#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "gpiolib.h" #define CREATE_TRACE_POINTS #include /* Implementation infrastructure for GPIO interfaces. * * 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_EXPORT 2 /* protected by sysfs_lock */ #define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */ #define FLAG_TRIG_FALL 4 /* trigger on falling edge */ #define FLAG_TRIG_RISE 5 /* trigger on rising edge */ #define FLAG_ACTIVE_LOW 6 /* value has active low */ #define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */ #define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */ #define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */ #define ID_SHIFT 16 /* add new flags before this one */ #define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1) #define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE)) #ifdef CONFIG_DEBUG_FS const char *label; #endif }; static struct gpio_desc gpio_desc[ARCH_NR_GPIOS]; #define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio) static DEFINE_MUTEX(gpio_lookup_lock); static LIST_HEAD(gpio_lookup_list); static LIST_HEAD(gpio_chips); #ifdef CONFIG_GPIO_SYSFS static DEFINE_IDR(dirent_idr); #endif static int gpiod_request(struct gpio_desc *desc, const char *label); static void gpiod_free(struct gpio_desc *desc); /* With descriptor prefix */ #ifdef CONFIG_DEBUG_FS #define gpiod_emerg(desc, fmt, ...) \ pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\ ##__VA_ARGS__) #define gpiod_crit(desc, fmt, ...) \ pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ ##__VA_ARGS__) #define gpiod_err(desc, fmt, ...) \ pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ ##__VA_ARGS__) #define gpiod_warn(desc, fmt, ...) \ pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ ##__VA_ARGS__) #define gpiod_info(desc, fmt, ...) \ pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ ##__VA_ARGS__) #define gpiod_dbg(desc, fmt, ...) \ pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\ ##__VA_ARGS__) #else #define gpiod_emerg(desc, fmt, ...) \ pr_emerg("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) #define gpiod_crit(desc, fmt, ...) \ pr_crit("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) #define gpiod_err(desc, fmt, ...) \ pr_err("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) #define gpiod_warn(desc, fmt, ...) \ pr_warn("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) #define gpiod_info(desc, fmt, ...) \ pr_info("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) #define gpiod_dbg(desc, fmt, ...) \ pr_debug("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__) #endif /* With chip prefix */ #define chip_emerg(chip, fmt, ...) \ pr_emerg("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) #define chip_crit(chip, fmt, ...) \ pr_crit("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) #define chip_err(chip, fmt, ...) \ pr_err("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) #define chip_warn(chip, fmt, ...) \ pr_warn("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) #define chip_info(chip, fmt, ...) \ pr_info("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) #define chip_dbg(chip, fmt, ...) \ pr_debug("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__) static inline void desc_set_label(struct gpio_desc *d, const char *label) { #ifdef CONFIG_DEBUG_FS d->label = label; #endif } /* * Return the GPIO number of the passed descriptor relative to its chip */ static int gpio_chip_hwgpio(const struct gpio_desc *desc) { return desc - &desc->chip->desc[0]; } /** * Convert a GPIO number to its descriptor */ struct gpio_desc *gpio_to_desc(unsigned gpio) { if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio)) return NULL; else return &gpio_desc[gpio]; } EXPORT_SYMBOL_GPL(gpio_to_desc); /** * Convert an offset on a certain chip to a corresponding descriptor */ static struct gpio_desc *gpiochip_offset_to_desc(struct gpio_chip *chip, unsigned int offset) { if (offset >= chip->ngpio) return ERR_PTR(-EINVAL); return &chip->desc[offset]; } /** * Convert a GPIO descriptor to the integer namespace. * This should disappear in the future but is needed since we still * use GPIO numbers for error messages and sysfs nodes */ int desc_to_gpio(const struct gpio_desc *desc) { return desc - &gpio_desc[0]; } EXPORT_SYMBOL_GPL(desc_to_gpio); /* 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) { const struct gpio_chip *chip = desc->chip; const int gpio = desc_to_gpio(desc); if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, "autorequest GPIO-%d\n", gpio)) { if (!try_module_get(chip->owner)) { gpiod_err(desc, "%s: module can't be gotten\n", __func__); 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; } /** * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs * @desc: descriptor to return the chip of */ struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) { return desc ? desc->chip : NULL; } EXPORT_SYMBOL_GPL(gpiod_to_chip); /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ static int gpiochip_find_base(int ngpio) { struct gpio_chip *chip; int base = ARCH_NR_GPIOS - ngpio; list_for_each_entry_reverse(chip, &gpio_chips, list) { /* found a free space? */ if (chip->base + chip->ngpio <= base) break; else /* nope, check the space right before the chip */ base = chip->base - ngpio; } if (gpio_is_valid(base)) { pr_debug("%s: found new base at %d\n", __func__, base); return base; } else { pr_err("%s: cannot find free range\n", __func__); return -ENOSPC; } } /** * gpiod_get_direction - return the current direction of a GPIO * @desc: GPIO to get the direction of * * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error. * * This function may sleep if gpiod_cansleep() is true. */ int gpiod_get_direction(const struct gpio_desc *desc) { struct gpio_chip *chip; unsigned offset; int status = -EINVAL; chip = gpiod_to_chip(desc); offset = gpio_chip_hwgpio(desc); if (!chip->get_direction) return status; status = chip->get_direction(chip, offset); if (status > 0) { /* GPIOF_DIR_IN, or other positive */ status = 1; /* FLAG_IS_OUT is just a cache of the result of get_direction(), * so it does not affect constness per se */ clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); } if (status == 0) { /* GPIOF_DIR_OUT */ set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); } return status; } EXPORT_SYMBOL_GPL(gpiod_get_direction); #ifdef CONFIG_GPIO_SYSFS /* lock protects against unexport_gpio() being called while * sysfs files are active. */ static DEFINE_MUTEX(sysfs_lock); /* * /sys/class/gpio/gpioN... only for GPIOs that are exported * /direction * * MAY BE OMITTED if kernel won't allow