gpiolib: use descriptors internally

Make sure gpiolib works internally with descriptors and (chip, offset)
pairs instead of using the global integer namespace. This prepares the
ground for the removal of the global gpio_desc[] array and the
introduction of the descriptor-based GPIO API.

Signed-off-by: Alexandre Courbot <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
[grant.likely: Squash in fix for link error when CONFIG_SYSFS=n]
Signed-off-by: Grant Likely <[e-mail]>

drivers/gpio/gpiolib.c

···
 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_set_debounce(struct gpio_desc *desc, unsigned debounce);
+static int gpiod_get_value_cansleep(struct gpio_desc *desc);
+static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
+static int gpiod_get_value(struct gpio_desc *desc);
+static void gpiod_set_value(struct gpio_desc *desc, int value);
+static int gpiod_cansleep(struct gpio_desc *desc);
+static int gpiod_to_irq(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 - &gpio_desc[0]) - desc->chip->base;
+}
+
+/**
+ * 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 - &gpio_desc[0];
+}
+
 
 /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
  * when setting direction, and otherwise illegal.  Until board setup code
···
  * 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, unsigned offset)
+static int gpio_ensure_requested(struct gpio_desc *desc)
 {
 	const struct gpio_chip *chip = desc->chip;
-	const int gpio = chip->base + offset;
+	const int gpio = desc_to_gpio(desc);
 
 	if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
 			"autorequest GPIO-%d\n", gpio)) {
···
 }
 
 /* caller holds gpio_lock *OR* gpio is marked as requested */
+static struct gpio_chip *gpiod_to_chip(struct gpio_desc *desc)
+{
+	return desc->chip;
+}
+
 struct gpio_chip *gpio_to_chip(unsigned gpio)
 {
-	return gpio_desc[gpio].chip;
+	return gpiod_to_chip(gpio_to_desc(gpio));
 }
 
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
···
 }
 
 /* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
-static int gpio_get_direction(unsigned gpio)
+static int gpiod_get_direction(struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
-	struct gpio_desc	*desc = &gpio_desc[gpio];
+	unsigned		offset;
 	int			status = -EINVAL;
 
-	chip = gpio_to_chip(gpio);
-	gpio -= chip->base;
+	chip = gpiod_to_chip(desc);
+	offset = gpio_chip_hwgpio(desc);
 
 	if (!chip->get_direction)
 		return status;
 
-	status = chip->get_direction(chip, gpio);
+	status = chip->get_direction(chip, offset);
 	if (status > 0) {
 		/* GPIOF_DIR_IN, or other positive */
 		status = 1;
···
 static ssize_t gpio_direction_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	const struct gpio_desc	*desc = dev_get_drvdata(dev);
-	unsigned		gpio = desc - gpio_desc;
+	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 {
-		gpio_get_direction(gpio);
+		gpiod_get_direction(desc);
 		status = sprintf(buf, "%s\n",
 			test_bit(FLAG_IS_OUT, &desc->flags)
 				? "out" : "in");
···
 static ssize_t gpio_direction_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t size)
 {
-	const struct gpio_desc	*desc = dev_get_drvdata(dev);
-	unsigned		gpio = desc - gpio_desc;
+	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 = gpio_direction_output(gpio, 1);
+		status = gpiod_direction_output(desc, 1);
 	else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
-		status = gpio_direction_output(gpio, 0);
+		status = gpiod_direction_output(desc, 0);
 	else if (sysfs_streq(buf, "in"))
-		status = gpio_direction_input(gpio);
+		status = gpiod_direction_input(desc);
 	else
 		status = -EINVAL;
 
···
 static ssize_t gpio_value_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	const struct gpio_desc	*desc = dev_get_drvdata(dev);
-	unsigned		gpio = desc - gpio_desc;
+	struct gpio_desc	*desc = dev_get_drvdata(dev);
 	ssize_t			status;
 
 	mutex_lock(&sysfs_lock);
···
 	} else {
 		int value;
 
-		value = !!gpio_get_value_cansleep(gpio);
+		value = !!gpiod_get_value_cansleep(desc);
 		if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 			value = !value;
 
