Merge tag 'gpio-v4.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO updates from Linus Walleij:
 "This is the bulk of GPIO changes for kernel v4.6.  There is quite a
  lot of interesting stuff going on.

  The patches to other subsystems and arch-wide are ACKed as far as
  possible, though I consider things like per-arch <asm/gpio.h> as
  essentially a part of the GPIO subsystem so it should not be needed.

  Core changes:

   - The gpio_chip is now a *real device*.  Until now the gpio chips
     were just piggybacking the parent device or (gasp) floating in
     space outside of the device model.

     We now finally make GPIO chips devices.  The gpio_chip will create
     a gpio_device which contains a struct device, and this gpio_device
     struct is kept private.  Anything that needs to be kept private
     from the rest of the kernel will gradually be moved over to the
     gpio_device.

   - As a result of making the gpio_device a real device, we have added
     resource management, so devm_gpiochip_add_data() will cut down on
     overhead and reduce code lines.  A huge slew of patches convert
     almost all drivers in the subsystem to use this.

   - Building on making the GPIO a real device, we add the first step of
     a new userspace ABI: the GPIO character device.  We take small
     steps here, so we first add a pure *information* ABI and the tool
     "lsgpio" that will list all GPIO devices on the system and all
     lines on these devices.

     We can now discover GPIOs properly from userspace.  We still have
     not come up with a way to actually *use* GPIOs from userspace.

   - To encourage people to use the character device for the future, we
     have it always-enabled when using GPIO.  The old sysfs ABI is still
     opt-in (and can be used in parallel), but is marked as deprecated.

     We will keep it around for the foreseeable future, but it will not
     be extended to cover ever more use cases.

  Cleanup:

   - Bjorn Helgaas removed a whole slew of per-architecture <asm/gpio.h>
     includes.

     This dates back to when GPIO was an opt-in feature and no shared
     library even existed: just a header file with proper prototypes was
     provided and all semantics were up to the arch to implement.  These
     patches make the GPIO chip even more a proper device and cleans out
     leftovers of the old in-kernel API here and there.

     Still some cruft is left but it's very little now.

   - There is still some clamping of return values for .get() going on,
     but we now return sane values in the vast majority of drivers and
     the errorpath is sanitized.  Some patches for powerpc, blackfin and
     unicore still drop in.

   - We continue to switch the ARM, MIPS, blackfin, m68k local GPIO
     implementations to use gpiochip_add_data() and cut down on code
     lines.

   - MPC8xxx is converted to use the generic GPIO helpers.

   - ATH79 is converted to use the generic GPIO helpers.

  New drivers:

   - WinSystems WS16C48

   - Acces 104-DIO-48E

   - F81866 (a F7188x variant)

   - Qoric (a MPC8xxx variant)

   - TS-4800

   - SPI serializers (pisosr): simple 74xx shift registers connected to
     SPI to obtain a dirt-cheap output-only GPIO expander.

   - Texas Instruments TPIC2810

   - Texas Instruments TPS65218

   - Texas Instruments TPS65912

   - X-Gene (ARM64) standby GPIO controller"

* tag 'gpio-v4.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (194 commits)
  Revert "Share upstreaming patches"
  gpio: mcp23s08: Fix clearing of interrupt.
  gpiolib: Fix comment referring to gpio_*() in gpiod_*()
  gpio: pca953x: Fix pca953x_gpio_set_multiple() on 64-bit
  gpio: xgene: Fix kconfig for standby GIPO contoller
  gpio: Add generic serializer DT binding
  gpio: uapi: use 0xB4 as ioctl() major
  gpio: tps65912: fix bad merge
  Revert "gpio: lp3943: Drop pin_used and lp3943_gpio_request/lp3943_gpio_free"
  gpio: omap: drop dev field from gpio_bank structure
  gpio: mpc8xxx: Slightly update the code for better readability
  gpio: mpc8xxx: Remove *read_reg and *write_reg from struct mpc8xxx_gpio_chip
  gpio: mpc8xxx: Fixup setting gpio direction output
  gpio: mcp23s08: Add support for mcp23s18
  dt-bindings: gpio: altera: Fix altr,interrupt-type property
  gpio: add driver for MEN 16Z127 GPIO controller
  gpio: lp3943: Drop pin_used and lp3943_gpio_request/lp3943_gpio_free
  gpio: timberdale: Switch to devm_ioremap_resource()
  gpio: ts4800: Add IMX51 dependency
  gpiolib: rewrite gpiodev_add_to_list
  ...

1 files changed, 605 insertions, 217 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5c1ba879f889..72065532c1c7 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -16,6 +16,11 @@
 #include <linux/gpio/driver.h>
 #include <linux/gpio/machine.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/idr.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/gpio.h>
 
 #include "gpiolib.h"
 
@@ -42,6 +47,14 @@
 #define	extra_checks	0
 #endif
 
+/* Device and char device-related information */
+static DEFINE_IDA(gpio_ida);
+static dev_t gpio_devt;
+#define GPIO_DEV_MAX 256 /* 256 GPIO chip devices supported */
+static struct bus_type gpio_bus_type = {
+	.name = "gpio",
+};
+
 /* 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.
@@ -50,8 +63,7 @@ DEFINE_SPINLOCK(gpio_lock);
 
 static DEFINE_MUTEX(gpio_lookup_lock);
 static LIST_HEAD(gpio_lookup_list);
-LIST_HEAD(gpio_chips);
-
+LIST_HEAD(gpio_devices);
 
 static void gpiochip_free_hogs(struct gpio_chip *chip);
 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
@@ -67,15 +79,16 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label)
  */
 struct gpio_desc *gpio_to_desc(unsigned gpio)
 {
-	struct gpio_chip *chip;
+	struct gpio_device *gdev;
 	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) {
+	list_for_each_entry(gdev, &gpio_devices, list) {
+		if (gdev->base <= gpio &&
+		    gdev->base + gdev->ngpio > gpio) {
 			spin_unlock_irqrestore(&gpio_lock, flags);
-			return &chip->desc[gpio - chip->base];
+			return &gdev->descs[gpio - gdev->base];
 		}
 	}
 