direction changes * * is read/write as "in" or "out" * * may also be written as "high" or "low", initializing * output value as specified ("out" implies "low") * /value * * always readable, subject to hardware behavior * * may be writable, as zero/nonzero * /edge * * configures behavior of poll(2) on /value * * available only if pin can generate IRQs on input * * is read/write as "none", "falling", "rising", or "both" * /active_low * * configures polarity of /value * * is read/write as zero/nonzero * * also affects existing and subsequent "falling" and "rising" * /edge configuration */ static ssize_t gpio_direction_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) { status = -EIO; } else { gpiod_get_direction(desc); status = sprintf(buf, "%s\n", test_bit(FLAG_IS_OUT, &desc->flags) ? "out" : "in"); } mutex_unlock(&sysfs_lock); return status; } static ssize_t gpio_direction_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else if (sysfs_streq(buf, "high")) status = gpiod_direction_output(desc, 1); else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low")) status = gpiod_direction_output(desc, 0); else if (sysfs_streq(buf, "in")) status = gpiod_direction_input(desc); else status = -EINVAL; mutex_unlock(&sysfs_lock); return status ? : size; } static /* const */ DEVICE_ATTR(direction, 0644, gpio_direction_show, gpio_direction_store); static ssize_t gpio_value_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc)); mutex_unlock(&sysfs_lock); return status; } static ssize_t gpio_value_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else if (!test_bit(FLAG_IS_OUT, &desc->flags)) status = -EPERM; else { long value; status = kstrtol(buf, 0, &value); if (status == 0) { gpiod_set_value_cansleep(desc, value); status = size; } } mutex_unlock(&sysfs_lock); return status; } static DEVICE_ATTR(value, 0644, gpio_value_show, gpio_value_store); static irqreturn_t gpio_sysfs_irq(int irq, void *priv) { struct kernfs_node *value_sd = priv; sysfs_notify_dirent(value_sd); return IRQ_HANDLED; } static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev, unsigned long gpio_flags) { struct kernfs_node *value_sd; unsigned long irq_flags; int ret, irq, id; if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags) return 0; irq = gpiod_to_irq(desc); if (irq < 0) return -EIO; id = desc->flags >> ID_SHIFT; value_sd = idr_find(&dirent_idr, id); if (value_sd) free_irq(irq, value_sd); desc->flags &= ~GPIO_TRIGGER_MASK; if (!gpio_flags) { gpiod_unlock_as_irq(desc); ret = 0; goto free_id; } irq_flags = IRQF_SHARED; if (test_bit(FLAG_TRIG_FALL, &gpio_flags)) irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; if (test_bit(FLAG_TRIG_RISE, &gpio_flags)) irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ? IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; if (!value_sd) { value_sd = sysfs_get_dirent(dev->kobj.sd, "value"); if (!value_sd) { ret = -ENODEV; goto err_out; } ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL); if (ret < 0) goto free_sd; id = ret; desc->flags &= GPIO_FLAGS_MASK; desc->flags |= (unsigned long)id << ID_SHIFT; if (desc->flags >> ID_SHIFT != id) { ret = -ERANGE; goto free_id; } } ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags, "gpiolib", value_sd); if (ret < 0) goto free_id; ret = gpiod_lock_as_irq(desc); if (ret < 0) { gpiod_warn(desc, "failed to flag the GPIO for IRQ\n"); goto free_id; } desc->flags |= gpio_flags; return 0; free_id: idr_remove(&dirent_idr, id); desc->flags &= GPIO_FLAGS_MASK; free_sd: if (value_sd) sysfs_put(value_sd); err_out: return ret; } static const struct { const char *name; unsigned long flags; } trigger_types[] = { { "none", 0 }, { "falling", BIT(FLAG_TRIG_FALL) }, { "rising", BIT(FLAG_TRIG_RISE) }, { "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, }; static ssize_t gpio_edge_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else { int i; status = 0; for (i = 0; i < ARRAY_SIZE(trigger_types); i++) if ((desc->flags & GPIO_TRIGGER_MASK) == trigger_types[i].flags) { status = sprintf(buf, "%s\n", trigger_types[i].name); break; } } mutex_unlock(&sysfs_lock); return status; } static ssize_t gpio_edge_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; int i; for (i = 0; i < ARRAY_SIZE(trigger_types); i++) if (sysfs_streq(trigger_types[i].name, buf)) goto found; return -EINVAL; found: mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else { status = gpio_setup_irq(desc, dev, trigger_types[i].flags); if (!status) status = size; } mutex_unlock(&sysfs_lock); return status; } static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store); static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, int value) { int status = 0; if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) return 0; if (value) set_bit(FLAG_ACTIVE_LOW, &desc->flags); else clear_bit(FLAG_ACTIVE_LOW, &desc->flags); /* reconfigure poll(2) support if enabled on one edge only */ if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; gpio_setup_irq(desc, dev, 0); status = gpio_setup_irq(desc, dev, trigger_flags); } return status; } static ssize_t gpio_active_low_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) status = -EIO; else status = sprintf(buf, "%d\n", !!test_bit(FLAG_ACTIVE_LOW, &desc->flags)); mutex_unlock(&sysfs_lock); return status; } static ssize_t gpio_active_low_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); if (!test_bit(FLAG_EXPORT, &desc->flags)) { status = -EIO; } else { long value; status = kstrtol(buf, 0, &value); if (status == 0) status = sysfs_set_active_low(desc, dev, value != 0); } mutex_unlock(&sysfs_lock); return status ? : size; } static DEVICE_ATTR(active_low, 0644, gpio_active_low_show, gpio_active_low_store); static struct attribute *gpio_attrs[] = { &dev_attr_value.attr, &dev_attr_active_low.attr, NULL, }; ATTRIBUTE_GROUPS(gpio); /* * /sys/class/gpio/gpiochipN/ * /base ... matching gpio_chip.base (N) * /label ... matching gpio_chip.label * /ngpio ... matching gpio_chip.ngpio */ static ssize_t chip_base_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_chip *chip = dev_get_drvdata(dev); return sprintf(buf, "%d\n", chip->base); } static DEVICE_ATTR(base, 0444, chip_base_show, NULL); static ssize_t chip_label_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_chip *chip = dev_get_drvdata(dev); return sprintf(buf, "%s\n", chip->label ? : ""); } static DEVICE_ATTR(label, 0444, chip_label_show, NULL); static ssize_t chip_ngpio_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct gpio_chip *chip = dev_get_drvdata(dev); return sprintf(buf, "%u\n", chip->ngpio); } static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); static 