···
 static ssize_t gpio_value_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t size)
 {
-	const struct gpio_desc	*desc = dev_get_drvdata(dev);
-	unsigned		gpio = desc - gpio_desc;
+	struct gpio_desc	*desc = dev_get_drvdata(dev);
 	ssize_t			status;
 
 	mutex_lock(&sysfs_lock);
···
 		if (status == 0) {
 			if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 				value = !value;
-			gpio_set_value_cansleep(gpio, value != 0);
+			gpiod_set_value_cansleep(desc, value != 0);
 			status = size;
 		}
 	}
···
 	if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
 		return 0;
 
-	irq = gpio_to_irq(desc - gpio_desc);
+	irq = gpiod_to_irq(desc);
 	if (irq < 0)
 		return -EIO;
 
···
 				struct class_attribute *attr,
 				const char *buf, size_t len)
 {
-	long	gpio;
-	int	status;
+	long			gpio;
+	struct gpio_desc	*desc;
+	int			status;
 
 	status = strict_strtol(buf, 0, &gpio);
 	if (status < 0)
 		goto done;
+
+	desc = gpio_to_desc(gpio);
 
 	/* 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 = gpio_request(gpio, "sysfs");
+	status = gpiod_request(desc, "sysfs");
 	if (status < 0) {
 		if (status == -EPROBE_DEFER)
 			status = -ENODEV;
 		goto done;
 	}
-	status = gpio_export(gpio, true);
+	status = gpiod_export(desc, true);
 	if (status < 0)
-		gpio_free(gpio);
+		gpiod_free(desc);
 	else
-		set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags);
+		set_bit(FLAG_SYSFS, &desc->flags);
 
 done:
 	if (status)
···
 				struct class_attribute *attr,
 				const char *buf, size_t len)
 {
-	long	gpio;
-	int	status;
+	long			gpio;
+	struct gpio_desc	*desc;
+	int			status;
 
 	status = strict_strtol(buf, 0, &gpio);
 	if (status < 0)
···
 
 	status = -EINVAL;
 
+	desc = gpio_to_desc(gpio);
 	/* reject bogus commands (gpio_unexport ignores them) */
-	if (!gpio_is_valid(gpio))
+	if (!desc)
 		goto done;
 
 	/* 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, &gpio_desc[gpio].flags)) {
+	if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
 		status = 0;
-		gpio_free(gpio);
+		gpiod_free(desc);
 	}
 done:
 	if (status)
···
  *
  * Returns zero on success, else an error.
  */
-int gpio_export(unsigned gpio, bool direction_may_change)
+static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
 {
 	unsigned long		flags;
-	struct gpio_desc	*desc;
 	int			status;
 	const char		*ioname = NULL;
 	struct device		*dev;
+	int			offset;
 
 	/* can't export until sysfs is available ... */
 	if (!gpio_class.p) {
···
 		return -ENOENT;
 	}
 
-	if (!gpio_is_valid(gpio)) {
-		pr_debug("%s: gpio %d is not valid\n", __func__, gpio);
+	if (!desc) {
+		pr_debug("%s: invalid gpio descriptor\n", __func__);
 		return -EINVAL;
 	}
 
 	mutex_lock(&sysfs_lock);
 
 	spin_lock_irqsave(&gpio_lock, flags);
-	desc = &gpio_desc[gpio];
 	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__, gpio,
+				__func__, desc_to_gpio(desc),
 				test_bit(FLAG_REQUESTED, &desc->flags),
 				test_bit(FLAG_EXPORT, &desc->flags));
 		status = -EPERM;
···
 		direction_may_change = false;
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
-	if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
-		ioname = desc->chip->names[gpio - desc->chip->base];
+	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", gpio);
+			    desc, ioname ? ioname : "gpio%u",
+			    desc_to_gpio(desc));
 	if (IS_ERR(dev)) {
 		status = PTR_ERR(dev);
 		goto fail_unlock;
···
 			goto fail_unregister_device;
 	}
 
-	if (gpio_to_irq(gpio) >= 0 && (direction_may_change ||
+	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)
···
 	device_unregister(dev);
 fail_unlock:
 	mutex_unlock(&sysfs_lock);
-	pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+	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);
 
