This reverts commit 923b93e451.
Make sure consumers do not overwrite gpio flags for pins that have
already been claimed.
While adding support for gpio drivers to refuse a request using
unsupported flags, the order of when the requested flag was checked and
the new flags were applied was reversed to that consumers could
overwrite flags for already requested gpios.
This not only affects device-tree setups where two drivers could request
the same gpio using conflicting configurations, but also allowed user
space to clear gpio flags for already claimed pins simply by attempting
to export them through the sysfs interface. By for example clearing the
FLAG_ACTIVE_LOW flag this way, user space could effectively change the
polarity of a signal.
Reverting this change obviously prevents gpio drivers from doing sanity
checks on the flags in their request callbacks. Fortunately only one
recently added driver (gpio-tps65218 in v4.6) appears to do this, and a
follow up patch could restore this functionality through a different
interface.
Cc: stable <stable@vger.kernel.org> # 4.4
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Most functions that take a GPIO descriptor in need to check the
descriptor for IS_ERR(). We do this mostly in the VALIDATE_DESC()
macro except for the gpiod_to_irq() function which needs special
handling.
Cc: stable@vger.kernel.org
Reported-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
commit 54d77198fd
("gpio: bail out silently on NULL descriptors")
doesn't work for gpiod_to_irq(): drivers assume that NULL
descriptors will give negative IRQ numbers in return.
It has been pointed out that returning 0 is NO_IRQ and that
drivers should be amended to treat this as an error, but that
is for the longer term: now let us repair the semantics.
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Reported-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
gpiolib relies on the reference counters to clean up the gpio_device
structure.
Although the number of get/put is properly aligned on gpiolib.c
itself, it does not take into consideration how the referece counters
are affected by other external functions such as cdev_add and device_add.
Because of this, after the last call to put_device, the reference counter
has a value of +3, therefore never calling gpiodevice_release.
Due to the fact that some of the device has already been cleaned on
gpiochip_remove, the library will end up OOPsing the kernel (e.g. a call
to of_gpiochip_find_and_xlate).
Cc: stable@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Under some circumstances, a gpiochip might be half cleaned from the
gpio_device list.
This patch makes sure that the chip pointer is still valid, before
calling the match function.
[ 104.088296] BUG: unable to handle kernel NULL pointer dereference at
0000000000000090
[ 104.089772] IP: [<ffffffff813d2045>] of_gpiochip_find_and_xlate+0x15/0x80
[ 104.128273] Call Trace:
[ 104.129802] [<ffffffff813d2030>] ? of_parse_own_gpio+0x1f0/0x1f0
[ 104.131353] [<ffffffff813cd910>] gpiochip_find+0x60/0x90
[ 104.132868] [<ffffffff813d21ba>] of_get_named_gpiod_flags+0x9a/0x120
...
[ 104.141586] [<ffffffff8163d12b>] gpio_led_probe+0x11b/0x360
Cc: stable@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
When adding the gpiochip, the GPIO HW drivers' callback get_direction()
could get called in atomic context. Some of the GPIO HW drivers may
sleep when accessing the register.
Move the lock before initializing the descriptors.
Reported-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
In fdeb8e1547
("gpio: reflect base and ngpio into gpio_device")
assumed that GPIO descriptors are either valid or error
pointers, but gpiod_get_[index_]optional() actually return
NULL descriptors and then all subsequent calls should just
bail out.
Cc: stable@vger.kernel.org
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Fixes: fdeb8e1547 ("gpio: reflect base and ngpio into gpio_device")
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
If we're using the compatible ioctl() we need to handle the
argument pointer in a special way or there will be trouble.
Fixes: 3c702e9987 ("gpio: add a userspace chardev ABI for GPIOs")
Reported-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
As irqchip and gpiochip functions are orthogonal, the IRQ
set-up or something else can have changed the direction of
the GPIO line from what the GPIO descriptor knows when we
get into gpiochip_lock_as_irq(). Make sure to re-read the
direction setting if we have the .get_direction() callback
enabled for the chip.