@@ -94,10 +107,12 @@ EXPORT_SYMBOL_GPL(gpio_to_desc);
 struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
 				    u16 hwnum)
 {
-	if (hwnum >= chip->ngpio)
+	struct gpio_device *gdev = chip->gpiodev;
+
+	if (hwnum >= gdev->ngpio)
 		return ERR_PTR(-EINVAL);
 
-	return &chip->desc[hwnum];
+	return &gdev->descs[hwnum];
 }
 
 /**
@@ -107,7 +122,7 @@ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
  */
 int desc_to_gpio(const struct gpio_desc *desc)
 {
-	return desc->chip->base + (desc - &desc->chip->desc[0]);
+	return desc->gdev->base + (desc - &desc->gdev->descs[0]);
 }
 EXPORT_SYMBOL_GPL(desc_to_gpio);
 
@@ -118,23 +133,25 @@ EXPORT_SYMBOL_GPL(desc_to_gpio);
  */
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
-	return desc ? desc->chip : NULL;
+	if (!desc || !desc->gdev || !desc->gdev->chip)
+		return NULL;
+	return desc->gdev->chip;
 }
 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;
+	struct gpio_device *gdev;
 	int base = ARCH_NR_GPIOS - ngpio;
 
-	list_for_each_entry_reverse(chip, &gpio_chips, list) {
+	list_for_each_entry_reverse(gdev, &gpio_devices, list) {
 		/* found a free space? */
-		if (chip->base + chip->ngpio <= base)
+		if (gdev->base + gdev->ngpio <= base)
 			break;
 		else
 			/* nope, check the space right before the chip */
-			base = chip->base - ngpio;
+			base = gdev->base - ngpio;
 	}
 
 	if (gpio_is_valid(base)) {
@@ -187,57 +204,45 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
  * Return -EBUSY if the new chip overlaps with some other chip's integer
  * space.
  */
-static int gpiochip_add_to_list(struct gpio_chip *chip)
+static int gpiodev_add_to_list(struct gpio_device *gdev)
 {
-	struct gpio_chip *iterator;
-	struct gpio_chip *previous = NULL;
+	struct gpio_device *prev, *next;
 
-	if (list_empty(&gpio_chips)) {
-		list_add_tail(&chip->list, &gpio_chips);
+	if (list_empty(&gpio_devices)) {
+		/* initial entry in list */
+		list_add_tail(&gdev->list, &gpio_devices);
 		return 0;
 	}
 
-	list_for_each_entry(iterator, &gpio_chips, list) {
-		if (iterator->base >= chip->base + chip->ngpio) {
-			/*
-			 * Iterator is the first GPIO chip so there is no
-			 * previous one
-			 */
-			if (!previous) {
-				goto found;
-			} else {
-				/*
-				 * We found a valid range(means
-				 * [base, base + ngpio - 1]) between previous
-				 * and iterator chip.
-				 */
-				if (previous->base + previous->ngpio
-						<= chip->base)
-					goto found;
-			}
-		}
-		previous = iterator;
+	next = list_entry(gpio_devices.next, struct gpio_device, list);
+	if (gdev->base + gdev->ngpio <= next->base) {
+		/* add before first entry */
+		list_add(&gdev->list, &gpio_devices);
+		return 0;
 	}
 
-	/*
-	 * We are beyond the last chip in the list and iterator now
-	 * points to the head.
-	 * Let iterator point to the last chip in the list.
-	 */
-
-	iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
-	if (iterator->base + iterator->ngpio <= chip->base) {
-		list_add(&chip->list, &iterator->list);
+	prev = list_entry(gpio_devices.prev, struct gpio_device, list);
+	if (prev->base + prev->ngpio <= gdev->base) {
+		/* add behind last entry */
+		list_add_tail(&gdev->list, &gpio_devices);
 		return 0;
 	}
 
-	dev_err(chip->parent,
-	       "GPIO integer space overlap, cannot add chip\n");
-	return -EBUSY;
+	list_for_each_entry_safe(prev, next, &gpio_devices, list) {
+		/* at the end of the list */
+		if (&next->list == &gpio_devices)
+			break;
 
-found:
-	list_add_tail(&chip->list, &iterator->list);
-	return 0;
+		/* add between prev and next */
+		if (prev->base + prev->ngpio <= gdev->base
+				&& gdev->base + gdev->ngpio <= next->base) {
+			list_add(&gdev->list, &prev->list);
+			return 0;
+		}
+	}
+
+	dev_err(&gdev->dev, "GPIO integer space overlap, cannot add chip\n");
+	return -EBUSY;
 }
 
 /**
@@ -245,23 +250,23 @@ found:
  */
 static struct gpio_desc *gpio_name_to_desc(const char * const name)
 {
-	struct gpio_chip *chip;
+	struct gpio_device *gdev;
 	unsigned long flags;
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	list_for_each_entry(chip, &gpio_chips, list) {
+	list_for_each_entry(gdev, &gpio_devices, list) {
 		int i;
 
-		for (i = 0; i != chip->ngpio; ++i) {
-			struct gpio_desc *gpio = &chip->desc[i];
+		for (i = 0; i != gdev->ngpio; ++i) {
+			struct gpio_desc *desc = &gdev->descs[i];
 
-			if (!gpio->name || !name)
+			if (!desc->name || !name)
 				continue;
 
-			if (!strcmp(gpio->name, name)) {
+			if (!strcmp(desc->name, name)) {
 				spin_unlock_irqrestore(&gpio_lock, flags);
-				return gpio;
+				return desc;
 			}
 		}
 	}
@@ -279,6 +284,7 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name)
  */
 static int gpiochip_set_desc_names(struct gpio_chip *gc)
 {
+	struct gpio_device *gdev = gc->gpiodev;
 	int i;
 
 	if (!gc->names)
@@ -290,18 +296,153 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
 
 		gpio = gpio_name_to_desc(gc->names[i]);
 		if (gpio)
-			dev_warn(gc->parent, "Detected name collision for "
-				 "GPIO name '%s'\n",
+			dev_warn(&gdev->dev,
+				 "Detected name collision for GPIO name '%s'\n",
 				 gc->names[i]);
 	}
 