···
  *
  * Returns zero on success, else an error.
  */
-int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
+static int gpiod_export_link(struct device *dev, const char *name,
+			     struct gpio_desc *desc)
 {
-	struct gpio_desc	*desc;
 	int			status = -EINVAL;
 
-	if (!gpio_is_valid(gpio))
+	if (!desc)
 		goto done;
 
 	mutex_lock(&sysfs_lock);
-
-	desc = &gpio_desc[gpio];
 
 	if (test_bit(FLAG_EXPORT, &desc->flags)) {
 		struct device *tdev;
···
 
 done:
 	if (status)
-		pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
+			 status);
 
 	return status;
 }
-EXPORT_SYMBOL_GPL(gpio_export_link);
 
+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
···
  *
  * Returns zero on success, else an error.
  */
-int gpio_sysfs_set_active_low(unsigned gpio, int value)
+static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
 {
-	struct gpio_desc	*desc;
 	struct device		*dev = NULL;
 	int			status = -EINVAL;
 
-	if (!gpio_is_valid(gpio))
+	if (!desc)
 		goto done;
 
 	mutex_lock(&sysfs_lock);
-
-	desc = &gpio_desc[gpio];
 
 	if (test_bit(FLAG_EXPORT, &desc->flags)) {
 		dev = class_find_device(&gpio_class, NULL, desc, match_export);
···
 
 done:
 	if (status)
-		pr_debug("%s: gpio%d status %d\n", __func__, gpio, 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);
 
···
  *
  * This is implicit on gpio_free().
  */
-void gpio_unexport(unsigned gpio)
+static void gpiod_unexport(struct gpio_desc *desc)
 {
-	struct gpio_desc	*desc;
 	int			status = 0;
 	struct device		*dev = NULL;
 
-	if (!gpio_is_valid(gpio)) {
+	if (!desc) {
 		status = -EINVAL;
 		goto done;
 	}
 
 	mutex_lock(&sysfs_lock);
-
-	desc = &gpio_desc[gpio];
 
 	if (test_bit(FLAG_EXPORT, &desc->flags)) {
 
···
 	}
 
 	mutex_unlock(&sysfs_lock);
+
 	if (dev) {
 		device_unregister(dev);
 		put_device(dev);
 	}
 done:
 	if (status)
-		pr_debug("%s: gpio%d status %d\n", __func__, gpio, 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 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)
 {
 }
 
···
  * on each other, and help provide better diagnostics in debugfs.
  * They're called even less than the "set direction" calls.
  */
-int gpio_request(unsigned gpio, const char *label)
+static int gpiod_request(struct gpio_desc *desc, const char *label)
 {
-	struct gpio_desc	*desc;
 	struct gpio_chip	*chip;
 	int			status = -EPROBE_DEFER;
 	unsigned long		flags;
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!gpio_is_valid(gpio)) {
+	if (!desc) {
 		status = -EINVAL;
 		goto done;
 	}
-	desc = &gpio_desc[gpio];
 	chip = desc->chip;
 	if (chip == NULL)
 		goto done;
···
 	if (chip->request) {
 		/* chip->request may sleep */
 		spin_unlock_irqrestore(&gpio_lock, flags);
-		status = chip->request(chip, gpio - chip->base);
+		status = chip->request(chip, gpio_chip_hwgpio(desc));
 		spin_lock_irqsave(&gpio_lock, flags);
 
 		if (status < 0) {
···
 	if (chip->get_direction) {
 		/* chip->get_direction may sleep */
 		spin_unlock_irqrestore(&gpio_lock, flags);
-		gpio_get_direction(gpio);
+		gpiod_get_direction(desc);
 		spin_lock_irqsave(&gpio_lock, flags);
 	}
 done:
 	if (status)
-		pr_debug("gpio_request: gpio-%d (%s) status %d\n",
-			gpio, label ? : "?", status);
+		pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
+			 desc ? desc_to_gpio(desc) : -1,
+			 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);
 
-void gpio_free(unsigned gpio)
+static void gpiod_free(struct gpio_desc *desc)
 {
 	unsigned long		flags;
-	struct gpio_desc	*desc;
 	struct gpio_chip	*chip;
 
 	might_sleep();
 