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; struct gpio_desc *desc; int status; status = kstrtol(buf, 0, &gpio); if (status < 0) goto done; desc = gpio_to_desc(gpio); /* reject invalid GPIOs */ if (!desc) { pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); return -EINVAL; } /* No extra locking here; FLAG_SYSFS just signifies that the * request and export were done by on behalf of userspace, so * they may be undone on its behalf too. */ status = gpiod_request(desc, "sysfs"); if (status < 0) { if (status == -EPROBE_DEFER) status = -ENODEV; goto done; } status = gpiod_export(desc, true); if (status < 0) gpiod_free(desc); else set_bit(FLAG_SYSFS, &desc->flags); done: if (status) pr_debug("%s: status %d\n", __func__, status); return status ? : len; } static ssize_t unexport_store(struct class *class, struct class_attribute *attr, const char *buf, size_t len) { long gpio; struct gpio_desc *desc; int status; status = kstrtol(buf, 0, &gpio); if (status < 0) goto done; desc = gpio_to_desc(gpio); /* reject bogus commands (gpio_unexport ignores them) */ if (!desc) { pr_warn("%s: invalid GPIO %ld\n", __func__, gpio); return -EINVAL; } status = -EINVAL; /* No extra locking here; FLAG_SYSFS just signifies that the * request and export were done by on behalf of userspace, so * they may be undone on its behalf too. */ if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) { status = 0; gpiod_free(desc); } done: if (status) pr_debug("%s: status %d\n", __func__, status); return status ? : len; } static struct class_attribute gpio_class_attrs[] = { __ATTR(export, 0200, NULL, export_store), __ATTR(unexport, 0200, NULL, unexport_store), __ATTR_NULL, }; static struct class gpio_class = { .name = "gpio", .owner = THIS_MODULE, .class_attrs = gpio_class_attrs, }; /** * gpiod_export - export a GPIO through sysfs * @gpio: gpio to make available, already requested * @direction_may_change: true if userspace may change gpio direction * Context: arch_initcall or later * * When drivers want to make a GPIO accessible to userspace after they * have requested it -- perhaps while debugging, or as part of their * public interface -- they may use this routine. If the GPIO can * change direction (some can't) and the caller allows it, userspace * will see "direction" sysfs attribute which may be used to change * the gpio's direction. A "value" attribute will always be provided. * * Returns zero on success, else an error. */ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) { struct gpio_chip *chip; unsigned long flags; int status; const char *ioname = NULL; struct device *dev; int offset; /* can't export until sysfs is available ... */ if (!gpio_class.p) { pr_debug("%s: called too early!\n", __func__); return -ENOENT; } if (!desc) { pr_debug("%s: invalid gpio descriptor\n", __func__); return -EINVAL; } chip = desc->chip; mutex_lock(&sysfs_lock); /* check if chip is being removed */ if (!chip || !chip->exported) { status = -ENODEV; goto fail_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 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_with_groups(&gpio_class, desc->chip->dev, MKDEV(0, 0), desc, gpio_groups, ioname ? ioname : "gpio%u", desc_to_gpio(desc)); if (IS_ERR(dev)) { status = PTR_ERR(dev); goto fail_unlock; } 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_remove_attr_direction; } set_bit(FLAG_EXPORT, &desc->flags); mutex_unlock(&sysfs_lock); return 0; fail_remove_attr_direction: device_remove_file(dev, &dev_attr_direction); 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); put_device(tdev); } 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); 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 * * 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_remove_file(dev, &dev_attr_edge); device_remove_file(dev, &dev_attr_direction); device_unregister(dev); put_device(dev); } if (status) gpiod_dbg(desc, "%s: status %d\n", __func__, status); } EXPORT_SYMBOL_GPL(gpiod_unexport); static int gpiochip_export(struct gpio_chip *chip) { int status; struct device *dev; /* Many systems register gpio chips for SOC support very early, * before driver model support is available. In those cases we * export this later, in gpiolib_sysfs_init() ... here we just * verify that _some_ field of gpio_class got initialized. */ if (!gpio_class.p) return 0; /* use chip->base for the ID; it's already known to be unique */ mutex_lock(&sysfs_lock); dev = device_create_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 = 0; while (gpio < chip->ngpio) chip->desc[gpio++].chip = NULL; spin_unlock_irqrestore(&gpio_lock, flags); chip_dbg(chip, "%s: status %d\n", __func__, status); } return status; } static void gpiochip_unexport(struct gpio_chip *chip) { int status; struct device *dev; struct gpio_desc *desc; unsigned int i; 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; 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]; 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_chip *chip; status = class_register(&gpio_class); if (status < 0) return status; /* Scan and register the gpio_chips which registered very * early (e.g. before the class_register above was called). * * We run before arch_initcall() so chip->dev nodes can have * registered, and so arch_initcall() can always gpio_export(). */ spin_lock_irqsave(&gpio_lock, flags); list_for_each_entry(chip, &gpio_chips, list) { if (!chip || chip->exported) continue; spin_unlock_irqrestore(&gpio_lock, flags); status = gpiochip_export(chip); spin_lock_irqsave(&gpio_lock, flags); } spin_unlock_irqrestore(&gpio_lock, flags); return status; } postcore_initcall(gpiolib_sysfs_init); #else static inline int gpiochip_export(struct gpio_chip *chip) { return 0; } static inline void gpiochip_unexport(struct gpio_chip *chip) { } #endif /* CONFIG_GPIO_SYSFS */ /* * Add a new chip to the global chips list, keeping the list of chips sorted * by base order. * * Return -EBUSY if the new chip overlaps with some other chip's integer * space. */ static int gpiochip_add_to_list(struct gpio_chip *chip) { struct list_head *pos = &gpio_chips; struct gpio_chip *_chip; int err = 0; /* find where to insert our chip */ list_for_each(pos, &gpio_chips) { _chip = list_entry(pos, struct gpio_chip, list); /* shall we insert before _chip? */ if (_chip->base >= chip->base + chip->ngpio) break; } /* are we stepping on the chip right before? */ if (pos != &gpio_chips && pos->prev != &gpio_chips) { _chip = list_entry(pos->prev, struct gpio_chip, list); if (_chip->base + _chip->ngpio > chip->base) { dev_err(chip->dev, "GPIO integer space overlap, cannot add chip\n"); err = -EBUSY; } } if (!err) list_add_tail(&chip->list, pos); return err; } /** * 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; } status = gpiochip_add_to_list(chip); if (status == 0) { chip->desc = &gpio_desc[chip->base]; for (id = 0; id < chip->ngpio; id++) { struct gpio_desc *desc = &chip->desc[id]; desc->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, * and in case chip->get_direction is not set, * we may expose the wrong direction in sysfs. */ desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0; } } spin_unlock_irqrestore(&gpio_lock, flags); if (status) goto fail; #ifdef CONFIG_PINCTRL INIT_LIST_HEAD(&chip->pin_ranges); #endif of_gpiochip_add(chip); acpi_gpiochip_add(chip); status = gpiochip_export(chip); if (status) { acpi_gpiochip_remove(chip); of_gpiochip_remove(chip); goto fail; } pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__, chip->base, chip->base + chip->ngpio - 1, chip->label ? : "generic"); return 0; unlock: spin_unlock_irqrestore(&gpio_lock, flags); fail: /* failures here can mean systems won't boot... */ pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__, 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; gpiochip_unexport(chip); spin_lock_irqsave(&gpio_lock, flags); gpiochip_remove_pin_ranges(chip); of_gpiochip_remove(chip); acpi_gpiochip_remove(chip); for (id = 0; id < chip->ngpio; id++) { if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) { status = -EBUSY; break; } } if (status == 0) { for (id = 0; id < chip->ngpio; id++) chip->desc[id].chip = NULL; list_del(&chip->list); } spin_unlock_irqrestore(&gpio_lock, flags); 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(void *data, int (*match)(struct gpio_chip *chip, void *data)) { struct gpio_chip *chip; unsigned long flags; spin_lock_irqsave(&gpio_lock, flags); list_for_each_entry(chip, &gpio_chips, list) if (match(chip, data)) break; /* No match? */ if (&chip->list == &gpio_chips) chip = NULL; spin_unlock_irqrestore(&gpio_lock, flags); return chip; } EXPORT_SYMBOL_GPL(gpiochip_find); static int gpiochip_match_name(struct gpio_chip *chip, void *data) { const char *name = data; return !strcmp(chip->label, name); } static struct gpio_chip *find_chip_by_name(const char *name) { return gpiochip_find((void *)name, gpiochip_match_name); } #ifdef CONFIG_PINCTRL /** * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping * @chip: the gpiochip to add the range for * @pinctrl: the dev_name() of the pin controller to map to * @gpio_offset: the start offset in the current gpio_chip number space * @pin_group: name of the pin group inside the pin controller */ int gpiochip_add_pingroup_range(struct gpio_chip *chip, struct pinctrl_dev *pctldev, unsigned int gpio_offset, const char *pin_group) { struct gpio_pin_range *pin_range; int ret; pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL); if (!pin_range) { chip_err(chip, "failed to allocate pin ranges\n"); return -ENOMEM; } /* Use local offset as range ID */ pin_range->range.id = gpio_offset; pin_range->range.gc = chip; pin_range->range.name = chip->label; pin_range->range.base = chip->base + gpio_offset; pin_range->pctldev = pctldev; ret = pinctrl_get_group_pins(pctldev, pin_group, &pin_range->range.pins, &pin_range->range.npins); if (ret < 0) { kfree(pin_range); return ret; } pinctrl_add_gpio_range(pctldev, &pin_range->range); chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n", gpio_offset, gpio_offset + pin_range->range.npins - 1, pinctrl_dev_get_devname(pctldev), pin_group); list_add_tail(&pin_range->node, &chip->pin_ranges); return 0; } EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range); /** * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping * @chip: the gpiochip to add the range for * @pinctrl_name: the dev_name() of the pin controller to map to * @gpio_offset: the start offset in the current gpio_chip number space * @pin_offset: the start offset in the pin controller number space * @npins: the number of pins from the offset of each pin space (GPIO and * pin controller) to accumulate in this range */ int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name, unsigned int gpio_offset, unsigned int pin_offset, unsigned int npins) { struct gpio_pin_range *pin_range; int ret; pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL); if (!pin_range) { chip_err(chip, "failed to allocate pin ranges\n"); return -ENOMEM; } /* Use local offset as range ID */ pin_range->range.id = gpio_offset; pin_range->range.gc = chip; pin_range->range.name = chip->label; pin_range->range.base = chip->base + gpio_offset; pin_range->range.pin_base = pin_offset; pin_range->range.npins = npins; pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name, &pin_range->range); if (IS_ERR(pin_range->pctldev)) { ret = PTR_ERR(pin_range->pctldev); chip_err(chip, "could not create pin range\n"); kfree(pin_range); return ret; } chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n", gpio_offset, gpio_offset + npins - 1, pinctl_name, pin_offset, pin_offset + npins - 1); list_add_tail(&pin_range->node, &chip->pin_ranges); return 0; } EXPORT_SYMBOL_GPL(gpiochip_add_pin_range); /** * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings * @chip: the chip to remove all the mappings for */ void gpiochip_remove_pin_ranges(struct gpio_chip *chip) { struct gpio_pin_range *pin_range, *tmp; list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) { list_del(&pin_range->node); pinctrl_remove_gpio_range(pin_range->pctldev, &pin_range->range); kfree(pin_range); } } EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges); #endif /* CONFIG_PINCTRL */ /* 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. */ static int gpiod_request(struct gpio_desc *desc, const char *label) { struct gpio_chip *chip; int status = -EPROBE_DEFER; unsigned long flags; if (!desc) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } spin_lock_irqsave(&gpio_lock, flags); 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_hwgpio(desc)); spin_lock_irqsave(&gpio_lock, flags); if (status < 0) { desc_set_label(desc, NULL); module_put(chip->owner); clear_bit(FLAG_REQUESTED, &desc->flags); goto done; } } if (chip->get_direction) { /* chip->get_direction may sleep */ spin_unlock_irqrestore(&gpio_lock, flags); gpiod_get_direction(desc); spin_lock_irqsave(&gpio_lock, flags); } done: if (status) gpiod_dbg(desc, "%s: status %d\n", __func__, status); spin_unlock_irqrestore(&gpio_lock, flags); return status; } int gpio_request(unsigned gpio, const char *label) { return gpiod_request(gpio_to_desc(gpio), label); } EXPORT_SYMBOL_GPL(gpio_request); static void gpiod_free(struct gpio_desc *desc) { unsigned long flags; struct gpio_chip *chip; might_sleep(); if (!desc) { WARN_ON(extra_checks); return; } gpiod_unexport(desc); spin_lock_irqsave(&gpio_lock, flags); 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_hwgpio(desc)); 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); } void gpio_free(unsigned gpio) { gpiod_free(gpio_to_desc(gpio)); } EXPORT_SYMBOL_GPL(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) { struct gpio_desc *desc; int err; desc = gpio_to_desc(gpio); err = gpiod_request(desc, label); if (err) return err; if (flags & GPIOF_OPEN_DRAIN) set_bit(FLAG_OPEN_DRAIN, &desc->flags); if (flags & GPIOF_OPEN_SOURCE) set_bit(FLAG_OPEN_SOURCE, &desc->flags); if (flags & GPIOF_DIR_IN) err = gpiod_direction_input(desc); else err = gpiod_direction_output(desc, (flags & GPIOF_INIT_HIGH) ? 