 	/* Then add all names to the GPIO descriptors */
 	for (i = 0; i != gc->ngpio; ++i)
-		gc->desc[i].name = gc->names[i];
+		gdev->descs[i].name = gc->names[i];
+
+	return 0;
+}
+
+/**
+ * gpio_ioctl() - ioctl handler for the GPIO chardev
+ */
+static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct gpio_device *gdev = filp->private_data;
+	struct gpio_chip *chip = gdev->chip;
+	int __user *ip = (int __user *)arg;
+
+	/* We fail any subsequent ioctl():s when the chip is gone */
+	if (!chip)
+		return -ENODEV;
+
+	/* Fill in the struct and pass to userspace */
+	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
+		struct gpiochip_info chipinfo;
+
+		strncpy(chipinfo.name, dev_name(&gdev->dev),
+			sizeof(chipinfo.name));
+		chipinfo.name[sizeof(chipinfo.name)-1] = '\0';
+		strncpy(chipinfo.label, gdev->label,
+			sizeof(chipinfo.label));
+		chipinfo.label[sizeof(chipinfo.label)-1] = '\0';
+		chipinfo.lines = gdev->ngpio;
+		if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
+			return -EFAULT;
+		return 0;
+	} else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
+		struct gpioline_info lineinfo;
+		struct gpio_desc *desc;
+
+		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+			return -EFAULT;
+		if (lineinfo.line_offset > gdev->ngpio)
+			return -EINVAL;
+
+		desc = &gdev->descs[lineinfo.line_offset];
+		if (desc->name) {
+			strncpy(lineinfo.name, desc->name,
+				sizeof(lineinfo.name));
+			lineinfo.name[sizeof(lineinfo.name)-1] = '\0';
+		} else {
+			lineinfo.name[0] = '\0';
+		}
+		if (desc->label) {
+			strncpy(lineinfo.consumer, desc->label,
+				sizeof(lineinfo.consumer));
+			lineinfo.consumer[sizeof(lineinfo.consumer)-1] = '\0';
+		} else {
+			lineinfo.consumer[0] = '\0';
+		}
+
+		/*
+		 * Userspace only need to know that the kernel is using
+		 * this GPIO so it can't use it.
+		 */
+		lineinfo.flags = 0;
+		if (test_bit(FLAG_REQUESTED, &desc->flags) ||
+		    test_bit(FLAG_IS_HOGGED, &desc->flags) ||
+		    test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
+		    test_bit(FLAG_EXPORT, &desc->flags) ||
+		    test_bit(FLAG_SYSFS, &desc->flags))
+			lineinfo.flags |= GPIOLINE_FLAG_KERNEL;
+		if (test_bit(FLAG_IS_OUT, &desc->flags))
+			lineinfo.flags |= GPIOLINE_FLAG_IS_OUT;
+		if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+			lineinfo.flags |= GPIOLINE_FLAG_ACTIVE_LOW;
+		if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+			lineinfo.flags |= GPIOLINE_FLAG_OPEN_DRAIN;
+		if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+			lineinfo.flags |= GPIOLINE_FLAG_OPEN_SOURCE;
+
+		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
+			return -EFAULT;
+		return 0;
+	}
+	return -EINVAL;
+}
+
+/**
+ * gpio_chrdev_open() - open the chardev for ioctl operations
+ * @inode: inode for this chardev
+ * @filp: file struct for storing private data
+ * Returns 0 on success
+ */
+static int gpio_chrdev_open(struct inode *inode, struct file *filp)
+{
+	struct gpio_device *gdev = container_of(inode->i_cdev,
+					      struct gpio_device, chrdev);
+
+	/* Fail on open if the backing gpiochip is gone */
+	if (!gdev || !gdev->chip)
+		return -ENODEV;
+	get_device(&gdev->dev);
+	filp->private_data = gdev;
+	return 0;
+}
 
+/**
+ * gpio_chrdev_release() - close chardev after ioctl operations
+ * @inode: inode for this chardev
+ * @filp: file struct for storing private data
+ * Returns 0 on success
+ */
+static int gpio_chrdev_release(struct inode *inode, struct file *filp)
+{
+	struct gpio_device *gdev = container_of(inode->i_cdev,
+					      struct gpio_device, chrdev);
+
+	if (!gdev)
+		return -ENODEV;
+	put_device(&gdev->dev);
 	return 0;
 }
 
+
+static const struct file_operations gpio_fileops = {
+	.release = gpio_chrdev_release,
+	.open = gpio_chrdev_open,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = gpio_ioctl,
+	.compat_ioctl = gpio_ioctl,
+};
+
+static void gpiodevice_release(struct device *dev)
+{
+	struct gpio_device *gdev = dev_get_drvdata(dev);
+
+	cdev_del(&gdev->chrdev);
+	list_del(&gdev->list);
+	ida_simple_remove(&gpio_ida, gdev->id);
+	kfree(gdev);
+}
+
 /**
  * gpiochip_add_data() - register a gpio_chip
  * @chip: the chip to register, with chip->base initialized
@@ -323,43 +464,107 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
 {
 	unsigned long	flags;
 	int		status = 0;
-	unsigned	id;
+	unsigned	i;
 	int		base = chip->base;
-	struct gpio_desc *descs;
+	struct gpio_device *gdev;
 
