linux-stable.git/drivers/pinctrl/core.c, branch v3.9.2

pinctrl/pinconfig: add debug interface

2013-02-10T20:11:54+00:00

This update adds a debugfs interface to modify a pin configuration
for a given state in the pinctrl map. This allows to modify the
configuration for a non-active state, typically sleep state.
This configuration is not applied right away, but only when the state
will be entered.

This solution is mandated for us by HW validation: in order
to test and verify several pin configurations during sleep without
recompiling the software.

Signed-off-by: Laurent Meunier 
Signed-off-by: Linus Walleij

pinctrl: core: Make pinctrl_release static

2013-01-30T10:00:58+00:00

'pinctrl_release' is used only in this file. Hence make it static.

Without this patch we get the following sparse error:
drivers/pinctrl/core.c:815:6: warning:
symbol 'pinctrl_release' was not declared. Should it be static?

Signed-off-by: Sachin Kamat 
Signed-off-by: Linus Walleij

drivers/pinctrl: grab default handles from device core

2013-01-23T15:39:51+00:00

This makes the device core auto-grab the pinctrl handle and set
the "default" (PINCTRL_STATE_DEFAULT) state for every device
that is present in the device model right before probe. This will
account for the lion's share of embedded silicon devcies.

A modification of the semantics for pinctrl_get() is also done:
previously if the pinctrl handle for a certain device was already
taken, the pinctrl core would return an error. Now, since the
core may have already default-grabbed the handle and set its
state to "default", if the handle was already taken, this will
be disregarded and the located, previously instanitated handle
will be returned to the caller.

This way all code in drivers explicitly requesting their pinctrl
handlers will still be functional, and drivers that want to
explicitly retrieve and switch their handles can still do that.
But if the desired functionality is just boilerplate of this
type in the probe() function:

struct pinctrl  *p;

p = devm_pinctrl_get_select_default(&dev);
if (IS_ERR(p)) {
   if (PTR_ERR(p) == -EPROBE_DEFER)
        return -EPROBE_DEFER;
        dev_warn(&dev, "no pinctrl handle\n");
}

The discussion began with the addition of such boilerplate
to the omap4 keypad driver:
http://marc.info/?l=linux-input&m=135091157719300&w=2

A previous approach using notifiers was discussed:
http://marc.info/?l=linux-kernel&m=135263661110528&w=2
This failed because it could not handle deferred probes.

This patch alone does not solve the entire dilemma faced:
whether code should be distributed into the drivers or
if it should be centralized to e.g. a PM domain. But it
solves the immediate issue of the addition of boilerplate
to a lot of drivers that just want to grab the default
state. As mentioned, they can later explicitly retrieve
the handle and set different states, and this could as
well be done by e.g. PM domains as it is only related
to a certain struct device * pointer.

ChangeLog v4->v5 (Stephen):
- Simplified the devicecore grab code.
- Deleted a piece of documentation recommending that pins
  be mapped to a device rather than hogged.
ChangeLog v3->v4 (Linus):
- Drop overzealous NULL checks.
- Move kref initialization to pinctrl_create().
- Seeking Tested-by from Stephen Warren so we do not disturb
  the Tegra platform.
- Seeking ACK on this from Greg (and others who like it) so I
  can merge it through the pinctrl subsystem.
ChangeLog v2->v3 (Linus):
- Abstain from using IS_ERR_OR_NULL() in the driver core,
  Russell recently sent a patch to remove it. Handle the
  NULL case explicitly even though it's a bogus case.
- Make sure we handle probe deferral correctly in the device
  core file. devm_kfree() the container on error so we don't
  waste memory for devices without pinctrl handles.
- Introduce reference counting into the pinctrl core using
   so that we don't release pinctrl handles
  that have been obtained for two or more places.
ChangeLog v1->v2 (Linus):
- Only store a pointer in the device struct, and only allocate
  this if it's really used by the device.

Cc: Felipe Balbi 
Cc: Benoit Cousson 
Cc: Dmitry Torokhov 
Cc: Thomas Petazzoni 
Cc: Mitch Bradley 
Cc: Ulf Hansson 
Cc: Rafael J. Wysocki 
Cc: Jean-Christophe PLAGNIOL-VILLARD 
Cc: Rickard Andersson 
Cc: Russell King 
Reviewed-by: Mark Brown 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Linus Walleij 
[swarren: fixed and simplified error-handling in pinctrl_bind_pins(), to
correctly handle deferred probe. Removed admonition from docs not to use
pinctrl hogs for devices]
Signed-off-by: Stephen Warren 
Signed-off-by: Linus Walleij

pinctrl: core: get devname from pinctrl_dev

2013-01-21T14:14:39+00:00

Add new function to get devname from pinctrl_dev. pinctrl_dev_get_name()
can only get pinctrl description name. If we want to use gpio driver to
find pinctrl device node, we need to fetch the pinctrl device name.

Signed-off-by: Haojian Zhuang 
Signed-off-by: Linus Walleij

pinctrl: add sleep mode management for hogs

2013-01-11T20:48:05+00:00

This fix allows handling sleep mode for hogged
pins in pinctrl. It provides functions to set pins
to sleep/default configurations according to their
current state.

Signed-off-by: Julien Delacou 
Reviewed-by: Stephen Warren 
Signed-off-by: Linus Walleij

pinctrl: skip deferral of hogs

2013-01-11T20:48:05+00:00

Up until now, as hogs were always taken at the end of the
pin control device registration, it didn't cause any problem.
But when starting to hog pins from the device core it will
cause deferral of the pin controller device itself since the
default pin fetch is done *before* the device probes, so
let's fix this annoyance (which is also aesthetically ugly).

Also take some care to make sure that if any one map entry
results in a deferral rather than a failure, then that
deferral will take precedence.

Reviewed-by: Stephen Warren 
Signed-off-by: Linus Walleij

pinctrl: fix comment mistake

2012-12-26T00:59:52+00:00

This variable pertains to pinctrl handles not muxes
specifically.

Signed-off-by: Linus Walleij

pinctrl: add function to retrieve range from pin

2012-11-21T07:55:12+00:00

This adds a function to the pinctrl core to retrieve the GPIO
range associated with a certain pin for a certain controller.
This is needed when a pinctrl driver want to look up the
corresponding struct gpio_chip for a certain pin. As the
GPIO drivers can now create these ranges themselves, the
pinctrl driver no longer knows about all its associated GPIO
chips.

Reviewed-by: Stephen Warren 
Reviewed-by: Viresh Kumar 
Signed-off-by: Linus Walleij

pinctrl: make range registration defer properly

2012-11-21T07:55:10+00:00

This makes the pinctrl_find_and_add_gpio_range() return
-EPROBE_DEFER if the range hosting pin controller cannot be
located. We may assume that the common case for why adding a
range fails is that the targe pin controller device has not
probed yet.

Reviewed-by: Stephen Warren 
Reviewed-by: Viresh Kumar 
Signed-off-by: Linus Walleij

gpiolib: rename find_pinctrl_*

2012-11-21T07:55:10+00:00

Rename the function find_pinctrl_and_add_gpio_range()
to pinctrl_find_and_add_gpio_range() so as to be consistent
with the rest of the functions.

Reviewed-by: Stephen Warren 
Reviewed-by: Viresh Kumar 
Signed-off-by: Linus Walleij