diff options
Diffstat (limited to 'kernel/drivers/gpio/gpiolib-sysfs.c')
-rw-r--r-- | kernel/drivers/gpio/gpiolib-sysfs.c | 567 |
1 files changed, 258 insertions, 309 deletions
diff --git a/kernel/drivers/gpio/gpiolib-sysfs.c b/kernel/drivers/gpio/gpiolib-sysfs.c index af3bc7a80..b57ed8e55 100644 --- a/kernel/drivers/gpio/gpiolib-sysfs.c +++ b/kernel/drivers/gpio/gpiolib-sysfs.c @@ -6,14 +6,29 @@ #include <linux/gpio/driver.h> #include <linux/interrupt.h> #include <linux/kdev_t.h> +#include <linux/slab.h> #include "gpiolib.h" -static DEFINE_IDR(dirent_idr); +#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; -/* lock protects against unexport_gpio() being called while - * sysfs files are active. + bool direction_can_change; +}; + +/* + * Lock to serialise gpiod export and unexport, and prevent re-export of + * gpiod whose chip is being unregistered. */ static DEFINE_MUTEX(sysfs_lock); @@ -38,38 +53,35 @@ static DEFINE_MUTEX(sysfs_lock); * /edge configuration */ -static ssize_t gpio_direction_show(struct device *dev, +static ssize_t direction_show(struct device *dev, struct device_attribute *attr, char *buf) { - struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; ssize_t status; - mutex_lock(&sysfs_lock); + mutex_lock(&data->mutex); - if (!test_bit(FLAG_EXPORT, &desc->flags)) { - status = -EIO; - } else { - gpiod_get_direction(desc); - status = sprintf(buf, "%s\n", + gpiod_get_direction(desc); + status = sprintf(buf, "%s\n", test_bit(FLAG_IS_OUT, &desc->flags) ? "out" : "in"); - } - mutex_unlock(&sysfs_lock); + mutex_unlock(&data->mutex); + return status; } -static ssize_t gpio_direction_store(struct device *dev, +static ssize_t direction_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { - struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; ssize_t status; - mutex_lock(&sysfs_lock); + mutex_lock(&data->mutex); - if (!test_bit(FLAG_EXPORT, &desc->flags)) - status = -EIO; - else if (sysfs_streq(buf, "high")) + 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); @@ -78,43 +90,40 @@ static ssize_t gpio_direction_store(struct device *dev, else status = -EINVAL; - mutex_unlock(&sysfs_lock); + mutex_unlock(&data->mutex); + return status ? : size; } +static DEVICE_ATTR_RW(direction); -static /* const */ DEVICE_ATTR(direction, 0644, - gpio_direction_show, gpio_direction_store); - -static ssize_t gpio_value_show(struct device *dev, +static ssize_t value_show(struct device *dev, struct device_attribute *attr, char *buf) { - struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; ssize_t status; - mutex_lock(&sysfs_lock); + mutex_lock(&data->mutex); - if (!test_bit(FLAG_EXPORT, &desc->flags)) - status = -EIO; - else - status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); + status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); + + mutex_unlock(&data->mutex); - mutex_unlock(&sysfs_lock); return status; } -static ssize_t gpio_value_store(struct device *dev, +static ssize_t value_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { - struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; ssize_t status; - mutex_lock(&sysfs_lock); + mutex_lock(&data->mutex); - if (!test_bit(FLAG_EXPORT, &desc->flags)) - status = -EIO; - else if (!test_bit(FLAG_IS_OUT, &desc->flags)) + if (!test_bit(FLAG_IS_OUT, &desc->flags)) { status = -EPERM; - else { + } else { long value; status = kstrtol(buf, 0, &value); @@ -124,172 +133,168 @@ static ssize_t gpio_value_store(struct device *dev, } } - mutex_unlock(&sysfs_lock); + mutex_unlock(&data->mutex); + return status; } - -static DEVICE_ATTR(value, 0644, - gpio_value_show, gpio_value_store); +static DEVICE_ATTR_RW(value); static irqreturn_t gpio_sysfs_irq(int irq, void *priv) { - struct kernfs_node *value_sd = priv; + struct gpiod_data *data = priv; + + sysfs_notify_dirent(data->value_kn); - sysfs_notify_dirent(value_sd); return IRQ_HANDLED; } -static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, - unsigned long gpio_flags) +/* Caller holds gpiod-data mutex. */ +static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags) { - struct kernfs_node *value_sd; + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; unsigned long irq_flags; - int ret, irq, id; + int