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linux-sg2042/drivers/gpio/gpiolib.c

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#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>
#define CREATE_TRACE_POINTS
#include <trace/events/gpio.h>
/* Optional implementation infrastructure for GPIO interfaces.
*
* Platforms may want to use this if they tend to use very many GPIOs
* that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
*
* When kernel footprint or instruction count is an issue, simpler
* implementations may be preferred. 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 /* sysfs 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 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 LIST_HEAD(gpio_chips);
#ifdef CONFIG_GPIO_SYSFS
static DEFINE_IDR(dirent_idr);
#endif
/*
* Internal gpiod_* API using descriptors instead of the integer namespace.
* Most of this should eventually go public.
*/
static int gpiod_request(struct gpio_desc *desc, const char *label);
static void gpiod_free(struct gpio_desc *desc);
static int gpiod_direction_input(struct gpio_desc *desc);
static int gpiod_direction_output(struct gpio_desc *desc, int value);
static int gpiod_get_direction(const struct gpio_desc *desc);
static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
static int gpiod_get_value_cansleep(const struct gpio_desc *desc);
static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
static int gpiod_get_value(const struct gpio_desc *desc);
static void gpiod_set_value(struct gpio_desc *desc, int value);
static int gpiod_cansleep(const struct gpio_desc *desc);
static int gpiod_to_irq(const struct gpio_desc *desc);
static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
static int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc);
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
static void gpiod_unexport(struct gpio_desc *desc);
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
*/
static 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];
}
/**
* 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
*/
static int desc_to_gpio(const struct gpio_desc *desc)
{
return desc->chip->base + gpio_chip_hwgpio(desc);
}
/* 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)) {
pr_err("GPIO-%d: module can't be gotten \n", gpio);
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;
}
static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
{
return desc ? desc->chip : NULL;
}
/* caller holds gpio_lock *OR* gpio is marked as requested */
struct gpio_chip *gpio_to_chip(unsigned gpio)
{
return gpiod_to_chip(gpio_to_desc(gpio));
}
/* 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;
}
}
/* caller ensures gpio is valid and requested, chip->get_direction may sleep */
static 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;
}
#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 {
int value;
value = !!gpiod_get_value_cansleep(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
status = sprintf(buf, "%d\n", value);
}
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 = strict_strtol(buf, 0, &value);
if (status == 0) {
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
gpiod_set_value_cansleep(desc, value != 0);
status = size;
}
}
mutex_unlock(&sysfs_lock);
return status;
}
static const DEVICE_ATTR(value, 0644,
gpio_value_show, gpio_value_store);
static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
{
struct sysfs_dirent *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 sysfs_dirent *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) {
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, NULL, "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;
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 = strict_strtol(buf, 0, &value);
if (status == 0)
status = sysfs_set_active_low(desc, dev, value != 0);
}
mutex_unlock(&sysfs_lock);
return status ? : size;
}
static const DEVICE_ATTR(active_low, 0644,
gpio_active_low_show, gpio_active_low_store);
static const struct attribute *gpio_attrs[] = {
&dev_attr_value.attr,
&dev_attr_active_low.attr,
NULL,
};
static const struct attribute_group gpio_attr_group = {
.attrs = (struct attribute **) gpio_attrs,
};
/*
* /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 const struct attribute *gpiochip_attrs[] = {
&dev_attr_base.attr,
&dev_attr_label.attr,
&dev_attr_ngpio.attr,
NULL,
};
static const struct attribute_group gpiochip_attr_group = {
.attrs = (struct attribute **) gpiochip_attrs,
};
/*
* /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 = strict_strtol(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 = strict_strtol(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,
};
/**
* gpio_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.