-	descs = kcalloc(chip->ngpio, sizeof(descs[0]), GFP_KERNEL);
-	if (!descs)
+	/*
+	 * First: allocate and populate the internal stat container, and
+	 * set up the struct device.
+	 */
+	gdev = kzalloc(sizeof(*gdev), GFP_KERNEL);
+	if (!gdev)
 		return -ENOMEM;
+	gdev->dev.bus = &gpio_bus_type;
+	gdev->chip = chip;
+	chip->gpiodev = gdev;
+	if (chip->parent) {
+		gdev->dev.parent = chip->parent;
+		gdev->dev.of_node = chip->parent->of_node;
+	} else {
+#ifdef CONFIG_OF_GPIO
+	/* If the gpiochip has an assigned OF node this takes precedence */
+		if (chip->of_node)
+			gdev->dev.of_node = chip->of_node;
+#endif
+	}
+	gdev->id = ida_simple_get(&gpio_ida, 0, 0, GFP_KERNEL);
+	if (gdev->id < 0) {
+		status = gdev->id;
+		goto err_free_gdev;
+	}
+	dev_set_name(&gdev->dev, "gpiochip%d", gdev->id);
+	device_initialize(&gdev->dev);
+	dev_set_drvdata(&gdev->dev, gdev);
+	if (chip->parent && chip->parent->driver)
+		gdev->owner = chip->parent->driver->owner;
+	else if (chip->owner)
+		/* TODO: remove chip->owner */
+		gdev->owner = chip->owner;
+	else
+		gdev->owner = THIS_MODULE;
 
-	chip->data = data;
+	gdev->descs = devm_kcalloc(&gdev->dev, chip->ngpio,
+				   sizeof(gdev->descs[0]), GFP_KERNEL);
+	if (!gdev->descs) {
+		status = -ENOMEM;
+		goto err_free_gdev;
+	}
 
 	if (chip->ngpio == 0) {
 		chip_err(chip, "tried to insert a GPIO chip with zero lines\n");
-		return -EINVAL;
+		status = -EINVAL;
+		goto err_free_gdev;
 	}
 
+	if (chip->label)
+		gdev->label = devm_kstrdup(&gdev->dev, chip->label, GFP_KERNEL);
+	else
+		gdev->label = devm_kstrdup(&gdev->dev, "unknown", GFP_KERNEL);
+	if (!gdev->label) {
+		status = -ENOMEM;
+		goto err_free_gdev;
+	}
+
+	gdev->ngpio = chip->ngpio;
+	gdev->data = data;
+
 	spin_lock_irqsave(&gpio_lock, flags);
 
+	/*
+	 * TODO: this allocates a Linux GPIO number base in the global
+	 * GPIO numberspace for this chip. In the long run we want to
+	 * get *rid* of this numberspace and use only descriptors, but
+	 * it may be a pipe dream. It will not happen before we get rid
+	 * of the sysfs interface anyways.
+	 */
 	if (base < 0) {
 		base = gpiochip_find_base(chip->ngpio);
 		if (base < 0) {
 			status = base;
 			spin_unlock_irqrestore(&gpio_lock, flags);
-			goto err_free_descs;
+			goto err_free_gdev;
 		}
+		/*
+		 * TODO: it should not be necessary to reflect the assigned
+		 * base outside of the GPIO subsystem. Go over drivers and
+		 * see if anyone makes use of this, else drop this and assign
+		 * a poison instead.
+		 */
 		chip->base = base;
 	}
+	gdev->base = base;
 
-	status = gpiochip_add_to_list(chip);
+	status = gpiodev_add_to_list(gdev);
 	if (status) {
 		spin_unlock_irqrestore(&gpio_lock, flags);
-		goto err_free_descs;
+		goto err_free_gdev;
 	}
 
-	for (id = 0; id < chip->ngpio; id++) {
-		struct gpio_desc *desc = &descs[id];
+	for (i = 0; i < chip->ngpio; i++) {
+		struct gpio_desc *desc = &gdev->descs[i];
 
-		desc->chip = chip;
+		desc->gdev = gdev;
 
 		/* REVISIT: most hardware initializes GPIOs as inputs (often
 		 * with pullups enabled) so power usage is minimized. Linux
@@ -370,17 +575,12 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
 		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);
+	INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
 
-	if (!chip->owner && chip->parent && chip->parent->driver)
-		chip->owner = chip->parent->driver->owner;
-
 	status = gpiochip_set_desc_names(chip);
 	if (status)
 		goto err_remove_from_list;
@@ -391,37 +591,73 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
 
 	acpi_gpiochip_add(chip);
 
-	status = gpiochip_sysfs_register(chip);
+	/*
+	 * By first adding the chardev, and then adding the device,
+	 * we get a device node entry in sysfs under
+	 * /sys/bus/gpio/devices/gpiochipN/dev that can be used for
+	 * coldplug of device nodes and other udev business.
+	 */
+	cdev_init(&gdev->chrdev, &gpio_fileops);
+	gdev->chrdev.owner = THIS_MODULE;
+	gdev->chrdev.kobj.parent = &gdev->dev.kobj;
+	gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id);
+	status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1);
+	if (status < 0)
+		chip_warn(chip, "failed to add char device %d:%d\n",
+			  MAJOR(gpio_devt), gdev->id);
+	else
+		chip_dbg(chip, "added GPIO chardev (%d:%d)\n",
+			 MAJOR(gpio_devt), gdev->id);
+	status = device_add(&gdev->dev);
 	if (status)
-		goto err_remove_chip;
+		goto err_remove_chardev;
+
+	status = gpiochip_sysfs_register(gdev);
+	if (status)
+		goto err_remove_device;
 
-	pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
-		chip->base, chip->base + chip->ngpio - 1,
-		chip->label ? : "generic");
+	/* From this point, the .release() function cleans up gpio_device */
+	gdev->dev.release = gpiodevice_release;
+	get_device(&gdev->dev);
+	pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n",
+		 __func__, gdev->base, gdev->base + gdev->ngpio - 1,
+		 dev_name(&gdev->dev), chip->label ? : "generic");
 
 	return 0;
 
+err_remove_device:
+	device_del(&gdev->dev);
+err_remove_chardev:
+	cdev_del(&gdev->chrdev);
 err_remove_chip:
 	acpi_gpiochip_remove(chip);
 	gpiochip_free_hogs(chip);
 	of_gpiochip_remove(chip);
 err_remove_from_list:
 	spin_lock_irqsave(&gpio_lock, flags);
-	list_del(&chip->list);
+	list_del(&gdev->list);
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	chip->desc = NULL;
-err_free_descs:
-	kfree(descs);
-
+err_free_gdev:
+	ida_simple_remove(&gpio_ida, gdev->id);
 	/* 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");
+	       gdev->base, gdev->base + gdev->ngpio - 1,
+	       chip->label ? : "generic");
+	kfree(gdev);
 	return status;
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_data);
 
