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: d7c51b47 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c63 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad95584 ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Fixes: a54756cb ("gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL")
Fixes: 7b8e00d9 ("gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
[Nick: fixed a build failure with CDEV_V1 disabled]
Co-authored-by: Nick Hainke <vincent@systemli.org>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

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: d7c51b47 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c63 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad95584 ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Fixes: a54756cb ("gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL")
Fixes: 7b8e00d9 ("gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Provide to_gpio_device() helper which can be utilized in the existing
and future code.

While at it, make sure it becomes no-op at compilation time.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Some of the functions are using struct fwnode_handle, some struct device
pointer. In the GPIO library the firmware node of the GPIO device is the
same as GPIO node of the GPIO chip. Due to this fact we may use former
to access properties everywhere in the code.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Tested-by: Marijn Suijten <marijn.suijten@somainline.org>
[Bartosz: stick to the 80-char limit where it's not hurting readability]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

<linux/kernel.h> is included only for using container_of().
Include <linux/container_of.h> instead, it is much lighter.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in the probe function.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in the probe function.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in the probe function.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Merge branch 'i2c/client_device_id_helper-immutable' of https://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux into gpio/for-next

Introduce the i2c_client_get_device_id() helper.

gpio-line-names really depends on ti,ngpios. However, the maximum value
we have seen across the board is on K2G and da850 platforms where it can
be upto 144.

Link: https://lore.kernel.org/linux-arm-kernel/20221115200357.qa2rvw3clbz7unzq@symptom/T/#u
Fixes: c830b87a ("dt-bindings: gpio: gpio-davinci: Convert to json-schema")
Reported-by: Robert Nelson <robertcnelson@gmail.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Merge tag 'intel-gpio-v6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/andy/linux-gpio-intel into gpio/for-next

intel-gpio for v6.2-1

* Miscellaneous updates to the core (cdev, acpi) and Intel Merrifield driver

The following is an automated git shortlog grouped by driver:

gpiolib:
 -  cdev: Fix typo in kernel doc for struct line
 -  acpi: Use METHOD_NAME__AEI macro for acpi_walk_resources

merrifield:
 -  Use str_enable_disable() helper

Note that this is a RFC patch and not meant to be merged. I looked into
a problem with linux-next-20221110 on the Qualcomm SA8540P automotive
board (sc8280xp) where the UFS host controller would fail to probe due
to repeated probe deferrals when trying to get reset-gpios via
devm_gpiod_get_optional().

of_get_named_gpiod_flags() returns -EPROBE_DEFER, which is caused by
of_gpiochip_match_node_and_xlate() returning 0 since the of_xlate function
pointer is not set for the qcom,sc8280xp-tlmm pinctrl driver. The
pinctrl driver doesn't define one, so of_gpiochip_add() should
automatically setup of_gpio_simple_xlate() on it's behalf. This doesn't
happen since the fwnode member on the struct gpiochip is set to null
when of_gpiochip_add() is called. Let's work around this by ensuring
that it's set if available.

Note that this broke sometime within the last few weeks within
linux-next and I haven't bisected this. I'm posting this in the hopes
that someone may know offhand which patch(es) may have broken this.
Signed-off-by: Brian Masney <bmasney@redhat.com>
Tested-by: Marijn Suijten <marijn.suijten@somainline.org>
Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Steev Klimaszewski <steev@kali.org> #Lenovo Thinkpad X13s
Tested-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Remove use of the deprecated mask_invert flag. Inverted mask
registers (where a '1' bit enables an IRQ) can be described more
directly as an unmask register.
Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The OF node store in chip->fwnode is used to explicitly override the FW
node for a GPIO chip. For chips that use the default FW node (i.e. that
of their parent device), this will be NULL and cause the chip not to be
fully registered.

Instead, use the GPIO device's FW node, which is set to either the node
of the parent device or the explicit override in chip->fwnode.

Fixes: 8afe8255 ("gpiolib: of: Prepare of_gpiochip_add() / of_gpiochip_remove() for fwnode")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Robert Marko <robimarko@gmail.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Tested-by: Brian Masney <bmasney@redhat.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The callers never call the function with invalid pointer.
Moreover, compiler quite likely dropped that check anyway
because we use that pointer before the check.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

GPIO library is getting rid of of_node, fwnode should be utilized instead.
Prepare of_mm_gpiochip_add_data() for fwnode.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Now that static device properties understand notion of child nodes and
references, let's teach gpiolib to handle them:

- GPIOs are represented as a references to software nodes representing
  gpiochip
- references must have 2 arguments - GPIO number within the chip and
  GPIO flags (GPIO_ACTIVE_LOW/GPIO_ACTIVE_HIGH, etc)
- a new PROPERTY_ENTRY_GPIO() macro is supplied to ensure the above
- name of the software node representing gpiochip must match label of
  the gpiochip, as we use it to locate gpiochip structure at runtime

The following illustrates use of software nodes to describe a "System"
button that is currently specified via use of gpio_keys_platform_data
in arch/mips/alchemy/board-mtx1.c. It follows bindings specified in
Documentation/devicetree/bindings/input/gpio-keys.yaml.

