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- #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 <linux/slab.h>
- #include "gpiolib.h"
- #define GPIO_IRQF_TRIGGER_FALLING BIT(0)
- #define GPIO_IRQF_TRIGGER_RISING BIT(1)
- #define GPIO_IRQF_TRIGGER_BOTH (GPIO_IRQF_TRIGGER_FALLING | \
- GPIO_IRQF_TRIGGER_RISING)
- struct gpiod_data {
- struct gpio_desc *desc;
- struct mutex mutex;
- struct kernfs_node *value_kn;
- int irq;
- unsigned char irq_flags;
- bool direction_can_change;
- };
- static DEFINE_MUTEX(sysfs_lock);
- static ssize_t direction_show(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- ssize_t status;
- mutex_lock(&data->mutex);
- gpiod_get_direction(desc);
- status = sprintf(buf, "%s\n",
- test_bit(FLAG_IS_OUT, &desc->flags)
- ? "out" : "in");
- mutex_unlock(&data->mutex);
- return status;
- }
- static ssize_t direction_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- ssize_t status;
- mutex_lock(&data->mutex);
- 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(&data->mutex);
- return status ? : size;
- }
- static DEVICE_ATTR_RW(direction);
- static ssize_t value_show(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- ssize_t status;
- mutex_lock(&data->mutex);
- status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
- mutex_unlock(&data->mutex);
- return status;
- }
- static ssize_t value_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- ssize_t status;
- mutex_lock(&data->mutex);
- 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(&data->mutex);
- return status;
- }
- static DEVICE_ATTR_RW(value);
- static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
- {
- struct gpiod_data *data = priv;
- sysfs_notify_dirent(data->value_kn);
- return IRQ_HANDLED;
- }
- static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- unsigned long irq_flags;
- int ret;
- data->irq = gpiod_to_irq(desc);
- if (data->irq < 0)
- return -EIO;
- data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value");
- if (!data->value_kn)
- return -ENODEV;
- irq_flags = IRQF_SHARED;
- if (flags & GPIO_IRQF_TRIGGER_FALLING)
- irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
- IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
- if (flags & GPIO_IRQF_TRIGGER_RISING)
- irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
- IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
-
- ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
- if (ret < 0)
- goto err_put_kn;
- ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags,
- "gpiolib", data);
- if (ret < 0)
- goto err_unlock;
- data->irq_flags = flags;
- return 0;
- err_unlock:
- gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
- err_put_kn:
- sysfs_put(data->value_kn);
- return ret;
- }
- static void gpio_sysfs_free_irq(struct device *dev)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- data->irq_flags = 0;
- free_irq(data->irq, data);
- gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
- sysfs_put(data->value_kn);
- }
- static const struct {
- const char *name;
- unsigned char flags;
- } trigger_types[] = {
- { "none", 0 },
- { "falling", GPIO_IRQF_TRIGGER_FALLING },
- { "rising", GPIO_IRQF_TRIGGER_RISING },
- { "both", GPIO_IRQF_TRIGGER_BOTH },
- };
- static ssize_t edge_show(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- ssize_t status = 0;
- int i;
- mutex_lock(&data->mutex);
- for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
- if (data->irq_flags == trigger_types[i].flags) {
- status = sprintf(buf, "%s\n", trigger_types[i].name);
- break;
- }
- }
- mutex_unlock(&data->mutex);
- return status;
- }
- static ssize_t edge_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- unsigned char flags;
- ssize_t status = size;
- int i;
- for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
- if (sysfs_streq(trigger_types[i].name, buf))
- break;
- }
- if (i == ARRAY_SIZE(trigger_types))
- return -EINVAL;
- flags = trigger_types[i].flags;
- mutex_lock(&data->mutex);
- if (flags == data->irq_flags) {
- status = size;
- goto out_unlock;
- }
- if (data->irq_flags)
- gpio_sysfs_free_irq(dev);
- if (flags) {
- status = gpio_sysfs_request_irq(dev, flags);
- if (!status)
- status = size;
- }
- out_unlock:
- mutex_unlock(&data->mutex);
- return status;
- }
- static DEVICE_ATTR_RW(edge);
- static int gpio_sysfs_set_active_low(struct device *dev, int value)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- int status = 0;
- unsigned int flags = data->irq_flags;
- 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);
-
- if (flags == GPIO_IRQF_TRIGGER_FALLING ||
- flags == GPIO_IRQF_TRIGGER_RISING) {
- gpio_sysfs_free_irq(dev);
- status = gpio_sysfs_request_irq(dev, flags);
- }
- return status;
- }
- static ssize_t active_low_show(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- ssize_t status;
- mutex_lock(&data->mutex);
- status = sprintf(buf, "%d\n",
- !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
- mutex_unlock(&data->mutex);
- return status;
- }
- static ssize_t active_low_store(struct device *dev,
- struct device_attribute *attr, const char *buf, size_t size)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- ssize_t status;
- long value;
- mutex_lock(&data->mutex);
- status = kstrtol(buf, 0, &value);
- if (status == 0)
- status = gpio_sysfs_set_active_low(dev, value);
- mutex_unlock(&data->mutex);
- return status ? : size;
- }
- static DEVICE_ATTR_RW(active_low);
- static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
- int n)
- {
- struct device *dev = container_of(kobj, struct device, kobj);
- struct gpiod_data *data = dev_get_drvdata(dev);
- struct gpio_desc *desc = data->desc;
- umode_t mode = attr->mode;
- bool show_direction = data->direction_can_change;
- if (attr == &dev_attr_direction.attr) {
- if (!show_direction)
- mode = 0;
- } else if (attr == &dev_attr_edge.attr) {
- if (gpiod_to_irq(desc) < 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
- };
- static ssize_t 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_RO(base);
- static ssize_t 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_RO(label);
- static ssize_t 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_RO(ngpio);
- static struct attribute *gpiochip_attrs[] = {
- &dev_attr_base.attr,
- &dev_attr_label.attr,
- &dev_attr_ngpio.attr,
- NULL,
- };
- ATTRIBUTE_GROUPS(gpiochip);
- 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);
-
- if (!desc) {
- pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
- return -EINVAL;
- }
-
- 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);
-
- if (!desc) {
- pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
- return -EINVAL;
- }
- status = -EINVAL;
-
- 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,
- };
- int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
- {
- struct gpio_chip *chip;
- struct gpio_device *gdev;
- struct gpiod_data *data;
- unsigned long flags;
- int status;
- const char *ioname = NULL;
- struct device *dev;
- int offset;
-
- 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;
- }
- gdev = desc->gdev;
- chip = gdev->chip;
- mutex_lock(&sysfs_lock);
-
- if (!chip || !gdev->mockdev) {
- status = -ENODEV;
- goto err_unlock;
- }
- 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 err_unlock;
- }
- spin_unlock_irqrestore(&gpio_lock, flags);
- data = kzalloc(sizeof(*data), GFP_KERNEL);
- if (!data) {
- status = -ENOMEM;
- goto err_unlock;
- }
- data->desc = desc;
- mutex_init(&data->mutex);
- if (chip->direction_input && chip->direction_output)
- data->direction_can_change = direction_may_change;
- else
- data->direction_can_change = false;
- offset = gpio_chip_hwgpio(desc);
- if (chip->names && chip->names[offset])
- ioname = chip->names[offset];
- dev = device_create_with_groups(&gpio_class, &gdev->dev,
- MKDEV(0, 0), data, gpio_groups,
- ioname ? ioname : "gpio%u",
- desc_to_gpio(desc));
- if (IS_ERR(dev)) {
- status = PTR_ERR(dev);
- goto err_free_data;
- }
- set_bit(FLAG_EXPORT, &desc->flags);
- mutex_unlock(&sysfs_lock);
- return 0;
- err_free_data:
- kfree(data);
- err_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 *desc)
- {
- struct gpiod_data *data = dev_get_drvdata(dev);
- return data->desc == desc;
- }
- int gpiod_export_link(struct device *dev, const char *name,
- struct gpio_desc *desc)
- {
- struct device *cdev;
- int ret;
- if (!desc) {
- pr_warn("%s: invalid GPIO\n", __func__);
- return -EINVAL;
- }
- cdev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (!cdev)
- return -ENODEV;
- ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name);
- put_device(cdev);
- return ret;
- }
- EXPORT_SYMBOL_GPL(gpiod_export_link);
- void gpiod_unexport(struct gpio_desc *desc)
- {
- struct gpiod_data *data;
- struct device *dev;
- if (!desc) {
- pr_warn("%s: invalid GPIO\n", __func__);
- return;
- }
- mutex_lock(&sysfs_lock);
- if (!test_bit(FLAG_EXPORT, &desc->flags))
- goto err_unlock;
- dev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (!dev)
- goto err_unlock;
- data = dev_get_drvdata(dev);
- clear_bit(FLAG_EXPORT, &desc->flags);
- device_unregister(dev);
-
- if (data->irq_flags)
- gpio_sysfs_free_irq(dev);
- mutex_unlock(&sysfs_lock);
- put_device(dev);
- kfree(data);
- return;
- err_unlock:
- mutex_unlock(&sysfs_lock);
- }
- EXPORT_SYMBOL_GPL(gpiod_unexport);
- int gpiochip_sysfs_register(struct gpio_device *gdev)
- {
- struct device *dev;
- struct device *parent;
- struct gpio_chip *chip = gdev->chip;
-
- if (!gpio_class.p)
- return 0;
-
- if (chip->parent)
- parent = chip->parent;
- else
- parent = &gdev->dev;
-
- dev = device_create_with_groups(&gpio_class, parent,
- MKDEV(0, 0),
- chip, gpiochip_groups,
- "gpiochip%d", chip->base);
- if (IS_ERR(dev))
- return PTR_ERR(dev);
- mutex_lock(&sysfs_lock);
- gdev->mockdev = dev;
- mutex_unlock(&sysfs_lock);
- return 0;
- }
- void gpiochip_sysfs_unregister(struct gpio_device *gdev)
- {
- struct gpio_desc *desc;
- struct gpio_chip *chip = gdev->chip;
- unsigned int i;
- if (!gdev->mockdev)
- return;
- device_unregister(gdev->mockdev);
-
- mutex_lock(&sysfs_lock);
- gdev->mockdev = NULL;
- mutex_unlock(&sysfs_lock);
-
- for (i = 0; i < chip->ngpio; i++) {
- desc = &gdev->descs[i];
- if (test_and_clear_bit(FLAG_SYSFS, &desc->flags))
- gpiod_free(desc);
- }
- }
- static int __init gpiolib_sysfs_init(void)
- {
- int status;
- unsigned long flags;
- struct gpio_device *gdev;
- status = class_register(&gpio_class);
- if (status < 0)
- return status;
-
- spin_lock_irqsave(&gpio_lock, flags);
- list_for_each_entry(gdev, &gpio_devices, list) {
- if (gdev->mockdev)
- continue;
-
- spin_unlock_irqrestore(&gpio_lock, flags);
- status = gpiochip_sysfs_register(gdev);
- spin_lock_irqsave(&gpio_lock, flags);
- }
- spin_unlock_irqrestore(&gpio_lock, flags);
- return status;
- }
- postcore_initcall(gpiolib_sysfs_init);
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