 /**
+ * gpiochip_get_data() - get per-subdriver data for the chip
+ */
+void *gpiochip_get_data(struct gpio_chip *chip)
+{
+	return chip->gpiodev->data;
+}
+EXPORT_SYMBOL_GPL(gpiochip_get_data);
+
+/**
  * gpiochip_remove() - unregister a gpio_chip
  * @chip: the chip to unregister
  *
@@ -429,39 +665,123 @@ EXPORT_SYMBOL_GPL(gpiochip_add_data);
  */
 void gpiochip_remove(struct gpio_chip *chip)
 {
+	struct gpio_device *gdev = chip->gpiodev;
 	struct gpio_desc *desc;
 	unsigned long	flags;
-	unsigned	id;
+	unsigned	i;
 	bool		requested = false;
 
-	gpiochip_sysfs_unregister(chip);
-
+	/* FIXME: should the legacy sysfs handling be moved to gpio_device? */
+	gpiochip_sysfs_unregister(gdev);
+	/* Numb the device, cancelling all outstanding operations */
+	gdev->chip = NULL;
 	gpiochip_irqchip_remove(chip);
-
 	acpi_gpiochip_remove(chip);
 	gpiochip_remove_pin_ranges(chip);
 	gpiochip_free_hogs(chip);
 	of_gpiochip_remove(chip);
+	/*
+	 * We accept no more calls into the driver from this point, so
+	 * NULL the driver data pointer
+	 */
+	gdev->data = NULL;
 
 	spin_lock_irqsave(&gpio_lock, flags);
-	for (id = 0; id < chip->ngpio; id++) {
-		desc = &chip->desc[id];
-		desc->chip = NULL;
+	for (i = 0; i < gdev->ngpio; i++) {
+		desc = &gdev->descs[i];
 		if (test_bit(FLAG_REQUESTED, &desc->flags))
 			requested = true;
 	}
-	list_del(&chip->list);
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	if (requested)
-		dev_crit(chip->parent,
+		dev_crit(&gdev->dev,
 			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
 
-	kfree(chip->desc);
-	chip->desc = NULL;
+	/*
+	 * The gpiochip side puts its use of the device to rest here:
+	 * if there are no userspace clients, the chardev and device will
+	 * be removed, else it will be dangling until the last user is
+	 * gone.
+	 */
+	put_device(&gdev->dev);
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove);
 
+static void devm_gpio_chip_release(struct device *dev, void *res)
+{
+	struct gpio_chip *chip = *(struct gpio_chip **)res;
+
+	gpiochip_remove(chip);
+}
+
+static int devm_gpio_chip_match(struct device *dev, void *res, void *data)
+
+{
+	struct gpio_chip **r = res;
+
+	if (!r || !*r) {
+		WARN_ON(!r || !*r);
+		return 0;
+	}
+
+	return *r == data;
+}
+
+/**
+ * devm_gpiochip_add_data() - Resource manager piochip_add_data()
+ * @dev: the device pointer on which irq_chip belongs to.
+ * @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.
+ *
+ * The gpio chip automatically be released when the device is unbound.
+ */
+int devm_gpiochip_add_data(struct device *dev, struct gpio_chip *chip,
+			   void *data)
+{
+	struct gpio_chip **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_gpio_chip_release, sizeof(*ptr),
+			     GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = gpiochip_add_data(chip, data);
+	if (ret < 0) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = chip;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_gpiochip_add_data);
+
+/**
+ * devm_gpiochip_remove() - Resource manager of gpiochip_remove()
+ * @dev: device for which which resource was allocated
+ * @chip: the chip to remove
+ *
+ * A gpio_chip with any GPIOs still requested may not be removed.
+ */
+void devm_gpiochip_remove(struct device *dev, struct gpio_chip *chip)
+{
+	int ret;
+
+	ret = devres_release(dev, devm_gpio_chip_release,
+			     devm_gpio_chip_match, chip);
+	if (!ret)
+		WARN_ON(ret);
+}
+EXPORT_SYMBOL_GPL(devm_gpiochip_remove);
+
 /**
  * gpiochip_find() - iterator for locating a specific gpio_chip
  * @data: data to pass to match function
@@ -477,17 +797,21 @@ struct gpio_chip *gpiochip_find(void *data,
 				int (*match)(struct gpio_chip *chip,
 					     void *data))
 {
+	struct gpio_device *gdev;
 	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))
+	list_for_each_entry(gdev, &gpio_devices, list)
+		if (match(gdev->chip, data))
 			break;
 
 	/* No match? */
-	if (&chip->list == &gpio_chips)
+	if (&gdev->list == &gpio_devices)
 		chip = NULL;
+	else
+		chip = gdev->chip;
+
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	return chip;
@@ -617,14 +941,14 @@ static int gpiochip_irq_reqres(struct irq_data *d)
 {
 	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
 
-	if (!try_module_get(chip->owner))
+	if (!try_module_get(chip->gpiodev->owner))
 		return -ENODEV;
 
 	if (gpiochip_lock_as_irq(chip, d->hwirq)) {
 		chip_err(chip,
 			"unable to lock HW IRQ %lu for IRQ\n",
 			d->hwirq);
-		module_put(chip->owner);
+		module_put(chip->gpiodev->owner);
 		return -EINVAL;
 	}
 	return 0;
@@ -635,7 +959,7 @@ 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);
-	module_put(chip->owner);
+	module_put(chip->gpiodev->owner);
 }
 
 static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
@@ -785,7 +1109,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
  */
 int gpiochip_generic_request(struct gpio_chip *chip, unsigned offset)
 {
-	return pinctrl_request_gpio(chip->base + offset);
+	return pinctrl_request_gpio(chip->gpiodev->base + offset);
 }
 EXPORT_SYMBOL_GPL(gpiochip_generic_request);
 
@@ -796,7 +1120,7 @@ EXPORT_SYMBOL_GPL(gpiochip_generic_request);
  */
 void gpiochip_generic_free(struct gpio_chip *chip, unsigned offset)
 {
-	pinctrl_free_gpio(chip->base + offset);
+	pinctrl_free_gpio(chip->gpiodev->base + offset);
 }
 EXPORT_SYMBOL_GPL(gpiochip_generic_free);
 
@@ -814,6 +1138,7 @@ int gpiochip_add_pingroup_range(struct gpio_chip *chip,
 			unsigned int gpio_offset, const char *pin_group)
 {
 	struct gpio_pin_range *pin_range;
+	struct gpio_device *gdev = chip->gpiodev;
 	int ret;
 
 	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
@@ -826,7 +1151,7 @@ int gpiochip_add_pingroup_range(struct gpio_chip *chip,
 	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.base = gdev->base + gpio_offset;
 	pin_range->pctldev = pctldev;
 
 	ret = pinctrl_get_group_pins(pctldev, pin_group,
@@ -843,7 +1168,7 @@ int gpiochip_add_pingroup_range(struct gpio_chip *chip,
 		 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);
+	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
 	return 0;
 }
@@ -863,6 +1188,7 @@ int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 			   unsigned int npins)
 {
 	struct gpio_pin_range *pin_range;
+	struct gpio_device *gdev = chip->gpiodev;
 	int ret;
 
 	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
@@ -875,7 +1201,7 @@ int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 	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.base = gdev->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,
@@ -891,7 +1217,7 @@ int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 		 pinctl_name,
 		 pin_offset, pin_offset + npins - 1);
 
-	list_add_tail(&pin_range->node, &chip->pin_ranges);
+	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
 	return 0;
 }
@@ -904,8 +1230,9 @@ EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
 {
 	struct gpio_pin_range *pin_range, *tmp;
+	struct gpio_device *gdev = chip->gpiodev;
 
-	list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
+	list_for_each_entry_safe(pin_range, tmp, &gdev->pin_ranges, node) {
 		list_del(&pin_range->node);
 		pinctrl_remove_gpio_range(pin_range->pctldev,
 				&pin_range->range);
@@ -922,7 +1249,7 @@ EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
  */
 static int __gpiod_request(struct gpio_desc *desc, const char *label)
 {
-	struct gpio_chip	*chip = desc->chip;
+	struct gpio_chip	*chip = desc->gdev->chip;
 	int			status;
 	unsigned long		flags;
 
@@ -971,27 +1298,50 @@ done:
 	return status;
 }
 
+/*
+ * This descriptor validation needs to be inserted verbatim into each
+ * function taking a descriptor, so we need to use a preprocessor
+ * macro to avoid endless duplication.
+ */
+#define VALIDATE_DESC(desc) do { \
+	if (!desc || !desc->gdev) { \
+		pr_warn("%s: invalid GPIO\n", __func__); \
+		return -EINVAL; \
+	} \
+	if ( !desc->gdev->chip ) { \
+		dev_warn(&desc->gdev->dev, \
+			 "%s: backing chip is gone\n", __func__); \
+		return 0; \
+	} } while (0)
+
+#define VALIDATE_DESC_VOID(desc) do { \
+	if (!desc || !desc->gdev) { \
+		pr_warn("%s: invalid GPIO\n", __func__); \
+		return; \
+	} \
+	if (!desc->gdev->chip) { \
+		dev_warn(&desc->gdev->dev, \
+			 "%s: backing chip is gone\n", __func__); \
+		return; \
+	} } while (0)
+
+
 int gpiod_request(struct gpio_desc *desc, const char *label)
 {
 	int status = -EPROBE_DEFER;
-	struct gpio_chip *chip;
+	struct gpio_device *gdev;
 
-	if (!desc) {
-		pr_warn("%s: invalid GPIO\n", __func__);
-		return -EINVAL;
-	}
+	VALIDATE_DESC(desc);
+	gdev = desc->gdev;
 
-	chip = desc->chip;
-	if (!chip)
-		goto done;
-
-	if (try_module_get(chip->owner)) {
+	if (try_module_get(gdev->owner)) {
 		status = __gpiod_request(desc, label);
 		if (status < 0)
-			module_put(chip->owner);
+			module_put(gdev->owner);
+		else
+			get_device(&gdev->dev);
 	}
 
-done:
 	if (status)
 		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
 
@@ -1010,7 +1360,7 @@ static bool __gpiod_free(struct gpio_desc *desc)
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	chip = desc->chip;
+	chip = desc->gdev->chip;
 	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
 		if (chip->free) {
 			spin_unlock_irqrestore(&gpio_lock, flags);
@@ -1033,10 +1383,12 @@ static bool __gpiod_free(struct gpio_desc *desc)
 
 void gpiod_free(struct gpio_desc *desc)
 {
-	if (desc && __gpiod_free(desc))
-		module_put(desc->chip->owner);
-	else
+	if (desc && desc->gdev && __gpiod_free(desc)) {
+		module_put(desc->gdev->owner);
+		put_device(&desc->gdev->dev);
+	} else {
 		WARN_ON(extra_checks);
+	}
 }
 
 /**
@@ -1059,7 +1411,7 @@ const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
 	if (offset >= chip->ngpio)
 		return NULL;
 
-	desc = &chip->desc[offset];
+	desc = &chip->gpiodev->descs[offset];
 
 	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
 		return NULL;
@@ -1111,7 +1463,8 @@ void gpiochip_free_own_desc(struct gpio_desc *desc)
 }
 EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
 
-/* Drivers MUST set GPIO direction before making get/set calls.  In
+/*
+ * 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
@@ -1134,12 +1487,9 @@ 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;
-	}
+	VALIDATE_DESC(desc);
+	chip = desc->gdev->chip;
 
-	chip = desc->chip;
 	if (!chip->get || !chip->direction_input) {
 		gpiod_warn(desc,
 			"%s: missing get() or direction_input() operations\n",
@@ -1178,7 +1528,7 @@ static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
 		return gpiod_direction_input(desc);
 
