diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 2377 |
1 files changed, 2377 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c new file mode 100644 index 000000000..6bc612b8a --- /dev/null +++ b/drivers/gpio/gpiolib.c @@ -0,0 +1,2377 @@ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/spinlock.h> +#include <linux/list.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/debugfs.h> +#include <linux/seq_file.h> +#include <linux/gpio.h> +#include <linux/of_gpio.h> +#include <linux/idr.h> +#include <linux/slab.h> +#include <linux/acpi.h> +#include <linux/gpio/driver.h> +#include <linux/gpio/machine.h> + +#include "gpiolib.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/gpio.h> + +/* 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. + */ +DEFINE_SPINLOCK(gpio_lock); + +#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio) + +static DEFINE_MUTEX(gpio_lookup_lock); +static LIST_HEAD(gpio_lookup_list); +LIST_HEAD(gpio_chips); + + +static void gpiochip_free_hogs(struct gpio_chip *chip); +static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip); + + +static inline void desc_set_label(struct gpio_desc *d, const char *label) +{ + d->label = label; +} + +/** + * Convert a GPIO number to its descriptor + */ +struct gpio_desc *gpio_to_desc(unsigned gpio) +{ + struct gpio_chip *chip; + unsigned long flags; + + spin_lock_irqsave(&gpio_lock, flags); + + list_for_each_entry(chip, &gpio_chips, list) { + if (chip->base <= gpio && chip->base + chip->ngpio > gpio) { + spin_unlock_irqrestore(&gpio_lock, flags); + return &chip->desc[gpio - chip->base]; + } + } + + spin_unlock_irqrestore(&gpio_lock, flags); + + if (!gpio_is_valid(gpio)) + WARN(1, "invalid GPIO %d\n", gpio); + + return NULL; +} +EXPORT_SYMBOL_GPL(gpio_to_desc); + +/** + * Get the GPIO descriptor corresponding to the given hw number for this chip. + */ +struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip, + u16 hwnum) +{ + if (hwnum >= chip->ngpio) + return ERR_PTR(-EINVAL); + + return &chip->desc[hwnum]; +} + +/** + * 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->chip->base + (desc - &desc->chip->desc[0]); +} +EXPORT_SYMBOL_GPL(desc_to_gpio); + + +/** + * 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(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; + clear_bit(FLAG_IS_OUT, &desc->flags); + } + if (status == 0) { + /* GPIOF_DIR_OUT */ + set_bit(FLAG_IS_OUT, &desc->flags); + } + return status; +} +EXPORT_SYMBOL_GPL(gpiod_get_direction); + +/* + * 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 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; + struct gpio_desc *descs; + + descs = kcalloc(chip->ngpio, sizeof(descs[0]), GFP_KERNEL); + if (!descs) + return -ENOMEM; + + spin_lock_irqsave(&gpio_lock, flags); + + if (base < 0) { + base = gpiochip_find_base(chip->ngpio); + if (base < 0) { + status = base; + spin_unlock_irqrestore(&gpio_lock, flags); + goto err_free_descs; + } + chip->base = base; + } + + status = gpiochip_add_to_list(chip); + if (status) { + spin_unlock_irqrestore(&gpio_lock, flags); + goto err_free_descs; + } + + for (id = 0; id < chip->ngpio; id++) { + struct gpio_desc *desc = &descs[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; + } + + chip->desc = descs; + + spin_unlock_irqrestore(&gpio_lock, flags); + +#ifdef CONFIG_PINCTRL + INIT_LIST_HEAD(&chip->pin_ranges); +#endif + + of_gpiochip_add(chip); + acpi_gpiochip_add(chip); + + status = gpiochip_export(chip); + if (status) + goto err_remove_chip; + + 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; + +err_remove_chip: + acpi_gpiochip_remove(chip); + gpiochip_free_hogs(chip); + of_gpiochip_remove(chip); + spin_lock_irqsave(&gpio_lock, flags); + list_del(&chip->list); + spin_unlock_irqrestore(&gpio_lock, flags); + chip->desc = NULL; +err_free_descs: + kfree(descs); + + /* 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. + */ +void gpiochip_remove(struct gpio_chip *chip) +{ + unsigned long flags; + unsigned