[v2] gpiolib: split character device into gpiolib-cdev
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Message ID 20200602141048.1995-1-warthog618@gmail.com
State New
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  • [v2] gpiolib: split character device into gpiolib-cdev
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Commit Message

Kent Gibson June 2, 2020, 2:10 p.m. UTC
Split the cdev specific functionality out of gpiolib.c and into
gpiolib-cdev.c. This improves the readability and maintainability of both
the cdev and core gpiolib code.

Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>

---
While this patch is complete and ready for review, I don't expect it to
be applied as is. There are a few cdev patches pending merge into 
gpio/devel that are sure to conflict, and it makes more sense to
rebase this on top of them than vice versa. But I thought it would
be worthwhile to get it out for review so it can be ready to be rebased
when the time is right.

Also, this is a naive split. That is, if applied as is, it will lose the
line history of the cdev code.  This is not what I intend, and I
understand can be avoided by encouraging git to remember the history
with a few moves, but I'm unsure how the maintainers would prefer that
to be done.

Bart,
 As this was your idea, I've taken the liberty of adding the Suggested-by.
 I hope that is ok.

Changes in v2:
 - rebased to latest gpio/devel and added base-commit to placate the
  build bot.  The comments above still apply, as there are still a
  couple of commits in gpio/fixes that will conflict.

Kent.

 drivers/gpio/Makefile       |    1 +
 drivers/gpio/gpiolib-cdev.c | 1148 +++++++++++++++++++++++++++++++++++
 drivers/gpio/gpiolib-cdev.h |   11 +
 drivers/gpio/gpiolib.c      | 1112 +--------------------------------
 4 files changed, 1164 insertions(+), 1108 deletions(-)
 create mode 100644 drivers/gpio/gpiolib-cdev.c
 create mode 100644 drivers/gpio/gpiolib-cdev.h


base-commit: a8173820f441ab3e2a45c4bb66b70da9a57a349e

Comments

Bartosz Golaszewski June 4, 2020, 12:04 p.m. UTC | #1
wt., 2 cze 2020 o 16:11 Kent Gibson <warthog618@gmail.com> napisał(a):
>
> Split the cdev specific functionality out of gpiolib.c and into
> gpiolib-cdev.c. This improves the readability and maintainability of both
> the cdev and core gpiolib code.
>
> Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> Signed-off-by: Kent Gibson <warthog618@gmail.com>
>
> ---
> While this patch is complete and ready for review, I don't expect it to
> be applied as is. There are a few cdev patches pending merge into
> gpio/devel that are sure to conflict, and it makes more sense to
> rebase this on top of them than vice versa. But I thought it would
> be worthwhile to get it out for review so it can be ready to be rebased
> when the time is right.
>
> Also, this is a naive split. That is, if applied as is, it will lose the
> line history of the cdev code.  This is not what I intend, and I
> understand can be avoided by encouraging git to remember the history
> with a few moves, but I'm unsure how the maintainers would prefer that
> to be done.
>
> Bart,
>  As this was your idea, I've taken the liberty of adding the Suggested-by.
>  I hope that is ok.
>
> Changes in v2:
>  - rebased to latest gpio/devel and added base-commit to placate the
>   build bot.  The comments above still apply, as there are still a
>   couple of commits in gpio/fixes that will conflict.
>
> Kent.

Thanks for doing this Kent!

This looks mostly good, see a single comment below.

Linus: do you think we can get this in for v5.8? Maybe apply this as
the last patch before your PR?

>
>  drivers/gpio/Makefile       |    1 +
>  drivers/gpio/gpiolib-cdev.c | 1148 +++++++++++++++++++++++++++++++++++
>  drivers/gpio/gpiolib-cdev.h |   11 +
>  drivers/gpio/gpiolib.c      | 1112 +--------------------------------
>  4 files changed, 1164 insertions(+), 1108 deletions(-)
>  create mode 100644 drivers/gpio/gpiolib-cdev.c
>  create mode 100644 drivers/gpio/gpiolib-cdev.h
>
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 65bf3940e33c..b5b58b624f37 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_GPIOLIB)           += gpiolib.o
>  obj-$(CONFIG_GPIOLIB)          += gpiolib-devres.o
>  obj-$(CONFIG_GPIOLIB)          += gpiolib-legacy.o
>  obj-$(CONFIG_GPIOLIB)          += gpiolib-devprop.o
> +obj-$(CONFIG_GPIOLIB)          += gpiolib-cdev.o
>  obj-$(CONFIG_OF_GPIO)          += gpiolib-of.o
>  obj-$(CONFIG_GPIO_SYSFS)       += gpiolib-sysfs.o
>  obj-$(CONFIG_GPIO_ACPI)                += gpiolib-acpi.o
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> new file mode 100644
> index 000000000000..971470bdc9c9
> --- /dev/null
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -0,0 +1,1148 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bitmap.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqreturn.h>
> +#include <linux/spinlock.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/cdev.h>
> +#include <linux/uaccess.h>
> +#include <linux/compat.h>
> +#include <linux/anon_inodes.h>
> +#include <linux/file.h>
> +#include <linux/kfifo.h>
> +#include <linux/poll.h>
> +#include <linux/timekeeping.h>
> +#include <uapi/linux/gpio.h>
> +
> +
> +#include "gpiolib.h"
> +
> +/* Implementation infrastructure for GPIO interfaces.
> + *
> + * The GPIO programming interface allows for inlining speed-critical
> + * get/set operations for common cases, so that access to SOC-integrated
> + * GPIOs can sometimes cost only an instruction or two per bit.
> + */

Is this comment relevant for the character device?

Bartosz
Kent Gibson June 4, 2020, 2:18 p.m. UTC | #2
On Thu, Jun 04, 2020 at 02:04:08PM +0200, Bartosz Golaszewski wrote:
> wt., 2 cze 2020 o 16:11 Kent Gibson <warthog618@gmail.com> napisał(a):
> >
> > Split the cdev specific functionality out of gpiolib.c and into
> > gpiolib-cdev.c. This improves the readability and maintainability of both
> > the cdev and core gpiolib code.
> >
> > Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > Signed-off-by: Kent Gibson <warthog618@gmail.com>
> >
> > ---
> > While this patch is complete and ready for review, I don't expect it to
> > be applied as is. There are a few cdev patches pending merge into
> > gpio/devel that are sure to conflict, and it makes more sense to
> > rebase this on top of them than vice versa. But I thought it would
> > be worthwhile to get it out for review so it can be ready to be rebased
> > when the time is right.
> >
> > Also, this is a naive split. That is, if applied as is, it will lose the
> > line history of the cdev code.  This is not what I intend, and I
> > understand can be avoided by encouraging git to remember the history
> > with a few moves, but I'm unsure how the maintainers would prefer that
> > to be done.
> >
> > Bart,
> >  As this was your idea, I've taken the liberty of adding the Suggested-by.
> >  I hope that is ok.
> >
> > Changes in v2:
> >  - rebased to latest gpio/devel and added base-commit to placate the
> >   build bot.  The comments above still apply, as there are still a
> >   couple of commits in gpio/fixes that will conflict.
> >
> > Kent.
> 
> Thanks for doing this Kent!
> 
> This looks mostly good, see a single comment below.
> 
> Linus: do you think we can get this in for v5.8? Maybe apply this as
> the last patch before your PR?
> 
> >
> >  drivers/gpio/Makefile       |    1 +
> >  drivers/gpio/gpiolib-cdev.c | 1148 +++++++++++++++++++++++++++++++++++
> >  drivers/gpio/gpiolib-cdev.h |   11 +
> >  drivers/gpio/gpiolib.c      | 1112 +--------------------------------
> >  4 files changed, 1164 insertions(+), 1108 deletions(-)
> >  create mode 100644 drivers/gpio/gpiolib-cdev.c
> >  create mode 100644 drivers/gpio/gpiolib-cdev.h
> >
> > diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> > index 65bf3940e33c..b5b58b624f37 100644
> > --- a/drivers/gpio/Makefile
> > +++ b/drivers/gpio/Makefile
> > @@ -7,6 +7,7 @@ obj-$(CONFIG_GPIOLIB)           += gpiolib.o
> >  obj-$(CONFIG_GPIOLIB)          += gpiolib-devres.o
> >  obj-$(CONFIG_GPIOLIB)          += gpiolib-legacy.o
> >  obj-$(CONFIG_GPIOLIB)          += gpiolib-devprop.o
> > +obj-$(CONFIG_GPIOLIB)          += gpiolib-cdev.o
> >  obj-$(CONFIG_OF_GPIO)          += gpiolib-of.o
> >  obj-$(CONFIG_GPIO_SYSFS)       += gpiolib-sysfs.o
> >  obj-$(CONFIG_GPIO_ACPI)                += gpiolib-acpi.o
> > diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> > new file mode 100644
> > index 000000000000..971470bdc9c9
> > --- /dev/null
> > +++ b/drivers/gpio/gpiolib-cdev.c
> > @@ -0,0 +1,1148 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#include <linux/bitmap.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irqreturn.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/device.h>
> > +#include <linux/err.h>
> > +#include <linux/gpio.h>
> > +#include <linux/gpio/driver.h>
> > +#include <linux/pinctrl/consumer.h>
> > +#include <linux/cdev.h>
> > +#include <linux/uaccess.h>
> > +#include <linux/compat.h>
> > +#include <linux/anon_inodes.h>
> > +#include <linux/file.h>
> > +#include <linux/kfifo.h>
> > +#include <linux/poll.h>
> > +#include <linux/timekeeping.h>
> > +#include <uapi/linux/gpio.h>
> > +
> > +
> > +#include "gpiolib.h"
> > +
> > +/* Implementation infrastructure for GPIO interfaces.
> > + *
> > + * The GPIO programming interface allows for inlining speed-critical
> > + * get/set operations for common cases, so that access to SOC-integrated
> > + * GPIOs can sometimes cost only an instruction or two per bit.
> > + */
> 
> Is this comment relevant for the character device?
> 

True - that comment should stay in gpiolib, and gpiolib-cdev should get
one of it's own.