Else we get problems like this:
iio iio:device2: interrupts on the rising edge
gpio gpiochip2: (8012e080.gpio): gpiochip_lock_as_irq:
tried to flag a GPIO set as output for IRQ
gpio gpiochip2: (8012e080.gpio): unable to lock HW IRQ 0 for IRQ
genirq: Failed to request resources for l3g4200d-trigger
(irq 111) on irqchip nmk1-32-63
iio iio:device2: failed to request trigger IRQ.
st-gyro-i2c: probe of 2-0068 failed with error -22
Fixes: 72d3200061 ("gpio: set up initial state from .get_direction()")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Core infrastructural changes:
- Support for natively single-ended GPIO driver stages. This
means that if the hardware has registers to configure open
drain or open source configuration, we use that rather than
(as we did before) try to emulate it by switching the line
to an input to get high impedance. This is also documented
throughly in Documentation/gpio/driver.txt for those of you
who did not understand one word of what I just wrote.
- Start to do away with the unnecessarily complex and
unitelligible ARCH_REQUIRE_GPIOLIB and
ARCH_WANT_OPTIONAL_GPIOLIB, another evolutional artifact from
the time when the GPIO subsystem was unmaintained. Archs can
now just select GPIOLIB and be done with it, cleanups to
arches will trickle in for the next kernel. Some minor archs
ACKed the changes immediately so these are included in this
pull request.
- Advancing the use of the data pointer inside the GPIO device
for storing driver data by switching the PowerPC, Super-H
Unicore and a few other subarches or subsystem drivers in
ALSA SoC, Input, serial, SSB, staging etc to use it.
- The initialization now reads the input/output state of the
GPIO lines, so that each GPIO descriptor knows - if this
callback is implemented - whether the line is input or
output. This also reflects nicely in userspace "lsgpio".
- It is now possible to name GPIO producer names, line names,
from the device tree. (Platform data has been supported for
a while.) I bet we will get a similar mechanism for ACPI
one of those days. This makes is possible to get sensible
producer names for e.g. GPIO rails in "lsgpio" in userspace.
New drivers:
- New driver for the Loongson1.
- The XLP driver now supports Broadcom Vulcan ARM64.
- The IT87 driver now supports IT8620 and IT8628.
- The PCA953X driver now supports Galileo Gen2.
Driver improvements:
- MCP23S08 was switched to use the gpiolib irqchip helpers and
now also suppors level-triggered interrupts.
- 74x164 and RCAR now supports the .set_multiple() callback
- AMDPT was converted to use generic GPIO.
- TC3589x, TPS65218, SX150X, F7188X, MENZ127, VX855, WM831X, WM8994
support the new single ended callback for open drain
and in some cases open source.
- Implement the .get_direction() callback for a few more drivers
like PL061, Xgene.
Cleanups:
- Paul Gortmaker combed through the drivers and de-modularized
those who are not really modules.
- Move the GPIO poweroff DT bindings to the power subdir where
they belong.
- Rename gpio-generic.c to gpio-mmio.c, which is much more to the
point. That's what it is handling, nothing more, nothing less.
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Merge tag 'gpio-v4.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO updates from Linus Walleij:
"This is the bulk of GPIO changes for kernel cycle v4.7:
Core infrastructural changes:
- Support for natively single-ended GPIO driver stages.
This means that if the hardware has registers to configure open
drain or open source configuration, we use that rather than (as we
did before) try to emulate it by switching the line to an input to
get high impedance.
This is also documented throughly in Documentation/gpio/driver.txt
for those of you who did not understand one word of what I just
wrote.
- Start to do away with the unnecessarily complex and unitelligible
ARCH_REQUIRE_GPIOLIB and ARCH_WANT_OPTIONAL_GPIOLIB, another
evolutional artifact from the time when the GPIO subsystem was
unmaintained.
Archs can now just select GPIOLIB and be done with it, cleanups to
arches will trickle in for the next kernel. Some minor archs ACKed
the changes immediately so these are included in this pull request.
