Commit Graph

42 Commits

Author SHA1 Message Date
Thomas Petazzoni
c2df3de0d0 gpio: zynq: properly support runtime PM for GPIO used as interrupts
The Zynq GPIO driver currently implements runtime PM by:

 - Enabling runtime PM support in ->probe() and letting the runtime PM
   reference counter drop to zero at the end of ->probe().

 - Increasing the runtime PM reference counter in ->request() and
   decreasing it in ->free().

However, the latter is not sufficient: when a GPIO is used as an
interrupt, ->request() and ->free() are not called. Due to this, the
runtime PM counter remains to zero when the only GPIOs in use are used
as interrupts, causing them to simply not work.

To address this problem, this commit implement the
->irq_request_resources() and ->irq_release_resources() hooks,
ensuring that the runtime PM counter is properly
incremented/decremented. Since we override the default hooks, we keep
the existing behavior by making sure they call gpiochip_reqres_irq() /
gpiochip_relres_irq() respectively.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2019-02-13 10:36:54 +01:00
Brandon Maier
6169005ceb gpio: zynq: Report gpio direction at boot
The Zynq's gpios can be configured by the bootloader. But Linux will
erroneously report all gpios as inputs unless we implement
get_direction().

Signed-off-by: Brandon Maier <Brandon.Maier@collins.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-12-07 13:37:25 +01:00
Wolfram Sang
38ccad0243 gpio: gpio-zynq: simplify getting .driver_data
We should get 'driver_data' from 'struct device' directly. Going via
platform_device is an unneeded step back and forth.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-11-05 08:54:41 +01:00
Michal Simek
060f3ebf6a gpio: zynq: Setup chip->base based on alias ID
In past Xilinx gpio-zynq driver was setting up gpio chip->base as 0
which was chagned to autodetection when driver was upstreamed. Older
systems, which were using this old version, setup SW stack which expects
zynq gpio base as 0 and right now there is no way how to set this up.

The patch is adding an option to setup chip->base based on aliases which
is something what some other drivers are doing too.
It means when gpio0 alias is setup then chip->base is 0. When gpio alias
is not setup gpiochip_find_base() set it up properly which is current
behavior.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-05-23 11:43:03 +02:00
Shubhrajyoti Datta
a76e865eea gpio: zynq: simplifly getting drvdata
Get the driver data directly by dev_get_drvdata.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-05-23 09:57:08 +02:00
Shubhrajyoti Datta
5e3a8ecd76 gpio: zynq: Remove call to platform_get_irq
Remove the call to  platform_get_irq use the cached
one instead.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-05-23 09:55:53 +02:00
Thierry Reding
f0fbe7bce7 gpio: Move irqdomain into struct gpio_irq_chip
In order to consolidate the multiple ways to associate an IRQ chip with
a GPIO chip, move more fields into the new struct gpio_irq_chip.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-11-08 14:06:21 +01:00
Michal Simek
16ee62e560 gpio: zynq: Fix driver function parameters alignment
Fix function parameters alignment reported by checkpatch.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 16:01:06 +02:00
Nava kishore Manne
2717cfcaf5 gpio: zynq: Fix warnings in the driver
This patch fixes the below warning
	-->Block comments should align the * on each line.
	-->suspect code indent for conditional statements.
	-->Prefer 'unsigned int' to bare use of 'unsigned'

Signed-off-by: Nava kishore Manne <navam@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 16:00:08 +02:00
Michal Simek
eb73d6eaa6 gpio: zynq: Fix empty lines in driver
Remove one additional line and add two new. All are reported by checkpatch.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:59:37 +02:00
Nava kishore Manne
6ae5104cba gpio: zynq: Fix kernel doc warnings
This patch fixes the kernel doc warnings in the driver.

Signed-off-by: Nava kishore Manne <navam@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:58:22 +02:00
Swapna Manupati
06aa09081d gpio: zynq: Provided workaround for GPIO
This patch provides workaround in the gpio driver
for Zynq and ZynqMP Platforms by reading pin value
of EMIO banks through DATA register as it was unable
to read the value of it from DATA_RO register.