Any suggestions on how to maintain line history?
I know you can trick git by moving the original file into two new ones,
then moving one of those back to the old name, but not sure if that is
what you would want to see in a patch.

Cheers,
Kent.
Bartosz Golaszewski June 4, 2020, 4:22 p.m. UTC | #3
czw., 4 cze 2020 o 16:18 Kent Gibson <warthog618@gmail.com> napisał(a):
>
> >
> > Is this comment relevant for the character device?
> >
>
> True - that comment should stay in gpiolib, and gpiolib-cdev should get
> one of it's own.
>
> Any suggestions on how to maintain line history?
> I know you can trick git by moving the original file into two new ones,
> then moving one of those back to the old name, but not sure if that is
> what you would want to see in a patch.
>

People don't seem to care much about this in the kernel. Files get
moved and git blame results get lost all the time. Don't stress about
it.

Bart
Kent Gibson June 4, 2020, 11:30 p.m. UTC | #4
On Thu, Jun 04, 2020 at 06:22:43PM +0200, Bartosz Golaszewski wrote:
> czw., 4 cze 2020 o 16:18 Kent Gibson <warthog618@gmail.com> napisał(a):
> >
> > >
> > > Is this comment relevant for the character device?
> > >
> >
> > True - that comment should stay in gpiolib, and gpiolib-cdev should get
> > one of it's own.
> >
> > Any suggestions on how to maintain line history?
> > I know you can trick git by moving the original file into two new ones,
> > then moving one of those back to the old name, but not sure if that is
> > what you would want to see in a patch.
> >
> 
> People don't seem to care much about this in the kernel. Files get
> moved and git blame results get lost all the time. Don't stress about
> it.
> 

Oh, ok.  I guess that explains why I couldn't find any examples of how
to do it in a patch - I had thought I wasn't looking hard enough.

There are still a couple of commits in gpio/fixes that will conflict -
are those getting merged into gpio/devel any time soon?
Or is there another branch I should rebase onto?

Cheers,
Kent.
Bartosz Golaszewski June 5, 2020, 9:26 a.m. UTC | #5
pt., 5 cze 2020 o 01:30 Kent Gibson <warthog618@gmail.com> napisał(a):
>
> On Thu, Jun 04, 2020 at 06:22:43PM +0200, Bartosz Golaszewski wrote:
> > czw., 4 cze 2020 o 16:18 Kent Gibson <warthog618@gmail.com> napisał(a):
> > >
> > > >
> > > > Is this comment relevant for the character device?
> > > >
> > >
> > > True - that comment should stay in gpiolib, and gpiolib-cdev should get
> > > one of it's own.
> > >
> > > Any suggestions on how to maintain line history?
> > > I know you can trick git by moving the original file into two new ones,
> > > then moving one of those back to the old name, but not sure if that is
> > > what you would want to see in a patch.
> > >
> >
> > People don't seem to care much about this in the kernel. Files get
> > moved and git blame results get lost all the time. Don't stress about
> > it.
> >
>
> Oh, ok.  I guess that explains why I couldn't find any examples of how
> to do it in a patch - I had thought I wasn't looking hard enough.
>

It's not like this information is lost: once you see (with git blame)
that a file has been moved, you can check out the revision from before
the move and see the file's history. Rinse and repeat if it was moved
more than once.

> There are still a couple of commits in gpio/fixes that will conflict -
> are those getting merged into gpio/devel any time soon?
> Or is there another branch I should rebase onto?
>

Linus W already sent out his main PR to Linus T. Sometimes he does
additional PRs near the end of the merge window so maybe we can get it
in this way?

Bart
Linus Walleij June 10, 2020, 9:13 a.m. UTC | #6
On Tue, Jun 2, 2020 at 4:11 PM Kent Gibson <warthog618@gmail.com> wrote:

> Split the cdev specific functionality out of gpiolib.c and into
> gpiolib-cdev.c. This improves the readability and maintainability of both
> the cdev and core gpiolib code.
>
> Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> Signed-off-by: Kent Gibson <warthog618@gmail.com>

Patch applied as early v5.9 development.

I will include it into linux-next after v5.8-rc1 is out.

Yours,
Linus Walleij
Bartosz Golaszewski June 10, 2020, 9:14 a.m. UTC | #7
śr., 10 cze 2020 o 11:13 Linus Walleij <linus.walleij@linaro.org> napisał(a):
>
> On Tue, Jun 2, 2020 at 4:11 PM Kent Gibson <warthog618@gmail.com> wrote:
>
> > Split the cdev specific functionality out of gpiolib.c and into
> > gpiolib-cdev.c. This improves the readability and maintainability of both
> > the cdev and core gpiolib code.
> >
> > Suggested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > Signed-off-by: Kent Gibson <warthog618@gmail.com>
>
> Patch applied as early v5.9 development.
>
> I will include it into linux-next after v5.8-rc1 is out.
>

Hi Linus,

FYI there's a v3 already on the list with a minor fix.

