linux-toradex.git/drivers/gpio/gpiolib-sysfs.c, branch v4.10

gpio: fix documentation for gpiod_unexport

2016-09-12T12:53:33+00:00

Both gpio_export and gpio_free APIs are obsolete now.

Signed-off-by: Amitesh Singh 
Signed-off-by: Linus Walleij

gpio: fix abi regression in sysfs

2016-02-25T15:08:45+00:00

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: Bamvor Jian Zhang 
Signed-off-by: Linus Walleij

gpio: reflect base and ngpio into gpio_device

2016-02-11T19:29:46+00:00

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: Linus Walleij

gpio: move descriptors into gpio_device

2016-02-11T19:29:45+00:00

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: Linus Walleij

gpio: move sysfs mock device to the gpio_device

2016-02-11T17:16:54+00:00

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: Linus Walleij

gpio: make the gpiochip a real device

2016-02-09T10:03:53+00:00

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 
Cc: Michael Welling 
Cc: Markus Pargmann 
Signed-off-by: Linus Walleij

gpio: change member .dev to .parent

2015-11-19T08:24:35+00:00

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 
Cc: Rafał Miłecki 
Cc: Richard Purdie 
Cc: Mauro Carvalho Chehab 
Cc: Alek Du 
Cc: Jaroslav Kysela 
Cc: Takashi Iwai 
Acked-by: Dmitry Torokhov 
Acked-by: Greg Kroah-Hartman 
Acked-by: Lee Jones 
Acked-by: Jiri Kosina 
Acked-by: Hans-Christian Egtvedt 
Acked-by: Jacek Anaszewski 
Signed-off-by: Linus Walleij

gpio: sysfs: move irq trigger flags to class-device data

2015-05-12T08:47:57+00:00

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: Johan Hovold 
Reviewed-by: Alexandre Courbot 
Signed-off-by: Linus Walleij

gpio: sysfs: remove FLAG_SYSFS_DIR

2015-05-12T08:47:52+00:00

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: Johan Hovold 
Reviewed-by: Alexandre Courbot 
Signed-off-by: Linus Walleij

gpio: sysfs: rename active-low helper

2015-05-12T08:47:48+00:00

Rename active-low helper using common prefix.

Also remove unnecessary manipulation of value argument.

Signed-off-by: Johan Hovold 
Reviewed-by: Alexandre Courbot 
Signed-off-by: Linus Walleij