1 : 0); if (err) goto free_gpio; if (flags & GPIOF_EXPORT) { err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE); if (err) goto free_gpio; } return 0; free_gpio: gpiod_free(desc); 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) { struct gpio_desc *desc; if (!GPIO_OFFSET_VALID(chip, offset)) return NULL; desc = &chip->desc[offset]; if (test_bit(FLAG_REQUESTED, &desc->flags) == 0) return NULL; #ifdef CONFIG_DEBUG_FS return desc->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. */ /** * gpiod_direction_input - set the GPIO direction to input * @desc: GPIO to set to input * * Set the direction of the passed GPIO to input, such as gpiod_get_value() can * be called safely on it. * * Return 0 in case of success, else an error code. */ int gpiod_direction_input(struct gpio_desc *desc) { unsigned long flags; struct gpio_chip *chip; int status = -EINVAL; int offset; if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } chip = desc->chip; if (!chip->get || !chip->direction_input) { gpiod_warn(desc, "%s: missing get() or direction_input() operations\n", __func__); return -EIO; } spin_lock_irqsave(&gpio_lock, flags); status = gpio_ensure_requested(desc); 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); offset = gpio_chip_hwgpio(desc); if (status) { status = chip->request(chip, offset); if (status < 0) { gpiod_dbg(desc, "%s: chip request fail, %d\n", __func__, status); /* and it's not available to anyone else ... * gpio_request() is the fully clean solution. */ goto lose; } } status = chip->direction_input(chip, offset); if (status == 0) clear_bit(FLAG_IS_OUT, &desc->flags); trace_gpio_direction(desc_to_gpio(desc), 1, status); lose: return status; fail: spin_unlock_irqrestore(&gpio_lock, flags); if (status) gpiod_dbg(desc, "%s: status %d\n", __func__, status); return status; } EXPORT_SYMBOL_GPL(gpiod_direction_input); /** * gpiod_direction_output - set the GPIO direction to input * @desc: GPIO to set to output * @value: initial output value of the GPIO * * Set the direction of the passed GPIO to output, such as gpiod_set_value() can * be called safely on it. The initial value of the output must be specified. * * Return 0 in case of success, else an error code. */ int gpiod_direction_output(struct gpio_desc *desc, int value) { unsigned long flags; struct gpio_chip *chip; int status = -EINVAL; int offset; if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } /* GPIOs used for IRQs shall not be set as output */ if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) { gpiod_err(desc, "%s: tried to set a GPIO tied to an IRQ as output\n", __func__); return -EIO; } /* Open drain pin should not be driven to 1 */ if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags)) return gpiod_direction_input(desc); /* Open source pin should not be driven to 0 */ if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags)) return gpiod_direction_input(desc); chip = desc->chip; if (!chip->set || !chip->direction_output) { gpiod_warn(desc, "%s: missing set() or direction_output() operations\n", __func__); return -EIO; } spin_lock_irqsave(&gpio_lock, flags); status = gpio_ensure_requested(desc); 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); offset = gpio_chip_hwgpio(desc); if (status) { status = chip->request(chip, offset); if (status < 0) { gpiod_dbg(desc, "%s: chip request fail, %d\n", __func__, status); /* and it's not available to anyone else ... * gpio_request() is the fully clean solution. */ goto lose; } } status = chip->direction_output(chip, offset, value); if (status == 0) set_bit(FLAG_IS_OUT, &desc->flags); trace_gpio_value(desc_to_gpio(desc), 0, value); trace_gpio_direction(desc_to_gpio(desc), 0, status); lose: return status; fail: spin_unlock_irqrestore(&gpio_lock, flags); if (status) gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status); return status; } EXPORT_SYMBOL_GPL(gpiod_direction_output); /** * gpiod_set_debounce - sets @debounce time for a @gpio * @gpio: the gpio to set debounce time * @debounce: debounce time is microseconds * * returns -ENOTSUPP if the controller does not support setting * debounce. */ int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) { unsigned long flags; struct gpio_chip *chip; int status = -EINVAL; int offset; if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } chip = desc->chip; if (!chip->set || !chip->set_debounce) { gpiod_dbg(desc, "%s: missing set() or set_debounce() operations\n", __func__); return -ENOTSUPP; } spin_lock_irqsave(&gpio_lock, flags); status = gpio_ensure_requested(desc); 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); offset = gpio_chip_hwgpio(desc); return chip->set_debounce(chip, offset, debounce); fail: spin_unlock_irqrestore(&gpio_lock, flags); if (status) gpiod_dbg(desc, "%s: status %d\n", __func__, status); return status; } EXPORT_SYMBOL_GPL(gpiod_set_debounce); /** * gpiod_is_active_low - test whether a GPIO is active-low or not * @desc: the gpio descriptor to test * * Returns 1 if the GPIO is active-low, 0 otherwise. */ int gpiod_is_active_low(const struct gpio_desc *desc) { return test_bit(FLAG_ACTIVE_LOW, &desc->flags); } EXPORT_SYMBOL_GPL(gpiod_is_active_low); /* 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. */ static bool _gpiod_get_raw_value(const struct gpio_desc *desc) { struct gpio_chip *chip; bool value; int offset; chip = desc->chip; offset = gpio_chip_hwgpio(desc); value = chip->get ? chip->get(chip, offset) : false; trace_gpio_value(desc_to_gpio(desc), 1, value); return value; } /** * gpiod_get_raw_value() - return a gpio's raw value * @desc: gpio whose value will be returned * * Return the GPIO's raw value, i.e. the value of the physical line disregarding * its ACTIVE_LOW status. * * This function should be called from contexts where we cannot sleep, and will * complain if the GPIO chip