Bart

Patch
diff mbox series

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 65bf3940e33c..b5b58b624f37 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -7,6 +7,7 @@  obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-devres.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-legacy.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-devprop.o
+obj-$(CONFIG_GPIOLIB)		+= gpiolib-cdev.o
 obj-$(CONFIG_OF_GPIO)		+= gpiolib-of.o
 obj-$(CONFIG_GPIO_SYSFS)	+= gpiolib-sysfs.o
 obj-$(CONFIG_GPIO_ACPI)		+= gpiolib-acpi.o
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
new file mode 100644
index 000000000000..971470bdc9c9
--- /dev/null
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -0,0 +1,1148 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bitmap.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/cdev.h>
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/kfifo.h>
+#include <linux/poll.h>
+#include <linux/timekeeping.h>
+#include <uapi/linux/gpio.h>
+
+
+#include "gpiolib.h"
+
+/* Implementation infrastructure for GPIO interfaces.
+ *
+ * The GPIO programming interface allows for inlining speed-critical
+ * get/set operations for common cases, so that access to SOC-integrated
+ * GPIOs can sometimes cost only an instruction or two per bit.
+ */
+
+/*
+ * GPIO line handle management
+ */
+
+/**
+ * struct linehandle_state - contains the state of a userspace handle
+ * @gdev: the GPIO device the handle pertains to
+ * @label: consumer label used to tag descriptors
+ * @descs: the GPIO descriptors held by this handle
+ * @numdescs: the number of descriptors held in the descs array
+ */
+struct linehandle_state {
+	struct gpio_device *gdev;
+	const char *label;
+	struct gpio_desc *descs[GPIOHANDLES_MAX];
+	u32 numdescs;
+};
+
+#define GPIOHANDLE_REQUEST_VALID_FLAGS \
+	(GPIOHANDLE_REQUEST_INPUT | \
+	GPIOHANDLE_REQUEST_OUTPUT | \
+	GPIOHANDLE_REQUEST_ACTIVE_LOW | \
+	GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
+	GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
+	GPIOHANDLE_REQUEST_BIAS_DISABLE | \
+	GPIOHANDLE_REQUEST_OPEN_DRAIN | \
+	GPIOHANDLE_REQUEST_OPEN_SOURCE)
+
+static int linehandle_validate_flags(u32 flags)
+{
+	/* Return an error if an unknown flag is set */
+	if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
+		return -EINVAL;
+
+	/*
+	 * Do not allow both INPUT & OUTPUT flags to be set as they are
+	 * contradictory.
+	 */
+	if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
+	    (flags & GPIOHANDLE_REQUEST_OUTPUT))
+		return -EINVAL;
+
+	/*
+	 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
+	 * the hardware actually supports enabling both at the same time the
+	 * electrical result would be disastrous.
+	 */
+	if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
+	    (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+		return -EINVAL;
+
+	/* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
+	if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
+	    ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+	     (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
+		return -EINVAL;
+
+	/* Bias flags only allowed for input or output mode. */
+	if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
+	      (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
+	    ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
+	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
+	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
+		return -EINVAL;
+
+	/* Only one bias flag can be set. */
+	if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
+	     (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
+			GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
+	    ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
+	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static long linehandle_set_config(struct linehandle_state *lh,
+				  void __user *ip)
+{
+	struct gpiohandle_config gcnf;
+	struct gpio_desc *desc;
+	int i, ret;
+	u32 lflags;
+	unsigned long *flagsp;
+
+	if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
+		return -EFAULT;
+
+	lflags = gcnf.flags;
+	ret = linehandle_validate_flags(lflags);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < lh->numdescs; i++) {
+		desc = lh->descs[i];
+		flagsp = &desc->flags;
+
+		assign_bit(FLAG_ACTIVE_LOW, flagsp,
+			lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
+
+		assign_bit(FLAG_OPEN_DRAIN, flagsp,
+			lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
+
+		assign_bit(FLAG_OPEN_SOURCE, flagsp,
+			lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
+
+		assign_bit(FLAG_PULL_UP, flagsp,
+			lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
+
+		assign_bit(FLAG_PULL_DOWN, flagsp,
+			lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
+
+		assign_bit(FLAG_BIAS_DISABLE, flagsp,
+			lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
+
+		/*
+		 * Lines have to be requested explicitly for input
+		 * or output, else the line will be treated "as is".
+		 */
+		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+			int val = !!gcnf.default_values[i];
+
+			ret = gpiod_direction_output(desc, val);
+			if (ret)
+				return ret;
+		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+			ret = gpiod_direction_input(desc);
+			if (ret)
+				return ret;
+		}
+
+		atomic_notifier_call_chain(&desc->gdev->notifier,
+					   GPIOLINE_CHANGED_CONFIG, desc);
+	}
+	return 0;
+}
+
+static long linehandle_ioctl(struct file *filep, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct linehandle_state *lh = filep->private_data;
+	void __user *ip = (void __user *)arg;
+	struct gpiohandle_data ghd;
+	DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
+	int i;
+
+	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
+		/* NOTE: It's ok to read values of output lines. */
+		int ret = gpiod_get_array_value_complex(false,
+							true,
+							lh->numdescs,
+							lh->descs,
+							NULL,
+							vals);
+		if (ret)
+			return ret;
+
+		memset(&ghd, 0, sizeof(ghd));
+		for (i = 0; i < lh->numdescs; i++)
+			ghd.values[i] = test_bit(i, vals);
+
+		if (copy_to_user(ip, &ghd, sizeof(ghd)))
+			return -EFAULT;
+
+		return 0;
+	} else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
+		/*
+		 * All line descriptors were created at once with the same
+		 * flags so just check if the first one is really output.
+		 */
+		if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
+			return -EPERM;
+
+		if (copy_from_user(&ghd, ip, sizeof(ghd)))
+			return -EFAULT;
+
+		/* Clamp all values to [0,1] */
+		for (i = 0; i < lh->numdescs; i++)
+			__assign_bit(i, vals, ghd.values[i]);
+
+		/* Reuse the array setting function */
+		return gpiod_set_array_value_complex(false,
+					      true,
+					      lh->numdescs,
+					      lh->descs,
+					      NULL,
+					      vals);
+	} else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
+		return linehandle_set_config(lh, ip);
+	}
+	return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long linehandle_ioctl_compat(struct file *filep, unsigned int cmd,
+			     unsigned long arg)
+{
+	return linehandle_ioctl(filep, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static int linehandle_release(struct inode *inode, struct file *filep)
+{
+	struct linehandle_state *lh = filep->private_data;
+	struct gpio_device *gdev = lh->gdev;
+	int i;
+
+	for (i = 0; i < lh->numdescs; i++)
+		gpiod_free(lh->descs[i]);
+	kfree(lh->label);
+	kfree(lh);
+	put_device(&gdev->dev);
+	return 0;
+}
+
+static const struct file_operations linehandle_fileops = {
+	.release = linehandle_release,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = linehandle_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = linehandle_ioctl_compat,
+#endif
+};
+
+static int linehandle_create(struct gpio_device *gdev, void __user *ip)
+{
+	struct gpiohandle_request handlereq;
+	struct linehandle_state *lh;
+	struct file *file;
+	int fd, i, count = 0, ret;
+	u32 lflags;
+
+	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
+		return -EFAULT;
+	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
+		return -EINVAL;
+
+	lflags = handlereq.flags;
+
+	ret = linehandle_validate_flags(lflags);
+	if (ret)
+		return ret;
+
+	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
+	if (!lh)
+		return -ENOMEM;
+	lh->gdev = gdev;
+	get_device(&gdev->dev);
+
+	/* Make sure this is terminated */
+	handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0';
+	if (strlen(handlereq.consumer_label)) {
+		lh->label = kstrdup(handlereq.consumer_label,
+				    GFP_KERNEL);
+		if (!lh->label) {
+			ret = -ENOMEM;
+			goto out_free_lh;
+		}
+	}
+
+	/* Request each GPIO */
+	for (i = 0; i < handlereq.lines; i++) {
+		u32 offset = handlereq.lineoffsets[i];
+		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+
+		if (IS_ERR(desc)) {
+			ret = PTR_ERR(desc);
+			goto out_free_descs;
+		}
+
+		ret = gpiod_request(desc, lh->label);
+		if (ret)
+			goto out_free_descs;
+		lh->descs[i] = desc;
+		count = i + 1;
+
+		if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
+			set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+		if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN)
+			set_bit(FLAG_OPEN_DRAIN, &desc->flags);
+		if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
+			set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+		if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE)
+			set_bit(FLAG_BIAS_DISABLE, &desc->flags);
+		if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)
+			set_bit(FLAG_PULL_DOWN, &desc->flags);
+		if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)
+			set_bit(FLAG_PULL_UP, &desc->flags);
+
+		ret = gpiod_set_transitory(desc, false);
+		if (ret < 0)
+			goto out_free_descs;
+
+		/*
+		 * Lines have to be requested explicitly for input
+		 * or output, else the line will be treated "as is".
+		 */
+		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
+			int val = !!handlereq.default_values[i];
+
+			ret = gpiod_direction_output(desc, val);
+			if (ret)
+				goto out_free_descs;
+		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+			ret = gpiod_direction_input(desc);
