The GPIO subsystem used to have a serious problem with undefined behavior
and use-after-free bugs on hot-unplug of GPIO chips. This can be
considered a corner-case by some as most GPIO controllers are enabled
early in the boot process and live until the system goes down but most
GPIO drivers do allow unbind over sysfs, many are loadable modules that
can be (force) unloaded and there are also GPIO devices that can be
dynamically detached, for instance CP2112 which is a USB GPIO expender.

Bugs can be triggered both from user-space as well as by in-kernel users.
We have the means of testing it from user-space via the character device
but the issues manifest themselves differently in the kernel.

This is a proposition of adding a new virtual driver - a configurable
GPIO consumer that can be configured over configfs (similarly to
gpio-sim) or described on the device-tree.

This driver is aimed as a helper in spotting any regressions in
hot-unplug handling in GPIOLIB.

Link: https://lore.kernel.org/r/20240708142912.120570-1-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Describe common "gpio-line-names" property to allow DTs to
specify names for GPIO lines.
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240708084107.38986-2-frieder@fris.deSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Use the extended irq_sim interface to supply the simulated interrupt
domain with callbacks allowing the GPIO sim to lock/unlock GPIOs
requested as interrupts.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240624093934.17089-3-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Currently users of the interrupt simulator don't have any way of being
notified about interrupts from the simulated domain being requested or
released. This causes a problem for one of the users - the GPIO
simulator - which is unable to lock the pins as interrupts.

Define a structure containing callbacks to be executed on various
irq_sim-related events (for now: irq request and release) and provide an
extended function for creating simulated interrupt domains that takes it
and a pointer to custom user data (to be passed to said callbacks) as
arguments.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240624093934.17089-2-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add compatible string for chip ls1046 to fix below warning.
arch/arm64/boot/dts/freescale/fsl-ls1046a-frwy.dtb: /soc/gpio@2300000: failed to match any schema with compatible: ['fsl,ls1046a-gpio', 'fsl,qoriq-gpio']
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240702201724.96681-1-Frank.Li@nxp.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

This function has been deprecated for some time and is now only used
within the GPIOLIB core. Remove it from the public header and unexport
it as all current users are linked against the compilation unit where
it is defined.

Link: https://lore.kernel.org/r/20240625073815.12376-1-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

This is a sloppy logic analyzer using GPIOs. It comes with a script to
isolate a CPU for polling. While this is definitely not a production
level analyzer, it can be a helpful first view when remote debugging.
Read the documentation for details.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240620094159.6785-2-wsa+renesas@sang-engineering.com
[Bartosz: moved the Kconfig entry into a different category]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Update description of reconfiguration rules, adding requirement that a
direction flag be set to enable changing configuration for a line.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240626052925.174272-5-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Update description of reconfiguration rules, adding requirement that a
direction flag be set or the configuration is considered invalid.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240626052925.174272-4-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add common gpio-line-names property for fsl,qoriq-gpio to fix below
warning.

arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-kbox-a-230-ls.dtb: gpio@2300000: 'gpio-line-names' does not match any of the regexes: 'pinctrl-[0-9]+'
        from schema $id: http://devicetree.org/schemas/gpio/fsl,qoriq-gpio.yamlSigned-off-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240627202151.456812-1-Frank.Li@nxp.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

ath79 target has already been converted to device tree based platform.
Use dynamic GPIO numberspace base to suppress the warning:

gpio gpiochip0: Static allocation of GPIO base is deprecated, use dynamic allocation.

Tested on Atheros AR7241 and AR9344.
Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Suggested-by: Jonas Gorski <jonas.gorski@gmail.com>
Link: https://lore.kernel.org/r/TYCP286MB089598EA71E964BD8AB9EFD3BCD62@TYCP286MB0895.JPNP286.PROD.OUTLOOK.COM
[Bartosz: tweaked the commit message]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In order to finally confine the unsafe gpiochip_get_desc() to
drivers/gpio/, let's convert this driver to using the safer alternative
that takes the gpio_device as argument.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240618111824.15593-1-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The gpio_suffixes array is defined in the gpiolib.h header. This means
the array is stored in .rodata of every compilation unit that includes
it. Put the definition for the array in gpiolib.c and export just the
symbol in the header. We need the size of the array so expose it too.
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20240612184821.58053-1-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The documentation does not make sufficiently clear that edge polarity is
based on changes to the logical line values, and that the physical
polarity of edges is dependent on the active low flag.

