linux.git/drivers/gpio/gpiolib-cdev.c, branch v6.5

gpiolib: Introduce gpio_device_get() and gpio_device_put()

2023-01-30T14:55:29+00:00

Introduce gpio_device_get() and gpio_device_put() helpers
and convert existing users.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Linus Walleij 
Signed-off-by: Bartosz Golaszewski

Merge tag 'gpio-updates-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

2022-12-15T17:45:51+00:00

Pull gpio updates from Bartosz Golaszewski:
 "We have a new GPIO multiplexer driver, bunch of driver updates and
  refactoring in the core GPIO library.

  GPIO core:
   - teach gpiolib to work with software nodes for HW description
   - remove ARCH_NR_GPIOS treewide as we no longer impose any limit on
     the number of GPIOS since the allocation became entirely dynamic
   - add support for HW quirks for Cirrus CS42L56 codec, Marvell NFC
     controller, Freescale PCIe and Ethernet controller, Himax LCDs and
     Mediatek mt2701
   - refactor OF quirk code
   - some general refactoring of the OF and ACPI code, adding new
     helpers, minor tweaks and fixes, making fwnode usage consistent
     etc.

  GPIO uAPI:
   - fix an issue where the user-space can trigger a NULL-pointer
     dereference in the kernel by opening a device file, forcing a
     driver unbind and then calling one of the syscalls on the
     associated file descriptor

  New drivers:
   - add gpio-latch: a new GPIO multiplexer based on latches connected
     to other GPIOs

  Driver updates:
   - convert i2c GPIO expanders to using .probe_new()
   - drop the gpio-sta2x11 driver
   - factor out common code for the ACCES IDIO-16 family of controllers
     and use this new library wherever applicable in drivers
   - add DT support to gpio-hisi
   - allow building gpio-davinci as a module and increase its maxItems
     property
   - add support for a new model to gpio-pca9570
   - other minor changes to various drivers"

* tag 'gpio-updates-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (66 commits)
  gpio: sim: set a limit on the number of GPIOs
  gpiolib: protect the GPIO device against being dropped while in use by user-space
  gpiolib: cdev: fix NULL-pointer dereferences
  gpiolib: Provide to_gpio_device() helper
  gpiolib: Unify access to the device properties
  gpio: Do not include  when not really needed.
  gpio: pcf857x: Convert to i2c's .probe_new()
  gpio: pca953x: Convert to i2c's .probe_new()
  gpio: max732x: Convert to i2c's .probe_new()
  dt-bindings: gpio: gpio-davinci: Increase maxItems in gpio-line-names
  gpiolib: ensure that fwnode is properly set
  gpio: sl28cpld: Replace irqchip mask_invert with unmask_base
  gpiolib: of: Use correct fwnode for DT-probed chips
  gpiolib: of: Drop redundant check in of_mm_gpiochip_remove()
  gpiolib: of: Prepare of_mm_gpiochip_add_data() for fwnode
  gpiolib: add support for software nodes
  gpiolib: consolidate GPIO lookups
  gpiolib: acpi: avoid leaking ACPI details into upper gpiolib layers
  gpiolib: acpi: teach acpi_find_gpio() to handle data-only nodes
  gpiolib: acpi: change acpi_find_gpio() to accept firmware node
  ...

gpiolib: protect the GPIO device against being dropped while in use by user-space

2022-12-07T08:35:59+00:00

While any of the GPIO cdev syscalls is in progress, the kernel can call
gpiochip_remove() (for instance, when a USB GPIO expander is disconnected)
which will set gdev->chip to NULL after which any subsequent access will
cause a crash.

To avoid that: use an RW-semaphore in which the syscalls take it for
reading (so that we don't needlessly prohibit the user-space from calling
syscalls simultaneously) while gpiochip_remove() takes it for writing so
that it can only happen once all syscalls return.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Fixes: a54756cb24ea ("gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL")
Fixes: 7b8e00d98168 ("gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL")
Signed-off-by: Bartosz Golaszewski 
[Nick: fixed a build failure with CDEV_V1 disabled]
Co-authored-by: Nick Hainke 
Reviewed-by: Kent Gibson 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Linus Walleij

gpiolib: cdev: fix NULL-pointer dereferences

2022-12-07T08:35:48+00:00

There are several places where we can crash the kernel by requesting
lines, unbinding the GPIO device, then calling any of the system calls
relevant to the GPIO character device's annonymous file descriptors:
ioctl(), read(), poll().