+			if (ret)
+				goto out_free_descs;
+		}
+		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
+			offset);
+	}
+	/* Let i point at the last handle */
+	i--;
+	lh->numdescs = handlereq.lines;
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = fd;
+		goto out_free_descs;
+	}
+
+	file = anon_inode_getfile("gpio-linehandle",
+				  &linehandle_fileops,
+				  lh,
+				  O_RDONLY | O_CLOEXEC);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto out_put_unused_fd;
+	}
+
+	handlereq.fd = fd;
+	if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
+		/*
+		 * fput() will trigger the release() callback, so do not go onto
+		 * the regular error cleanup path here.
+		 */
+		fput(file);
+		put_unused_fd(fd);
+		return -EFAULT;
+	}
+
+	fd_install(fd, file);
+
+	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
+		lh->numdescs);
+
+	return 0;
+
+out_put_unused_fd:
+	put_unused_fd(fd);
+out_free_descs:
+	for (i = 0; i < count; i++)
+		gpiod_free(lh->descs[i]);
+	kfree(lh->label);
+out_free_lh:
+	kfree(lh);
+	put_device(&gdev->dev);
+	return ret;
+}
+
+/*
+ * GPIO line event management
+ */
+
+/**
+ * struct lineevent_state - contains the state of a userspace event
+ * @gdev: the GPIO device the event pertains to
+ * @label: consumer label used to tag descriptors
+ * @desc: the GPIO descriptor held by this event
+ * @eflags: the event flags this line was requested with
+ * @irq: the interrupt that trigger in response to events on this GPIO
+ * @wait: wait queue that handles blocking reads of events
+ * @events: KFIFO for the GPIO events
+ * @timestamp: cache for the timestamp storing it between hardirq
+ * and IRQ thread, used to bring the timestamp close to the actual
+ * event
+ */
+struct lineevent_state {
+	struct gpio_device *gdev;
+	const char *label;
+	struct gpio_desc *desc;
+	u32 eflags;
+	int irq;
+	wait_queue_head_t wait;
+	DECLARE_KFIFO(events, struct gpioevent_data, 16);
+	u64 timestamp;
+};
+
+#define GPIOEVENT_REQUEST_VALID_FLAGS \
+	(GPIOEVENT_REQUEST_RISING_EDGE | \
+	GPIOEVENT_REQUEST_FALLING_EDGE)
+
+static __poll_t lineevent_poll(struct file *filep,
+				   struct poll_table_struct *wait)
+{
+	struct lineevent_state *le = filep->private_data;
+	__poll_t events = 0;
+
+	poll_wait(filep, &le->wait, wait);
+
+	if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+
+static ssize_t lineevent_read(struct file *filep,
+			      char __user *buf,
+			      size_t count,
+			      loff_t *f_ps)
+{
+	struct lineevent_state *le = filep->private_data;
+	struct gpioevent_data ge;
+	ssize_t bytes_read = 0;
+	int ret;
+
+	if (count < sizeof(ge))
+		return -EINVAL;
+
+	do {
+		spin_lock(&le->wait.lock);
+		if (kfifo_is_empty(&le->events)) {
+			if (bytes_read) {
+				spin_unlock(&le->wait.lock);
+				return bytes_read;
+			}
+
+			if (filep->f_flags & O_NONBLOCK) {
+				spin_unlock(&le->wait.lock);
+				return -EAGAIN;
+			}
+
+			ret = wait_event_interruptible_locked(le->wait,
+					!kfifo_is_empty(&le->events));
+			if (ret) {
+				spin_unlock(&le->wait.lock);
+				return ret;
+			}
+		}
+
+		ret = kfifo_out(&le->events, &ge, 1);
+		spin_unlock(&le->wait.lock);
+		if (ret != 1) {
+			/*
+			 * This should never happen - we were holding the lock
+			 * from the moment we learned the fifo is no longer
+			 * empty until now.
+			 */
+			ret = -EIO;
+			break;
+		}
+
+		if (copy_to_user(buf + bytes_read, &ge, sizeof(ge)))
+			return -EFAULT;
+		bytes_read += sizeof(ge);
+	} while (count >= bytes_read + sizeof(ge));
+
+	return bytes_read;
+}
+
+static int lineevent_release(struct inode *inode, struct file *filep)
+{
+	struct lineevent_state *le = filep->private_data;
+	struct gpio_device *gdev = le->gdev;
+
+	free_irq(le->irq, le);
+	gpiod_free(le->desc);
+	kfree(le->label);
+	kfree(le);
+	put_device(&gdev->dev);
+	return 0;
+}
+
+static long lineevent_ioctl(struct file *filep, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct lineevent_state *le = filep->private_data;
+	void __user *ip = (void __user *)arg;
+	struct gpiohandle_data ghd;
+
+	/*
+	 * We can get the value for an event line but not set it,
+	 * because it is input by definition.
+	 */
+	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
+		int val;
+
+		memset(&ghd, 0, sizeof(ghd));
+
+		val = gpiod_get_value_cansleep(le->desc);
+		if (val < 0)
+			return val;
+		ghd.values[0] = val;
+
+		if (copy_to_user(ip, &ghd, sizeof(ghd)))
+			return -EFAULT;
+
+		return 0;
+	}
+	return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long lineevent_ioctl_compat(struct file *filep, unsigned int cmd,
+				   unsigned long arg)
+{
+	return lineevent_ioctl(filep, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations lineevent_fileops = {
+	.release = lineevent_release,
+	.read = lineevent_read,
+	.poll = lineevent_poll,
+	.owner = THIS_MODULE,
+	.llseek = noop_llseek,
+	.unlocked_ioctl = lineevent_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = lineevent_ioctl_compat,
+#endif
+};
+
+static irqreturn_t lineevent_irq_thread(int irq, void *p)
+{
+	struct lineevent_state *le = p;
+	struct gpioevent_data ge;
+	int ret;
+
+	/* Do not leak kernel stack to userspace */
+	memset(&ge, 0, sizeof(ge));
+
+	/*
+	 * We may be running from a nested threaded interrupt in which case
+	 * we didn't get the timestamp from lineevent_irq_handler().
+	 */
+	if (!le->timestamp)
+		ge.timestamp = ktime_get_ns();
+	else
+		ge.timestamp = le->timestamp;
+
+	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
+	    && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+		int level = gpiod_get_value_cansleep(le->desc);
+
+		if (level)
+			/* Emit low-to-high event */
+			ge.id = GPIOEVENT_EVENT_RISING_EDGE;
+		else
+			/* Emit high-to-low event */
+			ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
+	} else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
+		/* Emit low-to-high event */
+		ge.id = GPIOEVENT_EVENT_RISING_EDGE;
+	} else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+		/* Emit high-to-low event */
+		ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
+	} else {
+		return IRQ_NONE;
+	}
+
+	ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
+					    1, &le->wait.lock);
+	if (ret)
+		wake_up_poll(&le->wait, EPOLLIN);
+	else
+		pr_debug_ratelimited("event FIFO is full - event dropped\n");
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t lineevent_irq_handler(int irq, void *p)
+{
+	struct lineevent_state *le = p;
+
+	/*
+	 * Just store the timestamp in hardirq context so we get it as
+	 * close in time as possible to the actual event.
+	 */
+	le->timestamp = ktime_get_ns();
+
+	return IRQ_WAKE_THREAD;
+}
+
+static int lineevent_create(struct gpio_device *gdev, void __user *ip)
+{
+	struct gpioevent_request eventreq;
+	struct lineevent_state *le;
+	struct gpio_desc *desc;
+	struct file *file;
+	u32 offset;
+	u32 lflags;
+	u32 eflags;
+	int fd;
+	int ret;
+	int irqflags = 0;
+
+	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
+		return -EFAULT;
+
+	offset = eventreq.lineoffset;
+	lflags = eventreq.handleflags;
+	eflags = eventreq.eventflags;
+
+	desc = gpiochip_get_desc(gdev->chip, offset);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	/* Return an error if a unknown flag is set */
+	if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
+	    (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
+		return -EINVAL;
+
+	/* This is just wrong: we don't look for events on output lines */
+	if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+		return -EINVAL;
+
+	/* Only one bias flag can be set. */
+	if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
+	     (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
+			GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
+	    ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
+	     (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
+		return -EINVAL;
+
+	le = kzalloc(sizeof(*le), GFP_KERNEL);
+	if (!le)
+		return -ENOMEM;
+	le->gdev = gdev;
+	get_device(&gdev->dev);
+
+	/* Make sure this is terminated */
+	eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0';
+	if (strlen(eventreq.consumer_label)) {
+		le->label = kstrdup(eventreq.consumer_label,
+				    GFP_KERNEL);
+		if (!le->label) {
+			ret = -ENOMEM;
+			goto out_free_le;
+		}
+	}
+
+	ret = gpiod_request(desc, le->label);
+	if (ret)
+		goto out_free_label;
+	le->desc = desc;
+	le->eflags = eflags;
+
+	if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
+		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+	if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE)
+		set_bit(FLAG_BIAS_DISABLE, &desc->flags);
+	if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)
+		set_bit(FLAG_PULL_DOWN, &desc->flags);
+	if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)
+		set_bit(FLAG_PULL_UP, &desc->flags);
+
+	ret = gpiod_direction_input(desc);
+	if (ret)
+		goto out_free_desc;
+
+	le->irq = gpiod_to_irq(desc);
+	if (le->irq <= 0) {
+		ret = -ENODEV;
+		goto out_free_desc;
+	}
+
+	if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
+		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+	if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
+		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+	irqflags |= IRQF_ONESHOT;
+
+	INIT_KFIFO(le->events);
+	init_waitqueue_head(&le->wait);
+
+	/* Request a thread to read the events */
+	ret = request_threaded_irq(le->irq,
+			lineevent_irq_handler,
+			lineevent_irq_thread,
+			irqflags,
+			le->label,
+			le);
+	if (ret)
+		goto out_free_desc;
+
+	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = fd;
+		goto out_free_irq;
+	}
+
+	file = anon_inode_getfile("gpio-event",
+				  &lineevent_fileops,
+				  le,
+				  O_RDONLY | O_CLOEXEC);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto out_put_unused_fd;
+	}
+
+	eventreq.fd = fd;
+	if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
+		/*
+		 * fput() will trigger the release() callback, so do not go onto
+		 * the regular error cleanup path here.
+		 */
+		fput(file);
+		put_unused_fd(fd);
+		return -EFAULT;
+	}
+
+	fd_install(fd, file);
+
+	return 0;
+
+out_put_unused_fd:
+	put_unused_fd(fd);
+out_free_irq:
+	free_irq(le->irq, le);
+out_free_desc:
+	gpiod_free(le->desc);
+out_free_label:
+	kfree(le->label);
+out_free_le:
+	kfree(le);
+	put_device(&gdev->dev);
+	return ret;
+}
+
+static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
+				  struct gpioline_info *info)
+{
+	struct gpio_chip *gc = desc->gdev->chip;
+	bool ok_for_pinctrl;
+	unsigned long flags;
+
+	/*
+	 * This function takes a mutex so we must check this before taking
+	 * the spinlock.
+	 *
+	 * FIXME: find a non-racy way to retrieve this information. Maybe a
+	 * lock common to both frameworks?
+	 */
+	ok_for_pinctrl =
+		pinctrl_gpio_can_use_line(gc->base + info->line_offset);
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	if (desc->name) {
+		strncpy(info->name, desc->name, sizeof(info->name));
+		info->name[sizeof(info->name) - 1] = '\0';
+	} else {
+		info->name[0] = '\0';
+	}
+
+	if (desc->label) {
+		strncpy(info->consumer, desc->label, sizeof(info->consumer));
+		info->consumer[sizeof(info->consumer) - 1] = '\0';
+	} else {
+		info->consumer[0] = '\0';
+	}
+
+	/*
+	 * Userspace only need to know that the kernel is using this GPIO so
+	 * it can't use it.
+	 */
+	info->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) ||
+	    !ok_for_pinctrl)
+		info->flags |= GPIOLINE_FLAG_KERNEL;
+	if (test_bit(FLAG_IS_OUT, &desc->flags))
+		info->flags |= GPIOLINE_FLAG_IS_OUT;
+	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+		info->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
+	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+		info->flags |= (GPIOLINE_FLAG_OPEN_DRAIN |
+				GPIOLINE_FLAG_IS_OUT);
+	if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+		info->flags |= (GPIOLINE_FLAG_OPEN_SOURCE |
+				GPIOLINE_FLAG_IS_OUT);
+	if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
+		info->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
+	if (test_bit(FLAG_PULL_DOWN, &desc->flags))
+		info->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
+	if (test_bit(FLAG_PULL_UP, &desc->flags))
+		info->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+}
+
+struct gpio_chardev_data {
+	struct gpio_device *gdev;
+	wait_queue_head_t wait;
+	DECLARE_KFIFO(events, struct gpioline_info_changed, 32);
+	struct notifier_block lineinfo_changed_nb;
+	unsigned long *watched_lines;
+};
+
+/*
+ * gpio_ioctl() - ioctl handler for the GPIO chardev
+ */
+static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct gpio_chardev_data *priv = filp->private_data;
+	struct gpio_device *gdev = priv->gdev;
+	struct gpio_chip *gc = gdev->chip;
+	void __user *ip = (void __user *)arg;
+	struct gpio_desc *desc;
+	__u32 offset;
+	int hwgpio;
+
+	/* We fail any subsequent ioctl():s when the chip is gone */
+	if (!gc)
+		return -ENODEV;
+
+	/* Fill in the struct and pass to userspace */
+	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
+		struct gpiochip_info chipinfo;
+
+		memset(&chipinfo, 0, sizeof(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;
+
+		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+			return -EFAULT;
+
+		desc = gpiochip_get_desc(gc, lineinfo.line_offset);
+		if (IS_ERR(desc))
+			return PTR_ERR(desc);
+
+		hwgpio = gpio_chip_hwgpio(desc);
+
+		gpio_desc_to_lineinfo(desc, &lineinfo);
+
+		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
+			return -EFAULT;
+		return 0;
+	} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
+		return linehandle_create(gdev, ip);
+	} else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
+		return lineevent_create(gdev, ip);
+	} else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
+		struct gpioline_info lineinfo;
+
+		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+			return -EFAULT;
+
+		desc = gpiochip_get_desc(gc, lineinfo.line_offset);
+		if (IS_ERR(desc))
+			return PTR_ERR(desc);
+
+		hwgpio = gpio_chip_hwgpio(desc);
+
+		if (test_bit(hwgpio, priv->watched_lines))
+			return -EBUSY;
+
+		gpio_desc_to_lineinfo(desc, &lineinfo);
+
+		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
+			return -EFAULT;
+
+		set_bit(hwgpio, priv->watched_lines);
+		return 0;
+	} else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
+		if (copy_from_user(&offset, ip, sizeof(offset)))
+			return -EFAULT;
+
+		desc = gpiochip_get_desc(gc, offset);
+		if (IS_ERR(desc))
+			return PTR_ERR(desc);
+
+		hwgpio = gpio_chip_hwgpio(desc);
+
+		if (!test_bit(hwgpio, priv->watched_lines))
+			return -EBUSY;
+
+		clear_bit(hwgpio, priv->watched_lines);
+		return 0;
+	}
+	return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long gpio_ioctl_compat(struct file *filp, unsigned int cmd,
+			      unsigned long arg)
+{
+	return gpio_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static struct gpio_chardev_data *
+to_gpio_chardev_data(struct notifier_block *nb)
+{
+	return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
+}
+
+static int lineinfo_changed_notify(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	struct gpio_chardev_data *priv = to_gpio_chardev_data(nb);
+	struct gpioline_info_changed chg;
+	struct gpio_desc *desc = data;
+	int ret;
+
+	if (!test_bit(gpio_chip_hwgpio(desc), priv->watched_lines))
+		return NOTIFY_DONE;
+
+	memset(&chg, 0, sizeof(chg));
+	chg.info.line_offset = gpio_chip_hwgpio(desc);
+	chg.event_type = action;
+	chg.timestamp = ktime_get_ns();
+	gpio_desc_to_lineinfo(desc, &chg.info);
+
+	ret = kfifo_in_spinlocked(&priv->events, &chg, 1, &priv->wait.lock);
+	if (ret)
+		wake_up_poll(&priv->wait, EPOLLIN);
+	else
+		pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
+
+	return NOTIFY_OK;
+}
+
+static __poll_t lineinfo_watch_poll(struct file *filep,
+				    struct poll_table_struct *pollt)
+{
+	struct gpio_chardev_data *priv = filep->private_data;
+	__poll_t events = 0;
+
+	poll_wait(filep, &priv->wait, pollt);
+
+	if (!kfifo_is_empty_spinlocked_noirqsave(&priv->events,
+						 &priv->wait.lock))
+		events = EPOLLIN | EPOLLRDNORM;
+
+	return events;
+}
+
+static ssize_t lineinfo_watch_read(struct file *filep, char __user *buf,
+				   size_t count, loff_t *off)
+{
+	struct gpio_chardev_data *priv = filep->private_data;
+	struct gpioline_info_changed event;
+	ssize_t bytes_read = 0;
+	int ret;
+
+	if (count < sizeof(event))
+		return -EINVAL;
+
+	do {
+		spin_lock(&priv->wait.lock);
+		if (kfifo_is_empty(&priv->events)) {
+			if (bytes_read) {
+				spin_unlock(&priv->wait.lock);
+				return bytes_read;
+			}
+
+			if (filep->f_flags & O_NONBLOCK) {
+				spin_unlock(&priv->wait.lock);
+				return -EAGAIN;
+			}
+
+			ret = wait_event_interruptible_locked(priv->wait,
+					!kfifo_is_empty(&priv->events));
+			if (ret) {
+				spin_unlock(&priv->wait.lock);
+				return ret;
+			}
+		}
+
+		ret = kfifo_out(&priv->events, &event, 1);
+		spin_unlock(&priv->wait.lock);
+		if (ret != 1) {
+			ret = -EIO;
+			break;
+			/* We should never get here. See lineevent_read(). */
+		}
+
+		if (copy_to_user(buf + bytes_read, &event, sizeof(event)))
+			return -EFAULT;
+		bytes_read += sizeof(event);
+	} while (count >= bytes_read + sizeof(event));
+
+	return bytes_read;
+}
+
+/**
+ * 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);
+	struct gpio_chardev_data *priv;
+	int ret = -ENOMEM;
+
+	/* Fail on open if the backing gpiochip is gone */
+	if (!gdev->chip)
+		return -ENODEV;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
+	if (!priv->watched_lines)
+		goto out_free_priv;
+
+	init_waitqueue_head(&priv->wait);
+	INIT_KFIFO(priv->events);
+	priv->gdev = gdev;
+
+	priv->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
+	ret = atomic_notifier_chain_register(&gdev->notifier,
+					     &priv->lineinfo_changed_nb);
+	if (ret)
+		goto out_free_bitmap;
+
+	get_device(&gdev->dev);
+	filp->private_data = priv;
+
+	ret = nonseekable_open(inode, filp);
+	if (ret)
+		goto out_unregister_notifier;
+
+	return ret;
+
+out_unregister_notifier:
+	atomic_notifier_chain_unregister(&gdev->notifier,
+					 &priv->lineinfo_changed_nb);
+out_free_bitmap:
+	bitmap_free(priv->watched_lines);
+out_free_priv:
+	kfree(priv);
+	return ret;
+}
+
+/**
+ * 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_chardev_data *priv = filp->private_data;
+	struct gpio_device *gdev = priv->gdev;
+
+	bitmap_free(priv->watched_lines);
+	atomic_notifier_chain_unregister(&gdev->notifier,
+					 &priv->lineinfo_changed_nb);
+	put_device(&gdev->dev);
+	kfree(priv);
+
+	return 0;
+}
+
+static const struct file_operations gpio_fileops = {
+	.release = gpio_chrdev_release,
+	.open = gpio_chrdev_open,
+	.poll = lineinfo_watch_poll,
+	.read = lineinfo_watch_read,
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.unlocked_ioctl = gpio_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = gpio_ioctl_compat,
+#endif
+};
+
+int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
+{
+	int ret;
+
+	cdev_init(&gdev->chrdev, &gpio_fileops);
+	gdev->chrdev.owner = THIS_MODULE;
+	gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
+
+	ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
+	if (ret)
+		return ret;
+
+	chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
+		 MAJOR(devt), gdev->id);
+
+	return 0;
+}
+
+void gpiolib_cdev_unregister(struct gpio_device *gdev)
+{
+	cdev_device_del(&gdev->chrdev, &gdev->dev);
+}
diff --git a/drivers/gpio/gpiolib-cdev.h b/drivers/gpio/gpiolib-cdev.h
new file mode 100644
index 000000000000..973578e7ad10
--- /dev/null
+++ b/drivers/gpio/gpiolib-cdev.h
@@ -0,0 +1,11 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef GPIOLIB_CDEV_H
+#define GPIOLIB_CDEV_H
+
+#include <linux/device.h>
+
+int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt);
+void gpiolib_cdev_unregister(struct gpio_device *gdev);
+
+#endif /* GPIOLIB_CDEV_H */
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 167860684be6..5e20f0cb5252 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -17,20 +17,15 @@ 
 #include <linux/gpio/driver.h>
 #include <linux/gpio/machine.h>
 #include <linux/pinctrl/consumer.h>
-#include <linux/cdev.h>
 #include <linux/fs.h>
-#include <linux/uaccess.h>
 #include <linux/compat.h>
-#include <linux/anon_inodes.h>
 #include <linux/file.h>
-#include <linux/kfifo.h>
-#include <linux/poll.h>
-#include <linux/timekeeping.h>
 #include <uapi/linux/gpio.h>
 