- Advancing the use of the data pointer inside the GPIO device for
storing driver data by switching the PowerPC, Super-H Unicore and
a few other subarches or subsystem drivers in ALSA SoC, Input,
serial, SSB, staging etc to use it.
- The initialization now reads the input/output state of the GPIO
lines, so that each GPIO descriptor knows - if this callback is
implemented - whether the line is input or output. This also
reflects nicely in userspace "lsgpio".
- It is now possible to name GPIO producer names, line names, from
the device tree. (Platform data has been supported for a while).
I bet we will get a similar mechanism for ACPI one of those days.
This makes is possible to get sensible producer names for e.g.
GPIO rails in "lsgpio" in userspace.
New drivers:
- New driver for the Loongson1.
- The XLP driver now supports Broadcom Vulcan ARM64.
- The IT87 driver now supports IT8620 and IT8628.
- The PCA953X driver now supports Galileo Gen2.
Driver improvements:
- MCP23S08 was switched to use the gpiolib irqchip helpers and now
also suppors level-triggered interrupts.
- 74x164 and RCAR now supports the .set_multiple() callback
- AMDPT was converted to use generic GPIO.
- TC3589x, TPS65218, SX150X, F7188X, MENZ127, VX855, WM831X, WM8994
support the new single ended callback for open drain and in some
cases open source.
- Implement the .get_direction() callback for a few more drivers like
PL061, Xgene.
Cleanups:
- Paul Gortmaker combed through the drivers and de-modularized those
who are not really modules.
- Move the GPIO poweroff DT bindings to the power subdir where they
belong.
- Rename gpio-generic.c to gpio-mmio.c, which is much more to the
point. That's what it is handling, nothing more, nothing less"
* tag 'gpio-v4.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (126 commits)
MIPS: do away with ARCH_[WANT_OPTIONAL|REQUIRE]_GPIOLIB
gpio: zevio: make it explicitly non-modular
gpio: timberdale: make it explicitly non-modular
gpio: stmpe: make it explicitly non-modular
gpio: sodaville: make it explicitly non-modular
pinctrl: sh-pfc: Let gpio_chip.to_irq() return zero on error
gpio: dwapb: Add ACPI device ID for DWAPB GPIO controller on X-Gene platforms
gpio: dt-bindings: add wd,mbl-gpio bindings
gpio: of: make it possible to name GPIO lines
gpio: make gpiod_to_irq() return negative for NO_IRQ
gpio: xgene: implement .get_direction()
gpio: xgene: Enable ACPI support for X-Gene GFC GPIO driver
gpio: tegra: Implement gpio_get_direction callback
gpio: set up initial state from .get_direction()
gpio: rename gpio-generic.c into gpio-mmio.c
gpio: generic: fix GPIO_GENERIC_PLATFORM is set to module case
gpio: dwapb: add gpio-signaled acpi event support
gpio: dwapb: convert device node to fwnode
gpio: dwapb: remove name from dwapb_port_property
gpio/qoriq: select IRQ_DOMAIN
...
If a translation returns zero, that means NO_IRQ, so we
should return an error since the function is documented to
return a negative code on error.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
If the gpiochip supports the .get_direction() callback, then
the initial state of the descriptor flags should be set up
as output accordingly. Also put in comments explaining what is
going on.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This renames gpiod_set_array_value_priv() to
gpiod_set_array_value_complex() and moves it to the gpiolib.h
private header file so we can reuse it in the subsystem.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Print the error number of GPIO hog failed during its configurations.
This helps in identifying the failure without instrumenting the code.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Since commit ff2b135922 ("gpio: make the gpiochip a real device"),
attempts to add a gpio chip prior to gpiolib initialization cause
the system to crash. This happens because gpio_bus_type has not been
registered yet. Defer creating gpio devices until after gpiolib has
been initialized to fix the problem.
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Fixes: ff2b135922 ("gpio: make the gpiochip a real device")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
It is possible that a gpio chip is registered before the gpiolib
initialization code has run. This means we can not use devm_ functions
to allocate memory at that time. Do it the old fashioned way.