While I observed it with the GPIO simulator, it will also happen for any
of the GPIO devices that can be hot-unplugged - for instance any HID GPIO
expander (e.g. CP2112).

This affects both v1 and v2 uAPI.

This fixes it partially by checking if gdev->chip is not NULL but it
doesn't entirely remedy the situation as we still have a race condition
in which another thread can remove the device after the check.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Fixes: a54756cb24ea ("gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL")
Fixes: 7b8e00d98168 ("gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL")
Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Linus Walleij

gpiolib: cdev: Fix typo in kernel doc for struct line

2022-10-25T16:48:55+00:00

When eflags has been renamed to the edflags, the kernel doc change were
missed. Update kernel doc accordingly.

Fixes: b1a92e94560d ("gpiolib: cdev: consolidate edge detector configuration flags")
Signed-off-by: Andy Shevchenko 
Reviewed-by: Kent Gibson

gpiolib: cdev: Add missing header(s)

2022-10-24T09:30:00+00:00

Do not imply that some of the generic headers may be always included.
Instead, include explicitly what we are direct user of.

While at it, sort headers alphabetically.

Signed-off-by: Andy Shevchenko 
Rewiewed-by: Kent Gibson

Merge tag 'gpio-updates-for-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

2022-10-08T16:46:29+00:00

Pull gpio updates from Bartosz Golaszewski:
 "We have a single new driver, support for a bunch of new models,
  improvements in drivers and core gpiolib code as well device-tree
  bindings changes.

  Summary:

  New driver:
   - IMX System Controller Unit GPIOs

  GPIO core:
   - add fdinfo output for the GPIO character device file descriptors
     (allows user-space to determine which processes own which GPIO
     lines)
   - improvements to OF GPIO code
   - new quirk for Asus UM325UAZ in gpiolib-acpi
   - new quirk for Freescale SPI in gpiolib-of

  Driver improvements:
   - add a new macro that reduces the amount of boilerplate code in ISA
     drivers and use it in relevant drivers
   - support two new models in gpio-pca953x
   - support new model in gpio-f7188x
   - convert more drivers to use immutable irq chips
   - other minor tweaks

  Device-tree bindings:
   - add DT bindings for gpio-imx-scu
   - convert Xilinx GPIO bindings to YAML
   - reference the properties from the SPI peripheral device-tree
     bindings instead of providing custom ones in the GPIO controller
     document
   - add parsing of GPIO hog nodes to the DT bindings for gpio-mpfs-gpio
   - relax the node name requirements in gpio-stmpe
   - add new models for gpio-rcar and gpio-pxa95xx
   - add a new vendor prefix: Diodes (for Diodes, Inc.)

  Misc:
   - pulled in the immutable branch from the x86 platform drivers tree
     including support for a new simatic board that depends on GPIO
     changes"

* tag 'gpio-updates-for-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (36 commits)
  gpio: tc3589x: Make irqchip immutable
  gpiolib: cdev: add fdinfo output for line request file descriptors
  gpio: twl4030: Reorder functions which allows to drop a forward declaraion
  gpiolib: fix OOB access in quirk callbacks
  gpiolib: of: factor out conversion from OF flags
  gpiolib: rework quirk handling in of_find_gpio()
  gpiolib: of: make Freescale SPI quirk similar to all others
  gpiolib: of: do not ignore requested index when applying quirks
  gpio: ws16c48: Ensure number of irq matches number of base
  gpio: 104-idio-16: Ensure number of irq matches number of base
  gpio: 104-idi-48: Ensure number of irq matches number of base
  gpio: 104-dio-48e: Ensure number of irq matches number of base
  counter: 104-quad-8: Ensure number of irq matches number of base
  isa: Introduce the module_isa_driver_with_irq helper macro
  gpio: pca953x: Add support for PCAL6534
  gpio: pca953x: Swap if statements to save later complexity
  gpio: pca953x: Fix pca953x_gpio_set_pull_up_down()
  dt-bindings: gpio: pca95xx: add entry for pcal6534 and PI4IOE5V6534Q
  dt-bindings: vendor-prefixes: add Diodes
  gpio: mt7621: Switch to use platform_get_irq() function
  ...

