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  1. 10 Feb, 2013 2 commits
    • Lee Jones's avatar
      pinctrl/abx500: replace IRQ offsets with table read-in values · a6a16d27
      Lee Jones authored 
      The ABx500 GPIO controller used to provide a set of virtual contiguous
IRQs for use by sub-devices, but they have been removed after a request
from Mainline Maintainers. Now the AB8500 core driver deals with almost
all IRQ related issues instead.

The ABx500 GPIO driver is now only used to convert between GPIO and IRQ
numbers which is actually quite difficult, as the ABx500 GPIO's
associated IRQs are clustered together throughout the interrupt number
space at irregular intervals. To solve this quandary, we have placed the
read-in values into the existing cluster information table to use during
conversion.
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
[Moved irq_base removal into this patch]
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      a6a16d27
    • Lee Jones's avatar
      pinctrl/abx500: move IRQ handling to ab8500-core · ac652d79
      Lee Jones authored 
      In its current state the gpio-ab8500 driver looks after some GPIO
lines found on the AB8500 MFD chip. It also controls all of its
own IRQ handling for these GPIOs by inventing some virtual IRQs
and handing those out to sub-devices. There has been quite a bit
of controversy over this and it was a contributing factor to the
driver being marked as BROKEN in Mainline.

The reason for adopting this method was due to added complexity
in the hardware. Unusually, each GPIO has two separate IRQs
associated with it, one for a rising and a different one for a
falling interrupt. Using this method complicates matters further
because the GPIO IRQs are actually sandwiched between a bunch
of IRQs which are handled solely by the AB8500 core driver.

The best way for us to take this forward is to get rid of the
virtual IRQs and only hand out the rising IRQ lines. If a
sub-driver wishes to request a falling interrupt, they can do
so by requesting a rising line in the normal way. They just
have to add IRQ_TYPE_EDGE_FALLING or IRQ_TYPE_EDGE_BOTH, if
they require both in the flags. Then if a falling IRQ is
triggered, the AB8500 core driver will know how to handle the
added complexity accordingly. This should greatly simply things.
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
[Augment to keep irq_base for a while (removed later)]
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      ac652d79
  3. 08 Feb, 2013 1 commit
  5. 07 Feb, 2013 2 commits
  7. 06 Feb, 2013 3 commits
  9. 05 Feb, 2013 18 commits
  11. 01 Feb, 2013 5 commits
  13. 30 Jan, 2013 7 commits
  15. 29 Jan, 2013 1 commit
  17. 23 Jan, 2013 1 commit
    • Linus Walleij's avatar
      drivers/pinctrl: grab default handles from device core · ab78029e
      Linus Walleij authored 
      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
  <linux/kref.h> 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 <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Mitch Bradley <wmb@firmworks.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Rickard Andersson <rickard.andersson@stericsson.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
[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: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      ab78029e
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