*/
static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
{
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;
}
mutex_lock(&sysfs_lock);
spin_lock_irqsave(&gpio_lock, flags);
if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
test_bit(FLAG_EXPORT, &desc->flags)) {
spin_unlock_irqrestore(&gpio_lock, flags);
pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
__func__, desc_to_gpio(desc),
test_bit(FLAG_REQUESTED, &desc->flags),
test_bit(FLAG_EXPORT, &desc->flags));
status = -EPERM;
goto fail_unlock;
}
if (!desc->chip->direction_input || !desc->chip->direction_output)
direction_may_change = false;
spin_unlock_irqrestore(&gpio_lock, flags);
offset = gpio_chip_hwgpio(desc);
if (desc->chip->names && desc->chip->names[offset])
ioname = desc->chip->names[offset];
dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
desc, ioname ? ioname : "gpio%u",
desc_to_gpio(desc));
if (IS_ERR(dev)) {
status = PTR_ERR(dev);
goto fail_unlock;
}
status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
if (status)
goto fail_unregister_device;
if (direction_may_change) {
status = device_create_file(dev, &dev_attr_direction);
if (status)
goto fail_unregister_device;
}
if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
!test_bit(FLAG_IS_OUT, &desc->flags))) {
status = device_create_file(dev, &dev_attr_edge);
if (status)
goto fail_unregister_device;
}
set_bit(FLAG_EXPORT, &desc->flags);
mutex_unlock(&sysfs_lock);
return 0;
fail_unregister_device:
device_unregister(dev);
fail_unlock:
mutex_unlock(&sysfs_lock);
pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
status);
return status;
}
int gpio_export(unsigned gpio, bool direction_may_change)
{
return gpiod_export(gpio_to_desc(gpio), direction_may_change);
}
EXPORT_SYMBOL_GPL(gpio_export);
static int match_export(struct device *dev, const void *data)
{
return dev_get_drvdata(dev) == data;
}
/**
* gpio_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.
*/
static int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
int status = -EINVAL;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}
mutex_lock(&sysfs_lock);
if (test_bit(FLAG_EXPORT, &desc->flags)) {
struct device *tdev;
tdev = class_find_device(&gpio_class, NULL, desc, match_export);
if (tdev != NULL) {
status = sysfs_create_link(&dev->kobj, &tdev->kobj,
name);
} else {
status = -ENODEV;
}
}
mutex_unlock(&sysfs_lock);
if (status)
pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
status);
return status;
}
int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
{
return gpiod_export_link(dev, name, gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_export_link);
/**
* gpio_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.
*/
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{
struct device *dev = NULL;
int status = -EINVAL;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}
mutex_lock(&sysfs_lock);
if (test_bit(FLAG_EXPORT, &desc->flags)) {
dev = class_find_device(&gpio_class, NULL, desc, match_export);
if (dev == NULL) {
status = -ENODEV;
goto unlock;
}
}
status = sysfs_set_active_low(desc, dev, value);
unlock:
mutex_unlock(&sysfs_lock);
if (status)
pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
status);
return status;
}
int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
/**
* gpio_unexport - reverse effect of gpio_export()
* @gpio: gpio to make unavailable
*
* This is implicit on gpio_free().
*/
static void gpiod_unexport(struct gpio_desc *desc)
{
int status = 0;
struct device *dev = NULL;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return;
}
mutex_lock(&sysfs_lock);
if (test_bit(FLAG_EXPORT, &desc->flags)) {
dev = class_find_device(&gpio_class, NULL, desc, match_export);
if (dev) {
gpio_setup_irq(desc, dev, 0);
clear_bit(FLAG_EXPORT, &desc->flags);
} else
status = -ENODEV;
}
mutex_unlock(&sysfs_lock);
if (dev) {
device_unregister(dev);
put_device(dev);
}
if (status)
pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
status);
}
void gpio_unexport(unsigned gpio)
{
gpiod_unexport(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_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(&gpio_class, chip->dev, MKDEV(0, 0), chip,
"gpiochip%d", chip->base);
if (!IS_ERR(dev)) {
status = sysfs_create_group(&dev->kobj,
&gpiochip_attr_group);
} else
status = PTR_ERR(dev);
chip->exported = (status == 0);
mutex_unlock(&sysfs_lock);
if (status) {
unsigned long flags;
unsigned gpio;
spin_lock_irqsave(&gpio_lock, flags);
gpio = 0;
while (gpio < chip->ngpio)
chip->desc[gpio++].chip = NULL;
spin_unlock_irqrestore(&gpio_lock, flags);
pr_debug("%s: chip %s status %d\n", __func__,
chip->label, status);
}
return status;
}
static void gpiochip_unexport(struct gpio_chip *chip)
{
int status;
struct device *dev;
mutex_lock(&sysfs_lock);
dev = class_find_device(&gpio_class, NULL, chip, match_export);
if (dev) {
put_device(dev);
device_unregister(dev);
chip->exported = 0;
status = 0;
} else
status = -ENODEV;
mutex_unlock(&sysfs_lock);
if (status)
pr_debug("%s: chip %s status %d\n", __func__,
chip->label, status);
}
static int __init gpiolib_sysfs_init(void)
{
int status;
unsigned long flags;
struct gpio_chip *chip;
status = class_register(&gpio_class);
if (status < 0)
return status;
/* Scan and register the gpio_chips which registered very
* early (e.g. before the class_register above was called).
*
* We run before arch_initcall() so chip->dev nodes can have
* registered, and so arch_initcall() can always gpio_export().
*/
spin_lock_irqsave(&gpio_lock, flags);
list_for_each_entry(chip, &gpio_chips, list) {
if (!chip || chip->exported)
continue;
spin_unlock_irqrestore(&gpio_lock, flags);
status = gpiochip_export(chip);
spin_lock_irqsave(&gpio_lock, flags);
}
spin_unlock_irqrestore(&gpio_lock, flags);
return status;
}
postcore_initcall(gpiolib_sysfs_init);
#else
static inline int gpiochip_export(struct gpio_chip *chip)
{
return 0;
}
static inline void gpiochip_unexport(struct gpio_chip *chip)
{
}
static inline int gpiod_export(struct gpio_desc *desc,
bool direction_may_change)
{
return -ENOSYS;
}
static inline int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
return -ENOSYS;
}
static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{
return -ENOSYS;
}
static inline void gpiod_unexport(struct gpio_desc *desc)
{
}
#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;
}
}
#ifdef CONFIG_PINCTRL
INIT_LIST_HEAD(&chip->pin_ranges);
#endif
of_gpiochip_add(chip);
unlock:
spin_unlock_irqrestore(&gpio_lock, flags);
if (status)
goto fail;
status = gpiochip_export(chip);
if (status)
goto fail;
pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
chip->base, chip->base + chip->ngpio - 1,
chip->label ? : "generic");
return 0;
fail:
/* failures here can mean systems won't boot... */
pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
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;
spin_lock_irqsave(&gpio_lock, flags);
gpiochip_remove_pin_ranges(chip);
of_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);
if (status == 0)
gpiochip_unexport(chip);
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);
#ifdef CONFIG_PINCTRL
/**
* 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) {
pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
chip->label);
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);
pr_err("%s: GPIO chip: could not create pin range\n",
chip->label);
kfree(pin_range);
return ret;
}
pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
chip->label, 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)
pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
desc_to_gpio(desc), label ? : "?", 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.
*/
static int gpiod_direction_input(struct gpio_desc *desc)
{
unsigned long flags;
struct gpio_chip *chip;
int status = -EINVAL;
int offset;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}
spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip;
if (!chip || !chip->get || !chip->direction_input)
goto fail;
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) {
pr_debug("GPIO-%d: chip request fail, %d\n",
desc_to_gpio(desc), 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)
pr_debug("%s: gpio-%d status %d\n", __func__,
desc_to_gpio(desc), status);
return status;
}
int gpio_direction_input(unsigned gpio)
{
return gpiod_direction_input(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_direction_input);
static int gpiod_direction_output(struct gpio_desc *desc, int value)
{
unsigned long flags;
struct gpio_chip *chip;
int status = -EINVAL;
int offset;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}
/* 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);
spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip;
if (!chip || !chip->set || !chip->direction_output)
goto fail;
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) {
pr_debug("GPIO-%d: chip request fail, %d\n",
desc_to_gpio(desc), 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)
pr_debug("%s: gpio-%d status %d\n", __func__,
desc_to_gpio(desc), status);
return status;
}
int gpio_direction_output(unsigned gpio, int value)
{
return gpiod_direction_output(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(gpio_direction_output);
/**
* gpio_set_debounce - sets @debounce time for a @gpio
* @gpio: the gpio to set debounce time
* @debounce: debounce time is microseconds
*/
static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{
unsigned long flags;
struct gpio_chip *chip;
int status = -EINVAL;
int offset;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}
spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip;
if (!chip || !chip->set || !chip->set_debounce)
goto fail;
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)
pr_debug("%s: gpio-%d status %d\n", __func__,
desc_to_gpio(desc), status);
return status;
}
int gpio_set_debounce(unsigned gpio, unsigned debounce)
{
return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
}
EXPORT_SYMBOL_GPL(gpio_set_debounce);
/* 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.