 #include "gpiolib.h"
 #include "gpiolib-of.h"
 #include "gpiolib-acpi.h"
+#include "gpiolib-cdev.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/gpio.h>
@@ -425,1098 +420,6 @@  bool gpiochip_line_is_valid(const struct gpio_chip *gc,
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
 
-/*
- * GPIO line handle management
- */
-
-/**
- * struct linehandle_state - contains the state of a userspace handle
- * @gdev: the GPIO device the handle pertains to
- * @label: consumer label used to tag descriptors
- * @descs: the GPIO descriptors held by this handle
- * @numdescs: the number of descriptors held in the descs array
- */
-struct linehandle_state {
-	struct gpio_device *gdev;
-	const char *label;
-	struct gpio_desc *descs[GPIOHANDLES_MAX];
-	u32 numdescs;
-};
-
-#define GPIOHANDLE_REQUEST_VALID_FLAGS \
-	(GPIOHANDLE_REQUEST_INPUT | \
-	GPIOHANDLE_REQUEST_OUTPUT | \
-	GPIOHANDLE_REQUEST_ACTIVE_LOW | \
-	GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
-	GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
-	GPIOHANDLE_REQUEST_BIAS_DISABLE | \
-	GPIOHANDLE_REQUEST_OPEN_DRAIN | \
-	GPIOHANDLE_REQUEST_OPEN_SOURCE)
-
-static int linehandle_validate_flags(u32 flags)
-{
-	/* Return an error if an unknown flag is set */
-	if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
-		return -EINVAL;
-
-	/*
-	 * Do not allow both INPUT & OUTPUT flags to be set as they are
-	 * contradictory.
-	 */
-	if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
-	    (flags & GPIOHANDLE_REQUEST_OUTPUT))
-		return -EINVAL;
-
-	/*
-	 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
-	 * the hardware actually supports enabling both at the same time the
-	 * electrical result would be disastrous.
-	 */
-	if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
-	    (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
-		return -EINVAL;
-
-	/* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
-	if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
-	    ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
-	     (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
-		return -EINVAL;
-
-	/* Bias flags only allowed for input or output mode. */
-	if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
-	      (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
-	    ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
-	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
-	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
-		return -EINVAL;
-
-	/* Only one bias flag can be set. */
-	if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
-	     (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
-			GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
-	    ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
-	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
-		return -EINVAL;
-
-	return 0;
-}
-
-static long linehandle_set_config(struct linehandle_state *lh,
-				  void __user *ip)
-{
-	struct gpiohandle_config gcnf;
-	struct gpio_desc *desc;
-	int i, ret;
-	u32 lflags;
-	unsigned long *flagsp;
-
-	if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
-		return -EFAULT;
-
-	lflags = gcnf.flags;
-	ret = linehandle_validate_flags(lflags);
-	if (ret)
-		return ret;
-
-	for (i = 0; i < lh->numdescs; i++) {
-		desc = lh->descs[i];
-		flagsp = &desc->flags;
-
-		assign_bit(FLAG_ACTIVE_LOW, flagsp,
-			lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
-
-		assign_bit(FLAG_OPEN_DRAIN, flagsp,
-			lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
-
-		assign_bit(FLAG_OPEN_SOURCE, flagsp,
-			lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
-
-		assign_bit(FLAG_PULL_UP, flagsp,
-			lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
-
-		assign_bit(FLAG_PULL_DOWN, flagsp,
-			lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
-
-		assign_bit(FLAG_BIAS_DISABLE, flagsp,
-			lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
-
-		/*
-		 * Lines have to be requested explicitly for input
-		 * or output, else the line will be treated "as is".
-		 */
-		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
-			int val = !!gcnf.default_values[i];
-
-			ret = gpiod_direction_output(desc, val);
-			if (ret)
-				return ret;
-		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
-			ret = gpiod_direction_input(desc);
-			if (ret)
-				return ret;
-		}
-
-		atomic_notifier_call_chain(&desc->gdev->notifier,
-					   GPIOLINE_CHANGED_CONFIG, desc);
-	}
-	return 0;
-}
-
-static long linehandle_ioctl(struct file *filep, unsigned int cmd,
-			     unsigned long arg)
-{
-	struct linehandle_state *lh = filep->private_data;
-	void __user *ip = (void __user *)arg;
-	struct gpiohandle_data ghd;
-	DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
-	int i;
-
-	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
-		/* NOTE: It's ok to read values of output lines. */
-		int ret = gpiod_get_array_value_complex(false,
-							true,
-							lh->numdescs,
-							lh->descs,
-							NULL,
-							vals);
-		if (ret)
-			return ret;
-
-		memset(&ghd, 0, sizeof(ghd));
-		for (i = 0; i < lh->numdescs; i++)
-			ghd.values[i] = test_bit(i, vals);
-
-		if (copy_to_user(ip, &ghd, sizeof(ghd)))
-			return -EFAULT;
-
-		return 0;
-	} else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
-		/*
-		 * All line descriptors were created at once with the same
-		 * flags so just check if the first one is really output.
-		 */
-		if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
-			return -EPERM;
-
-		if (copy_from_user(&ghd, ip, sizeof(ghd)))
-			return -EFAULT;
-
-		/* Clamp all values to [0,1] */
-		for (i = 0; i < lh->numdescs; i++)
-			__assign_bit(i, vals, ghd.values[i]);
-
-		/* Reuse the array setting function */
-		return gpiod_set_array_value_complex(false,
-					      true,
-					      lh->numdescs,
-					      lh->descs,
-					      NULL,
-					      vals);
-	} else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
-		return linehandle_set_config(lh, ip);
-	}
-	return -EINVAL;
-}
-
-#ifdef CONFIG_COMPAT
-static long linehandle_ioctl_compat(struct file *filep, unsigned int cmd,
-			     unsigned long arg)
-{
-	return linehandle_ioctl(filep, cmd, (unsigned long)compat_ptr(arg));
-}
-#endif
-
-static int linehandle_release(struct inode *inode, struct file *filep)
-{
-	struct linehandle_state *lh = filep->private_data;
-	struct gpio_device *gdev = lh->gdev;
-	int i;
-
-	for (i = 0; i < lh->numdescs; i++)
-		gpiod_free(lh->descs[i]);
-	kfree(lh->label);
-	kfree(lh);
-	put_device(&gdev->dev);
-	return 0;
-}
-
-static const struct file_operations linehandle_fileops = {
-	.release = linehandle_release,
-	.owner = THIS_MODULE,
-	.llseek = noop_llseek,
-	.unlocked_ioctl = linehandle_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl = linehandle_ioctl_compat,
-#endif
-};
-
-static int linehandle_create(struct gpio_device *gdev, void __user *ip)
-{
-	struct gpiohandle_request handlereq;
-	struct linehandle_state *lh;
-	struct file *file;
-	int fd, i, count = 0, ret;
-	u32 lflags;
-
-	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
-		return -EFAULT;
-	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
-		return -EINVAL;
-
-	lflags = handlereq.flags;
-
-	ret = linehandle_validate_flags(lflags);
-	if (ret)
-		return ret;
-
-	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
-	if (!lh)
-		return -ENOMEM;
-	lh->gdev = gdev;
-	get_device(&gdev->dev);
-
-	/* Make sure this is terminated */
-	handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0';
-	if (strlen(handlereq.consumer_label)) {
-		lh->label = kstrdup(handlereq.consumer_label,
-				    GFP_KERNEL);
-		if (!lh->label) {
-			ret = -ENOMEM;
-			goto out_free_lh;
-		}
-	}
-
-	/* Request each GPIO */
-	for (i = 0; i < handlereq.lines; i++) {
-		u32 offset = handlereq.lineoffsets[i];
-		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
-
-		if (IS_ERR(desc)) {
-			ret = PTR_ERR(desc);
-			goto out_free_descs;
-		}
-
-		ret = gpiod_request(desc, lh->label);
-		if (ret)
-			goto out_free_descs;
-		lh->descs[i] = desc;
-		count = i + 1;
-
-		if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
-			set_bit(FLAG_ACTIVE_LOW, &desc->flags);
-		if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN)
-			set_bit(FLAG_OPEN_DRAIN, &desc->flags);
-		if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
-			set_bit(FLAG_OPEN_SOURCE, &desc->flags);
-		if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE)
-			set_bit(FLAG_BIAS_DISABLE, &desc->flags);
-		if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)
-			set_bit(FLAG_PULL_DOWN, &desc->flags);
-		if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)
-			set_bit(FLAG_PULL_UP, &desc->flags);
-
-		ret = gpiod_set_transitory(desc, false);
-		if (ret < 0)
-			goto out_free_descs;
-
-		/*
-		 * Lines have to be requested explicitly for input
-		 * or output, else the line will be treated "as is".
-		 */
-		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
-			int val = !!handlereq.default_values[i];
-
-			ret = gpiod_direction_output(desc, val);
-			if (ret)
-				goto out_free_descs;
-		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
-			ret = gpiod_direction_input(desc);
-			if (ret)
-				goto out_free_descs;
-		}
-		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
-			offset);
-	}
-	/* Let i point at the last handle */
-	i--;
-	lh->numdescs = handlereq.lines;
-
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
-	if (fd < 0) {
-		ret = fd;
-		goto out_free_descs;
-	}
-
-	file = anon_inode_getfile("gpio-linehandle",
-				  &linehandle_fileops,
-				  lh,
-				  O_RDONLY | O_CLOEXEC);
-	if (IS_ERR(file)) {
-		ret = PTR_ERR(file);
-		goto out_put_unused_fd;
-	}
-
-	handlereq.fd = fd;
-	if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
-		/*
-		 * fput() will trigger the release() callback, so do not go onto
-		 * the regular error cleanup path here.
-		 */