ret; - if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) - return 0; - - irq = gpiod_to_irq(desc); - if (irq < 0) + data->irq = gpiod_to_irq(desc); + if (data->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) { - gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); - ret = 0; - goto free_id; - } + data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value"); + if (!data->value_kn) + return -ENODEV; irq_flags = IRQF_SHARED; - if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) + if (flags & GPIO_IRQF_TRIGGER_FALLING) irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; - if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) + if (flags & GPIO_IRQF_TRIGGER_RISING) irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; - if (!value_sd) { - value_sd = sysfs_get_dirent(dev->kobj.sd, "value"); - if (!value_sd) { - ret = -ENODEV; - goto err_out; - } - - ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL); - if (ret < 0) - goto free_sd; - id = ret; - - desc->flags &= GPIO_FLAGS_MASK; - desc->flags |= (unsigned long)id << ID_SHIFT; - - if (desc->flags >> ID_SHIFT != id) { - ret = -ERANGE; - goto free_id; - } - } + /* + * FIXME: This should be done in the irq_request_resources callback + * when the irq is requested, but a few drivers currently fail + * to do so. + * + * Remove this redundant call (along with the corresponding + * unlock) when those drivers have been fixed. + */ + ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); + if (ret < 0) + goto err_put_kn; - ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags, - "gpiolib", value_sd); + ret = request_any_context_irq(data->irq, gpio_sysfs_irq, irq_flags, + "gpiolib", data); if (ret < 0) - goto free_id; + goto err_unlock; - ret = gpiochip_lock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); - if (ret < 0) { - gpiod_warn(desc, "failed to flag the GPIO for IRQ\n"); - goto free_id; - } + data->irq_flags = flags; - 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: +err_unlock: + gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); +err_put_kn: + sysfs_put(data->value_kn); + return ret; } +/* + * Caller holds gpiod-data mutex (unless called after class-device + * deregistration). + */ +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->chip, gpio_chip_hwgpio(desc)); + sysfs_put(data->value_kn); +} + static const struct { const char *name; - unsigned long flags; + unsigned char flags; } trigger_types[] = { { "none", 0 }, - { "falling", BIT(FLAG_TRIG_FALL) }, - { "rising", BIT(FLAG_TRIG_RISE) }, - { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, + { "falling", GPIO_IRQF_TRIGGER_FALLING }, + { "rising", GPIO_IRQF_TRIGGER_RISING }, + { "both", GPIO_IRQF_TRIGGER_BOTH }, }; -static ssize_t gpio_edge_show(struct device *dev, +static ssize_t edge_show(struct device *dev, struct device_attribute *attr, char *buf) { - const struct gpio_desc *desc = dev_get_drvdata(dev); - ssize_t status; + struct gpiod_data *data = dev_get_drvdata(dev); + ssize_t status = 0; + int i; - mutex_lock(&sysfs_lock); - - if (!test_bit(FLAG_EXPORT, &desc->flags)) - status = -EIO; - else { - int i; + mutex_lock(&data->mutex); - 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; - } + 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(&sysfs_lock); + mutex_unlock(&data->mutex); + return status; } -static ssize_t gpio_edge_store(struct device *dev, +static ssize_t 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; + 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++) + for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { if (sysfs_streq(trigger_types[i].name, buf)) - goto found; - return -EINVAL; + break; + } -found: - mutex_lock(&sysfs_lock); + if (i == ARRAY_SIZE(trigger_types)) + return -EINVAL; - if (!test_bit(FLAG_EXPORT, &desc->flags)) - status = -EIO; - else { - status = gpio_setup_irq(desc, dev, trigger_types[i].flags); + 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; } - mutex_unlock(&sysfs_lock); +out_unlock: + mutex_unlock(&data->mutex); return status; } +static DEVICE_ATTR_RW(edge); -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) +/* Caller holds gpiod-data mutex. */ +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; @@ -300,69 +305,59 @@ static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, 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); + 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 gpio_active_low_show(struct device *dev, +static ssize_t active_low_show(struct device *dev, struct device_attribute *attr, char *buf) { - const struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; ssize_t status; - mutex_lock(&sysfs_lock); + mutex_lock(&data->mutex); - if (!test_bit(FLAG_EXPORT, &desc->flags)) - status = -EIO; - else - status = sprintf(buf, "%d\n", + status = sprintf(buf, "%d\n", !