functions potentially sleep. */ int gpiod_get_raw_value(const struct gpio_desc *desc) { if (!desc) return 0; /* Should be using gpio_get_value_cansleep() */ WARN_ON(desc->chip->can_sleep); return _gpiod_get_raw_value(desc); } EXPORT_SYMBOL_GPL(gpiod_get_raw_value); /** * gpiod_get_value() - return a gpio's value * @desc: gpio whose value will be returned * * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into * account. * * This function should be called from contexts where we cannot sleep, and will * complain if the GPIO chip functions potentially sleep. */ int gpiod_get_value(const struct gpio_desc *desc) { int value; if (!desc) return 0; /* Should be using gpio_get_value_cansleep() */ WARN_ON(desc->chip->can_sleep); value = _gpiod_get_raw_value(desc); if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) value = !value; return value; } EXPORT_SYMBOL_GPL(gpiod_get_value); /* * _gpio_set_open_drain_value() - Set the open drain gpio's value. * @desc: gpio descriptor whose state need to be set. * @value: Non-zero for setting it HIGH otherise it will set to LOW. */ static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value) { int err = 0; struct gpio_chip *chip = desc->chip; int offset = gpio_chip_hwgpio(desc); if (value) { err = chip->direction_input(chip, offset); if (!err) clear_bit(FLAG_IS_OUT, &desc->flags); } else { err = chip->direction_output(chip, offset, 0); if (!err) set_bit(FLAG_IS_OUT, &desc->flags); } trace_gpio_direction(desc_to_gpio(desc), value, err); if (err < 0) gpiod_err(desc, "%s: Error in set_value for open drain err %d\n", __func__, err); } /* * _gpio_set_open_source_value() - Set the open source gpio's value. * @desc: gpio descriptor whose state need to be set. * @value: Non-zero for setting it HIGH otherise it will set to LOW. */ static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value) { int err = 0; struct gpio_chip *chip = desc->chip; int offset = gpio_chip_hwgpio(desc); if (value) { err = chip->direction_output(chip, offset, 1); if (!err) set_bit(FLAG_IS_OUT, &desc->flags); } else { err = chip->direction_input(chip, offset); if (!err) clear_bit(FLAG_IS_OUT, &desc->flags); } trace_gpio_direction(desc_to_gpio(desc), !value, err); if (err < 0) gpiod_err(desc, "%s: Error in set_value for open source err %d\n", __func__, err); } static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value) { struct gpio_chip *chip; chip = desc->chip; trace_gpio_value(desc_to_gpio(desc), 0, value); if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) _gpio_set_open_drain_value(desc, value); else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) _gpio_set_open_source_value(desc, value); else chip->set(chip, gpio_chip_hwgpio(desc), value); } /** * gpiod_set_raw_value() - assign a gpio's raw value * @desc: gpio whose value will be assigned * @value: value to assign * * Set the raw value of the GPIO, i.e. the value of its physical line without * regard for its ACTIVE_LOW status. * * This function should be called from contexts where we cannot sleep, and will * complain if the GPIO chip functions potentially sleep. */ void gpiod_set_raw_value(struct gpio_desc *desc, int value) { if (!desc) return; /* Should be using gpio_set_value_cansleep() */ WARN_ON(desc->chip->can_sleep); _gpiod_set_raw_value(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_raw_value); /** * gpiod_set_value() - assign a gpio's value * @desc: gpio whose value will be assigned * @value: value to assign * * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into * account * * This function should be called from contexts where we cannot sleep, and will * complain if the GPIO chip functions potentially sleep. */ void gpiod_set_value(struct gpio_desc *desc, int value) { if (!desc) return; /* Should be using gpio_set_value_cansleep() */ WARN_ON(desc->chip->can_sleep); if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) value = !value; _gpiod_set_raw_value(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value); /** * gpiod_cansleep() - report whether gpio value access may sleep * @desc: gpio to check * */ int gpiod_cansleep(const struct gpio_desc *desc) { if (!desc) return 0; return desc->chip->can_sleep; } EXPORT_SYMBOL_GPL(gpiod_cansleep); /** * gpiod_to_irq() - return the IRQ corresponding to a GPIO * @desc: gpio whose IRQ will be returned (already requested) * * Return the IRQ corresponding to the passed GPIO, or an error code in case of * error. */ int gpiod_to_irq(const struct gpio_desc *desc) { struct gpio_chip *chip; int offset; if (!desc) return -EINVAL; chip = desc->chip; offset = gpio_chip_hwgpio(desc); return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO; } EXPORT_SYMBOL_GPL(gpiod_to_irq); /** * gpiod_lock_as_irq() - lock a GPIO to be used as IRQ * @gpio: the GPIO line to lock as used for IRQ * * This is used directly by GPIO drivers that want to lock down * a certain GPIO line to be used as IRQs, for example in the * .to_irq() callback of their gpio_chip, or in the .irq_enable() * of its irq_chip implementation if the GPIO is known from that * code. */ int gpiod_lock_as_irq(struct gpio_desc *desc) { if (!desc) return -EINVAL; if (test_bit(FLAG_IS_OUT, &desc->flags)) { gpiod_err(desc, "%s: tried to flag a GPIO set as output for IRQ\n", __func__); return -EIO; } set_bit(FLAG_USED_AS_IRQ, &desc->flags); return 0; } EXPORT_SYMBOL_GPL(gpiod_lock_as_irq); int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset) { return gpiod_lock_as_irq(gpiochip_offset_to_desc(chip, offset)); } EXPORT_SYMBOL_GPL(gpio_lock_as_irq); /** * gpiod_unlock_as_irq() - unlock a GPIO used as IRQ * @gpio: the GPIO line to unlock from IRQ usage * * This is used directly by GPIO drivers that want to indicate * that a certain GPIO is no longer used exclusively for IRQ. */ void gpiod_unlock_as_irq(struct gpio_desc *desc) { if (!desc) return; clear_bit(FLAG_USED_AS_IRQ, &desc->flags); } EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq); void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset) { return gpiod_unlock_as_irq(gpiochip_offset_to_desc(chip, offset)); } EXPORT_SYMBOL_GPL(gpio_unlock_as_irq); /** * gpiod_get_raw_value_cansleep() - return a gpio's raw value * @desc: gpio whose value will be returned * * Return the GPIO's raw value, i.e. the value of the physical line disregarding * its ACTIVE_LOW status. * * This function is to be called from contexts that can sleep. */ int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) { might_sleep_if(extra_checks); if (!desc) return 0; return _gpiod_get_raw_value(desc); } EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep); /** * gpiod_get_value_cansleep() - return a gpio's value * @desc: gpio whose value will be returned * * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into * account. * * This function is to be called from contexts that can sleep. */ int gpiod_get_value_cansleep(const struct gpio_desc *desc) { int value; might_sleep_if(extra_checks); if (!desc) return 0; value = _gpiod_get_raw_value(desc); if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) value = !value; return value; } EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep); /** * gpiod_set_raw_value_cansleep() - assign a gpio's raw value * @desc: gpio whose value will be assigned * @value: value to assign * * Set the raw value of the GPIO, i.e. the value of its physical line without * regard for its ACTIVE_LOW status. * * This function is to be called from contexts that can sleep. */ void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) { might_sleep_if(extra_checks); if (!desc) return; _gpiod_set_raw_value(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep); /** * gpiod_set_value_cansleep() - assign a gpio's value * @desc: gpio whose value will be assigned * @value: value to assign * * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into * account * * This function is to be called from contexts that can sleep. */ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) { might_sleep_if(extra_checks); if (!desc) return; if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) value = !value; _gpiod_set_raw_value(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep); /** * gpiod_add_lookup_table() - register GPIO device consumers * @table: table of consumers to register */ void gpiod_add_lookup_table(struct gpiod_lookup_table *table) { mutex_lock(&gpio_lookup_lock); list_add_tail(&table->list, &gpio_lookup_list); mutex_unlock(&gpio_lookup_lock); } #ifdef CONFIG_OF static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, unsigned int idx, enum gpio_lookup_flags *flags) { static const char *suffixes[] = { "gpios", "gpio" }; char prop_name[32]; /* 32 is max size of property name */ enum of_gpio_flags of_flags; struct gpio_desc *desc; unsigned int i; for (i = 0; i < ARRAY_SIZE(suffixes); i++) { if (con_id) snprintf(prop_name, 32, "%s-%s", con_id, suffixes[i]); else snprintf(prop_name, 32, "%s", suffixes[i]); desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, &of_flags); if (!IS_ERR(desc)) break; } if (IS_ERR(desc)) return desc; if (of_flags & OF_GPIO_ACTIVE_LOW) *flags |= GPIO_ACTIVE_LOW; return desc; } #else static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, unsigned int idx, enum gpio_lookup_flags *flags) { return ERR_PTR(-ENODEV); } #endif static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id, unsigned int idx, enum gpio_lookup_flags *flags) { static const char * const suffixes[] = { "gpios", "gpio" }; struct acpi_device *adev = ACPI_COMPANION(dev); struct acpi_gpio_info info; struct gpio_desc *desc; char propname[32]; int i; /* Try first from _DSD */ for (i = 0; i < ARRAY_SIZE(suffixes); i++) { if (con_id && strcmp(con_id, "gpios")) { snprintf(propname, sizeof(propname), "%s-%s", con_id, suffixes[i]); } else { snprintf(propname, sizeof(propname), "%s", suffixes[i]); } desc = acpi_get_gpiod_by_index(adev, propname, idx, &info); if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER)) break; } /* Then from plain _CRS GPIOs */ if (IS_ERR(desc)) { desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info); if (IS_ERR(desc)) return desc; } if (info.active_low) *flags |= GPIO_ACTIVE_LOW; return desc; } static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev) { const char *dev_id = dev ? dev_name(dev) : NULL; struct gpiod_lookup_table *table; mutex_lock(&gpio_lookup_lock); list_for_each_entry(table, &gpio_lookup_list, list) { if (table->dev_id && dev_id) { /* * Valid strings on both ends, must be identical to have * a match */ if (!strcmp(table->dev_id, dev_id)) goto found; } else { /* * One of the pointers is NULL, so both must be to have * a match */ if (dev_id == table->dev_id) goto found; } } table = NULL; found: mutex_unlock(&gpio_lookup_lock); return table; } static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, unsigned int idx, enum gpio_lookup_flags *flags) { struct gpio_desc *desc = ERR_PTR(-ENOENT); struct gpiod_lookup_table *table; struct gpiod_lookup *p; table = gpiod_find_lookup_table(dev); if (!table) return desc; for (p = &table->table[0]; p->chip_label; p++) { struct gpio_chip *chip; /* idx must always match exactly */ if (p->idx != idx) continue; /* If the lookup entry has a con_id, require exact match */ if (p->con_id && (!con_id || strcmp(p->con_id, con_id))) continue; chip = find_chip_by_name(p->chip_label); if (!chip) { dev_err(dev, "cannot find GPIO chip %s\n", p->chip_label); return ERR_PTR(-ENODEV); } if (chip->ngpio <= p->chip_hwnum) { dev_err(dev, "requested GPIO %d is out of range [0..%d] for chip %s\n", idx, chip->ngpio, chip->label); return ERR_PTR(-EINVAL); } desc = gpiochip_offset_to_desc(chip, p->chip_hwnum); *flags = p->flags; return desc; } return desc; } /** * gpio_get - obtain a GPIO for a given GPIO function * @dev: GPIO consumer, can be NULL for system-global GPIOs * @con_id: function within the GPIO consumer * @flags: optional GPIO initialization flags * * Return the GPIO descriptor corresponding to the function con_id of device * dev, -ENOENT if no GPIO has been assigned to the requested function, or * another IS_ERR() code if an error occured while trying to acquire the GPIO. */ struct gpio_desc *__must_check __gpiod_get(struct device *dev, const char *con_id, enum gpiod_flags flags) { return gpiod_get_index(dev, con_id, 0, flags); } EXPORT_SYMBOL_GPL(__gpiod_get); /** * gpiod_get_optional - obtain an optional GPIO for a given GPIO function * @dev: GPIO consumer, can be NULL for system-global GPIOs * @con_id: function within the GPIO consumer * @flags: optional GPIO initialization flags * * This is equivalent to gpiod_get(), except that when no GPIO was assigned to * the requested function it will return NULL. This is convenient for drivers * that need to handle optional GPIOs. */ struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev, const char *con_id, enum gpiod_flags flags) { return gpiod_get_index_optional(dev, con_id, 0, flags); } EXPORT_SYMBOL_GPL(__gpiod_get_optional); /** * gpiod_get_index - obtain a GPIO from a multi-index GPIO function * @dev: GPIO consumer, can be NULL for system-global GPIOs * @con_id: function within the GPIO consumer * @idx: index of the GPIO to obtain in the consumer * @flags: optional GPIO initialization flags * * This variant of