Use kobj_to_dev() API instead of container_of().
Signed-off-by: NWang Qing <wangqing@vivo.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

The string literal "gpiochip" is used in several places.
Add a definition for it, and use it everywhere, to make sure everything
stays in sync.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20191127084253.16356-2-geert+renesas@glider.beReviewed-by: NUlrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use the SPDX headers and cut down on boilerplate to indicate the
license in the core gpiolib implementation.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

A bunch of core gpiolib files still include the <linux/gpio.h>
legacy API header for no good reason. After this only the
gpiolib-legacy.c file includes it, which is fine.

The sysfs ABI code has a pointless wrapper function around
gpio_to_desc() we can just loose.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

A 'perf record' on an app continuously writing in the 'value'
attribute show that most of the time is spent in kstrtol()

--17.99%--value_store
          |
          |--10.17%--kstrtoint
          |          |
          |          |--8.82%--kstrtoll
          |
          |--2.50%--gpiod_set_value_cansleep
          |
          |--1.82%--u16_gpio_set
          |
          |--1.46%--value_store

The normal case is to write 0 or 1 in the attribute, therefore
this patch avoids the call to kstrtol() in the most common cases

Then 'perf record' shows

--7.21%--value_store
          |
          |--2.69%--u16_gpio_set
          |
          |--1.47%--value_store
          |
          |--1.08%--gpiod_set_value_cansleep
          |
          |--0.60%--mutex_lock
          |
           --0.58%--mutex_unlock
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

A bench with 'perf record' shows that most of time spent in value_show()
is spent in sprintf()

--42.41%--sysfs_kf_read
          |
          |--39.73%--dev_attr_show
          |          |
          |          |--38.23%--value_show
          |          |          |
          |          |          |--29.22%--sprintf
          |          |          |
          |          |          |--2.94%--gpiod_get_value_cansleep
          |          |          |

value_show() only returns "0\n" or "1\n", therefore the use of
sprintf() can be avoided

With this patch we get the following result with 'perf record'

--13.89%--sysfs_kf_read
          |
          |--10.72%--dev_attr_show
          |          |
          |          |--9.44%--value_show
          |          |          |
          |          |          |--4.61%--gpiod_get_value_cansleep
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

'value' attribute is supposed to only return 0 or 1 according to
the documentation.
With today's implementation, if gpiod_get_value_cansleep() fails
the printed 'value' is a negative value.

This patch ensures that an error is returned on read instead.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The GPIO 'value' attribute is time critical. A small bench with
'perf record' on the app below shows that 80% of the time spent in
sysfs_kf_seq_show() is spent in memset() for zeroising the buffer.

|--67.48%--sysfs_kf_seq_show
|          |
|          |--54.40%--memset
|          |
|          |--11.49%--dev_attr_show
|          |          |
|          |          |--10.06%--value_show
|          |          |          |
|          |          |          |--4.75%--sprintf
|          |          |          |          |

This patch changes the attribute type to prealloc, eliminating the
need to zeroise the buffer at each read. 'perf record' gives the
following result.

|--42.41%--sysfs_kf_read
|          |
|          |--39.73%--dev_attr_show
|          |          |
|          |          |--38.23%--value_show
|          |          |          |
|          |          |          |--29.22%--sprintf
|          |          |          |          |

Test done with the following small app:

int main(int argc, char **argv)
{
	int fd = open(argv[1], O_RDONLY);

	for (;;) {
		int buf[512];

		read(fd, buf, 512);
		lseek(fd, 0, SEEK_SET);
	}
	exit(0);
}
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

General support for state persistence is added to gpiolib with the
introduction of a new pinconf parameter to propagate the request to
hardware. The existing persistence support for sleep is adapted to
include hardware support if the GPIO driver provides it. Persistence
continues to be enabled by default; in-kernel consumers can opt out, but
userspace (currently) does not have a choice.

The *_SLEEP_MAY_LOSE_VALUE and *_SLEEP_MAINTAIN_VALUE symbols are
renamed, dropping the SLEEP prefix to reflect that the concept is no
longer sleep-specific.  I feel that renaming to just *_MAY_LOSE_VALUE
could initially be misinterpreted, so I've further changed the symbols
to *_TRANSITORY and *_PERSISTENT to address this.