Signed-off-by: Swapna Manupati <swapnam@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:57:06 +02:00
Shubhrajyoti Datta
e11de4de28 gpio: zynq: Add support for suspend resume
Add support for suspend resume. Now that we can lose context across
a suspend/ resume cycle. Add support for the context restore.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:43:53 +02:00
Soren Brinkmann
3638bd4a06 gpio: zynq: Clarify quirk and provide helper function
The one quirk used in the zynq GPIO driver was called FOO which is not
very descriptive. Rename the quirk to IS_ZYNQ as it indicates whether
the HW is a zynq or zynqmp device to allow handling of device-specific
differences of the HW.
Also provide a helper function to test whether the HW is zynq or zynqmp.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-16 11:13:12 +02:00
Masahiro Yamada
7808c42b40 gpio: zynq: remove unneeded (void *) casts in of_match_table
of_device_id::data is an opaque pointer.  No explicit cast is needed.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-05-22 17:13:04 +02:00
Nava kishore Manne
e3296f19c8 gpio: Added zynq specific check for special pins on bank zero
This patch adds zynq specific check for bank 0 pins 7 and 8
are special and cannot be used as inputs

Signed-off-by: Nava kishore Manne <navam@xilinx.com>
Reported-by: Jonas Karlsson <Jonas.d.karlsson@gmail.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-09-23 15:26:20 +02:00
Helmut Grohne
0f84f29ff3 gpio: zynq: initialize clock even without CONFIG_PM
When the PM initialization was moved in the commit referenced below, the
code enabling the clock was removed from the probe function. On
CONFIG_PM=y kernels, this is not a problem as the pm resume hook enables
the clock, but when power management is disabled, all those pm_*
functions are noops and the clock is never enabled resulting in a
dysfunctional gpio controller.

Put the clock initialization back to support CONFIG_PM=n.

Cc: stable@vger.kernel.org
Signed-off-by: Helmut Grohne <h.grohne@intenta.de>
Fixes: 3773c195d3 ("gpio: zynq: Do PM initialization earlier to support gpio hogs")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-06-08 10:36:29 +02:00
Shubhrajyoti Datta
615d23f80e gpio: zynq: Fix the error path
pm_runtime_disable is called only in remove it is missed
out in the error path.
Fix the same.

Signed-off-by: Shubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-04-09 20:14:36 +02:00
Linus Walleij
31a8944752 gpio: zynq: use gpiochip data pointer
This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-01-05 11:21:20 +01:00
Michal Simek
3773c195d3 gpio: zynq: Do PM initialization earlier to support gpio hogs
GPIO hogs registration is call at the end of gpiochip_add() function.
Calling sequence is:
gpiochip_add -> of_gpiochip_add -> of_gpiochip_scan_hogs ->
gpiod_hog -> gpiochip_request_own_desc -> __gpiod_request ->
chip->request -> zynq_gpio_request which calls pm_runtime_get_sync()
which returns -13 because PM is not initialized yet.

Initialize PM before gpiochip_add is called to fix this issue.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-12-14 14:10:04 +01:00
Linus Walleij
58383c7842 gpio: change member .dev to .parent
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: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-11-19 09:24:35 +01:00
Linus Walleij
fa9795d112 gpio: zynq: use container_of() to get state container
The state container of the Zynq GPIO driver is sometimes
extracted from the gpio_chip exploiting the fact that offsetof()
the struct gpio_chip inside the struct zynq_gpio is 0, so
the container_of() is in practice a noop. However if a member
is added to struct zynq_gpio in front of struct gpio_chip,
things will break. Using proper container_of() avoids this
problem.

Semantically this is a noop, the compiler will optimize it away,
but syntactically it makes me happier.

Also replace some explicit container_of() calls with the helper
function.

Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Ezra Savard <ezra.savard@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Acked-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-10-02 04:19:33 -07:00
Thomas Gleixner
bd0b9ac405 genirq: Remove irq argument from irq flow handlers
Most interrupt flow handlers do not use the irq argument. Those few
which use it can retrieve the irq number from the irq descriptor.

Remove the argument.

Search and replace was done with coccinelle and some extra helper
scripts around it. Thanks to Julia for her help!

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
2015-09-16 15:47:51 +02:00
Linus Walleij
5f6f02cd49 Linux 4.2-rc4
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Merge tag 'v4.2-rc4' into devel

Linux 4.2-rc4
2015-08-13 14:42:55 +02:00
Linus Walleij
bcae888039 Merge branch 'queue/irq/gpio' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into devel 2015-07-17 14:45:31 +02:00
Michal Simek
6b956af080 gpio: zynq: Fix problem with unbalanced pm_runtime_enable
Add missing pm_runtime_disabled to remove().

Error log:
root@zynqmp:~# modprobe gpio_zynq
root@zynqmp:~# lsmod
    Not tainted
gpio_zynq 7086 0 - Live 0xffffffbffc00a000
root@zynqmp:~# rmmod gpio_zynq
root@zynqmp:~# lsmod
    Not tainted
root@zynqmp:~# modprobe gpio_zynq
[  246.924438] zynq-gpio ff0a0000.gpio: Unbalanced pm_runtime_enable!
root@zynqmp:~# rmmod gpio_zynq
root@zynqmp:~# lsmod
    Not tainted

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-07-16 13:00:43 +02:00
Masahiro Yamada
80d2bf55a1 gpio: zynq: add missing module_exit function
This driver is tristate, so it should be cleanable.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-07-16 00:11:02 +02:00
Jiang Liu
476f8b4c94 gpio: Use irq_desc_get_xxx() to avoid redundant lookup of irq_desc
Use irq_desc_get_xxx() to avoid redundant lookup of irq_desc while we
already have a pointer to corresponding irq_desc.

Preparatory patch for the removal of the 'irq' argument from irq flow
handlers.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-14 12:12:20 +02:00
Thomas Gleixner
47c0846292 gpio/zynq: Use irq_set_chip_handler_name_locked()
Hand in irq_data and avoid the redundant lookup of irq_desc.

Originally-from: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-14 12:12:19 +02:00
Anurag Kumar Vulisha
bdf7a4ae37 gpio: Added support to Zynq Ultrascale+ MPSoC
Added support to Zynq Ultrascale+ MPSoC on the existing zynq
gpio driver.

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-06-10 09:44:17 +02:00
Colin Cronin
20a8a96873 Drivers: gpio: Fix spelling errors
Fixed several spelling errors in gpio-lynxpoint, gpio-pca953x,
gpio-tegra, gpio-zynq, gpiolib-of, gpiolib.

Signed-off-by: Colin Cronin <colinpatrickcronin@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-19 16:52:30 +02:00
Rafael J. Wysocki
6ed23b806e PM: Merge the SET*_RUNTIME_PM_OPS() macros
The SET_PM_RUNTIME_PM_OPS() and SET_RUNTIME_PM_OPS() macros are
identical except that one of them is not empty for CONFIG_PM set,
while the other one is not empty for CONFIG_PM_RUNTIME set,
respectively.

However, after commit b2b49ccbdd (PM: Kconfig: Set PM_RUNTIME if
PM_SLEEP is selected) PM_RUNTIME is always set if PM is set, so one
of these macros is now redundant.

For this reason, replace SET_PM_RUNTIME_PM_OPS() with
SET_RUNTIME_PM_OPS() everywhere and redefine the SET_PM_RUNTIME_PM_OPS
symbol as SET_RUNTIME_PM_OPS in case new code is starting to use the
macro being removed here.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-12-04 00:51:30 +01:00
Linus Walleij
da26d5d803 gpio: remove remaining users of gpiochip_remove() retval
Some drivers accidentally still use the return value from
gpiochip_remove(). Get rid of them so we can simplify this function
and get rid of the return value.