id; + + gpiochip_unexport(chip); + + gpiochip_irqchip_remove(chip); + + acpi_gpiochip_remove(chip); + gpiochip_remove_pin_ranges(chip); + gpiochip_free_hogs(chip); + of_gpiochip_remove(chip); + + spin_lock_irqsave(&gpio_lock, flags); + for (id = 0; id < chip->ngpio; id++) { + if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) + dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n"); + } + for (id = 0; id < chip->ngpio; id++) + chip->desc[id].chip = NULL; + + list_del(&chip->list); + spin_unlock_irqrestore(&gpio_lock, flags); + + kfree(chip->desc); + chip->desc = NULL; +} +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_GPIOLIB_IRQCHIP + +/* + * The following is irqchip helper code for gpiochips. + */ + +/** + * gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip + * @gpiochip: the gpiochip to set the irqchip chain to + * @irqchip: the irqchip to chain to the gpiochip + * @parent_irq: the irq number corresponding to the parent IRQ for this + * chained irqchip + * @parent_handler: the parent interrupt handler for the accumulated IRQ + * coming out of the gpiochip. If the interrupt is nested rather than + * cascaded, pass NULL in this handler argument + */ +void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip, + struct irq_chip *irqchip, + int parent_irq, + irq_flow_handler_t parent_handler) +{ + unsigned int offset; + + if (!gpiochip->irqdomain) { + chip_err(gpiochip, "called %s before setting up irqchip\n", + __func__); + return; + } + + if (parent_handler) { + if (gpiochip->can_sleep) { + chip_err(gpiochip, + "you cannot have chained interrupts on a " + "chip that may sleep\n"); + return; + } + /* + * The parent irqchip is already using the chip_data for this + * irqchip, so our callbacks simply use the handler_data. + */ + irq_set_handler_data(parent_irq, gpiochip); + irq_set_chained_handler(parent_irq, parent_handler); + } + + /* Set the parent IRQ for all affected IRQs */ + for (offset = 0; offset < gpiochip->ngpio; offset++) + irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset), + parent_irq); +} +EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip); + +/* + * This lock class tells lockdep that GPIO irqs are in a different + * category than their parents, so it won't report false recursion. + */ +static struct lock_class_key gpiochip_irq_lock_class; + +/** + * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip + * @d: the irqdomain used by this irqchip + * @irq: the global irq number used by this GPIO irqchip irq + * @hwirq: the local IRQ/GPIO line offset on this gpiochip + * + * This function will set up the mapping for a certain IRQ line on a + * gpiochip by assigning the gpiochip as chip data, and using the irqchip + * stored inside the gpiochip. + */ +static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hwirq) +{ + struct gpio_chip *chip = d->host_data; + + irq_set_chip_data(irq, chip); + irq_set_lockdep_class(irq, &gpiochip_irq_lock_class); + irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler); + /* Chips that can sleep need nested thread handlers */ + if (chip->can_sleep && !chip->irq_not_threaded) + irq_set_nested_thread(irq, 1); +#ifdef CONFIG_ARM + set_irq_flags(irq, IRQF_VALID); +#else + irq_set_noprobe(irq); +#endif + /* + * No set-up of the hardware will happen if IRQ_TYPE_NONE + * is passed as default type. + */ + if (chip->irq_default_type != IRQ_TYPE_NONE) + irq_set_irq_type(irq, chip->irq_default_type); + + return 0; +} + +static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq) +{ + struct gpio_chip *chip = d->host_data; + +#ifdef CONFIG_ARM + set_irq_flags(irq, 0); +#endif + if (chip->can_sleep) + irq_set_nested_thread(irq, 0); + irq_set_chip_and_handler(irq, NULL, NULL); + irq_set_chip_data(irq, NULL); +} + +static const struct irq_domain_ops gpiochip_domain_ops = { + .map = gpiochip_irq_map, + .unmap = gpiochip_irq_unmap, + /* Virtually all GPIO irqchips are twocell:ed */ + .xlate = irq_domain_xlate_twocell, +}; + +static int gpiochip_irq_reqres(struct irq_data *d) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(d); + + if (gpiochip_lock_as_irq(chip, d->hwirq)) { + chip_err(chip, + "unable to lock HW IRQ %lu for IRQ\n", + d->hwirq); + return -EINVAL; + } + return 0; +} + +static void gpiochip_irq_relres(struct irq_data *d) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(d); + + gpiochip_unlock_as_irq(chip, d->hwirq); +} + +static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset) +{ + return irq_find_mapping(chip->irqdomain, offset); +} + +/** + * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip + * @gpiochip: the gpiochip to remove the irqchip from + * + * This is called only from gpiochip_remove() + */ +static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) +{ + unsigned int offset; + + acpi_gpiochip_free_interrupts(gpiochip); + + /* Remove all IRQ mappings and delete the domain */ + if (gpiochip->irqdomain) { + for (offset = 0; offset < gpiochip->ngpio; offset++) + irq_dispose_mapping( + irq_find_mapping(gpiochip->irqdomain, offset)); + irq_domain_remove(gpiochip->irqdomain); + } + + if (gpiochip->irqchip) { + gpiochip->irqchip->irq_request_resources = NULL; + gpiochip->irqchip->irq_release_resources = NULL; + gpiochip->irqchip = NULL; + } +} + +/** + * gpiochip_irqchip_add() - adds an irqchip to a gpiochip + * @gpiochip: the gpiochip to add the irqchip to + * @irqchip: the irqchip to add to the gpiochip + * @first_irq: if not dynamically assigned, the base (first) IRQ to + * allocate gpiochip irqs from + * @handler: the irq handler to use (often a predefined irq core function) + * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE + * to have the core avoid setting up any default type in the hardware. + * + * This function closely associates a certain irqchip with a certain + * gpiochip, providing an irq domain to translate the local IRQs to + * global irqs in the gpiolib core, and making sure that the gpiochip + * is passed as chip data to all related functions. Driver callbacks + * need to use container_of() to get their local state containers back + * from the gpiochip passed as chip data. An irqdomain will be stored + * in the gpiochip that shall be used by the driver to handle IRQ number + * translation. The gpiochip will need to be initialized and registered + * before calling this function. + * + * This function will handle two cell:ed simple IRQs and assumes all + * the pins on the gpiochip can generate a unique IRQ. Everything else + * need to be open coded. + */ +int gpiochip_irqchip_add(struct gpio_chip *gpiochip, + struct irq_chip *irqchip, + unsigned int first_irq, + irq_flow_handler_t handler, + unsigned int type) +{ + struct device_node *of_node; + unsigned int offset; + unsigned irq_base = 0; + + if (!gpiochip || !irqchip) + return -EINVAL; + + if (!gpiochip->dev) { + pr_err("missing gpiochip .dev parent pointer\n"); + return -EINVAL; + } + of_node = gpiochip->dev->of_node; +#ifdef CONFIG_OF_GPIO + /* + * If the gpiochip has an assigned OF node this takes precendence + * FIXME: get rid of this and use gpiochip->dev->of_node everywhere + */ + if (gpiochip->of_node) + of_node = gpiochip->of_node; +#endif + gpiochip->irqchip = irqchip; + gpiochip->irq_handler = handler; + gpiochip->irq_default_type = type; + gpiochip->to_irq = gpiochip_to_irq; + gpiochip->irqdomain = irq_domain_add_simple(of_node, + gpiochip->ngpio, first_irq, + &gpiochip_domain_ops, gpiochip); + if (!gpiochip->irqdomain) { + gpiochip->irqchip = NULL; + return -EINVAL; + } + irqchip->irq_request_resources = gpiochip_irq_reqres; + irqchip->irq_release_resources = gpiochip_irq_relres; + + /* + * Prepare the mapping since the irqchip shall be orthogonal to + * any gpiochip calls. If the first_irq was zero, this is + * necessary to allocate descriptors for all IRQs. + */ + for (offset = 0; offset < gpiochip->ngpio; offset++) { + irq_base = irq_create_mapping(gpiochip->irqdomain, offset); + if (offset == 0) + /* + * Store the base into the gpiochip to be used when + * unmapping the irqs. + */ + gpiochip->irq_base = irq_base; + } + + acpi_gpiochip_request_interrupts(gpiochip); + + return 0; +} +EXPORT_SYMBOL_GPL(gpiochip_irqchip_add); + +#else /* CONFIG_GPIOLIB_IRQCHIP */ + +static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {} + +#endif /* CONFIG_GPIOLIB_IRQCHIP */ + +#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 = desc->chip; + int status; + unsigned long flags; + + spin_lock_irqsave(&gpio_lock, flags); + + /* 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; + 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); + 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: + spin_unlock_irqrestore(&gpio_lock, flags); + return status; +} + +int gpiod_request(struct gpio_desc *desc, const char *label) +{ + int status = -EPROBE_DEFER; + struct gpio_chip *chip; + + if (!desc) { + pr_warn("%s: invalid GPIO\n", __func__); + return -EINVAL; + } + + chip = desc->chip; + if (!chip) + goto done; + + if (try_module_get(chip->owner)) { + status = __gpiod_request(desc, label); + if (status < 0) + module_put(chip->owner); + } + +done: + if (status) + gpiod_dbg(desc, "%s: status %d\n", __func__, status); + + return status; +} + +static bool __gpiod_free(struct gpio_desc *desc) +{ + bool ret = false; + unsigned long flags; + struct gpio_chip *chip; + + might_sleep(); + + 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); + 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); + clear_bit(FLAG_IS_HOGGED, &desc->flags); + ret = true; + } + + spin_unlock_irqrestore(&gpio_lock, flags); + return ret; +} + +void gpiod_free(struct gpio_desc *desc) +{ + if (desc && __gpiod_free(desc)) + module_put(desc->chip->owner); + else + WARN_ON(extra_checks); +} + +/** + * 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. + * The string returned is the label passed to gpio_request(); if none has been + * passed it is a meaningless, non-NULL 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; + return desc->label; +} +EXPORT_SYMBOL_GPL(gpiochip_is_requested); + +/** + * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor + * @desc: GPIO descriptor to request + * @label: label for the GPIO + * + * Function allows GPIO chip drivers to request and use their own GPIO + * descriptors via gpiolib API. Difference to gpiod_request() is that this + * function will not increase reference count of the GPIO chip module. This + * allows the GPIO chip module to be unloaded as needed (we assume that the + * GPIO chip driver handles freeing the GPIOs it has requested). + */ +struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum, + const char *label) +{ + struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum); + int err; + + if (IS_ERR(desc)) { + chip_err(chip, "failed to get GPIO descriptor\n"); + return desc; + } + + err = __gpiod_request(desc, label); + if (err < 0) + return ERR_PTR(err); + + return desc; +} +EXPORT_SYMBOL_GPL(gpiochip_request_own_desc); + +/** + * gpiochip_free_own_desc - Free GPIO requested by the chip driver + * @desc: GPIO descriptor to free + * + * Function frees the given GPIO requested previously with + * gpiochip_request_own_desc(). + */ +void gpiochip_free_own_desc(struct gpio_desc *desc) +{ + if (desc) + __gpiod_free(desc); +} +EXPORT_SYMBOL_GPL(gpiochip_free_own_desc); + +/* 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) +{ + struct gpio_chip *chip; + int status = -EINVAL; + + 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; + } + + status = chip->direction_input(chip, gpio_chip_hwgpio(desc)); + if (status == 0) + clear_bit(FLAG_IS_OUT, &desc->flags); + + trace_gpio_direction(desc_to_gpio(desc), 1, status); + + return status; +} +EXPORT_SYMBOL_GPL(gpiod_direction_input); + +static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value) +{ + struct gpio_chip *chip; + int status = -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; + } + + status = chip->direction_output(chip, gpio_chip_hwgpio(desc), 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); + return status; +} + +/** + * gpiod_direction_output_raw - set the GPIO direction to output + * @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 + * as raw value on the physical line without regard for the ACTIVE_LOW status. + * + * Return 0 in case of success, else an error code. + */ +int gpiod_direction_output_raw(struct gpio_desc *desc, int value) +{ + if (!desc || !desc->chip) { + pr_warn("%s: invalid GPIO\n", __func__); + return -EINVAL; + } + return _gpiod_direction_output_raw(desc, value); +} +EXPORT_SYMBOL_GPL(gpiod_direction_output_raw); + +/** + * gpiod_direction_output - set the GPIO direction to output + * @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 + * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into + * account. + * + * Return 0 in case of success, else an error code. + */ +int gpiod_direction_output(struct gpio_desc *desc, int value) +{ + if (!desc || !desc->chip) { + pr_warn("%s: invalid GPIO\n", __func__); + return -EINVAL; + } + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + value = !value; + return _gpiod_direction_output_raw(desc, value); +} +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) +{ + struct gpio_chip *chip; + + 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; + } + + return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce); +} +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); +} + +/* + * set multiple outputs on the same chip; + * use the chip's set_multiple function if available; + * otherwise set the outputs sequentially; + * @mask: bit mask array; one bit per output; BITS_PER_LONG bits per word + * defines which outputs are to be changed + * @bits: bit value array; one bit per output; BITS_PER_LONG bits per word + * defines the values the outputs specified by mask are to be set to + */ +static void gpio_chip_set_multiple(struct gpio_chip *chip, + unsigned long *mask, unsigned long *bits) +{ + if (chip->set_multiple) { + chip->set_multiple(chip, mask, bits); + } else { + int i; + for (i = 0; i < chip->ngpio; i++) { + if (mask[BIT_WORD(i)] == 0) { + /* no more set bits in this mask word; + * skip ahead to the next word */ + i = (BIT_WORD(i) + 1) * BITS_PER_LONG - 1; + continue; + } + /* set outputs if the corresponding mask bit is set */ + if (__test_and_clear_bit(i, mask)) { + chip->set(chip, i, test_bit(i, bits)); + } + } + } +} + +static void gpiod_set_array_priv(bool raw, bool can_sleep, + unsigned int array_size, + struct gpio_desc **desc_array, + int *value_array) +{ + int i = 0; + + while (i < array_size) { + struct gpio_chip *chip = desc_array[i]->chip; + unsigned long mask[BITS_TO_LONGS(chip->ngpio)]; + unsigned long bits[BITS_TO_LONGS(chip->ngpio)]; + int count = 0; + + if (!can_sleep) { + WARN_ON(chip->can_sleep); + } + memset(mask, 0, sizeof(mask)); + do { + struct gpio_desc *desc = desc_array[i]; + int hwgpio = gpio_chip_hwgpio(desc); + int value = value_array[i]; + + if (!raw && test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + value = !value; + trace_gpio_value(desc_to_gpio(desc), 0, value); + /* + * collect all normal outputs belonging to the same chip + * open drain and open source outputs are set individually + */ + 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 { + __set_bit(hwgpio, mask); + if (value) { + __set_bit(hwgpio, bits); + } else { + __clear_bit(hwgpio, bits); + } + count++; + } + i++; + } while ((i < array_size) && (desc_array[i]->chip == chip)); + /* push collected bits to outputs */ + if (count != 0) { + gpio_chip_set_multiple(chip, mask, bits); + } + } +} + +/** + * 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_set_raw_array() - assign values to an array of GPIOs + * @array_size: number of elements in the descriptor / value arrays + * @desc_array: array of GPIO descriptors whose values will be assigned + * @value_array: array of values to assign + * + * Set the raw values of the GPIOs, i.e. the values of the physical lines + * without regard for their 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_array(unsigned int