gpiod_get() allows to access GPIOs other than the first * defined one for functions that define several GPIOs. * * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the * requested function and/or index, or another IS_ERR() code if an error * occured while trying to acquire the GPIO. */ struct gpio_desc *__must_check __gpiod_get_index(struct device *dev, const char *con_id, unsigned int idx, enum gpiod_flags flags) { struct gpio_desc *desc = NULL; int status; enum gpio_lookup_flags lookupflags = 0; dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id); /* Using device tree? */ if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) { dev_dbg(dev, "using device tree for GPIO lookup\n"); desc = of_find_gpio(dev, con_id, idx, &lookupflags); } else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) { dev_dbg(dev, "using ACPI for GPIO lookup\n"); desc = acpi_find_gpio(dev, con_id, idx, &lookupflags); } /* * Either we are not using DT or ACPI, or their lookup did not return * a result. In that case, use platform lookup as a fallback. */ if (!desc || desc == ERR_PTR(-ENOENT)) { dev_dbg(dev, "using lookup tables for GPIO lookup"); desc = gpiod_find(dev, con_id, idx, &lookupflags); } if (IS_ERR(desc)) { dev_dbg(dev, "lookup for GPIO %s failed\n", con_id); return desc; } status = gpiod_request(desc, con_id); if (status < 0) return ERR_PTR(status); if (lookupflags & GPIO_ACTIVE_LOW) set_bit(FLAG_ACTIVE_LOW, &desc->flags); if (lookupflags & GPIO_OPEN_DRAIN) set_bit(FLAG_OPEN_DRAIN, &desc->flags); if (lookupflags & GPIO_OPEN_SOURCE) set_bit(FLAG_OPEN_SOURCE, &desc->flags); /* No particular flag request, return here... */ if (flags & GPIOD_FLAGS_BIT_DIR_SET) return desc; /* Process flags */ if (flags & GPIOD_FLAGS_BIT_DIR_OUT) status = gpiod_direction_output(desc, flags & GPIOD_FLAGS_BIT_DIR_VAL); else status = gpiod_direction_input(desc); if (status < 0) { dev_dbg(dev, "setup of GPIO %s failed\n", con_id); gpiod_put(desc); return ERR_PTR(status); } return desc; } EXPORT_SYMBOL_GPL(__gpiod_get_index); /** * fwnode_get_named_gpiod - obtain a GPIO from firmware node * @fwnode: handle of the firmware node * @propname: name of the firmware property representing the GPIO * * This function can be used for drivers that get their configuration * from firmware. * * Function properly finds the corresponding GPIO using whatever is the * underlying firmware interface and then makes sure that the GPIO * descriptor is requested before it is returned to the caller. * * In case of error an ERR_PTR() is returned. */ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, const char *propname) { struct gpio_desc *desc = ERR_PTR(-ENODEV); bool active_low = false; int ret; if (!fwnode) return ERR_PTR(-EINVAL); if (is_of_node(fwnode)) { enum of_gpio_flags flags; desc = of_get_named_gpiod_flags(of_node(fwnode), propname, 0, &flags); if (!IS_ERR(desc)) active_low = flags & OF_GPIO_ACTIVE_LOW; } else if (is_acpi_node(fwnode)) { struct acpi_gpio_info info; desc = acpi_get_gpiod_by_index(acpi_node(fwnode), propname, 0, &info); if (!IS_ERR(desc)) active_low = info.active_low; } if (IS_ERR(desc)) return desc; ret = gpiod_request(desc, NULL); if (ret) return ERR_PTR(ret); /* Only value flag can be set from both DT and ACPI is active_low */ if (active_low) set_bit(FLAG_ACTIVE_LOW, &desc->flags); return desc; } EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod); /** * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO * function * @dev: GPIO consumer, can be NULL for system-global GPIOs * @con_id: function within the GPIO consumer * @index: index of the GPIO to obtain in the consumer * @flags: optional GPIO initialization flags * * This is equivalent to gpiod_get_index(), except that when no GPIO with the * specified index was assigned to the requested function it will return NULL. * This is convenient for drivers that need to handle optional GPIOs. */ struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev, const char *con_id, unsigned int index, enum gpiod_flags flags) { struct gpio_desc *desc; desc = gpiod_get_index(dev, con_id, index, flags); if (IS_ERR(desc)) { if (PTR_ERR(desc) == -ENOENT) return NULL; } return desc; } EXPORT_SYMBOL_GPL(__gpiod_get_index_optional); /** * gpiod_put - dispose of a GPIO descriptor * @desc: GPIO descriptor to dispose of * * No descriptor can be used after gpiod_put() has been called on it. */ void gpiod_put(struct gpio_desc *desc) { gpiod_free(desc); } EXPORT_SYMBOL_GPL(gpiod_put); #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 = &chip->desc[0]; int is_out; int is_irq; for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) { if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) continue; gpiod_get_direction(gdesc); is_out = test_bit(FLAG_IS_OUT, &gdesc->flags); is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags); seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s", gpio, gdesc->label, is_out ? "out" : "in ", chip->get ? (chip->get(chip, i) ? "hi" : "lo") : "? ", is_irq ? "IRQ" : " "); seq_printf(s, "\n"); } } static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) { unsigned long flags; struct gpio_chip *chip = NULL; loff_t index = *pos; s->private = ""; spin_lock_irqsave(&gpio_lock, flags); list_for_each_entry(chip, &gpio_chips, list) if (index-- == 0) { spin_unlock_irqrestore(&gpio_lock, flags); return chip; } spin_unlock_irqrestore(&gpio_lock, flags); return NULL; } static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) { unsigned long flags; struct gpio_chip *chip = v; void *ret = NULL; spin_lock_irqsave(&gpio_lock, flags); if (list_is_last(&chip->list, &gpio_chips)) ret = NULL; else ret = list_entry(chip->list.next, struct gpio_chip, list); spin_unlock_irqrestore(&gpio_lock, flags); s->private = "\n"; ++*pos; return ret; } static void gpiolib_seq_stop(struct seq_file *s, void *v) { } static int gpiolib_seq_show(struct seq_file *s, void *v) { struct gpio_chip *chip = v; struct device *dev; seq_printf(s, "%sGPIOs %d-%d", (char *)s->private, 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"); if (chip->dbg_show) chip->dbg_show(s, chip); else gpiolib_dbg_show(s, chip); return 0; } static const struct seq_operations gpiolib_seq_ops = { .start = gpiolib_seq_start, .next = gpiolib_seq_next, .stop = gpiolib_seq_stop, .show = gpiolib_seq_show, }; static int gpiolib_open(struct inode *inode, struct file *file) { return seq_open(file, &gpiolib_seq_ops); } static const struct file_operations gpiolib_operations = { .owner = THIS_MODULE, .open = gpiolib_open, .read = seq_read, .llseek = seq_lseek, .release = seq_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 */