Cc: Abdoulaye Berthe <berthe.ab@gmail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-09-23 17:51:17 +02:00
abdoulaye berthe
88d5e520aa driver:gpio remove all usage of gpio_remove retval in driver
this remove all reference to gpio_remove retval in all driver
except pinctrl and gpio. the same thing is done for gpio and
pinctrl in two different patches.

Signed-off-by: Abdoulaye Berthe <berthe.ab@gmail.com>
Acked-by: Michael Büsch <m@bues.ch>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-09-18 11:03:10 -07:00
Ezra Savard
59e22114b2 gpio: zynq: Fixed broken wakeup implementation
Use of unmask/mask in set_wake was an incorrect implementation. The new
implementation correctly sets wakeup for the gpio chip's IRQ so the gpio chip
will not sleep while wakeup-enabled gpio are in use.

Signed-off-by: Ezra Savard <ezra.savard@xilinx.com>
Reviewed-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-09-04 18:23:29 +02:00
Ezra Savard
a194677881 gpio: zynq: Mask non-wakeup GPIO interrupts on suspend
Added flag to the GPIO chip so that IRQ from non-wakeup GPIO will
not wake the system.

Signed-off-by: Ezra Savard <ezra.savard@xilinx.com>
Reviewed-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-09-04 18:22:17 +02:00
Lars-Peter Clausen
016da14439 gpio: zynq: Take bank offset into account when reporting a IRQ
When looking up the IRQ the bank offset needs to be taken into account.
Otherwise interrupts for banks other than bank 0 get incorrectly reported as
interrupts for bank 0.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-09-03 13:56:31 +02:00
Lars-Peter Clausen
5a2533a747 gpio: zynq: Reduce level of indention in zynq_gpio_irqhandler()
zynq_gpio_irqhandler() uses up to 7 tabs of indention in some parts. Refactor
things to use a helper function for the inner loop to reduce the indention to a
sane level.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-08-29 08:31:57 +02:00
Michal Simek
51dd2e8ec9 gpio: zynq: Remove .owner field for driver
There is no need to init .owner field.

Based on the patch from Peter Griffin <peter.griffin@linaro.org>
"mmc: remove .owner field for drivers using module_platform_driver"

This patch removes the superflous .owner field for drivers which
use the module_platform_driver API, as this is overriden in
platform_driver_register anyway."

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-08-29 07:46:20 +02:00
Lars-Peter Clausen
6dd8595083 gpio: zynq: Fix IRQ handlers
The Zynq GPIO interrupt handling code as two main issues:
1) It does not support IRQF_ONESHOT interrupt since it uses handle_simple_irq()
for the interrupt handler. handle_simple_irq() does not do masking and unmasking
of the IRQ that is required for this chip to be able to support IRQF_ONESHOT
IRQs, causing the CPU to lock up in a interrupt storm if such a interrupt is
requested.
2) Interrupts are acked after the primary interrupt handlers for all asserted
interrupts in a bank have been called. For edge triggered interrupt this is to
late and may cause a interrupt to be missed. For level triggered oneshot
interrupts this is to early and causes the interrupt handler to run twice per
interrupt.

This patch addresses the issue by updating the driver to use the correct IRQ
chip handler functions that are appropriate for this kind of IRQ controller.

The following diagram gives an overview of how the interrupt detection circuit
works, it is not necessarily a accurate depiction of the real hardware though.

     INT_POL/INT_ON_ANY
           |
           | +---+                       INT_STATUS
           `-|   |                            |
             | E |-.                          |
         ,---|   |  \     |\          +----+  |  +---+
         |   +---+   `----| | ,-------|S   | ,*--|   |
GPIO_IN -*                | |-        |   Q|-    | & |-- IRQ_OUT
         |   +---+  ,-----| |       ,-|R   |   ,o|   |
         `---|   | /      |/       |  +----+  |  +---+
             | = |-        |       |          |
           ,-|   |    INT_TYPE    ACK     INT_MASK
           | +---+
           |
        INT_POL

GPIO_IN is the raw signal level connected to the hardware pin. This signal is
routed to a edge detector and to a level detector. The edge detector can be
configured to either detect a rising or falling edge or both edges. The level
detector can detect either a level high or level low event. Depending on the
setting of the INT_TYPE register either the edge or level event will be
propagated to the INT_STATUS register. As long as a interrupt condition is
detected the INT_STATUS register will be set to 1. It can be cleared to 0 if
(and only if) the interrupt condition is no longer detected and software
acknowledges the interrupt by writing a 1 to the address of the INT_STATUS
register. There is also the INT_MASK register which can be used to disable the
propagation of the INT_STATUS signal to the upstream IRQ controller. What is
important to note is that the interrupt detection logic itself can not be
disabled, only the propagation of the INT_STATUS register can be delayed. This
means that for level type interrupts the interrupt must only be acknowledged
after the interrupt source has been cleared otherwise it will stay asserted and
the interrupt handler will be run a second time. For IRQF_ONESHOT interrupts
this means that the IRQ must only be acknowledged after the threaded interrupt
has finished running. If a second interrupt comes in between handling the first
interrupt and acknowledging it the external interrupt will be asserted, which
means trying to acknowledge the first interrupt will not clear the INT_STATUS
register and the interrupt handler will be run a second time when the IRQ is
unmasked, so no interrupts will be lost. The handle_fasteoi_irq() handler in
combination with the IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED flags will
have the desired behavior. For edge triggered interrupts a slightly different
strategy is necessary. For edge triggered interrupts the interrupt condition is
only true when the edge itself is detected, this means this is the only time the
INT_STATUS register is set, acknowledging the interrupt any time after that will
clear the INT_STATUS register until the next interrupt happens. This means in
order to not loose any interrupts the interrupt needs to be acknowledged before
running the interrupt handler. If a second interrupt occurs after the first
interrupt handler has finished but before the interrupt is unmasked the
INT_STATUS register will be re-asserted and the interrupt handler runs a second
time once the interrupt is unmasked. This means with this flow handling strategy
no interrupts are lost for edge triggered interrupts. The handle_level_irq()
handler will have the desired behavior. (Note: The handle_edge_irq() only needs
to be used for edge triggered interrupts where the controller stops detecting
the interrupt event when the interrupt is masked, for this controller the
detection logic still works, while only the propagation is delayed when the
interrupt is masked.)

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-08-17 09:12:35 -05:00
Lars-Peter Clausen
190dc2e684 gpio: zynq: Clear pending interrupt when enabling a IRQ
The Zynq GPIO controller does not disable the interrupt detection when the
interrupt is masked and only disables the propagation of the interrupt. This
means when the controller detects an interrupt condition while the interrupt is
logically disabled (and masked) it will propagate the recorded interrupt event
once the interrupt is enabled. This will cause the interrupt consumer to see
spurious interrupts to prevent this first make sure that the interrupt is not
asserted and then enable it.

E.g. when a interrupt is requested with request_irq() it will be configured
according to the requested type (edge/level triggered, etc.) after that it will
be enabled. But the detection circuit might have already registered a false
interrupt before the interrupt type was correctly configured and once the
interrupt is unmasked this false interrupt will be propagated and the interrupt
handler for the just request interrupt will called.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-23 16:29:14 +02:00
Harini Katakam
3242ba117e gpio: Add driver for Zynq GPIO controller
Add support for GPIO controller used by Xilinx Zynq.

v3 changes:
 - Use linux/gpio/driver.h instead of linux/gpio.h
 - Make irq a local variable in probe

v2 changes:
 - convert to pm_runtime_force_(suspend|resume)
 - add pm_runtime_set_active in probe()
 - also (un)prepare clocks when they are dis-/enabled
 - add some missing calls to pm_runtime_get()
 - use pm_runtime_put() instead of sync variant
 - remove gpio chip in driver remove()
 - remove redundant type casts
 - directly use IO helpers
 - use BIT macro to set/clear bits
 - migrate to GPIOLIB_IRQCHIP

Signed-off-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-10 11:11:41 +02:00