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
When firmware does not use _DSD properties that allow properly name GPIO
resources, the kernel falls back on parsing _CRS resources, and will
return entries described as GpioInt() as general purpose GPIOs even
though they are meant to be used simply as interrupt sources for the
device:
Device (ETSA)
{
Name (_HID, "ELAN0001")
...
Method(_CRS, 0x0, NotSerialized)
{
Name(BUF0,ResourceTemplate ()
{
I2CSerialBus(
0x10, /* SlaveAddress */
ControllerInitiated, /* SlaveMode */
400000, /* ConnectionSpeed */
AddressingMode7Bit, /* AddressingMode */
"\\_SB.I2C1", /* ResourceSource */
)
GpioInt (Edge, ActiveLow, ExclusiveAndWake, PullNone,,
"\\_SB.GPSW") { BOARD_TOUCH_GPIO_INDEX }
} )
Return (BUF0)
}
...
}
This gives troubles with drivers such as Elan Touchscreen driver
(elants_i2c) that uses devm_gpiod_get to look up "reset" GPIO line and
decide whether the driver is responsible for powering up and resetting
the device, or firmware is. In the above case the lookup succeeds, we
map GPIO as output and later fail to request client->irq interrupt that
is mapped to the same GPIO.
Let's ignore resources described as GpioInt() while parsing _CRS when
requesting output GPIOs (but allow them when requesting GPIOD_ASIS or
GPIOD_IN as some drivers, such as i2c-hid, do request GPIO as input and
then map it to interrupt with gpiod_to_irq).
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Some GPIO controllers has a special hardware bit we can flip
to support open drain / source. This means that on these hardwares
we do not need to emulate OD/OS by setting the line to input
instead of actively driving it high/low. Add an optional vtable
callback to the driver set_single_ended() so that driver can
implement this in hardware if they have it.
We may need a pinctrl_gpio_set_config() call at some point to
propagate this down to a backing pin control device on systems
with split GPIO/pin control.
Reported-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The original code of gpiodev_add_to_list is not very clear which
lead to bugs or compiling warning, reference the following patches:
Bugs:
1. Commit ef7c755303 ("gpiolib: improve overlap check of range of
gpio").
2. Commit 96098df125 ("gpiolib: fix chip order in gpio list")
Warning:
1. Commit e28ecca6ea ("gpio: fix warning about iterator").
of gpio").
There is a off-list discussion about how to improve it consequently.
This commit try to follow this by rewriting the whole functions.
Tested pass with my gpio mockup driver and test scripts[1].
[1] http://www.spinics.net/lists/linux-gpio/msg09598.html
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
I named the field representing the current user of GPIO line as
"label" but this is too vague and ambiguous. Before anyone gets
confused, rename it to "consumer" and indicate clearly in the
documentation that this is a string set by the user of the line.
Also clean up leftovers in the documentation.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Add device managed APIs devm_gpiochip_add_data() and
devm_gpiochip_remove() for the APIs gpiochip_add_data()
and gpiochip_remove().
This helps in reducing code in error path and sometimes
removal of .remove callback for driver unbind.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
This fixes the wrongly indicated lines in the userspace
ABI: test for the right BITS, do not treat bit numbers as
bitmasks.
Reported-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This adds a GPIO line ABI for getting name, label and a few select
flags from the kernel.
This hides the kernel internals and only tells userspace what it
may need to know: the different in-kernel consumers are masked
behind the flag "kernel" and that is all userspace needs to know.
However electric characteristics like active low, open drain etc
are reflected to userspace, as this is important information.
We provide information on all lines on all chips, later on we will
likely add a flag for the chardev consumer so we can filter and
display only the lines userspace actually uses in e.g. lsgpio,
but then we first need an ABI for userspace to grab and use
(get/set/select direction) a GPIO line.
Sample output from "lsgpio" on ux500:
GPIO chip: gpiochip7, "8011e000.gpio", 32 GPIO lines
line 0: unnamed unlabeled
line 1: unnamed unlabeled
(...)
line 25: unnamed "SFH7741 Proximity Sensor" [kernel output open-drain]
line 26: unnamed unlabeled
(...)
Tested-by: Michael Welling <mwelling@ieee.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The gpio_chip label is useful for userspace to understand what
kind of GPIO chip it is dealing with. Let's store a copy of this
label in the gpio_device, add it to the struct passed to userspace
for GPIO_GET_CHIPINFO_IOCTL and modify lsgpio to show it.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The use of kmalloc() to allocate the gpio_device leaves the contained struct
device object in an unknown state. Calling dev_set_name() on a struct device
of unknown state can trigger the free() of an invalid pointer, as seen in the
following backtrace (collected by Tony Lindgren):
kfree
kobject_set_name_vargs
dev_set_name
gpiochip_add_data
omap_gpio_probe
platform_drv_probe
...
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reported-by: Michael Welling <mwelling@ieee.org>
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Michael Welling <mwelling@ieee.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Josh Cartwright <joshc@ni.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
My left hand merges code to privatize the descriptor handling
while my right hand merges drivers that poke around and
disrespect with the same gpiolib internals.
So let's expose the proper APIs for drivers to ask the gpiolib
core if a line is marked as open drain or open source and
get some order around things so this driver compiles again.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Nicolas Saenz Julienne <nicolassaenzj@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
We move to manage this pointer under gpiolib control rather than
leave it in the subdevice's gpio_chip. We can not NULL it after
gpiochip_remove so at to keep things tight.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Instead of keeping this reference to the pin ranges in the
client driver-supplied gpio_chip, move it to the internal
gpio_device as the drivers have no need to inspect this.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
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 <linus.walleij@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
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 <linus.walleij@linaro.org>
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 <linus.walleij@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
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: Linus Walleij <linus.walleij@linaro.org>
Infrastructural changes:
- In struct gpio_chip, rename the .dev node to .parent to better reflect
the fact that this is not the GPIO struct device abstraction. We will
add that soon so this would be totallt confusing.
- It was noted that the driver .get_value() callbacks was
sometimes reporting negative -ERR values to the gpiolib core, expecting
them to be propagated to consumer gpiod_get_value() and gpio_get_value()
calls. This was not happening, so as there was a mess of drivers
returning negative errors and some returning "anything else than zero"
to indicate that a line was active. As some would have bit 31 set to
indicate "line active" it clashed with negative error codes. This is
fixed by the largeish series clamping values in all drivers with
!!value to [0,1] and then augmenting the code to propagate error codes
to consumers. (Includes some ACKed patches in other subsystems.)
- Add a void *data pointer to struct gpio_chip. The container_of() design
pattern is indeed very nice, but we want to reform the struct gpio_chip
to be a non-volative, stateless business, and keep states internal to
the gpiolib to be able to hold on to the state when adding a proper
userspace ABI (character device) further down the road. To achieve this,
drivers need a handle at the internal state that is not dependent on
their struct gpio_chip() so we add gpiochip_add_data() and
gpiochip_get_data() following the pattern of many other subsystems.
All the "use gpiochip data pointer" patches transforms drivers to this
scheme.
- The Generic GPIO chip header has been merged into the general
<linux/gpio/driver.h> header, and the custom header for that removed.
Instead of having a separate mm_gpio_chip struct for these generic
drivers, merge that into struct gpio_chip, simplifying the code and
removing the need for separate and confusing includes.
Misc improvements:
- Stabilize the way GPIOs are looked up from the ACPI legacy
specification.
- Incremental driver features for PXA, PCA953X, Lantiq (patches from the
OpenWRT community), RCAR, Zynq, PL061, 104-idi-48
New drivers:
- Add a GPIO chip to the ALSA SoC AC97 driver.
- Add a new Broadcom NSP SoC driver (this lands in the pinctrl dir, but
the branch is merged here too to account for infrastructural changes).
- The sx150x driver now supports the sx1502.
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Merge tag 'gpio-v4.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO updates from Linus Walleij:
"Here is the bulk of GPIO changes for v4.5.
Notably there are big refactorings mostly by myself, aimed at getting
the gpio_chip into a shape that makes me believe I can proceed to
preserve state for a proper userspace ABI (character device) that has
already been proposed once, but resulted in the feedback that I need
to go back and restructure stuff. So I've been restructuring stuff.
On the way I ran into brokenness (return code from the get_value()
callback) and had to fix it. Also, refactored generic GPIO to be
simpler.
Some of that is still waiting to trickle down from the subsystems all
over the kernel that provide random gpio_chips, I've touched every
single GPIO driver in the kernel now, oh man I didn't know I was
responsible for so much...
Apart from that we're churning along as usual.
I took some effort to test and retest so it should merge nicely and we
shook out a couple of bugs in -next.
Infrastructural changes:
- In struct gpio_chip, rename the .dev node to .parent to better
reflect the fact that this is not the GPIO struct device
abstraction. We will add that soon so this would be totallt
confusing.
- It was noted that the driver .get_value() callbacks was sometimes
reporting negative -ERR values to the gpiolib core, expecting them
to be propagated to consumer gpiod_get_value() and gpio_get_value()
calls. This was not happening, so as there was a mess of drivers
returning negative errors and some returning "anything else than
zero" to indicate that a line was active. As some would have bit
31 set to indicate "line active" it clashed with negative error
codes. This is fixed by the largeish series clamping values in all
drivers with !!value to [0,1] and then augmenting the code to
propagate error codes to consumers. (Includes some ACKed patches
in other subsystems.)
- Add a void *data pointer to struct gpio_chip. The container_of()
design pattern is indeed very nice, but we want to reform the
struct gpio_chip to be a non-volative, stateless business, and keep
states internal to the gpiolib to be able to hold on to the state
when adding a proper userspace ABI (character device) further down
the road. To achieve this, drivers need a handle at the internal
state that is not dependent on their struct gpio_chip() so we add
gpiochip_add_data() and gpiochip_get_data() following the pattern
of many other subsystems. All the "use gpiochip data pointer"
patches transforms drivers to this scheme.
- The Generic GPIO chip header has been merged into the general
<linux/gpio/driver.h> header, and the custom header for that
removed. Instead of having a separate mm_gpio_chip struct for
these generic drivers, merge that into struct gpio_chip,
simplifying the code and removing the need for separate and
confusing includes.
Misc improvements:
- Stabilize the way GPIOs are looked up from the ACPI legacy
specification.
- Incremental driver features for PXA, PCA953X, Lantiq (patches from
the OpenWRT community), RCAR, Zynq, PL061, 104-idi-48
New drivers:
- Add a GPIO chip to the ALSA SoC AC97 driver.
- Add a new Broadcom NSP SoC driver (this lands in the pinctrl dir,
but the branch is merged here too to account for infrastructural
changes).
- The sx150x driver now supports the sx1502"
* tag 'gpio-v4.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (220 commits)
gpio: generic: make bgpio_pdata always visible
gpiolib: fix chip order in gpio list
gpio: mpc8xxx: Do not use gpiochip_get_data() in mpc8xxx_gpio_save_regs()
gpio: mm-lantiq: Do not use gpiochip_get_data() in ltq_mm_save_regs()
gpio: brcmstb: Allow building driver for BMIPS_GENERIC
gpio: brcmstb: Set endian flags for big-endian MIPS
gpio: moxart: fix build regression
gpio: xilinx: Do not use gpiochip_get_data() in xgpio_save_regs()
leds: pca9532: use gpiochip data pointer
leds: tca6507: use gpiochip data pointer
hid: cp2112: use gpiochip data pointer
bcma: gpio: use gpiochip data pointer
avr32: gpio: use gpiochip data pointer
video: fbdev: via: use gpiochip data pointer
gpio: pch: Optimize pch_gpio_get()
Revert "pinctrl: lantiq: Implement gpio_chip.to_irq"
pinctrl: nsp-gpio: use gpiochip data pointer
pinctrl: vt8500-wmt: use gpiochip data pointer
pinctrl: exynos5440: use gpiochip data pointer
pinctrl: at91-pio4: use gpiochip data pointer
...
Pull input updates from Dmitry Torokhov:
- new driver for eGalaxTouch serial touchscreen
- new driver for TS-4800 touchscreen
- an update for Goodix touchscreen driver
- PS/2 mouse module was reworked to limit number of protocols we try on
pass-through ports to speed up their detection time
- wacom_w8001 touchscreen driver now reports pen and touch via separate
instances of input devices
- other driver changes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (42 commits)
Input: elantech - mark protocols v2 and v3 as semi-mt
Input: wacom_w8001 - drop use of ABS_MT_TOOL_TYPE
Input: gpio-keys - fix check for disabling unsupported keys
Input: omap-keypad - remove dead check
Input: ti_am335x_tsc - fix HWPEN interrupt handling
Input: omap-keypad - set tasklet data earlier
Input: rohm_bu21023 - fix handling of retrying firmware update
Input: ALPS - report v3 pinnacle trackstick device only if is present
Input: ALPS - detect trackstick presence for v7 protocol
Input: pcap_ts - use to_delayed_work
Input: bma150 - constify bma150_cfg structure
Input: i8042 - add Fujitsu Lifebook U745 to the nomux list
Input: egalax_ts_serial - fix potential NULL dereference on error
Input: uinput - sanity check on ff_effects_max and EV_FF
Input: uinput - rework ABS validation
Input: uinput - add new UINPUT_DEV_SETUP and UI_ABS_SETUP ioctl
Input: goodix - use "inverted_[xy]" flags instead of "rotated_screen"
Input: goodix - add axis swapping and axis inversion support
Input: goodix - use goodix_i2c_write_u8 instead of i2c_master_send
Input: goodix - add power management support
...
In some situations the gpio_list order is not correct.
As a consequence gpiochip_find_base returns the same
base number twice. This happens when a first ship is added
with manual base number, then other ships are added using
automatic base number.
To prevent this behaviour, this patch add the new chip after
the last element of the gpio list.
Signed-off-by: Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This adds a void * pointer to gpio_chip so that driver can
assign and retrieve some states. This is done to get rid of
container_of() calls for gpio_chips embedded inside state
containers, so we can remove the need to have the gpio_chip
or later (planned) struct gpio_device be dynamically allocated
at registration time, so that its struct device can be properly
reference counted and not bound to its parent device (e.g.
a platform_device) but instead live on after unregistration
if it is opened by e.g. a char device or sysfs.
The data is added with the new function gpiochip_add_data()
and for compatibility we add static inline wrapper function
gpiochip_add() that will call gpiochip_add_data() with
NULL as argument. The latter will be removed once we have
exorcised gpiochip_add() from the kernel.
gpiochip_get_data() is added as a static inline accessor
for drivers to quickly get their data out.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
When a GPIO is used as an interrupt in ACPI, the irq_type was not
available for device driver.
Make available polarity and triggering information in acpi_find_gpio by
renaming acpi_gpio_info field active_low to polarity and adding triggering
field (edge/level).
For sanity, in gpiolib.c replace info.active_low by
"info.polarity == GPIO_ACTIVE_LOW".
Set the irq_type if necessary in acpi_dev_gpio_irq_get.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We were getting build warning about "iterator" being used uninitialized.
Use iterator properly to fix the build warning and in the process remove
the variable "pos" which is not required now.
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This reverts commit 45ad7db90b.
We have fixed all the drivers that were returning ambious values
not clamped to [0,1] or an error code, so return the error
propagating behaviour of the API.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
commit e20538b82f
("gpio: Propagate errors from chip->get()")
started to propagate errors from the .get() functions since
we can get errors from the infrastructure of e.g. slowbus
GPIO expanders.
However it turns out a bunch of drivers relied on the core
to clamp the value, so we need to revert to the old behaviour
and go over all drivers and fix them to conform to the
expectations of the core before we go back to propagating
the error code.
Cc: stable@vger.kernel.org # 4.3+
Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Cc: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Fixes: e20538b82f ("gpio: Propagate errors from chip->get()")
Reported-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