-		fput(file);
-		put_unused_fd(fd);
-		return -EFAULT;
-	}
-
-	fd_install(fd, file);
-
-	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
-		lh->numdescs);
-
-	return 0;
-
-out_put_unused_fd:
-	put_unused_fd(fd);
-out_free_descs:
-	for (i = 0; i < count; i++)
-		gpiod_free(lh->descs[i]);
-	kfree(lh->label);
-out_free_lh:
-	kfree(lh);
-	put_device(&gdev->dev);
-	return ret;
-}
-
-/*
- * GPIO line event management
- */
-
-/**
- * struct lineevent_state - contains the state of a userspace event
- * @gdev: the GPIO device the event pertains to
- * @label: consumer label used to tag descriptors
- * @desc: the GPIO descriptor held by this event
- * @eflags: the event flags this line was requested with
- * @irq: the interrupt that trigger in response to events on this GPIO
- * @wait: wait queue that handles blocking reads of events
- * @events: KFIFO for the GPIO events
- * @timestamp: cache for the timestamp storing it between hardirq
- * and IRQ thread, used to bring the timestamp close to the actual
- * event
- */
-struct lineevent_state {
-	struct gpio_device *gdev;
-	const char *label;
-	struct gpio_desc *desc;
-	u32 eflags;
-	int irq;
-	wait_queue_head_t wait;
-	DECLARE_KFIFO(events, struct gpioevent_data, 16);
-	u64 timestamp;
-};
-
-#define GPIOEVENT_REQUEST_VALID_FLAGS \
-	(GPIOEVENT_REQUEST_RISING_EDGE | \
-	GPIOEVENT_REQUEST_FALLING_EDGE)
-
-static __poll_t lineevent_poll(struct file *filep,
-				   struct poll_table_struct *wait)
-{
-	struct lineevent_state *le = filep->private_data;
-	__poll_t events = 0;
-
-	poll_wait(filep, &le->wait, wait);
-
-	if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
-		events = EPOLLIN | EPOLLRDNORM;
-
-	return events;
-}
-
-
-static ssize_t lineevent_read(struct file *filep,
-			      char __user *buf,
-			      size_t count,
-			      loff_t *f_ps)
-{
-	struct lineevent_state *le = filep->private_data;
-	struct gpioevent_data ge;
-	ssize_t bytes_read = 0;
-	int ret;
-
-	if (count < sizeof(ge))
-		return -EINVAL;
-
-	do {
-		spin_lock(&le->wait.lock);
-		if (kfifo_is_empty(&le->events)) {
-			if (bytes_read) {
-				spin_unlock(&le->wait.lock);
-				return bytes_read;
-			}
-
-			if (filep->f_flags & O_NONBLOCK) {
-				spin_unlock(&le->wait.lock);
-				return -EAGAIN;
-			}
-
-			ret = wait_event_interruptible_locked(le->wait,
-					!kfifo_is_empty(&le->events));
-			if (ret) {
-				spin_unlock(&le->wait.lock);
-				return ret;
-			}
-		}
-
-		ret = kfifo_out(&le->events, &ge, 1);
-		spin_unlock(&le->wait.lock);
-		if (ret != 1) {
-			/*
-			 * This should never happen - we were holding the lock
-			 * from the moment we learned the fifo is no longer
-			 * empty until now.
-			 */
-			ret = -EIO;
-			break;
-		}
-
-		if (copy_to_user(buf + bytes_read, &ge, sizeof(ge)))
-			return -EFAULT;
-		bytes_read += sizeof(ge);
-	} while (count >= bytes_read + sizeof(ge));
-
-	return bytes_read;
-}
-
-static int lineevent_release(struct inode *inode, struct file *filep)
-{
-	struct lineevent_state *le = filep->private_data;
-	struct gpio_device *gdev = le->gdev;
-
-	free_irq(le->irq, le);
-	gpiod_free(le->desc);
-	kfree(le->label);
-	kfree(le);
-	put_device(&gdev->dev);
-	return 0;
-}
-
-static long lineevent_ioctl(struct file *filep, unsigned int cmd,
-			    unsigned long arg)
-{
-	struct lineevent_state *le = filep->private_data;
-	void __user *ip = (void __user *)arg;
-	struct gpiohandle_data ghd;
-
-	/*
-	 * We can get the value for an event line but not set it,
-	 * because it is input by definition.
-	 */
-	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
-		int val;
-
-		memset(&ghd, 0, sizeof(ghd));
-
-		val = gpiod_get_value_cansleep(le->desc);
-		if (val < 0)
-			return val;
-		ghd.values[0] = val;
-
-		if (copy_to_user(ip, &ghd, sizeof(ghd)))
-			return -EFAULT;
-
-		return 0;
-	}
-	return -EINVAL;
-}
-
-#ifdef CONFIG_COMPAT
-static long lineevent_ioctl_compat(struct file *filep, unsigned int cmd,
-				   unsigned long arg)
-{
-	return lineevent_ioctl(filep, cmd, (unsigned long)compat_ptr(arg));
-}
-#endif
-
-static const struct file_operations lineevent_fileops = {
-	.release = lineevent_release,
-	.read = lineevent_read,
-	.poll = lineevent_poll,
-	.owner = THIS_MODULE,
-	.llseek = noop_llseek,
-	.unlocked_ioctl = lineevent_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl = lineevent_ioctl_compat,
-#endif
-};
-
-static irqreturn_t lineevent_irq_thread(int irq, void *p)
-{
-	struct lineevent_state *le = p;
-	struct gpioevent_data ge;
-	int ret;
-
-	/* Do not leak kernel stack to userspace */
-	memset(&ge, 0, sizeof(ge));
-
-	/*
-	 * We may be running from a nested threaded interrupt in which case
-	 * we didn't get the timestamp from lineevent_irq_handler().
-	 */
-	if (!le->timestamp)
-		ge.timestamp = ktime_get_ns();
-	else
-		ge.timestamp = le->timestamp;
-
-	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
-	    && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
-		int level = gpiod_get_value_cansleep(le->desc);
-		if (level)
-			/* Emit low-to-high event */
-			ge.id = GPIOEVENT_EVENT_RISING_EDGE;
-		else
-			/* Emit high-to-low event */
-			ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
-	} else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
-		/* Emit low-to-high event */
-		ge.id = GPIOEVENT_EVENT_RISING_EDGE;
-	} else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
-		/* Emit high-to-low event */
-		ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
-	} else {
-		return IRQ_NONE;
-	}
-
-	ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
-					    1, &le->wait.lock);
-	if (ret)
-		wake_up_poll(&le->wait, EPOLLIN);
-	else
-		pr_debug_ratelimited("event FIFO is full - event dropped\n");
-
-	return IRQ_HANDLED;
-}
-
-static irqreturn_t lineevent_irq_handler(int irq, void *p)
-{
-	struct lineevent_state *le = p;
-
-	/*
-	 * Just store the timestamp in hardirq context so we get it as
-	 * close in time as possible to the actual event.
-	 */
-	le->timestamp = ktime_get_ns();
-
-	return IRQ_WAKE_THREAD;
-}
-
-static int lineevent_create(struct gpio_device *gdev, void __user *ip)
-{
-	struct gpioevent_request eventreq;
-	struct lineevent_state *le;
-	struct gpio_desc *desc;
-	struct file *file;
-	u32 offset;
-	u32 lflags;
-	u32 eflags;
-	int fd;
-	int ret;
-	int irqflags = 0;
-
-	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
-		return -EFAULT;
-
-	offset = eventreq.lineoffset;
-	lflags = eventreq.handleflags;
-	eflags = eventreq.eventflags;
-
-	desc = gpiochip_get_desc(gdev->chip, offset);
-	if (IS_ERR(desc))
-		return PTR_ERR(desc);
-
-	/* Return an error if a unknown flag is set */
-	if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
-	    (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
-		return -EINVAL;
-
-	/* This is just wrong: we don't look for events on output lines */
-	if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
-	    (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
-	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
-		return -EINVAL;
-
-	/* Only one bias flag can be set. */
-	if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
-	     (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
-			GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
-	    ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
-	     (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
-		return -EINVAL;
-
-	le = kzalloc(sizeof(*le), GFP_KERNEL);
-	if (!le)
-		return -ENOMEM;
-	le->gdev = gdev;
-	get_device(&gdev->dev);
-
-	/* Make sure this is terminated */
-	eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0';
-	if (strlen(eventreq.consumer_label)) {
-		le->label = kstrdup(eventreq.consumer_label,
-				    GFP_KERNEL);
-		if (!le->label) {
-			ret = -ENOMEM;
-			goto out_free_le;
-		}
-	}
-
-	ret = gpiod_request(desc, le->label);
-	if (ret)
-		goto out_free_label;
-	le->desc = desc;
-	le->eflags = eflags;
-
-	if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
-		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
-	if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE)
-		set_bit(FLAG_BIAS_DISABLE, &desc->flags);
-	if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)
-		set_bit(FLAG_PULL_DOWN, &desc->flags);
-	if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)
-		set_bit(FLAG_PULL_UP, &desc->flags);
-
-	ret = gpiod_direction_input(desc);
-	if (ret)
-		goto out_free_desc;
-
-	le->irq = gpiod_to_irq(desc);
-	if (le->irq <= 0) {
-		ret = -ENODEV;
-		goto out_free_desc;
-	}
-
-	if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
-		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
-			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
-	if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
-		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
-			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
-	irqflags |= IRQF_ONESHOT;
-
-	INIT_KFIFO(le->events);
-	init_waitqueue_head(&le->wait);
-
-	/* Request a thread to read the events */
-	ret = request_threaded_irq(le->irq,
-			lineevent_irq_handler,
-			lineevent_irq_thread,
-			irqflags,
-			le->label,
-			le);
-	if (ret)
-		goto out_free_desc;
-
-	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
-	if (fd < 0) {
-		ret = fd;
-		goto out_free_irq;
-	}
-
-	file = anon_inode_getfile("gpio-event",
-				  &lineevent_fileops,
-				  le,
-				  O_RDONLY | O_CLOEXEC);
-	if (IS_ERR(file)) {
-		ret = PTR_ERR(file);
-		goto out_put_unused_fd;
-	}
-
-	eventreq.fd = fd;
-	if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
-		/*
-		 * fput() will trigger the release() callback, so do not go onto
-		 * the regular error cleanup path here.
-		 */
-		fput(file);
-		put_unused_fd(fd);
-		return -EFAULT;
-	}
-
-	fd_install(fd, file);
-
-	return 0;
-
-out_put_unused_fd:
-	put_unused_fd(fd);
-out_free_irq:
-	free_irq(le->irq, le);
-out_free_desc:
-	gpiod_free(le->desc);
-out_free_label:
-	kfree(le->label);
-out_free_le:
-	kfree(le);