gpiolib: cdev: add fdinfo output for line request file descriptors

2022-09-26T12:15:38+00:00

Add fdinfo output for file descriptors created for user-space line
requests in GPIO uAPI v2. The fdinfo file now contains the name of the
GPIO chip that is the "parent" of the request as well as offsets of
the lines requested. This allows user-space to parse the /proc/$PID/fdinfo
entries and deduce the PID of the process that requested a specific line.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Kent Gibson

gpiolib: cdev: Set lineevent_state::irq after IRQ register successfully

2022-09-21T07:32:11+00:00

When running gpio test on nxp-ls1028 platform with below command
gpiomon --num-events=3 --rising-edge gpiochip1 25
There will be a warning trace as below:
Call trace:
free_irq+0x204/0x360
lineevent_free+0x64/0x70
gpio_ioctl+0x598/0x6a0
__arm64_sys_ioctl+0xb4/0x100
invoke_syscall+0x5c/0x130
......
el0t_64_sync+0x1a0/0x1a4
The reason of this issue is that calling request_threaded_irq()
function failed, and then lineevent_free() is invoked to release
the resource. Since the lineevent_state::irq was already set, so
the subsequent invocation of free_irq() would trigger the above
warning call trace. To fix this issue, set the lineevent_state::irq
after the IRQ register successfully.

Fixes: 468242724143 ("gpiolib: cdev: refactor lineevent cleanup into lineevent_free")
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li 
Reviewed-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

Merge tag 'gpio-updates-for-v6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

2022-08-05T01:34:05+00:00

Pull gpio updates from Bartosz Golaszewski:
 "Here are the updates for this merge window from the GPIO subsystem.

  We have more lines removed than added thanks to dropping of a driver
  for a platform that's no longer supported. Otherwise the changes are
  pretty straightforward: support for some new models, various
  improvements to existing drivers, some tweaks to the core library code
  and DT bindings updates.

  Summary:

   - remove gpio-vr41xx driver as the only platform using it got dropped
     too

   - add support for suspend/resume to gpio-davinci

   - improvements to the GPIO character device code

   - add support for disabling bias for in-kernel users (up until now
     only user-space could set it)

   - drop unused devm_gpio_free()

   - fix a refcount issue in gpiolib OF

   - use device match helpers where applicable

   - add support for a new model to gpio-rockchip

   - non-functional improvements in gpio-adp5588

   - improve and simplify teardown in gpio-twl4030 and gpio-ucb1400

   - modernize the gpio-74xx-mmio and gpio-adnp drivers

   - coding style improvements in gpio-xilinx, gpio-104-idi-48

   - support new model (pca9571) in gpio-pca9570

   - convert the DT bindings to YAML for gpio-mvebu and update the
     document

   - don't return error codes from remove() in gpio-brcmstb

   - add a library for the intel 8255 PPI interface and use it in
     drivers

   - reduce using magic numbers and improve code readability in several
     drivers

   - convert DT bindings to YAML for gpio-tpic2810

   - add new models to DT bindings for gpio-frl-imx

   - Kconfig improvements

   - other minor tweaks and improvements"

* tag 'gpio-updates-for-v6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (52 commits)
  dt-bindings: gpio: fsl-imx-gpio: Add i.MXRT compatibles
  gpio: 74xx-mmio: Use bits instead of plain numbers for flags
  gpio: xilinx: add missing blank line after declarations
  MAINTAINERS: Update Intel 8255 GPIO driver file list
  gpio: gpio-mm: Implement and utilize register structures
  gpio: 104-idi-48: Implement and utilize register structures
  gpio: 104-dio-48e: Implement and utilize register structures
  gpio: i8255: Introduce the Intel 8255 interface library module
  gpio: 104-idio-16: Implement and utilize register structures
  gpio: ws16c48: Implement and utilize register structures
  gpio: remove VR41XX related gpio driver
  dt-bindings: gpio: add pull-disable flag
  gpiolib: acpi: support bias pull disable
  gpiolib: of: support bias pull disable
  gpiolib: add support for bias pull disable
  gpio: 74xx-mmio: use bits.h macros for all masks
  gpio: 74xx-mmio: Check MMIO_74XX_DIR_IN flag in mmio_74xx_dir_in()
  gpio: 74xx-mmio: Make use of device properties
  gpiolib: cdev: compile out HTE unless CONFIG_HTE selected
  gpiolib: cdev: consolidate edge detector configuration flags
  ...