The sysfs interface is modified only to keep consistency with the
chardev interface in enforcing persistence for userspace exports.
Signed-off-by: NAndrew Jeffery <andrew@aj.id.au>
Reviewed-by: NCharles Keepax <ckeepax@opensource.cirrus.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Fix up some references to parameters to match the code.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Check user-given gpio number and reject it before
calling gpio_to_desc() because gpio_to_desc() is
for kernel driver and it expects given gpio number
is valid (means 0 to 511).
If given number is invalid, gpio_to_desc() calls
WARN() and dump registers and stack for debug.
This means user can easily kick WARN() just by
writing invalid gpio number (e.g. 512) to
/sys/class/gpio/export.

Fixes: 0e9a5edf ("gpio: fix deferred probe detection for legacy API")
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The class_attrs pointer is long depreciated, and is about to be finally
removed, so move to use the class_groups pointer instead.
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: <linux-gpio@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Both gpio_export and gpio_free APIs are obsolete now.
Signed-off-by: NAmitesh Singh <singh.amitesh@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

We started to assign the gpio_device as parent for the sysfs
but this changes the expected layout of sysfs. Restore the
previous behaviour.
Signed-off-by: NBamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Some information about the GPIO chip need to stay around also
after the gpio_chip has been removed and only the gpio_device
persist. The base and ngpio are such things, for example we
don't want a new chip arriving to overlap the number space
of a dangling gpio_device, and the chardev may still query
the device for the number of lines etc.

Note that the code that assigns base and insert gpio_device
into the global list no longer check for a missing gpio_chip:
we respect the number space allocated by any other gpio_device.

As a consequence of the gdev being referenced directly from
the gpio_desc, we need to verify it differently from all
in-kernel API calls that fall through to direct queries to
the gpio_chip vtable: we first check that desc is !NULL, then
that desc->gdev is !NULL, then, if desc->gdev->chip is NULL,
we *BAIL OUT* without any error, so as to manage the case
where operations are requested on a device that is gone.

These checks were non-uniform and partly missing in the past:
so to simplify: create the macros VALIDATE_DESC() that will
return -EINVAL if the desc or desc->gdev is missing and just
0 if the chip is gone, and conversely VALIDATE_DESC_VOID()
for the case where the function does not return an error.
By using these macros, we get warning messages about missing
gdev with reference to the right function in the kernel log.

Despite the macro business this simplifies the code and make
it more readable than if we copy/paste the same descriptor
checking code into all code ABI call sites (IMHO).
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

We need gpio_device to hold the descriptors so that they can
be lifecycled with the struct gpio_device held from userspace.
Move the descriptor array into gpio_device. Also rename it from
"desc" (singularis) to "descs" (pluralis) to reflect the fact
that it is an array.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Since gpio_device is the struct that survives if the backing
gpio_chip is removed, move the sysfs mock device to this state
container so it becomes part of the dangling state of the
GPIO device on removal.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

GPIO chips have been around for years, but were never real devices,
instead they were piggy-backing on a parent device (such as a
platform_device or amba_device) but this was always optional.
GPIO chips could also exist without any device at all, with its
struct device *parent (ex *dev) pointer being set to null.

When sysfs was in use, a mock device would be created, with the
optional parent assigned, or just floating orphaned with NULL
as parent.

If sysfs is active, it will use this device as parent.

We now create a gpio_device struct containing a real
struct device and move the subsystem over to using that. The
list of struct gpio_chip:s is augmented to hold struct
gpio_device:s and we find gpio_chips:s by first looking up
the struct gpio_device.

The struct gpio_device is designed to stay around even if the
gpio_chip is removed, so as to satisfy users in userspace
that need a backing data structure to hold the state of the
session initiated with e.g. a character device even if there is
no physical chip anymore.

From this point on, gpiochips are devices.

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The name .dev in a struct is normally reserved for a struct device
that is let us say a superclass to the thing described by the struct.
struct gpio_chip stands out by confusingly using a struct device *dev
to point to the parent device (such as a platform_device) that
represents the hardware. As we want to give gpio_chip:s real devices,
this is not working. We need to rename this member to parent.

This was done by two coccinelle scripts, I guess it is possible to
combine them into one, but I don't know such stuff. They look like
this:

@@
struct gpio_chip *var;
@@
-var->dev
+var->parent

and:

@@
struct gpio_chip var;
@@
-var.dev
+var.parent

and:

@@
struct bgpio_chip *var;
@@
-var->gc.dev
+var->gc.parent

Plus a few instances of bgpio that I couldn't figure out how
to teach Coccinelle to rewrite.

This patch hits all over the place, but I *strongly* prefer this
solution to any piecemal approaches that just exercise patch
mechanics all over the place. It mainly hits drivers/gpio and
drivers/pinctrl which is my own backyard anyway.

Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Alek Du <alek.du@intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This reverts commit ddd54040.

We need to preserve only using this naming strategy for names
coming from chip->names[], the descripor->name field is for the
new interface.

The name is now stored in the gpio descriptor as well, for example to
allow to store names from DT. This patch changes the sysfs gpio files
to use the gpio descriptor name.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Move irq trigger flags, which as sysfs-interface specific, to the class
device data.

This avoids accessing the gpio-descriptor flags field using non-atomic
operations without any locking, and allows for a more clear separation
of the sysfs interface from gpiolib core.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Remove FLAG_SYSFS_DIR, which is sysfs-interface specific, and store it
in the class-device data instead.

Note that the flag is only used during export.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Rename active-low helper using common prefix.

Also remove unnecessary manipulation of value argument.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Make sure to deregister the class device (and release the irq) while
holding the sysfs lock in gpio_unexport to prevent racing with
gpio_export.

Note that this requires the recently introduced per-gpio locking to
avoid a deadlock with the kernfs active protection when waiting for the
attribute operations to drain during deregistration.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add a per-gpio mutex to serialise attribute operations rather than use
one global mutex for all gpios and chips.

Having a single global lock for all gpios in a system adds unnecessary
latency to the sysfs interface, and especially when having gpio
controllers connected over slow buses.

Now that the global gpio-sysfs interrupt table is gone and with per-gpio
data in place, we can easily switch to using a more fine-grained locking
scheme.

Keep the global mutex to serialise the global (class) operations of gpio
export and unexport and chip removal.

Also document the locking assumptions made.

Note that this is also needed to fix a race between gpiod_export and
gpiod_unexport.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Drop unnecessary locking from gpiod_export_link. If the class device has
not already been unregistered, class_find_device returns the ref-counted
class device so there's no need for locking.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Remove goto from success path.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add separate helper functions for irq request and free.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Only call irq helper if actually reconfiguring interrupt state.

This is a preparatory step in introducing separate gpio-irq request and
free functions.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Store the value sysfs entry in the gpiod data rather than in a global
table accessed through an index stored in the overloaded gpio-descriptor
flag field.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Remove redundant gpio-descriptor parameters from sysfs_set_active_low and
gpio_setup_irq.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add gpiod class-device data.

This is a first step in getting rid of the insane gpio-descriptor flag
overloading, backward irq-interface implementation, and course grained
sysfs-interface locking (a single static mutex for every operation on
all exported gpios in a system).
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The attribute operations will never be called for an unregistered device
so remove redundant checks for FLAG_EXPORT.

Note that kernfs will also guarantee that any active sysfs operation has
finished before the attribute is removed during deregistration.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Make sure to release any irq only after the class device has been
deregistered.

This avoids a race between gpiod_unexport and edge_store, where an irq
could be allocated just before the gpio class device is deregistered
without relying on FLAG_EXPORT and the global sysfs lock.

Note that there is no need to hold the sysfs lock when releasing the irq
after the class device is gone as kernfs will prevent further attribute
operations.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use DEVICE_ATTR_RO and DEVICE_ATTR_RW rather than specifying masks and
callbacks directly.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Remove gpiod_sysfs_set_active_low (and gpio_sysfs_set_active_low) which
allowed code to change the polarity of a gpio line even after it had
been exported through sysfs.

Drivers should not care, and generally does not know, about gpio-line
polarity which is a hardware feature that needs to be described by
firmware.

It is currently possible to define gpio-line polarity in device-tree and
acpi firmware or using platform data. Userspace can also change the
polarity through sysfs.

Note that drivers using the legacy gpio interface could still use
GPIOF_ACTIVE_LOW to change the polarity before exporting the gpio.

There are no in-kernel users of this interface.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Harry Wei <harryxiyou@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@zh-kernel.org
Cc: linux-arch@vger.kernel.org
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Rename the gpio-chip export/unexport functions to the more descriptive
names gpiochip_sysfs_register and gpiochip_sysfs_unregister.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Clean gpio-chip class device registration and deregistration.

The class device is registered when a gpio-chip is added (or from
gpiolib_sysfs_init post-core init call), and deregistered when the chip
is removed.

Store the class device in struct gpio_chip directly rather than do a
class-device lookup on deregistration. This also removes the need for
the exported flag.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Reduce scope of sysfs_lock protection during chip export and unexport,
which is only needed to prevent gpiod (re-)exports during chip removal.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>