-	if (!gpio_is_valid(gpio)) {
+	if (!desc) {
 		WARN_ON(extra_checks);
 		return;
 	}
 
-	gpio_unexport(gpio);
+	gpiod_unexport(desc);
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	desc = &gpio_desc[gpio];
 	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->base);
+			chip->free(chip, gpio_chip_hwgpio(desc));
 			spin_lock_irqsave(&gpio_lock, flags);
 		}
 		desc_set_label(desc, NULL);
···
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
 }
+
+void gpio_free(unsigned gpio)
+{
+	gpiod_free(gpio_to_desc(gpio));
+}
 EXPORT_SYMBOL_GPL(gpio_free);
 
 /**
···
  */
 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
 {
+	struct gpio_desc *desc;
 	int err;
 
-	err = gpio_request(gpio, label);
+	desc = gpio_to_desc(gpio);
+
+	err = gpiod_request(desc, label);
 	if (err)
 		return err;
 
 	if (flags & GPIOF_OPEN_DRAIN)
-		set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags);
+		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
 
 	if (flags & GPIOF_OPEN_SOURCE)
-		set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);
+		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
 
 	if (flags & GPIOF_DIR_IN)
-		err = gpio_direction_input(gpio);
+		err = gpiod_direction_input(desc);
 	else
-		err = gpio_direction_output(gpio,
+		err = gpiod_direction_output(desc,
 				(flags & GPIOF_INIT_HIGH) ? 1 : 0);
 
 	if (err)
 		goto free_gpio;
 
 	if (flags & GPIOF_EXPORT) {
-		err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE);
+		err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
 		if (err)
 			goto free_gpio;
 	}
···
 	return 0;
 
  free_gpio:
-	gpio_free(gpio);
+	gpiod_free(desc);
 	return err;
 }
 EXPORT_SYMBOL_GPL(gpio_request_one);
···
 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
 {
 	unsigned gpio = chip->base + offset;
+	struct gpio_desc *desc = &gpio_desc[gpio];
 
-	if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
+	if (!gpio_is_valid(gpio) || desc->chip != chip)
 		return NULL;
-	if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
+	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
 		return NULL;
 #ifdef CONFIG_DEBUG_FS
-	return gpio_desc[gpio].label;
+	return desc->label;
 #else
 	return "?";
 #endif
···
  * rely on gpio_request() having been called beforehand.
  */
 
-int gpio_direction_input(unsigned gpio)
+static int gpiod_direction_input(struct gpio_desc *desc)
 {
 	unsigned long		flags;
 	struct gpio_chip	*chip;
-	struct gpio_desc	*desc = &gpio_desc[gpio];
 	int			status = -EINVAL;
+	int			offset;
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!gpio_is_valid(gpio))
+	if (!desc)
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->get || !chip->direction_input)
 		goto fail;
-	gpio -= chip->base;
-	if (gpio >= chip->ngpio)
-		goto fail;
-	status = gpio_ensure_requested(desc, gpio);
+	status = gpio_ensure_requested(desc);
 	if (status < 0)
 		goto fail;
 
···
 
 	might_sleep_if(chip->can_sleep);
 
+	offset = gpio_chip_hwgpio(desc);
 	if (status) {
-		status = chip->request(chip, gpio);
+		status = chip->request(chip, offset);
 		if (status < 0) {
 			pr_debug("GPIO-%d: chip request fail, %d\n",
-				chip->base + gpio, status);
+				desc_to_gpio(desc), status);
 			/* and it's not available to anyone else ...
 			 * gpio_request() is the fully clean solution.
 			 */
···
 		}
 	}
 
-	status = chip->direction_input(chip, gpio);
+	status = chip->direction_input(chip, offset);
 	if (status == 0)
 		clear_bit(FLAG_IS_OUT, &desc->flags);
 
-	trace_gpio_direction(chip->base + gpio, 1, status);
+	trace_gpio_direction(desc_to_gpio(desc), 1, status);
 lose:
 	return status;
 fail:
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	if (status)
+	if (status) {
+		int gpio = -1;
+		if (desc)
+			gpio = desc_to_gpio(desc);
 		pr_debug("%s: gpio-%d status %d\n",
 			__func__, gpio, status);
+	}
 	return status;
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+	return gpiod_direction_input(gpio_to_desc(gpio));
 }
 EXPORT_SYMBOL_GPL(gpio_direction_input);
 
-int gpio_direction_output(unsigned gpio, int value)
+static int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
 	unsigned long		flags;
 	struct gpio_chip	*chip;
-	struct gpio_desc	*desc = &gpio_desc[gpio];
 	int			status = -EINVAL;
+	int offset;
 
 	/* Open drain pin should not be driven to 1 */
 	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
-		return gpio_direction_input(gpio);
+		return gpiod_direction_input(desc);
 
 	/* Open source pin should not be driven to 0 */
 	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
-		return gpio_direction_input(gpio);
+		return gpiod_direction_input(desc);
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!gpio_is_valid(gpio))
+	if (!desc)
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->set || !chip->direction_output)
 		goto fail;
-	gpio -= chip->base;
-	if (gpio >= chip->ngpio)
-		goto fail;
-	status = gpio_ensure_requested(desc, gpio);
+	status = gpio_ensure_requested(desc);
 	if (status < 0)
 		goto fail;
 
···
 
 	might_sleep_if(chip->can_sleep);
 
+	offset = gpio_chip_hwgpio(desc);
 	if (status) {
-		status = chip->request(chip, gpio);
+		status = chip->request(chip, offset);
 		if (status < 0) {
 			pr_debug("GPIO-%d: chip request fail, %d\n",
-				chip->base + gpio, status);
+				desc_to_gpio(desc), status);
 			/* and it's not available to anyone else ...
 			 * gpio_request() is the fully clean solution.
 			 */
···
 		}
 	}
 
-	status = chip->direction_output(chip, gpio, value);
+	status = chip->direction_output(chip, offset, value);
 	if (status == 0)
 		set_bit(FLAG_IS_OUT, &desc->flags);
-	trace_gpio_value(chip->base + gpio, 0, value);
-	trace_gpio_direction(chip->base + gpio, 0, status);
+	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)
+	if (status) {
+		int gpio = -1;
+		if (desc)
+			gpio = desc_to_gpio(desc);
 		pr_debug("%s: gpio-%d status %d\n",
 			__func__, gpio, 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: the gpio to set debounce time
  * @debounce: debounce time is microseconds
  */
-int gpio_set_debounce(unsigned gpio, unsigned debounce)
+static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 {
 	unsigned long		flags;
 	struct gpio_chip	*chip;
-	struct gpio_desc	*desc = &gpio_desc[gpio];
 	int			status = -EINVAL;
+	int			offset;
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!gpio_is_valid(gpio))
+	if (!desc)
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->set || !chip->set_debounce)
 		goto fail;
-	gpio -= chip->base;
-	if (gpio >= chip->ngpio)
-		goto fail;
-	status = gpio_ensure_requested(desc, gpio);
+
+	status = gpio_ensure_requested(desc);
 	if (status < 0)
 		goto fail;
 
···
 
 	might_sleep_if(chip->can_sleep);
 
-	return chip->set_debounce(chip, gpio, debounce);
+	offset = gpio_chip_hwgpio(desc);
+	return chip->set_debounce(chip, offset, debounce);
 
 fail:
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	if (status)
+	if (status) {
+		int gpio = -1;
+		if (desc)
+			gpio = desc_to_gpio(desc);
 		pr_debug("%s: gpio-%d status %d\n",
 			__func__, gpio, 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);
 
···
  * It returns the zero or nonzero value provided by the associated
  * gpio_chip.get() method; or zero if no such method is provided.
  */
-int __gpio_get_value(unsigned gpio)
+static int gpiod_get_value(struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
 	int value;
+	int offset;
 
-	chip = gpio_to_chip(gpio);
+	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, gpio - chip->base) : 0;
-	trace_gpio_value(gpio, 1, value);
+	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);
 
···
  * @chip: Gpio chip.
  * @value: Non-zero for setting it HIGH otherise it will set to LOW.
  */
-static void _gpio_set_open_drain_value(unsigned gpio,
-			struct gpio_chip *chip, int value)
+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, gpio - chip->base);
+		err = chip->direction_input(chip, offset);
 		if (!err)
-			clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+			clear_bit(FLAG_IS_OUT, &desc->flags);
 	} else {
-		err = chip->direction_output(chip, gpio - chip->base, 0);
+		err = chip->direction_output(chip, offset, 0);
 		if (!err)
-			set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+			set_bit(FLAG_IS_OUT, &desc->flags);
 	}
-	trace_gpio_direction(gpio, value, err);
+	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__, gpio, err);
+					__func__, desc_to_gpio(desc), err);
 }
 
 /*
···
  * @chip: Gpio chip.
  * @value: Non-zero for setting it HIGH otherise it will set to LOW.
  */
-static void _gpio_set_open_source_value(unsigned gpio,
-			struct gpio_chip *chip, int value)
+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, gpio - chip->base, 1);
+		err = chip->direction_output(chip, offset, 1);
 		if (!err)
-			set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+			set_bit(FLAG_IS_OUT, &desc->flags);
 	} else {
-		err = chip->direction_input(chip, gpio - chip->base);
+		err = chip->direction_input(chip, offset);
 		if (!err)
-			clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);
+			clear_bit(FLAG_IS_OUT, &desc->flags);
 	}
-	trace_gpio_direction(gpio, !value, err);
+	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__, gpio, err);
+					__func__, desc_to_gpio(desc), err);
 }
-
 
 /**
  * __gpio_set_value() - assign a gpio's value
···
  * This is used directly or indirectly to implement gpio_set_value().
  * It invokes the associated gpio_chip.set() method.
  */
-void __gpio_set_value(unsigned gpio, int value)
+static void gpiod_set_value(struct gpio_desc *desc, int value)
 {
 	struct gpio_chip	*chip;
 
-	chip = gpio_to_chip(gpio);
+	chip = desc->chip;
 	/* Should be using gpio_set_value_cansleep() */
 	WARN_ON(chip->can_sleep);
-	trace_gpio_value(gpio, 0, value);
-	if (test_bit(FLAG_OPEN_DRAIN,  &gpio_desc[gpio].flags))
-		_gpio_set_open_drain_value(gpio, chip, value);
-	else if (test_bit(FLAG_OPEN_SOURCE,  &gpio_desc[gpio].flags))
-		_gpio_set_open_source_value(gpio, chip, value);
+	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->base, value);
+		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);
 
···
  * 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(struct gpio_desc *desc)
+{
+	/* only call this on GPIOs that are valid! */
+	return desc->chip->can_sleep;
+}
+
 int __gpio_cansleep(unsigned gpio)
 {
-	struct gpio_chip	*chip;
-
-	/* only call this on GPIOs that are valid! */
-	chip = gpio_to_chip(gpio);
-
-	return chip->can_sleep;
+	return gpiod_cansleep(gpio_to_desc(gpio));
 }
 EXPORT_SYMBOL_GPL(__gpio_cansleep);
 
···
  * It returns the number of the IRQ signaled by this (input) GPIO,
  * or a negative errno.
  */
-int __gpio_to_irq(unsigned gpio)
+static int gpiod_to_irq(struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
+	int			offset;
 
-	chip = gpio_to_chip(gpio);
-	return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
+	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.
  */
 
-int gpio_get_value_cansleep(unsigned gpio)
+static int gpiod_get_value_cansleep(struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
 	int value;
+	int offset;
 
 	might_sleep_if(extra_checks);
-	chip = gpio_to_chip(gpio);
-	value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
-	trace_gpio_value(gpio, 1, value);
+	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);
 
-void gpio_set_value_cansleep(unsigned gpio, int value)
+static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 {
 	struct gpio_chip	*chip;
 
 	might_sleep_if(extra_checks);
-	chip = gpio_to_chip(gpio);
-	trace_gpio_value(gpio, 0, value);
-	if (test_bit(FLAG_OPEN_DRAIN,  &gpio_desc[gpio].flags))
-		_gpio_set_open_drain_value(gpio, chip, value);
-	else if (test_bit(FLAG_OPEN_SOURCE,  &gpio_desc[gpio].flags))
-		_gpio_set_open_source_value(gpio, chip, value);
+	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->base, value);
+		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
 
···
 		if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
 			continue;
 
-		gpio_get_direction(gpio);
+		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,