-	chip = desc->chip;
+	chip = desc->gdev->chip;
 	if (!chip->set || !chip->direction_output) {
 		gpiod_warn(desc,
 		       "%s: missing set() or direction_output() operations\n",
@@ -1207,10 +1557,7 @@ static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
  */
 int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 {
-	if (!desc || !desc->chip) {
-		pr_warn("%s: invalid GPIO\n", __func__);
-		return -EINVAL;
-	}
+	VALIDATE_DESC(desc);
 	return _gpiod_direction_output_raw(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
@@ -1229,10 +1576,7 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
  */
 int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
-	if (!desc || !desc->chip) {
-		pr_warn("%s: invalid GPIO\n", __func__);
-		return -EINVAL;
-	}
+	VALIDATE_DESC(desc);
 	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 		value = !value;
 	return _gpiod_direction_output_raw(desc, value);
@@ -1251,12 +1595,8 @@ 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;
+	VALIDATE_DESC(desc);
+	chip = desc->gdev->chip;
 	if (!chip->set || !chip->set_debounce) {
 		gpiod_dbg(desc,
 			  "%s: missing set() or set_debounce() operations\n",
@@ -1276,6 +1616,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_debounce);
  */
 int gpiod_is_active_low(const struct gpio_desc *desc)
 {
+	VALIDATE_DESC(desc);
 	return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
 }
 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
@@ -1308,7 +1649,7 @@ static int _gpiod_get_raw_value(const struct gpio_desc *desc)
 	int offset;
 	int value;
 
-	chip = desc->chip;
+	chip = desc->gdev->chip;
 	offset = gpio_chip_hwgpio(desc);
 	value = chip->get ? chip->get(chip, offset) : -EIO;
 	value = value < 0 ? value : !!value;
@@ -1328,10 +1669,9 @@ static int _gpiod_get_raw_value(const struct gpio_desc *desc)
  */
 int gpiod_get_raw_value(const struct gpio_desc *desc)
 {
-	if (!desc)
-		return 0;
+	VALIDATE_DESC(desc);
 	/* Should be using gpio_get_value_cansleep() */
-	WARN_ON(desc->chip->can_sleep);
+	WARN_ON(desc->gdev->chip->can_sleep);
 	return _gpiod_get_raw_value(desc);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
@@ -1349,10 +1689,10 @@ EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
 int gpiod_get_value(const struct gpio_desc *desc)
 {
 	int value;
-	if (!desc)
-		return 0;
+
+	VALIDATE_DESC(desc);
 	/* Should be using gpio_get_value_cansleep() */
-	WARN_ON(desc->chip->can_sleep);
+	WARN_ON(desc->gdev->chip->can_sleep);
 
 	value = _gpiod_get_raw_value(desc);
 	if (value < 0)
@@ -1373,7 +1713,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_value);
 static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
 {
 	int err = 0;
-	struct gpio_chip *chip = desc->chip;
+	struct gpio_chip *chip = desc->gdev->chip;
 	int offset = gpio_chip_hwgpio(desc);
 
 	if (value) {
@@ -1400,7 +1740,7 @@ static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
 static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value)
 {
 	int err = 0;
-	struct gpio_chip *chip = desc->chip;
+	struct gpio_chip *chip = desc->gdev->chip;
 	int offset = gpio_chip_hwgpio(desc);
 
 	if (value) {
@@ -1423,7 +1763,7 @@ static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
 {
 	struct gpio_chip	*chip;
 
-	chip = desc->chip;
+	chip = desc->gdev->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);
@@ -1471,7 +1811,7 @@ static void gpiod_set_array_value_priv(bool raw, bool can_sleep,
 	int i = 0;
 
 	while (i < array_size) {
-		struct gpio_chip *chip = desc_array[i]->chip;
+		struct gpio_chip *chip = desc_array[i]->gdev->chip;
 		unsigned long mask[BITS_TO_LONGS(chip->ngpio)];
 		unsigned long bits[BITS_TO_LONGS(chip->ngpio)];
 		int count = 0;
@@ -1505,7 +1845,8 @@ static void gpiod_set_array_value_priv(bool raw, bool can_sleep,
 				count++;
 			}
 			i++;
-		} while ((i < array_size) && (desc_array[i]->chip == chip));
+		} while ((i < array_size) &&
+			 (desc_array[i]->gdev->chip == chip));
 		/* push collected bits to outputs */
 		if (count != 0)
 			gpio_chip_set_multiple(chip, mask, bits);
@@ -1525,10 +1866,9 @@ static void gpiod_set_array_value_priv(bool raw, bool can_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);
+	VALIDATE_DESC_VOID(desc);
+	/* Should be using gpiod_set_value_cansleep() */
+	WARN_ON(desc->gdev->chip->can_sleep);
 	_gpiod_set_raw_value(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
@@ -1546,10 +1886,9 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
  */
 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);
+	VALIDATE_DESC_VOID(desc);
+	/* Should be using gpiod_set_value_cansleep() */
+	WARN_ON(desc->gdev->chip->can_sleep);
 	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 		value = !value;
 	_gpiod_set_raw_value(desc, value);
@@ -1607,9 +1946,8 @@ EXPORT_SYMBOL_GPL(gpiod_set_array_value);
  */
 int gpiod_cansleep(const struct gpio_desc *desc)
 {
-	if (!desc)
-		return 0;
-	return desc->chip->can_sleep;
+	VALIDATE_DESC(desc);
+	return desc->gdev->chip->can_sleep;
 }
 EXPORT_SYMBOL_GPL(gpiod_cansleep);
 
@@ -1625,9 +1963,8 @@ int gpiod_to_irq(const struct gpio_desc *desc)
 	struct gpio_chip	*chip;
 	int			offset;
 
-	if (!desc)
-		return -EINVAL;
-	chip = desc->chip;
+	VALIDATE_DESC(desc);
+	chip = desc->gdev->chip;
 	offset = gpio_chip_hwgpio(desc);
 	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
 }
@@ -1646,14 +1983,14 @@ 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)) {
+	if (test_bit(FLAG_IS_OUT, &chip->gpiodev->descs[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);
+	set_bit(FLAG_USED_AS_IRQ, &chip->gpiodev->descs[offset].flags);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
@@ -1671,10 +2008,37 @@ 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);
+	clear_bit(FLAG_USED_AS_IRQ, &chip->gpiodev->descs[offset].flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
 