*/
/**
* __gpio_get_value() - return a gpio's value
* @gpio: gpio whose value will be returned
* Context: any
*
* This is used directly or indirectly to implement gpio_get_value().
* It returns the zero or nonzero value provided by the associated
* gpio_chip.get() method; or zero if no such method is provided.
*/
static int gpiod_get_value(const struct gpio_desc *desc)
{
struct gpio_chip *chip;
int value;
int offset;
if (!desc)
return 0;
chip = desc->chip;
offset = gpio_chip_hwgpio(desc);
/* Should be using gpio_get_value_cansleep() */
WARN_ON(chip->can_sleep);
value = chip->get ? chip->get(chip, offset) : 0;
trace_gpio_value(desc_to_gpio(desc), 1, value);
return value;
}
int __gpio_get_value(unsigned gpio)
{
return gpiod_get_value(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(__gpio_get_value);
/*
* _gpio_set_open_drain_value() - Set the open drain gpio's value.
* @gpio: Gpio whose state need to be set.
* @chip: Gpio chip.
* @value: Non-zero for setting it HIGH otherise it will set to LOW.
*/
static void _gpio_set_open_drain_value(struct gpio_desc *desc, int 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)
pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
__func__, desc_to_gpio(desc), err);
}
/*
* _gpio_set_open_source() - Set the open source gpio's value.
* @gpio: Gpio whose state need to be set.
* @chip: Gpio chip.
* @value: Non-zero for setting it HIGH otherise it will set to LOW.
*/
static void _gpio_set_open_source_value(struct gpio_desc *desc, int 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)
pr_err("%s: Error in set_value for open source gpio%d err %d\n",
__func__, desc_to_gpio(desc), err);
}
/**
* __gpio_set_value() - assign a gpio's value
* @gpio: gpio whose value will be assigned
* @value: value to assign
* Context: any
*
* This is used directly or indirectly to implement gpio_set_value().
* It invokes the associated gpio_chip.set() method.
*/
static void gpiod_set_value(struct gpio_desc *desc, int value)
{
struct gpio_chip *chip;
if (!desc)
return;
chip = desc->chip;
/* Should be using gpio_set_value_cansleep() */
WARN_ON(chip->can_sleep);
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);
}
void __gpio_set_value(unsigned gpio, int value)
{
return gpiod_set_value(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(__gpio_set_value);
/**
* __gpio_cansleep() - report whether gpio value access will sleep
* @gpio: gpio in question
* Context: any
*
* This is used directly or indirectly to implement gpio_cansleep(). It
* returns nonzero if access reading or writing the GPIO value can sleep.
*/
static int gpiod_cansleep(const struct gpio_desc *desc)
{
if (!desc)
return 0;
/* only call this on GPIOs that are valid! */
return desc->chip->can_sleep;
}
int __gpio_cansleep(unsigned gpio)
{
return gpiod_cansleep(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(__gpio_cansleep);
/**
* __gpio_to_irq() - return the IRQ corresponding to a GPIO
* @gpio: gpio whose IRQ will be returned (already requested)
* Context: any
*
* This is used directly or indirectly to implement gpio_to_irq().
* It returns the number of the IRQ signaled by this (input) GPIO,
* or a negative errno.
*/
static 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;
}
int __gpio_to_irq(unsigned gpio)
{
return gpiod_to_irq(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(__gpio_to_irq);
/* There's no value in making it easy to inline GPIO calls that may sleep.
* Common examples include ones connected to I2C or SPI chips.
*/
static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
struct gpio_chip *chip;
int value;
int offset;
might_sleep_if(extra_checks);
if (!desc)
return 0;
chip = desc->chip;
offset = gpio_chip_hwgpio(desc);
value = chip->get ? chip->get(chip, offset) : 0;
trace_gpio_value(desc_to_gpio(desc), 1, value);
return value;
}
int gpio_get_value_cansleep(unsigned gpio)
{
return gpiod_get_value_cansleep(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
{
struct gpio_chip *chip;
might_sleep_if(extra_checks);
if (!desc)
return;
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);
}
void gpio_set_value_cansleep(unsigned gpio, int value)
{
return gpiod_set_value_cansleep(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
#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;
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);
seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
gpio, gdesc->label,
is_out ? "out" : "in ",
chip->get
? (chip->get(chip, i) ? "hi" : "lo")
: "? ");
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 */
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