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); - mutex_unlock(&sysfs_lock); + mutex_unlock(&data->mutex); return status; } -static ssize_t gpio_active_low_store(struct device *dev, +static ssize_t active_low_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { - struct gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); ssize_t status; + long value; - mutex_lock(&sysfs_lock); + mutex_lock(&data->mutex); - if (!test_bit(FLAG_EXPORT, &desc->flags)) { - status = -EIO; - } else { - long value; + status = kstrtol(buf, 0, &value); + if (status == 0) + status = gpio_sysfs_set_active_low(dev, value); - status = kstrtol(buf, 0, &value); - if (status == 0) - status = sysfs_set_active_low(desc, dev, value != 0); - } - - mutex_unlock(&sysfs_lock); + mutex_unlock(&data->mutex); return status ? : size; } - -static DEVICE_ATTR(active_low, 0644, - gpio_active_low_show, gpio_active_low_store); +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 gpio_desc *desc = dev_get_drvdata(dev); + struct gpiod_data *data = dev_get_drvdata(dev); + struct gpio_desc *desc = data->desc; umode_t mode = attr->mode; - bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags); + bool show_direction = data->direction_can_change; if (attr == &dev_attr_direction.attr) { if (!show_direction) @@ -402,32 +397,32 @@ static const struct attribute_group *gpio_groups[] = { * /ngpio ... matching gpio_chip.ngpio */ -static ssize_t chip_base_show(struct device *dev, +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(base, 0444, chip_base_show, NULL); +static DEVICE_ATTR_RO(base); -static ssize_t chip_label_show(struct device *dev, +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(label, 0444, chip_label_show, NULL); +static DEVICE_ATTR_RO(label); -static ssize_t chip_ngpio_show(struct device *dev, +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(ngpio, 0444, chip_ngpio_show, NULL); +static DEVICE_ATTR_RO(ngpio); static struct attribute *gpiochip_attrs[] = { &dev_attr_base.attr, @@ -552,6 +547,7 @@ static struct class gpio_class = { int gpiod_export(struct gpio_desc *desc, bool direction_may_change) { struct gpio_chip *chip; + struct gpiod_data *data; unsigned long flags; int status; const char *ioname = NULL; @@ -574,9 +570,9 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) mutex_lock(&sysfs_lock); /* check if chip is being removed */ - if (!chip || !chip->exported) { + if (!chip || !chip->cdev) { status = -ENODEV; - goto fail_unlock; + goto err_unlock; } spin_lock_irqsave(&gpio_lock, flags); @@ -588,43 +584,54 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) test_bit(FLAG_REQUESTED, &desc->flags), test_bit(FLAG_EXPORT, &desc->flags)); status = -EPERM; - goto fail_unlock; + goto err_unlock; } + spin_unlock_irqrestore(&gpio_lock, flags); - if (desc->chip->direction_input && desc->chip->direction_output && - direction_may_change) { - set_bit(FLAG_SYSFS_DIR, &desc->flags); + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) { + status = -ENOMEM; + goto err_unlock; } - spin_unlock_irqrestore(&gpio_lock, flags); + 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 (desc->chip->names && desc->chip->names[offset]) - ioname = desc->chip->names[offset]; + if (chip->names && chip->names[offset]) + ioname = chip->names[offset]; - dev = device_create_with_groups(&gpio_class, desc->chip->dev, - MKDEV(0, 0), desc, gpio_groups, + dev = device_create_with_groups(&gpio_class, chip->dev, + MKDEV(0, 0), data, gpio_groups, ioname ? ioname : "gpio%u", desc_to_gpio(desc)); if (IS_ERR(dev)) { status = PTR_ERR(dev); - goto fail_unlock; + goto err_free_data; } set_bit(FLAG_EXPORT, &desc->flags); mutex_unlock(&sysfs_lock); return 