array_size, + struct gpio_desc **desc_array, int *value_array) +{ + if (!desc_array) + return; + gpiod_set_array_priv(true, false, array_size, desc_array, value_array); +} +EXPORT_SYMBOL_GPL(gpiod_set_raw_array); + +/** + * gpiod_set_array() - assign values to an array of GPIOs + * @array_size: number of elements in the descriptor / value arrays + * @desc_array: array of GPIO descriptors whose values will be assigned + * @value_array: array of values to assign + * + * Set the logical values of the GPIOs, i.e. taking their 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_array(unsigned int array_size, + struct gpio_desc **desc_array, int *value_array) +{ + if (!desc_array) + return; + gpiod_set_array_priv(false, false, array_size, desc_array, value_array); +} +EXPORT_SYMBOL_GPL(gpiod_set_array); + +/** + * 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); + +/** + * gpiochip_lock_as_irq() - lock a GPIO to be used as IRQ + * @chip: the chip the GPIO to lock belongs to + * @offset: the offset of the GPIO to lock as IRQ + * + * This is used directly by GPIO drivers that want to lock down + * a certain GPIO line to be used for IRQs. + */ +int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset) +{ + if (offset >= chip->ngpio) + return -EINVAL; + + if (test_bit(FLAG_IS_OUT, &chip->desc[offset].flags)) { + chip_err(chip, + "%s: tried to flag a GPIO set as output for IRQ\n", + __func__); + return -EIO; + } + + set_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags); + return 0; +} +EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq); + +/** + * gpiochip_unlock_as_irq() - unlock a GPIO used as IRQ + * @chip: the chip the GPIO to lock belongs to + * @offset: the offset of the GPIO to lock as IRQ + * + * This is used directly by GPIO drivers that want to indicate + * that a certain GPIO is no longer used exclusively for IRQ. + */ +void gpiochip_unlock_as_irq(struct gpio_chip *chip, unsigned int offset) +{ + if (offset >= chip->ngpio) + return; + + clear_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags); +} +EXPORT_SYMBOL_GPL(gpiochip_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_set_raw_array_cansleep() - assign values to an array of GPIOs + * @array_size: number of elements in the descriptor / value arrays + * @desc_array: array of GPIO descriptors whose values will be assigned + * @value_array: array of values to assign + * + * Set the raw values of the GPIOs, i.e. the values of the physical lines + * without regard for their ACTIVE_LOW status. + * + * This function is to be called from contexts that can sleep. + */ +void gpiod_set_raw_array_cansleep(unsigned int array_size, + struct gpio_desc **desc_array, + int *value_array) +{ + might_sleep_if(extra_checks); + if (!desc_array) + return; + gpiod_set_array_priv(true, true, array_size, desc_array, value_array); +} +EXPORT_SYMBOL_GPL(gpiod_set_raw_array_cansleep); + +/** + * gpiod_set_array_cansleep() - assign values to an array of GPIOs + * @array_size: number of elements in the descriptor / value arrays + * @desc_array: array of GPIO descriptors whose values will be assigned + * @value_array: array of values to assign + * + * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status + * into account. + * + * This function is to be called from contexts that can sleep. + */ +void gpiod_set_array_cansleep(unsigned int array_size, + struct gpio_desc **desc_array, + int *value_array) +{ + might_sleep_if(extra_checks); + if (!desc_array) + return; + gpiod_set_array_priv(false, true, array_size, desc_array, value_array); +} +EXPORT_SYMBOL_GPL(gpiod_set_array_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); +} + +static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, + unsigned int idx, + enum gpio_lookup_flags *flags) +{ + 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(gpio_suffixes); i++) { + if (con_id) + snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id, + gpio_suffixes[i]); + else + snprintf(prop_name, sizeof(prop_name), "%s", + gpio_suffixes[i]); + + desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, + &of_flags); + if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER)) + break; + } + + if (IS_ERR(desc)) + return desc; + + if (of_flags & OF_GPIO_ACTIVE_LOW) + *flags |= GPIO_ACTIVE_LOW; + + return desc; +} + +static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id, + unsigned int idx, + enum gpio_lookup_flags *flags) +{ + 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(gpio_suffixes); i++) { + if (con_id && strcmp(con_id, "gpios")) { + snprintf(propname, sizeof(propname), "%s-%s", + con_id, gpio_suffixes[i]); + } else { + snprintf(propname, sizeof(propname), "%s", + gpio_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_get_desc(chip, p->chip_hwnum); + *flags = p->flags; + + return desc; + } + + return desc; +} + +static int dt_gpio_count(struct device *dev, const char *con_id) +{ + int ret; + char propname[32]; + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) { + if (con_id) + snprintf(propname, sizeof(propname), "%s-%s", + con_id, gpio_suffixes[i]); + else + snprintf(propname, sizeof(propname), "%s", + gpio_suffixes[i]); + + ret = of_gpio_named_count(dev->of_node, propname); + if (ret >= 0) + break; + } + return ret; +} + +static int platform_gpio_count(struct device *dev, const char *con_id) +{ + struct gpiod_lookup_table *table; + struct gpiod_lookup *p; + unsigned int count = 0; + + table = gpiod_find_lookup_table(dev); + if (!table) + return -ENOENT; + + for (p = &table->table[0]; p->chip_label; p++) { + if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) || + (!con_id && !p->con_id)) + count++; + } + if (!count) + return -ENOENT; + + return count; +} + +/** + * gpiod_count - return the number of GPIOs associated with a device / function + * or -ENOENT if no GPIO has been assigned to the requested function + * @dev: GPIO consumer, can be NULL for system-global GPIOs + * @con_id: function within the GPIO consumer + */ +int gpiod_count(struct device *dev, const char *con_id) +{ + int count = -ENOENT; + + if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) + count = dt_gpio_count(dev, con_id); + else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) + count = acpi_gpio_count(dev, con_id); + + if (count < 0) + count = platform_gpio_count(dev, con_id); + + return count; +} +EXPORT_SYMBOL_GPL(gpiod_count); + +/** + * gpiod_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_configure_flags - helper function to configure a given GPIO + * @desc: gpio whose value will be assigned + * @con_id: function within the GPIO consumer + * @lflags: gpio_lookup_flags - returned from of_find_gpio() or + * of_get_gpio_hog() + * @dflags: gpiod_flags - optional GPIO initialization flags + * + * Return 0 on success, -ENOENT if no GPIO has been assigned to the + * requested function and/or index, or another IS_ERR() code if an error + * occurred while trying to acquire the GPIO. + */ +static int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id, + unsigned long lflags, enum gpiod_flags dflags) +{ + int status; + + if (lflags & GPIO_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (lflags & GPIO_OPEN_DRAIN) + set_bit(FLAG_OPEN_DRAIN, &desc->flags); + if (lflags & GPIO_OPEN_SOURCE) + set_bit(FLAG_OPEN_SOURCE, &desc->flags); + + /* No particular flag request, return here... */ + if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) { + pr_debug("no flags found for %s\n", con_id); + return 0; + } + + /* Process flags */ + if (dflags & GPIOD_FLAGS_BIT_DIR_OUT) + status = gpiod_direction_output(desc, + dflags & GPIOD_FLAGS_BIT_DIR_VAL); + else + status = gpiod_direction_input(desc); + + return status; +} + +/** + * 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); + + if (dev) { + /* Using device tree? */ + if (IS_ENABLED(CONFIG_OF) && dev->of_node) { + dev_dbg(dev, "using device tree for GPIO lookup\n"); + desc = of_find_gpio(dev, con_id, idx, &lookupflags); + } else if (ACPI_COMPANION(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\n"); + 