ err = gpio_request_one(array->gpio, array->flags, array->label);
+ if (err)
+ goto err_free;
+ }
+ return 0;
+
+err_free:
+ while (i--)
+ gpio_free((--array)->gpio);
+ return err;
+}
+EXPORT_SYMBOL_GPL(gpio_request_array);
+
+/**
+ * gpio_free_array - release multiple GPIOs in a single call
+ * @array: array of the 'struct gpio'
+ * @num: how many GPIOs in the array
+ */
+void gpio_free_array(const struct gpio *array, size_t num)
+{
+ while (num--)
+ gpio_free((array++)->gpio);
+}
+EXPORT_SYMBOL_GPL(gpio_free_array);
+
+/**
+ * gpiochip_is_requested - return string iff signal was requested
+ * @chip: controller managing the signal
+ * @offset: of signal within controller's 0..(ngpio - 1) range
+ *
+ * Returns NULL if the GPIO is not currently requested, else a string.
+ * If debugfs support is enabled, the string returned is the label passed
+ * to gpio_request(); otherwise it is a meaningless constant.
+ *
+ * This function is for use by GPIO controller drivers. The label can
+ * help with diagnostics, and knowing that the signal is used as a GPIO
+ * can help avoid accidentally multiplexing it to another controller.
+ */
+const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
+{
+ unsigned gpio = chip->base + offset;
+
+ if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
+ return NULL;
+ if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
+ return NULL;
+#ifdef CONFIG_DEBUG_FS
+ return gpio_desc[gpio].label;
+#else
+ return "?";
+#endif
+}
+EXPORT_SYMBOL_GPL(gpiochip_is_requested);
+
+
+/* Drivers MUST set GPIO direction before making get/set calls. In
+ * some cases this is done in early boot, before IRQs are enabled.
+ *
+ * As a rule these aren't called more than once (except for drivers
+ * using the open-drain emulation idiom) so these are natural places
+ * to accumulate extra debugging checks. Note that we can't (yet)
+ * rely on gpio_request() having been called beforehand.
+ */
+
+int gpio_direction_input(unsigned gpio)
+{
+ unsigned long flags;
+ struct gpio_chip *chip;
+ struct gpio_desc *desc = &gpio_desc[gpio];
+ int status = -EINVAL;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (!gpio_is_valid(gpio))
+ goto fail;
+ chip = desc->chip;
+ if (!chip || !chip->get || !chip->direction_input)
+ goto fail;
+ gpio -= chip->base;
+ if (gpio >= chip->ngpio)
+ goto fail;
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
+
+ /* now we know the gpio is valid and chip won't vanish */
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ might_sleep_if(chip->can_sleep);
+
+ if (status) {
+ status = chip->request(chip, gpio);
+ if (status < 0) {
+ pr_debug("GPIO-%d: chip request fail, %d\n",
+ chip->base + gpio, status);
+ /* and it's not available to anyone else ...
+ * gpio_request() is the fully clean solution.
+ */
+ goto lose;
+ }
+ }
+
+ status = chip->direction_input(chip, gpio);
+ if (status == 0)
+ clear_bit(FLAG_IS_OUT, &desc->flags);
+
+ trace_gpio_direction(chip->base + gpio, 1, status);
+lose:
+ return status;
+fail:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ if (status)
+ pr_debug("%s: gpio-%d status %d\n",
+ __func__, gpio, status);
+ return status;
+}
+EXPORT_SYMBOL(gpio_direction_input);
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+ unsigned long flags;
+ struct gpio_chip *chip;
+ struct gpio_desc *desc = &gpio_desc[gpio];
+ int status = -EINVAL;
+
+ /* Open drain pin should not be driven to 1 */
+ if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+ return gpio_direction_input(gpio);
+
+ /* Open source pin should not be driven to 0 */
+ if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+ return gpio_direction_input(gpio);
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (!gpio_is_valid(gpio))
+ goto fail;
+ chip = desc->chip;
+ if (!chip || !chip->set || !chip->direction_output)
+ goto fail;
+ gpio -= chip->base;
+ if (gpio >= chip->ngpio)
+ goto fail;
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
+
+ /* now we know the gpio is valid and chip won't vanish */
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ might_sleep_if(chip->can_sleep);
+
+ if (status) {
+ status = chip->request(chip, gpio);
+ if (status < 0) {
+ pr_debug("GPIO-%d: chip request fail, %d\n",
+ chip->base + gpio, status);
+ /* and it's not available to anyone else ...
+ * gpio_request() is the fully clean solution.
+ */
+ goto lose;
+ }
+ }
+
+ status = chip->direction_output(chip, gpio, value);
+ if (status == 0)
+ set_bit(FLAG_IS_OUT, &desc->flags);
+ trace_gpio_value(chip->base + gpio, 0, value);
+ trace_gpio_direction(chip->base + gpio, 0, status);
+lose:
+ return status;
+fail:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ if (status)
+ pr_debug("%s: gpio-%d status %d\n",
+ __func__, gpio, status);
+ return status;
+}
+EXPORT_SYMBOL(gpio_direction_output);
+
+/**
+ * gpio_set_debounce - sets @debounce time for a @gpio
+ * @gpio: the gpio to set debounce time
+ * @debounce: debounce time is microseconds
+ */
+int gpio_set_debounce(unsigned gpio, unsigned debounce)
+{
+ unsigned long flags;
+ struct gpio_chip *chip;
+ struct gpio_desc *desc = &gpio_desc[gpio];
+ int status = -EINVAL;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (!gpio_is_valid(gpio))
+ goto fail;
+ chip = desc->chip;
+ if (!chip || !chip->set || !chip->set_debounce)
+ goto fail;
+ gpio -= chip->base;
+ if (gpio >= chip->ngpio)
+ goto fail;
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
+
+ /* now we know the gpio is valid and chip won't vanish */
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ might_sleep_if(chip->can_sleep);
+
+ return chip->set_debounce(chip, gpio, debounce);
+
+fail:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ if (status)
+ pr_debug("%s: gpio-%d status %d\n",
+ __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_set_debounce);
+
+/* I/O calls are only valid after configuration completed; the relevant
+ * "is this a valid GPIO" error checks should already have been done.
+ *
+ * "Get" operations are often inlinable as reading a pin value register,
+ * and masking the relevant bit in that register.
+ *
+ * When "set" operations are inlinable, they involve writing that mask to
+ * one register to set a low value, or a different register to set it high.
+ * Otherwise locking is needed, so there may be little value to inlining.
+ *
+ *------------------------------------------------------------------------
+ *
+ * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
+ * have requested the GPIO. That can include implicit requesting by
+ * a direction setting call. Marking a gpio as requested locks its chip
+ * in memory, guaranteeing that these table lookups need no more locking
+ * and that gpiochip_remove() will fail.
+ *
+ * REVISIT when debugging, consider adding some instrumentation to ensure
+ * that the GPIO was actually requested.
+ */
+
+/**
+ * __gpio_get_value() - return a gpio's value
+ * @gpio: gpio whose value will be returned
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_get_value().
+ * It returns the zero or nonzero value provided by the associated
+ * gpio_chip.get() method; or zero if no such method is provided.
+ */
+int __gpio_get_value(unsigned gpio)
+{
+ struct gpio_chip *chip;
+ int value;
+
+ chip = gpio_to_chip(gpio);
+ /* Should be using gpio_get_value_cansleep() */
+ WARN_ON(chip->can_sleep);
+ value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
+ trace_gpio_value(gpio, 1, value);
+ return value;
+}
+EXPORT_SYMBOL(__gpio_get_value);
+
+/*
+ * _gpio_set_open_drain_value() - Set the open drain gpio's value.
+ * @gpio: Gpio whose state need to be set.
+ * @chip: Gpio chip.
+ * @value: Non-zero for setting it HIGH otherise it will set to LOW.
+ */
+static void _gpio_set_open_drain_value(unsigned gpio,
+ struct gpio_chip *chip, int value)
+{
+ int err = 0;
+ if (value) {
+ err = chip->direction_input(chip, gpio - chip->base);
+ if (!err)
+ clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+ } else {
+ err = chip->direction_output(chip, gpio - chip->base, 0);
+ if (!err)
+ set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+ }
+ trace_gpio_direction(gpio, value, err);
+ if (err < 0)
+ pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
+ __func__, gpio, err);
+}
+
+/*
+ * _gpio_set_open_source() - Set the open source gpio's value.
+ * @gpio: Gpio whose state need to be set.
+ * @chip: Gpio chip.
+ * @value: Non-zero for setting it HIGH otherise it will set to LOW.
+ */
+static void _gpio_set_open_source_value(unsigned gpio,
+ struct gpio_chip *chip, int value)
+{
+ int err = 0;
+ if (value) {
+ err = chip->direction_output(chip, gpio - chip->base, 1);
+ if (!err)
+ set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+ } else {
+ err = chip->direction_input(chip, gpio - chip->base);
+ if (!err)
+ clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+ }
+ trace_gpio_direction(gpio, !value, err);
+ if (err < 0)
+ pr_err("%s: Error in set_value for open source gpio%d err %d\n",
+ __func__, gpio, err);
+}
+
+
+/**
+ * __gpio_set_value() - assign a gpio's value
+ * @gpio: gpio whose value will be assigned
+ * @value: value to assign
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_set_value().
+ * It invokes the associated gpio_chip.set() method.
+ */
+void __gpio_set_value(unsigned gpio, int value)
+{
+ struct gpio_chip *chip;
+
+ chip = gpio_to_chip(gpio);
+ /* Should be using gpio_set_value_cansleep() */
+ WARN_ON(chip->can_sleep);
+ trace_gpio_value(gpio, 0, value);
+ if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
+ _gpio_set_open_drain_value(gpio, chip, value);
+ else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
+ _gpio_set_open_source_value(gpio, chip, value);
+ else
+ chip->set(chip, gpio - chip->base, value);
+}
+EXPORT_SYMBOL(__gpio_set_value);
+
+/**
+ * __gpio_cansleep() - report whether gpio value access will sleep
+ * @gpio: gpio in question
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_cansleep(). It
+ * returns nonzero if access reading or writing the GPIO value can sleep.
+ */
+int __gpio_cansleep(unsigned gpio)
+{
+ struct gpio_chip *chip;
+
+ /* only call this on GPIOs that are valid! */
+ chip = gpio_to_chip(gpio);
+
+ return chip->can_sleep;
+}
+EXPORT_SYMBOL_GPL(__gpio_cansleep);
+
+/**
+ * __gpio_to_irq() - return the IRQ corresponding to a GPIO
+ * @gpio: gpio whose IRQ will be returned (already requested)
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_to_irq().
+ * It returns the number of the IRQ signaled by this (input) GPIO,
+ * or a negative errno.
+ */
+int __gpio_to_irq(unsigned gpio)
+{
+ struct gpio_chip *chip;
+
+ chip = gpio_to_chip(gpio);
+ return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
+}
+EXPORT_SYMBOL_GPL(__gpio_to_irq);
+
+
+
+/* There's no value in making it easy to inline GPIO calls that may sleep.
+ * Common examples include ones connected to I2C or SPI chips.
+ */
+
+int gpio_get_value_cansleep(unsigned gpio)
+{
+ struct gpio_chip *chip;
+ int value;
+
+ might_sleep_if(extra_checks);
+ chip = gpio_to_chip(gpio);
+ value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
+ trace_gpio_value(gpio, 1, value);
+ return value;
+}
+EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
+
+void gpio_set_value_cansleep(unsigned gpio, int value)
+{
+ struct gpio_chip *chip;
+
+ might_sleep_if(extra_checks);
+ chip = gpio_to_chip(gpio);
+ trace_gpio_value(gpio, 0, value);
+ if (test_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags))
+ _gpio_set_open_drain_value(gpio, chip, value);
+ else if (test_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags))
+ _gpio_set_open_source_value(gpio, chip, value);
+ else
+ chip->set(chip, gpio - chip->base, value);
+}
+EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
+
+
+#ifdef CONFIG_DEBUG_FS
+
+static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+ unsigned i;
+ unsigned gpio = chip->base;
+ struct gpio_desc *gdesc = &gpio_desc[gpio];
+ int is_out;
+
+ for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
+ if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
+ continue;
+
+ is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
+ seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
+ gpio, gdesc->label,
+ is_out ? "out" : "in ",
+ chip->get
+ ? (chip->get(chip, i) ? "hi" : "lo")
+ : "? ");
+ seq_printf(s, "\n");
+ }
+}
+
+static int gpiolib_show(struct seq_file *s, void *unused)
+{
+ struct gpio_chip *chip = NULL;
+ unsigned gpio;
+ int started = 0;
+
+ /* REVISIT this isn't locked against gpio_chip removal ... */
+
+ for (gpio = 0; gpio_is_valid(gpio); gpio++) {
+ struct device *dev;
+
+ if (chip == gpio_desc[gpio].chip)
+ continue;
+ chip = gpio_desc[gpio].chip;
+ if (!chip)
+ continue;
+
+ seq_printf(s, "%sGPIOs %d-%d",
+ started ? "\n" : "",
+ chip->base, chip->base + chip->ngpio - 1);
+ dev = chip->dev;
+ if (dev)
+ seq_printf(s, ", %s/%s",
+ dev->bus ? dev->bus->name : "no-bus",
+ dev_name(dev));
+ if (chip->label)
+ seq_printf(s, ", %s", chip->label);
+ if (chip->can_sleep)
+ seq_printf(s, ", can sleep");
+ seq_printf(s, ":\n");
+
+ started = 1;
+ if (chip->dbg_show)
+ chip->dbg_show(s, chip);
+ else
+ gpiolib_dbg_show(s, chip);
+ }
+ return 0;
+}
+
+static int gpiolib_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, gpiolib_show, NULL);
+}
+
+static const struct file_operations gpiolib_operations = {
+ .open = gpiolib_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int __init gpiolib_debugfs_init(void)
+{
+ /* /sys/kernel/debug/gpio */
+ (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
+ NULL, NULL, &gpiolib_operations);
+ return 0;
+}
+subsys_initcall(gpiolib_debugfs_init);
+
+#endif /* DEBUG_FS */