830 lines
19 KiB
C
830 lines
19 KiB
C
#include <linux/idr.h>
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#include <linux/mutex.h>
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#include <linux/device.h>
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#include <linux/sysfs.h>
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#include <linux/gpio/consumer.h>
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#include <linux/gpio/driver.h>
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#include <linux/interrupt.h>
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#include <linux/kdev_t.h>
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#include "gpiolib.h"
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static DEFINE_IDR(dirent_idr);
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/* lock protects against unexport_gpio() being called while
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* sysfs files are active.
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*/
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static DEFINE_MUTEX(sysfs_lock);
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/*
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* /sys/class/gpio/gpioN... only for GPIOs that are exported
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* /direction
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* * MAY BE OMITTED if kernel won't allow direction changes
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* * is read/write as "in" or "out"
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* * may also be written as "high" or "low", initializing
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* output value as specified ("out" implies "low")
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* /value
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* * always readable, subject to hardware behavior
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* * may be writable, as zero/nonzero
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* /edge
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* * configures behavior of poll(2) on /value
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* * available only if pin can generate IRQs on input
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* * is read/write as "none", "falling", "rising", or "both"
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* /active_low
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* * configures polarity of /value
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* * is read/write as zero/nonzero
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* * also affects existing and subsequent "falling" and "rising"
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* /edge configuration
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*/
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static ssize_t gpio_direction_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags)) {
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status = -EIO;
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} else {
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gpiod_get_direction(desc);
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status = sprintf(buf, "%s\n",
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test_bit(FLAG_IS_OUT, &desc->flags)
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? "out" : "in");
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_direction_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else if (sysfs_streq(buf, "high"))
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status = gpiod_direction_output_raw(desc, 1);
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else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
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status = gpiod_direction_output_raw(desc, 0);
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else if (sysfs_streq(buf, "in"))
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status = gpiod_direction_input(desc);
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else
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status = -EINVAL;
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mutex_unlock(&sysfs_lock);
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return status ? : size;
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}
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static /* const */ DEVICE_ATTR(direction, 0644,
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gpio_direction_show, gpio_direction_store);
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static ssize_t gpio_value_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else
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status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_value_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else if (!test_bit(FLAG_IS_OUT, &desc->flags))
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status = -EPERM;
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else {
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long value;
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status = kstrtol(buf, 0, &value);
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if (status == 0) {
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gpiod_set_value_cansleep(desc, value);
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status = size;
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}
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static const DEVICE_ATTR(value, 0644,
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gpio_value_show, gpio_value_store);
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static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
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{
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struct kernfs_node *value_sd = priv;
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sysfs_notify_dirent(value_sd);
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return IRQ_HANDLED;
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}
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static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
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unsigned long gpio_flags)
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{
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struct kernfs_node *value_sd;
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unsigned long irq_flags;
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int ret, irq, id;
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if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
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return 0;
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irq = gpiod_to_irq(desc);
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if (irq < 0)
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return -EIO;
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id = desc->flags >> ID_SHIFT;
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value_sd = idr_find(&dirent_idr, id);
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if (value_sd)
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free_irq(irq, value_sd);
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desc->flags &= ~GPIO_TRIGGER_MASK;
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if (!gpio_flags) {
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gpiod_unlock_as_irq(desc);
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ret = 0;
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goto free_id;
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}
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irq_flags = IRQF_SHARED;
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if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
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irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
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IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
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if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
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irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
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IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
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if (!value_sd) {
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value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
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if (!value_sd) {
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ret = -ENODEV;
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goto err_out;
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}
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ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
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if (ret < 0)
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goto free_sd;
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id = ret;
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desc->flags &= GPIO_FLAGS_MASK;
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desc->flags |= (unsigned long)id << ID_SHIFT;
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if (desc->flags >> ID_SHIFT != id) {
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ret = -ERANGE;
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goto free_id;
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}
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}
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ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
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"gpiolib", value_sd);
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if (ret < 0)
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goto free_id;
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ret = gpiod_lock_as_irq(desc);
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if (ret < 0) {
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gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
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goto free_id;
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}
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desc->flags |= gpio_flags;
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return 0;
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free_id:
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idr_remove(&dirent_idr, id);
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desc->flags &= GPIO_FLAGS_MASK;
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free_sd:
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if (value_sd)
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sysfs_put(value_sd);
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err_out:
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return ret;
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}
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static const struct {
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const char *name;
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unsigned long flags;
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} trigger_types[] = {
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{ "none", 0 },
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{ "falling", BIT(FLAG_TRIG_FALL) },
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{ "rising", BIT(FLAG_TRIG_RISE) },
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{ "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
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};
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static ssize_t gpio_edge_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else {
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int i;
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status = 0;
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for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
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if ((desc->flags & GPIO_TRIGGER_MASK)
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== trigger_types[i].flags) {
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status = sprintf(buf, "%s\n",
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trigger_types[i].name);
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break;
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}
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_edge_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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int i;
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for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
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if (sysfs_streq(trigger_types[i].name, buf))
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goto found;
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return -EINVAL;
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found:
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else {
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status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
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if (!status)
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status = size;
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
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static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
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int value)
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{
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int status = 0;
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if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
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return 0;
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if (value)
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set_bit(FLAG_ACTIVE_LOW, &desc->flags);
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else