-	put_device(&gdev->dev);
-	return ret;
-}
-
-static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
-				  struct gpioline_info *info)
-{
-	struct gpio_chip *gc = desc->gdev->chip;
-	bool ok_for_pinctrl;
-	unsigned long flags;
-
-	/*
-	 * This function takes a mutex so we must check this before taking
-	 * the spinlock.
-	 *
-	 * FIXME: find a non-racy way to retrieve this information. Maybe a
-	 * lock common to both frameworks?
-	 */
-	ok_for_pinctrl =
-		pinctrl_gpio_can_use_line(gc->base + info->line_offset);
-
-	spin_lock_irqsave(&gpio_lock, flags);
-
-	if (desc->name) {
-		strncpy(info->name, desc->name, sizeof(info->name));
-		info->name[sizeof(info->name) - 1] = '\0';
-	} else {
-		info->name[0] = '\0';
-	}
-
-	if (desc->label) {
-		strncpy(info->consumer, desc->label, sizeof(info->consumer));
-		info->consumer[sizeof(info->consumer) - 1] = '\0';
-	} else {
-		info->consumer[0] = '\0';
-	}
-
-	/*
-	 * Userspace only need to know that the kernel is using this GPIO so
-	 * it can't use it.
-	 */
-	info->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) ||
-	    !ok_for_pinctrl)
-		info->flags |= GPIOLINE_FLAG_KERNEL;
-	if (test_bit(FLAG_IS_OUT, &desc->flags))
-		info->flags |= GPIOLINE_FLAG_IS_OUT;
-	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
-		info->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
-	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
-		info->flags |= (GPIOLINE_FLAG_OPEN_DRAIN |
-				GPIOLINE_FLAG_IS_OUT);
-	if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
-		info->flags |= (GPIOLINE_FLAG_OPEN_SOURCE |
-				GPIOLINE_FLAG_IS_OUT);
-	if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
-		info->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
-	if (test_bit(FLAG_PULL_DOWN, &desc->flags))
-		info->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
-	if (test_bit(FLAG_PULL_UP, &desc->flags))
-		info->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
-
-	spin_unlock_irqrestore(&gpio_lock, flags);
-}
-
-struct gpio_chardev_data {
-	struct gpio_device *gdev;
-	wait_queue_head_t wait;
-	DECLARE_KFIFO(events, struct gpioline_info_changed, 32);
-	struct notifier_block lineinfo_changed_nb;
-	unsigned long *watched_lines;
-};
-
-/*
- * gpio_ioctl() - ioctl handler for the GPIO chardev
- */
-static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
-{
-	struct gpio_chardev_data *priv = filp->private_data;
-	struct gpio_device *gdev = priv->gdev;
-	struct gpio_chip *gc = gdev->chip;
-	void __user *ip = (void __user *)arg;
-	struct gpio_desc *desc;
-	__u32 offset;
-	int hwgpio;
-
-	/* We fail any subsequent ioctl():s when the chip is gone */
-	if (!gc)
-		return -ENODEV;
-
-	/* Fill in the struct and pass to userspace */
-	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
-		struct gpiochip_info chipinfo;
-
-		memset(&chipinfo, 0, sizeof(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;
-
-		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
-			return -EFAULT;
-
-		desc = gpiochip_get_desc(gc, lineinfo.line_offset);
-		if (IS_ERR(desc))
-			return PTR_ERR(desc);
-
-		hwgpio = gpio_chip_hwgpio(desc);
-
-		gpio_desc_to_lineinfo(desc, &lineinfo);
-
-		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
-			return -EFAULT;
-		return 0;
-	} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
-		return linehandle_create(gdev, ip);
-	} else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
-		return lineevent_create(gdev, ip);
-	} else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
-		struct gpioline_info lineinfo;
-
-		if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
-			return -EFAULT;
-
-		desc = gpiochip_get_desc(gc, lineinfo.line_offset);
-		if (IS_ERR(desc))
-			return PTR_ERR(desc);
-
-		hwgpio = gpio_chip_hwgpio(desc);
-
-		if (test_bit(hwgpio, priv->watched_lines))
-			return -EBUSY;
-
-		gpio_desc_to_lineinfo(desc, &lineinfo);
-
-		if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
-			return -EFAULT;
-
-		set_bit(hwgpio, priv->watched_lines);
-		return 0;
-	} else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
-		if (copy_from_user(&offset, ip, sizeof(offset)))
-			return -EFAULT;
-
-		desc = gpiochip_get_desc(gc, offset);
-		if (IS_ERR(desc))
-			return PTR_ERR(desc);
-
-		hwgpio = gpio_chip_hwgpio(desc);
-
-		if (!test_bit(hwgpio, priv->watched_lines))
-			return -EBUSY;
-
-		clear_bit(hwgpio, priv->watched_lines);
-		return 0;
-	}
-	return -EINVAL;
-}
-
-#ifdef CONFIG_COMPAT
-static long gpio_ioctl_compat(struct file *filp, unsigned int cmd,
-			      unsigned long arg)
-{
-	return gpio_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
-}
-#endif
-
-static struct gpio_chardev_data *
-to_gpio_chardev_data(struct notifier_block *nb)
-{
-	return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
-}
-
-static int lineinfo_changed_notify(struct notifier_block *nb,
-				   unsigned long action, void *data)
-{
-	struct gpio_chardev_data *priv = to_gpio_chardev_data(nb);
-	struct gpioline_info_changed chg;
-	struct gpio_desc *desc = data;
-	int ret;
-
-	if (!test_bit(gpio_chip_hwgpio(desc), priv->watched_lines))
-		return NOTIFY_DONE;
-
-	memset(&chg, 0, sizeof(chg));
-	chg.info.line_offset = gpio_chip_hwgpio(desc);
-	chg.event_type = action;
-	chg.timestamp = ktime_get_ns();
-	gpio_desc_to_lineinfo(desc, &chg.info);
-
-	ret = kfifo_in_spinlocked(&priv->events, &chg, 1, &priv->wait.lock);
-	if (ret)
-		wake_up_poll(&priv->wait, EPOLLIN);
-	else
-		pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
-
-	return NOTIFY_OK;
-}
-
-static __poll_t lineinfo_watch_poll(struct file *filep,
-				    struct poll_table_struct *pollt)
-{
-	struct gpio_chardev_data *priv = filep->private_data;
-	__poll_t events = 0;
-
-	poll_wait(filep, &priv->wait, pollt);
-
-	if (!kfifo_is_empty_spinlocked_noirqsave(&priv->events,
-						 &priv->wait.lock))
-		events = EPOLLIN | EPOLLRDNORM;
-
-	return events;
-}
-
-static ssize_t lineinfo_watch_read(struct file *filep, char __user *buf,
-				   size_t count, loff_t *off)
-{
-	struct gpio_chardev_data *priv = filep->private_data;
-	struct gpioline_info_changed event;
-	ssize_t bytes_read = 0;
-	int ret;
-
-	if (count < sizeof(event))
-		return -EINVAL;
-
-	do {
-		spin_lock(&priv->wait.lock);
-		if (kfifo_is_empty(&priv->events)) {
-			if (bytes_read) {
-				spin_unlock(&priv->wait.lock);
-				return bytes_read;
-			}
-
-			if (filep->f_flags & O_NONBLOCK) {
-				spin_unlock(&priv->wait.lock);
-				return -EAGAIN;
-			}
-
-			ret = wait_event_interruptible_locked(priv->wait,
-					!kfifo_is_empty(&priv->events));
-			if (ret) {
-				spin_unlock(&priv->wait.lock);
-				return ret;
-			}
-		}
-
-		ret = kfifo_out(&priv->events, &event, 1);
-		spin_unlock(&priv->wait.lock);
-		if (ret != 1) {
-			ret = -EIO;
-			break;
-			/* We should never get here. See lineevent_read(). */
-		}
-
-		if (copy_to_user(buf + bytes_read, &event, sizeof(event)))
-			return -EFAULT;
-		bytes_read += sizeof(event);
-	} while (count >= bytes_read + sizeof(event));
-
-	return bytes_read;
-}
-
-/**
- * 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);
-	struct gpio_chardev_data *priv;
-	int ret = -ENOMEM;
-
-	/* Fail on open if the backing gpiochip is gone */
-	if (!gdev->chip)
-		return -ENODEV;
-
-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
-
-	priv->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
-	if (!priv->watched_lines)
-		goto out_free_priv;
-
-	init_waitqueue_head(&priv->wait);
-	INIT_KFIFO(priv->events);
-	priv->gdev = gdev;
-
-	priv->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
-	ret = atomic_notifier_chain_register(&gdev->notifier,
-					     &priv->lineinfo_changed_nb);
-	if (ret)
-		goto out_free_bitmap;
-
-	get_device(&gdev->dev);
-	filp->private_data = priv;
-
-	ret = nonseekable_open(inode, filp);
-	if (ret)
-		goto out_unregister_notifier;
-
-	return ret;
-
-out_unregister_notifier:
-	atomic_notifier_chain_unregister(&gdev->notifier,
-					 &priv->lineinfo_changed_nb);
-out_free_bitmap:
-	bitmap_free(priv->watched_lines);
-out_free_priv:
-	kfree(priv);
-	return ret;
-}
-
-/**
- * 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_chardev_data *priv = filp->private_data;
-	struct gpio_device *gdev = priv->gdev;
-
-	bitmap_free(priv->watched_lines);
-	atomic_notifier_chain_unregister(&gdev->notifier,
-					 &priv->lineinfo_changed_nb);
-	put_device(&gdev->dev);
-	kfree(priv);
-
-	return 0;
-}
-
-static const struct file_operations gpio_fileops = {
-	.release = gpio_chrdev_release,
-	.open = gpio_chrdev_open,
-	.poll = lineinfo_watch_poll,
-	.read = lineinfo_watch_read,
-	.owner = THIS_MODULE,
-	.llseek = no_llseek,
-	.unlocked_ioctl = gpio_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl = gpio_ioctl_compat,
-#endif
-};
-
 static void gpiodevice_release(struct device *dev)
 {
 	struct gpio_device *gdev = dev_get_drvdata(dev);
@@ -1532,17 +435,10 @@  static int gpiochip_setup_dev(struct gpio_device *gdev)
 {
 	int ret;
 
-	cdev_init(&gdev->chrdev, &gpio_fileops);
-	gdev->chrdev.owner = THIS_MODULE;
-	gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id);
-
-	ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
+	ret = gpiolib_cdev_register(gdev, gpio_devt);
 	if (ret)
 		return ret;
 
-	chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
-		 MAJOR(gpio_devt), gdev->id);
-
 	ret = gpiochip_sysfs_register(gdev);
 	if (ret)
 		goto err_remove_device;
@@ -1555,7 +451,7 @@  static int gpiochip_setup_dev(struct gpio_device *gdev)
 	return 0;
 
 err_remove_device:
-	cdev_device_del(&gdev->chrdev, &gdev->dev);
+	gpiolib_cdev_unregister(gdev);
 	return ret;
 }
 
@@ -1877,7 +773,7 @@  void gpiochip_remove(struct gpio_chip *gc)
 	 * be removed, else it will be dangling until the last user is
 	 * gone.
 	 */
-	cdev_device_del(&gdev->chrdev, &gdev->dev);
+	gpiolib_cdev_unregister(gdev);
 	put_device(&gdev->dev);
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove);