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  1. 15 Feb, 2016 13 commits
  3. 11 Feb, 2016 7 commits
    • Linus Walleij's avatar
      gpio: reference count the gpio device for each desc · 33a68e86
      Linus Walleij authored 
      Every time a descriptor is retrieved from the gpiolib, we issue
module_get() to reference count the module supplying the GPIOs.
We also need to call device_get() and device_put() as we also
reference the backing gpio_device when doing this.

Since the sysfs GPIO interface is using gpiod_get() this will
also reference count the sysfs requests until all GPIOs are
unexported.
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      33a68e86
    • Linus Walleij's avatar
      gpio: reflect base and ngpio into gpio_device · fdeb8e15
      Linus Walleij authored 
      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: default avatarLinus Walleij <linus.walleij@linaro.org>
      fdeb8e15
    • Linus Walleij's avatar
      gpio/pinctrl: sunxi: stop poking around in private vars · 6cee3821
      Linus Walleij authored 
      This kind of hacks disturbs the refactoring of the gpiolib.

The descriptor table belongs to the gpiolib, if we want to know
something about something in it, use or define the proper accessor
functions. Let's add this gpiochip_lins_is_irq() to do what the
sunxi driver is trying at so we can privatize the descriptors
properly.

Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      6cee3821
    • Linus Walleij's avatar
      gpio: move descriptors into gpio_device · 1c3cdb18
      Linus Walleij authored 
      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: default avatarLinus Walleij <linus.walleij@linaro.org>
      1c3cdb18
    • Linus Walleij's avatar
      gpio: move sysfs mock device to the gpio_device · afbc4f31
      Linus Walleij authored 
      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: default avatarLinus Walleij <linus.walleij@linaro.org>
      afbc4f31
    • Linus Walleij's avatar
      gpio: remember to finally free gpio_device · 9efd9e69
      Linus Walleij authored 
      When the device core reference count for the device goes to
0 and it calls .release() we free resources and so can also
finally free up the GPIO state container, struct gpio_device.
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      9efd9e69
    • Nicolas Saenz Julienne's avatar
      gpio: add tps65218 gpio · c366c76a
      Nicolas Saenz Julienne authored 
      Driver for the GPIO block found in ti's tps65218 pmics.

The device has two GPIOs and one GPO pin which can be configured as follows:
GPIO1:
	-general-purpose, open-drain output controlled by GPO1 user bit and/or
	 sequencer
	-DDR3 reset input signal from SOC. Signal is either latched or
	 passed-trough to GPO2 pin. See below for details.
GPO2:
	-general-purpose output controlled by GPO2 user bit
	-DDR3 reset output signal. Signal is controlled by GPIO1 and PGOOD.
	 See below for details.
	-Output buffer can be configured as open-drain or push-pull.
GPIO3:
	-general-purpose, open-drain output controlled by GPO3 user bit and/or
	 sequencer
	-reset input-signal for DCDC1 and DCDC2.

The input configurations are not meant to be used by the user so the driver
only offers GPOs.

v2: Added request routine that evaluates the fw config flags and removed module
    owner
v3: Added .direction_input() routine, and took care of all Linus Walleij
suggestions (clamp to bool, use proper include)
Signed-off-by: default avatarNicolas Saenz Julienne <nicolassaenzj@gmail.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      c366c76a
  5. 10 Feb, 2016 7 commits
  7. 09 Feb, 2016 7 commits
    • Linus Walleij's avatar
      Merge branch 'chardev' into devel · 60afe31d
      Linus Walleij authored
      60afe31d
    • Linus Walleij's avatar
      gpio: ABI: mark the sysfs ABI as obsolete · fe95046e
      Linus Walleij authored 
      This marks the (optional) sysfs GPIO ABI as obsolete and schedules
it for removal in 2020.

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      fe95046e
    • Linus Walleij's avatar
      gpio: add a userspace character device ABI · 40c159b7
      Linus Walleij authored 
      Put in some documentation for the new character device ABI
so we can properly etch it in stone.
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      40c159b7
    • Linus Walleij's avatar
      tools/gpio: create GPIO tools · 6d591c46
      Linus Walleij authored 
      This creates GPIO tools under tools/gpio/* and adds a single
example program to list the GPIOs on a system. When proper
devices are created it provides this minimal output:

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      6d591c46
    • Linus Walleij's avatar
      gpio: add a userspace chardev ABI for GPIOs · 3c702e99
      Linus Walleij authored 
      A new chardev that is to be used for userspace GPIO access is
added in this patch. It is intended to gradually replace the
horribly broken sysfs ABI.

Using a chardev has many upsides:

- All operations are per-gpiochip, which is the actual
  device underlying the GPIOs, making us tie in to the
  kernel device model properly.

- Hotpluggable GPIO controllers can come and go, as this
  kind of problem has been know to userspace for character
  devices since ages, and if a gpiochip handle is held in
  userspace we know we will break something, whereas the
  sysfs is stateless.

- The one-value-per-file rule of sysfs is really hard to
  maintain when you want to twist more than one knob at a time,
  for example have in-kernel APIs to switch several GPIO
  lines at the same time, and this will be possible to do
  with a single ioctl() from userspace, saving a lot of
  context switching.

We also need to add a new bus type for GPIO. This is
necessary for example for userspace coldplug, where sysfs is
traversed to find the boot-time device nodes and create the
character devices in /dev.

This new chardev ABI is *non* *optional* and can be counted
on to be present in the future, emphasizing the preference
of this ABI.

The ABI only implements one single ioctl() to get the name
and number of GPIO lines of a chip. Even this is debatable:
see it as a minimal example for review. This ABI shall be
ruthlessly reviewed and etched in stone.

The old /sys/class/gpio is still optional to compile in,
but will be deprecated.

Unique device IDs are created using IDR, which is overkill
and insanely scalable, but also well tested.

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      3c702e99
    • Linus Walleij's avatar
      gpio: refer to gpio device in prints and debugfs · 34ffd85d
      Linus Walleij authored 
      We use the new struct device inside gpio_chip to related debug
prints and warnings, and we also add it to the debugfs dump.

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      34ffd85d
    • Linus Walleij's avatar
      gpio: make the gpiochip a real device · ff2b1359
      Linus Walleij authored 
      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: default avatarLinus Walleij <linus.walleij@linaro.org>
      ff2b1359
  9. 08 Feb, 2016 2 commits
    • Liu Gang's avatar
      drivers/gpio: Switch gpio-mpc8xxx to use gpio-generic · 42178e2a
      Liu Gang authored 
      The new Layerscape platforms has the same ip block/controller
as GPIO on PowerPC platforms(MPC8XXX), but the GPIO registers
may be big or little endian. So the code needs to get the
endian property from DTB, then make additional functions to
fit all the PowerPC/Layerscape GPIO register read/write
operations.

gpio-generic.c provides an universal infrastructure for both
big and little endian register operations. So switch the
gpio-mpc8xxx to use gpio-generic can simplify the driver and
reduce a lot of code.

The IRQ and some workaround parts in gpio-mpc8xxx.c will be
updated with the new API interfaces but following the
original functionalities.
Signed-off-by: default avatarLiu Gang <Gang.Liu@nxp.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      42178e2a
    • Linus Walleij's avatar
      Merge branch 'error-return-from-get' into devel · daec0bed
      Linus Walleij authored
      daec0bed
  11. 05 Feb, 2016 2 commits
  13. 28 Jan, 2016 2 commits
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