+bool gpiochip_line_is_irq(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return false;
+
+	return test_bit(FLAG_USED_AS_IRQ, &chip->gpiodev->descs[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_irq);
+
+bool gpiochip_line_is_open_drain(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return false;
+
+	return test_bit(FLAG_OPEN_DRAIN, &chip->gpiodev->descs[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_open_drain);
+
+bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return false;
+
+	return test_bit(FLAG_OPEN_SOURCE, &chip->gpiodev->descs[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_open_source);
+
 /**
  * gpiod_get_raw_value_cansleep() - return a gpio's raw value
  * @desc: gpio whose value will be returned
@@ -1687,8 +2051,7 @@ EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
 {
 	might_sleep_if(extra_checks);
-	if (!desc)
-		return 0;
+	VALIDATE_DESC(desc);
 	return _gpiod_get_raw_value(desc);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
@@ -1707,9 +2070,7 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc)
 	int value;
 
 	might_sleep_if(extra_checks);
-	if (!desc)
-		return 0;
-
+	VALIDATE_DESC(desc);
 	value = _gpiod_get_raw_value(desc);
 	if (value < 0)
 		return value;
@@ -1734,8 +2095,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
 {
 	might_sleep_if(extra_checks);
-	if (!desc)
-		return;
+	VALIDATE_DESC_VOID(desc);
 	_gpiod_set_raw_value(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
@@ -1753,9 +2113,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 {
 	might_sleep_if(extra_checks);
-	if (!desc)
-		return;
-
+	VALIDATE_DESC_VOID(desc);
 	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 		value = !value;
 	_gpiod_set_raw_value(desc, value);
@@ -2358,8 +2716,8 @@ 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]);
+		if (test_bit(FLAG_IS_HOGGED, &chip->gpiodev->descs[id].flags))
+			gpiochip_free_own_desc(&chip->gpiodev->descs[id]);
 	}
 }
 
@@ -2456,17 +2814,38 @@ void gpiod_put_array(struct gpio_descs *descs)
 }
 EXPORT_SYMBOL_GPL(gpiod_put_array);
 
+static int __init gpiolib_dev_init(void)
+{
+	int ret;
+
+	/* Register GPIO sysfs bus */
+	ret  = bus_register(&gpio_bus_type);
+	if (ret < 0) {
+		pr_err("gpiolib: could not register GPIO bus type\n");
+		return ret;
+	}
+
+	ret = alloc_chrdev_region(&gpio_devt, 0, GPIO_DEV_MAX, "gpiochip");
+	if (ret < 0) {
+		pr_err("gpiolib: failed to allocate char dev region\n");
+		bus_unregister(&gpio_bus_type);
+	}
+	return ret;
+}
+core_initcall(gpiolib_dev_init);
+
 #ifdef CONFIG_DEBUG_FS
 
-static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 {
 	unsigned		i;
-	unsigned		gpio = chip->base;
-	struct gpio_desc	*gdesc = &chip->desc[0];
+	struct gpio_chip	*chip = gdev->chip;
+	unsigned		gpio = gdev->base;
+	struct gpio_desc	*gdesc = &gdev->descs[0];
 	int			is_out;
 	int			is_irq;
 
-	for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
+	for (i = 0; i < gdev->ngpio; i++, gpio++, gdesc++) {
 		if (!test_bit(FLAG_REQUESTED, &gdesc->flags)) {
 			if (gdesc->name) {
 				seq_printf(s, " gpio-%-3d (%-20.20s)\n",
@@ -2492,16 +2871,16 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 {
 	unsigned long flags;
-	struct gpio_chip *chip = NULL;
+	struct gpio_device *gdev = NULL;
 	loff_t index = *pos;
 
 	s->private = "";
 
 	spin_lock_irqsave(&gpio_lock, flags);
-	list_for_each_entry(chip, &gpio_chips, list)
+	list_for_each_entry(gdev, &gpio_devices, list)
 		if (index-- == 0) {
 			spin_unlock_irqrestore(&gpio_lock, flags);
-			return chip;
+			return gdev;
 		}
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
@@ -2511,14 +2890,14 @@ static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
 	unsigned long flags;
-	struct gpio_chip *chip = v;
+	struct gpio_device *gdev = v;
 	void *ret = NULL;
 
 	spin_lock_irqsave(&gpio_lock, flags);
-	if (list_is_last(&chip->list, &gpio_chips))
+	if (list_is_last(&gdev->list, &gpio_devices))
 		ret = NULL;
 	else
-		ret = list_entry(chip->list.next, struct gpio_chip, list);
+		ret = list_entry(gdev->list.next, struct gpio_device, list);
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	s->private = "\n";
@@ -2533,15 +2912,24 @@ 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;
+	struct gpio_device *gdev = v;
+	struct gpio_chip *chip = gdev->chip;
+	struct device *parent;
+
+	if (!chip) {
+		seq_printf(s, "%s%s: (dangling chip)", (char *)s->private,
+			   dev_name(&gdev->dev));
+		return 0;
+	}
 
-	seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
-			chip->base, chip->base + chip->ngpio - 1);
-	dev = chip->parent;
-	if (dev)
-		seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
-			dev_name(dev));
+	seq_printf(s, "%s%s: GPIOs %d-%d", (char *)s->private,
+		   dev_name(&gdev->dev),
+		   gdev->base, gdev->base + gdev->ngpio - 1);
+	parent = chip->parent;
+	if (parent)
+		seq_printf(s, ", parent: %s/%s",
+			   parent->bus ? parent->bus->name : "no-bus",
+			   dev_name(parent));
 	if (chip->label)
 		seq_printf(s, ", %s", chip->label);
 	if (chip->can_sleep)
@@ -2551,7 +2939,7 @@ static int gpiolib_seq_show(struct seq_file *s, void *v)
 	if (chip->dbg_show)
 		chip->dbg_show(s, chip);
 	else
-		gpiolib_dbg_show(s, chip);
+		gpiolib_dbg_show(s, gdev);
 
 	return 0;
 }