0; -fail_unlock: +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 *data) +static int match_export(struct device *dev, const void *desc) { - return dev_get_drvdata(dev) == data; + struct gpiod_data *data = dev_get_drvdata(dev); + + return data->desc == desc; } /** @@ -641,82 +648,26 @@ static int match_export(struct device *dev, const void *data) int gpiod_export_link(struct device *dev, const char *name, struct gpio_desc *desc) { - int status = -EINVAL; + struct device *cdev; + int ret; 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); - put_device(tdev); - } else { - status = -ENODEV; - } - } - - mutex_unlock(&sysfs_lock); + cdev = class_find_device(&gpio_class, NULL, desc, match_export); + if (!cdev) + return -ENODEV; - if (status) - gpiod_dbg(desc, "%s: status %d\n", __func__, status); + ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name); + put_device(cdev); - return status; + return ret; } 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); - put_device(dev); -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 * @@ -724,8 +675,8 @@ EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low); */ void gpiod_unexport(struct gpio_desc *desc) { - int status = 0; - struct device *dev = NULL; + struct gpiod_data *data; + struct device *dev; if (!desc) { pr_warn("%s: invalid GPIO\n", __func__); @@ -734,82 +685,79 @@ void gpiod_unexport(struct gpio_desc *desc) mutex_lock(&sysfs_lock); - if (test_bit(FLAG_EXPORT, &desc->flags)) { + if (!test_bit(FLAG_EXPORT, &desc->flags)) + goto err_unlock; - 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; - } + 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); + + /* + * Release irq after deregistration to prevent race with edge_store. + */ + if (data->irq_flags) + gpio_sysfs_free_irq(dev); mutex_unlock(&sysfs_lock); - if (dev) { - device_unregister(dev); - put_device(dev); - } + put_device(dev); + kfree(data); - if (status) - gpiod_dbg(desc, "%s: status %d\n", __func__, status); + return; + +err_unlock: + mutex_unlock(&sysfs_lock); } EXPORT_SYMBOL_GPL(gpiod_unexport); -int gpiochip_export(struct gpio_chip *chip) +int gpiochip_sysfs_register(struct gpio_chip *chip) { - int status; struct device *dev; - /* Many systems register gpio chips for SOC support very early, + /* + * Many systems add 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 + * register 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); + return PTR_ERR(dev); - if (status) - chip_dbg(chip, "%s: status %d\n", __func__, status); + mutex_lock(&sysfs_lock); + chip->cdev = dev; + mutex_unlock(&sysfs_lock); - return status; + return 0; } -void gpiochip_unexport(struct gpio_chip *chip) +void gpiochip_sysfs_unregister(struct gpio_chip *chip) { - int status; - struct device *dev; struct gpio_desc *desc; unsigned int i; + if (!chip->cdev) + return; + + device_unregister(chip->cdev); + + /* prevent further gpiod exports */ mutex_lock(&sysfs_lock); - dev = class_find_device(&gpio_class, NULL, chip, match_export); - if (dev) { - put_device(dev); - device_unregister(dev); - /* prevent further gpiod exports */ - chip->exported = false; - status = 0; - } else - status = -ENODEV; + chip->cdev = NULL; mutex_unlock(&sysfs_lock); - if (status) - chip_dbg(chip, "%s: status %d\n", __func__, status); - /* unregister gpiod class devices owned by sysfs */ for (i = 0; i < chip->ngpio; i++) { desc = &chip->desc[i]; @@ -836,19 +784,20 @@ static int __init gpiolib_sysfs_init(void) */ spin_lock_irqsave(&gpio_lock, flags); list_for_each_entry(chip, &gpio_chips, list) { - if (chip->exported) + if (chip->cdev) continue; /* - * TODO we yield gpio_lock here because gpiochip_export() - * acquires a mutex. This is unsafe and needs to be fixed. + * TODO we yield gpio_lock here because + * gpiochip_sysfs_register() acquires a mutex. This is unsafe + * and needs to be fixed. * * Also it would be nice to use gpiochip_find() here so we * can keep gpio_chips local to gpiolib.c, but the yield of * gpio_lock prevents us from doing this. */ spin_unlock_irqrestore(&gpio_lock, flags); - status = gpiochip_export(chip); + status = gpiochip_sysfs_register(chip); spin_lock_irqsave(&gpio_lock, flags); } spin_unlock_irqrestore(&gpio_lock, flags); |