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); + + status = gpiod_configure_flags(desc, con_id, lookupflags, flags); + 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_hog - Hog the specified GPIO desc given the provided flags + * @desc: gpio whose value will be assigned + * @name: gpio line name + * @lflags: gpio_lookup_flags - returned from of_find_gpio() or + * of_get_gpio_hog() + * @dflags: gpiod_flags - optional GPIO initialization flags + */ +int gpiod_hog(struct gpio_desc *desc, const char *name, + unsigned long lflags, enum gpiod_flags dflags) +{ + struct gpio_chip *chip; + struct gpio_desc *local_desc; + int hwnum; + int status; + + chip = gpiod_to_chip(desc); + hwnum = gpio_chip_hwgpio(desc); + + local_desc = gpiochip_request_own_desc(chip, hwnum, name); + if (IS_ERR(local_desc)) { + pr_debug("requesting own GPIO %s failed\n", name); + return PTR_ERR(local_desc); + } + + status = gpiod_configure_flags(desc, name, lflags, dflags); + if (status < 0) { + pr_debug("setup of GPIO %s failed\n", name); + gpiochip_free_own_desc(desc); + return status; + } + + /* Mark GPIO as hogged so it can be identified and removed later */ + set_bit(FLAG_IS_HOGGED, &desc->flags); + + pr_info("GPIO line %d (%s) hogged as %s%s\n", + desc_to_gpio(desc), name, + (dflags&GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input", + (dflags&GPIOD_FLAGS_BIT_DIR_OUT) ? + (dflags&GPIOD_FLAGS_BIT_DIR_VAL) ? "/high" : "/low":""); + + return 0; +} + +/** + * gpiochip_free_hogs - Scan gpio-controller chip and release GPIO hog + * @chip: gpio chip to act on + * + * This is only used by of_gpiochip_remove to free hogged gpios + */ +static void gpiochip_free_hogs(struct gpio_chip *chip) +{ + int id; + + for (id = 0; id < chip->ngpio; id++) { + if (test_bit(FLAG_IS_HOGGED, &chip->desc[id].flags)) + gpiochip_free_own_desc(&chip->desc[id]); + } +} + +/** + * gpiod_get_array - obtain multiple GPIOs from a multi-index 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 function acquires all the GPIOs defined under a given function. + * + * Return a struct gpio_descs containing an array of descriptors, -ENOENT if + * no GPIO has been assigned to the requested function, or another IS_ERR() + * code if an error occurred while trying to acquire the GPIOs. + */ +struct gpio_descs *__must_check gpiod_get_array(struct device *dev, + const char *con_id, + enum gpiod_flags flags) +{ + struct gpio_desc *desc; + struct gpio_descs *descs; + int count; + + count = gpiod_count(dev, con_id); + if (count < 0) + return ERR_PTR(count); + + descs = kzalloc(sizeof(*descs) + sizeof(descs->desc[0]) * count, + GFP_KERNEL); + if (!descs) + return ERR_PTR(-ENOMEM); + + for (descs->ndescs = 0; descs->ndescs < count; ) { + desc = gpiod_get_index(dev, con_id, descs->ndescs, flags); + if (IS_ERR(desc)) { + gpiod_put_array(descs); + return ERR_CAST(desc); + } + descs->desc[descs->ndescs] = desc; + descs->ndescs++; + } + return descs; +} +EXPORT_SYMBOL_GPL(gpiod_get_array); + +/** + * gpiod_get_array_optional - obtain multiple GPIOs from a multi-index 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_array(), except that when no GPIO was + * assigned to the requested function it will return NULL. + */ +struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev, + const char *con_id, + enum gpiod_flags flags) +{ + struct gpio_descs *descs; + + descs = gpiod_get_array(dev, con_id, flags); + if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT)) + return NULL; + + return descs; +} +EXPORT_SYMBOL_GPL(gpiod_get_array_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); + +/** + * gpiod_put_array - dispose of multiple GPIO descriptors + * @descs: struct gpio_descs containing an array of descriptors + */ +void gpiod_put_array(struct gpio_descs *descs) +{ + unsigned int i; + + for (i = 0; i < descs->ndescs; i++) + gpiod_put(descs->desc[i]); + + kfree(descs); +} +EXPORT_SYMBOL_GPL(gpiod_put_array); + +#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 */ |