Clarify the relationship between the active low flag and edge polarity
for the functions that read edge events.
Suggested-by: David C. Rankin <drankinatty@gmail.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240610092157.9147-3-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The documentation does not make sufficiently clear that the uAPI deals with
logical line values, nor does it describe the influence of the active low
flag on the mapping between physical and logical line values.

Clarify the relationship between physical and logical line values and the
effect of the active low flag for ioctls passing line values.
Suggested-by: David C. Rankin <drankinatty@gmail.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240610092157.9147-2-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

GPIO chips should be added with driver-private data associated with the
chip. If none is needed, NULL can be used. All users already do this
except one, fix that here. With no more users of the base gpiochip_add()
we can drop this function so no more users show up later.
Signed-off-by: Andrew Davis <afd@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240610135313.142571-1-afd@ti.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Drop the hand-coded devres action callback for destroying the mutex in
favor of devm_mutex_init().
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240610140548.35358-4-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

We included kernel.h for ARRAY_SIZE() which has since been moved into
its own header. Use it instead.
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240610140548.35358-3-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Use the dedicated helper for comparing device names against strings.
While at it: reshuffle the code a bit for less indentation.
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240610140548.35358-2-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In legacy sysfs GPIO, when using poll(2) on the sysfs GPIO value for
state change awaiting, a subsequent read(2) is required for consuming
the event, which the doc recommends the use of lseek(2) or
close-and-reopen to reset the file offset afterwards.

The recommendations however, require at least 2 syscalls to consume
the event. Gladly, use of pread(2) require only 1 syscall for the
consumption. Let's advertise this usage by prioritizing its placement.
Signed-off-by: Huichun Feng <foxhoundsk.tw@gmail.com>
Link: https://lore.kernel.org/r/20240609173728.2950808-1-foxhoundsk.tw@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Show more info for interrupt only lines in debugfs. It's useful
to monitor the lines that have been never requested as GPIOs,
but IRQs.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240530191418.1138003-3-andriy.shevchenko@linux.intel.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

If line has been locked as IRQ without requesting,
still check its label and return it, if not NULL.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240530191418.1138003-2-andriy.shevchenko@linux.intel.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpiochip_set_desc_names() cannot fail so drop its return value.

Link: https://lore.kernel.org/r/20240527194613.197810-1-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Squash warnings such as:

    arch/arm/boot/dts/aspeed/aspeed-ast2500-evb.dtb: sgpio@1e780200: '#interrupt-cells' does not match any of the regexes: 'pinctrl-[0-9]+'

Also, mark #interrupt-cells as required. The kernel devicetrees already
specified it where compatible nodes were defined, and u-boot pulls in
the kernel devicetrees, so this should have minimal practical impact.
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240530-dt-warnings-gpio-sgpio-interrupt-cells-v2-2-912cd16e641f@codeconstruct.com.auSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Some devicetrees specify gpio-line-names in the sgpio node despite it
not being defined by the binding. It's a reasonable thing to do, so
define the property to squash warnings such as:

    arch/arm/boot/dts/aspeed/aspeed-bmc-vegman-rx20.dtb: sgpio@1e780200: 'gpio-line-names' does not match any of the regexes: 'pinctrl-[0-9]+'
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20240530-dt-warnings-gpio-sgpio-interrupt-cells-v2-1-912cd16e641f@codeconstruct.com.auSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Convert binding doc from txt to yaml.

Remove redundated "gpio1: gpio@2300000" example.
Add gpio-controller at example "gpio@1100".
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240531164357.1419858-1-Frank.Li@nxp.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The TI TCA9535 variant has the same programming model as the NXP PCA9535.

Document the "ti,tca9535" compatible string.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240531121801.2161154-2-festevam@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add support for the TI TCA9535 variant.

The NXP PCA9535 is already supported by the driver.

TCA9535 supports lower voltage operation (down to 1.65V VCC)
compared to PCA (down to 2.3V VCC).

>From a software perspective, these models are equivalent as they
have the same register map.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20240531121801.2161154-1-festevam@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The GPIO_BRCMSTB hardware IP is also included in the bcm2712
SoC so enable the driver to also be built for ARCH_BCM2835.
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240530181737.1261450-1-pbrobinson@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The handling of kfifo_out() errors in read functions obscures any error.
The error condition should never occur but, while a ret is set to -EIO, it
is subsequently ignored and the read functions instead return the number
of bytes copied to that point, potentially masking the fact that any error
occurred.