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clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
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/* reconfigure poll(2) support if enabled on one edge only */
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if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
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!!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
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unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
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gpio_setup_irq(desc, dev, 0);
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status = gpio_setup_irq(desc, dev, trigger_flags);
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}
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return status;
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}
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static ssize_t gpio_active_low_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else
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status = sprintf(buf, "%d\n",
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!!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_active_low_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags)) {
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status = -EIO;
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} else {
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long value;
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status = kstrtol(buf, 0, &value);
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if (status == 0)
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status = sysfs_set_active_low(desc, dev, value != 0);
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}
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mutex_unlock(&sysfs_lock);
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return status ? : size;
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}
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static const DEVICE_ATTR(active_low, 0644,
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gpio_active_low_show, gpio_active_low_store);
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static const struct attribute *gpio_attrs[] = {
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&dev_attr_value.attr,
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&dev_attr_active_low.attr,
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NULL,
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};
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static const struct attribute_group gpio_attr_group = {
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.attrs = (struct attribute **) gpio_attrs,
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};
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/*
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* /sys/class/gpio/gpiochipN/
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* /base ... matching gpio_chip.base (N)
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* /label ... matching gpio_chip.label
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* /ngpio ... matching gpio_chip.ngpio
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*/
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static ssize_t chip_base_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_chip *chip = dev_get_drvdata(dev);
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return sprintf(buf, "%d\n", chip->base);
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}
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static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
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static ssize_t chip_label_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_chip *chip = dev_get_drvdata(dev);
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return sprintf(buf, "%s\n", chip->label ? : "");
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}
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static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
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static ssize_t chip_ngpio_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_chip *chip = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", chip->ngpio);
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}
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static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
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static const struct attribute *gpiochip_attrs[] = {
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&dev_attr_base.attr,
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&dev_attr_label.attr,
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&dev_attr_ngpio.attr,
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NULL,
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};
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static const struct attribute_group gpiochip_attr_group = {
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.attrs = (struct attribute **) gpiochip_attrs,
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};
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/*
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* /sys/class/gpio/export ... write-only
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* integer N ... number of GPIO to export (full access)
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* /sys/class/gpio/unexport ... write-only
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* integer N ... number of GPIO to unexport
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*/
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static ssize_t export_store(struct class *class,
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struct class_attribute *attr,
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const char *buf, size_t len)
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{
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long gpio;
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struct gpio_desc *desc;
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int status;
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status = kstrtol(buf, 0, &gpio);
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if (status < 0)
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goto done;
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desc = gpio_to_desc(gpio);
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/* reject invalid GPIOs */
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if (!desc) {
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pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
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return -EINVAL;
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}
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/* No extra locking here; FLAG_SYSFS just signifies that the
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* request and export were done by on behalf of userspace, so
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* they may be undone on its behalf too.
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*/
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status = gpiod_request(desc, "sysfs");
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if (status < 0) {
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if (status == -EPROBE_DEFER)
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status = -ENODEV;
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goto done;
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}
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status = gpiod_export(desc, true);
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if (status < 0)
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gpiod_free(desc);
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else
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set_bit(FLAG_SYSFS, &desc->flags);
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done:
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if (status)
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pr_debug("%s: status %d\n", __func__, status);
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return status ? : len;
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}
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static ssize_t unexport_store(struct class *class,
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struct class_attribute *attr,
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const char *buf, size_t len)
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{
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long gpio;
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struct gpio_desc *desc;
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int status;
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status = kstrtol(buf, 0, &gpio);
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if (status < 0)
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goto done;
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desc = gpio_to_desc(gpio);
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/* reject bogus commands (gpio_unexport ignores them) */
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if (!desc) {
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pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
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return -EINVAL;
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}
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status = -EINVAL;
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/* No extra locking here; FLAG_SYSFS just signifies that the
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* request and export were done by on behalf of userspace, so
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* they may be undone on its behalf too.
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*/
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if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
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status = 0;
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gpiod_free(desc);
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}
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done:
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if (status)
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pr_debug("%s: status %d\n", __func__, status);
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return status ? : len;
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}
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static struct class_attribute gpio_class_attrs[] = {
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__ATTR(export, 0200, NULL, export_store),
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__ATTR(unexport, 0200, NULL, unexport_store),
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__ATTR_NULL,
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};
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static struct class gpio_class = {
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.name = "gpio",
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.owner = THIS_MODULE,
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.class_attrs = gpio_class_attrs,
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};
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/**
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* gpiod_export - export a GPIO through sysfs
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* @gpio: gpio to make available, already requested
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* @direction_may_change: true if userspace may change gpio direction
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* Context: arch_initcall or later
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*
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* When drivers want to make a GPIO accessible to userspace after they
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* have requested it -- perhaps while debugging, or as part of their
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* public interface -- they may use this routine. If the GPIO can
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* change direction (some can't) and the caller allows it, userspace
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* will see "direction" sysfs attribute which may be used to change
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* the gpio's direction. A "value" attribute will always be provided.
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*
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* Returns zero on success, else an error.
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*/
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int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
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{
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unsigned long flags;
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int status;
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const char *ioname = NULL;
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struct device *dev;
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int offset;
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/* can't export until sysfs is available ... */
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if (!gpio_class.p) {
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pr_debug("%s: called too early!\n", __func__);
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return -ENOENT;
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}
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if (!desc) {
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pr_debug("%s: invalid gpio descriptor\n", __func__);
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return -EINVAL;
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}
|
|
|
|
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);
|