static const struct software_node mxt1_gpiochip2_node = {
	.name = "alchemy-gpio2",
};

static const struct property_entry mtx1_gpio_button_props[] = {
	PROPERTY_ENTRY_U32("linux,code", BTN_0),
	PROPERTY_ENTRY_STRING("label", "System button"),
	PROPERTY_ENTRY_GPIO("gpios", &mxt1_gpiochip2_node, 7, GPIO_ACTIVE_LOW),
	{ }
};

Similarly, arch/arm/mach-tegra/board-paz00.c can be converted to:

static const struct software_node tegra_gpiochip_node = {
	.name = "tegra-gpio",
};

static struct property_entry wifi_rfkill_prop[] __initdata = {
	PROPERTY_ENTRY_STRING("name", "wifi_rfkill"),
	PROPERTY_ENTRY_STRING("type", "wlan"),
	PROPERTY_ENTRY_GPIO("reset-gpios",
			    &tegra_gpiochip_node, 25, GPIO_ACTIVE_HIGH);
	PROPERTY_ENTRY_GPIO("shutdown-gpios",
			    &tegra_gpiochip_node, 85, GPIO_ACTIVE_HIGH);
	{ },
};

static struct platform_device wifi_rfkill_device = {
	.name	= "rfkill_gpio",
	.id	= -1,
};

...

	software_node_register(&tegra_gpiochip_node);
	device_create_managed_software_node(&wifi_rfkill_device.dev,
					    wifi_rfkill_prop, NULL);
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Ensure that all paths to obtain/look up GPIOD from generic
consumer-visible APIs go through the new gpiod_find_and_request()
helper, so that we can easily extend it with support for new firmware
mechanisms.

The only exception is OF-specific [devm_]gpiod_get_from_of_node() API
that is still being used by a couple of drivers and will be removed as
soon as patches converting them to use generic fwnode/device APIs are
accepted.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

There is no need for the generic parts of GPIOLIB to be aware of
implementation details of ACPI-bases lookups.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In preparation of switching all ACPI-based GPIO lookups to go through
acpi_find_gpio() we need to make sure it can handle data-only ACPI
nodes, same as existing acpi_node_get_gpiod().
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In preparation of switching all ACPI-based GPIO lookups to go through
acpi_find_gpio() let's change it to accept device node as its argument
as we do not always have access to device structure.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In preparation of switching all OF-based GPIO lookups to go through
of_find_gpio() let's change it to accept device node as its argument as
we do not always have access to device structure.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Introduces new helper function to aid in .probe_new() refactors. In order
to use existing i2c_get_device_id() on the probe callback, the device
match table needs to be accessible in that function, which would require
bigger refactors in some drivers using the deprecated .probe callback.

This issue was discussed in more detail in the IIO mailing list.

Link: https://lore.kernel.org/all/20221023132302.911644-11-u.kleine-koenig@pengutronix.de/Suggested-by: Nuno Sá <noname.nuno@gmail.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Added module build support for the davinci gpio driver
Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Signed-off-by: Nicolas Frayer <nfrayer@baylibre.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In preparation to complete fwnode switch, integrate
of_gpiochip_init_valid_mask() into gpiochip_init_valid_mask().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

GPIO library is getting rid of of_node, fwnode should be utilized instead.
Prepare of_gpiochip_add() / of_gpiochip_remove() for fwnode.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Now that there are no more users of these APIs in the kernel we can
remove them.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

devm_fwnode_get_gpiod_from_child() is going away as the name is too
unwieldy, let's switch to using the new devm_fwnode_gpiod_get().
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

devm_fwnode_get_gpiod_from_child() is going away as the name is too
unwieldy, let's switch to using the new devm_fwnode_gpiod_get().
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add support for HiSilicon GPIO controller in embedded platform, which
boot from devicetree.
Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Jay Fang <f.fangjian@huawei.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add the new compatible for HiSilicon gpio controller driver.
Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

It's actually preferable to use Generic regmap GPIO over other
simple approaches. Add a TODO item for that.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Bindings for Freescale PCIe controller use a separate property called
"reset-gpio-active-high" to control polarity of its reset line, add it
to the list of quirks in gpiolib so that gpiod API can be used in the
driver.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Several legacy bindings use a separate property to specify polarity of
GPIOs instead of specifying it directly in the GPIO property. Factor
out this code to make it easier to add more such cases.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Make use of device_match_of_node() instead of open coding its
functionality.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Dialog semiconductors SLG7XL45106 is an 8-bit I2C GPO expander.
The output port is controlled by a data byte with register
address. Add a compatible string for the same. Also update
the driver to write and read from it.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add struct pca9570_platform_data for adding the platform data
structure. Also modify the existing structs for pca9570 and pca9571
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

This patch adds compatible string for the SLG7XL45106,
I2C GPO expander.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

It's possible that PCI device can provide an IO port resource for
the device. regmap MMIO currently uses MMIO by default. With an
additional flag we enable support for IO port accesses.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

This driver implements a GPIO multiplexer based on latches connected to
other GPIOs. A set of data GPIOs is connected to the data input of
multiple latches. The clock input of each latch is driven by another
set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
are output only.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
[Bartosz: fixed the strange of_device_id formatting]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>