Log a warning and return -EIO in the case of a kfifo_out() error to make
it clear something very odd is going on here.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240529131953.195777-4-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The allocation of the linereq events kfifo is performed in two separate
places.  Add a helper function to remove the duplication.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240529131953.195777-3-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The initialisation of the linereq events kfifo relies on the struct being
zeroed and a subsequent call to kfifo_alloc().  The call to kfifo_alloc()
is deferred until edge detection is first enabled for the linereq.  If the
kfifo is inadvertently accessed before the call to kfifo_alloc(), as was
the case in a recently discovered bug, it behaves as a FIFO of size 1 with
an element size of 0, so writes and reads to the kfifo appear successful
but copy no actual data.

As a defensive measure, initialise the kfifo with INIT_KFIFO() when the
events kfifo is constructed.  This initialises the kfifo element size
and zeroes its data pointer, so any inadvertant access prior to the
kfifo_alloc() call will trigger an oops.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240529131953.195777-2-warthog618@gmail.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

rdc_gpio_config() uses pci_{read,write}_config_dword() that return
PCIBIOS_* codes. rdc_gpio_config() is used for
direction_{input,output}() in the struct gpio_chip which both require
normal errnos to be returned.

Similarly, rdc321x_gpio_probe() that is probe function returns
PCIBIOS_* codes without converting them first into normal errnos.

Convert PCIBIOS_* returns code using pcibios_err_to_errno() into normal
errno before returning them to fix both issues.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240527132345.13956-2-ilpo.jarvinen@linux.intel.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

amd_gpio_init() uses pci_read_config_dword() that returns PCIBIOS_*
codes. The return code is then returned as is but amd_gpio_init() is
a module init function that should return normal errnos.

Convert PCIBIOS_* returns code using pcibios_err_to_errno() into normal
errno before returning it from amd_gpio_init().
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240527132345.13956-1-ilpo.jarvinen@linux.intel.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Do not issue "can't read the data register offset!" when gpio,syscon-dev
is not set albeit unneeded. gpio-syscon is used with rk3328 chip, but
this iomem region is documented in
Documentation/devicetree/bindings/gpio/rockchip,rk3328-grf-gpio.yaml and
does not require gpio,syscon-dev setting.
Signed-off-by: Etienne Buira <etienne.buira@free.fr>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/Zktwd4Y8zu6XSGaE@Z926fQmE5jqhFMgp6Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Convert Zevio GPIO Controller from text to dtschema.
Adding `interrupts` property fixes the following warning:
linux/out/arch/arm/boot/dts/nspire/nspire-tp.dtb: gpio@90000000:
'interrupts' does not match any of the regexes: 'pinctrl-[0-9]+'`
while executing `make dtbs_check` on Texas Instruments
nspire boards.
Signed-off-by: Pratik Farkase <pratik.farkase@wsisweden.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20240522151616.27397-1-pratik.farkase@wsisweden.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Userspace may trigger a speculative read of an address outside the gpio
descriptor array.
Users can do that by calling gpio_ioctl() with an offset out of range.
Offset is copied from user and then used as an array index to get
the gpio descriptor without sanitization in gpio_device_get_desc().

This change ensures that the offset is sanitized by using
array_index_nospec() to mitigate any possibility of speculative
information leaks.

This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.
Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
Link: https://lore.kernel.org/r/20240523085332.1801-1-hagarhem@amazon.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In order to discourage people to use old and legacy GPIO APIs
remove the respective documentation completely. It also helps
further cleanups of the legacy GPIO API leftovers, which is
ongoing task.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hu Haowen <2023002089@link.tyut.edu.cn>
Link: https://lore.kernel.org/r/20240508101703.830066-1-andriy.shevchenko@linux.intel.comSigned-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

percpu.h depends on smp.h, but doesn't include it directly because of
circular header dependency issues; percpu.h is needed in a bunch of low
level headers.

This fixes a randconfig build error on mips:

  include/linux/alloc_tag.h: In function '__alloc_tag_ref_set':
  include/asm-generic/percpu.h:31:40: error: implicit declaration of function 'raw_smp_processor_id' [-Werror=implicit-function-declaration]
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 24e44cc2 ("mm: percpu: enable per-cpu allocation tagging")
Closes: https://lore.kernel.org/oe-kbuild-all/202405210052.DIrMXJNz-lkp@intel.com/Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>