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authorLinus Torvalds <torvalds@linux-foundation.org>2021-09-07 12:27:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-07 12:27:27 -0700
commit5e6a5845dd651b00754a62edec2f0a439182024d (patch)
treed93d10b5dc505b64b62ce42cee2bf926d6b42051 /Documentation/driver-api
parent75b96f0ec5faf730128c32187e3e28441c27a094 (diff)
parent889a1b3f35db6ba5ba6a0c23a3a55594570b6a17 (diff)
Merge tag 'gpio-updates-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio updates from Bartosz Golaszewski: "We mostly have various improvements and refactoring all over the place but also some interesting new features - like the virtio GPIO driver that allows guest VMs to use host's GPIOs. We also have a new/old GPIO driver for rockchip - this one has been split out of the pinctrl driver. Summary: - new driver: gpio-virtio allowing a guest VM running linux to access GPIO lines provided by the host - split the GPIO driver out of the rockchip pin control driver - add support for a new model to gpio-aspeed-sgpio, refactor the driver and use generic device property interfaces, improve property sanitization - add ACPI support to gpio-tegra186 - improve the code setting the line names to support multiple GPIO banks per device - constify a bunch of OF functions in the core GPIO code and make the declaration for one of the core OF functions we use consistent within its header - use software nodes in intel_quark_i2c_gpio - add support for the gpio-line-names property in gpio-mt7621 - use the standard GPIO function for setting the GPIO names in gpio-brcmstb - fix a bunch of leaks and other bugs in gpio-mpc8xxx - use generic pm callbacks in gpio-ml-ioh - improve resource management and PM handling in gpio-mlxbf2 - modernize and improve the gpio-dwapb driver - coding style improvements in gpio-rcar - documentation fixes and improvements - update the MAINTAINERS entry for gpio-zynq - minor tweaks in several drivers" * tag 'gpio-updates-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (35 commits) gpio: mpc8xxx: Use 'devm_gpiochip_add_data()' to simplify the code and avoid a leak gpio: mpc8xxx: Fix a potential double iounmap call in 'mpc8xxx_probe()' gpio: mpc8xxx: Fix a resources leak in the error handling path of 'mpc8xxx_probe()' gpio: viperboard: remove platform_set_drvdata() call in probe gpio: virtio: Add missing mailings lists in MAINTAINERS entry gpio: virtio: Fix sparse warnings gpio: remove the obsolete MX35 3DS BOARD MC9S08DZ60 GPIO functions gpio: max730x: Use the right include gpio: Add virtio-gpio driver gpio: mlxbf2: Use DEFINE_RES_MEM_NAMED() helper macro gpio: mlxbf2: Use devm_platform_ioremap_resource() gpio: mlxbf2: Drop wrong use of ACPI_PTR() gpio: mlxbf2: Convert to device PM ops gpio: dwapb: Get rid of legacy platform data mfd: intel_quark_i2c_gpio: Convert GPIO to use software nodes gpio: dwapb: Read GPIO base from gpio-base property gpio: dwapb: Unify ACPI enumeration checks in get_irq() and configure_irqs() gpiolib: Deduplicate forward declaration in the consumer.h header MAINTAINERS: update gpio-zynq.yaml reference gpio: tegra186: Add ACPI support ...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/gpio/consumer.rst10
-rw-r--r--Documentation/driver-api/gpio/driver.rst11
2 files changed, 13 insertions, 8 deletions
diff --git a/Documentation/driver-api/gpio/consumer.rst b/Documentation/driver-api/gpio/consumer.rst
index 3366a991b4aa..47869ca8ccf0 100644
--- a/Documentation/driver-api/gpio/consumer.rst
+++ b/Documentation/driver-api/gpio/consumer.rst
@@ -72,6 +72,10 @@ for the GPIO. Values can be:
* GPIOD_OUT_HIGH_OPEN_DRAIN same as GPIOD_OUT_HIGH but also enforce the line
to be electrically used with open drain.
+Note that the initial value is *logical* and the physical line level depends on
+whether the line is configured active high or active low (see
+:ref:`active_low_semantics`).
+
The two last flags are used for use cases where open drain is mandatory, such
as I2C: if the line is not already configured as open drain in the mappings
(see board.txt), then open drain will be enforced anyway and a warning will be
@@ -252,6 +256,8 @@ that can't be accessed from hardIRQ handlers, these calls act the same as the
spinlock-safe calls.
+.. _active_low_semantics:
+
The active low and open drain semantics
---------------------------------------
As a consumer should not have to care about the physical line level, all of the
@@ -309,9 +315,11 @@ work on the raw line value::
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
-The active low state of a GPIO can also be queried using the following call::
+The active low state of a GPIO can also be queried and toggled using the
+following calls::
int gpiod_is_active_low(const struct gpio_desc *desc)
+ void gpiod_toggle_active_low(struct gpio_desc *desc)
Note that these functions should only be used with great moderation; a driver
should not have to care about the physical line level or open drain semantics.
diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst
index d6b0d779859b..bbc53920d4dd 100644
--- a/Documentation/driver-api/gpio/driver.rst
+++ b/Documentation/driver-api/gpio/driver.rst
@@ -547,13 +547,10 @@ To use the helpers please keep the following in mind:
the irqchip can initialize. E.g. .dev and .can_sleep shall be set up
properly.
-- Nominally set all handlers to handle_bad_irq() in the setup call and pass
- handle_bad_irq() as flow handler parameter in gpiochip_irqchip_add() if it is
- expected for GPIO driver that irqchip .set_type() callback will be called
- before using/enabling each GPIO IRQ. Then set the handler to
- handle_level_irq() and/or handle_edge_irq() in the irqchip .set_type()
- callback depending on what your controller supports and what is requested
- by the consumer.
+- Nominally set gpio_irq_chip.handler to handle_bad_irq. Then, if your irqchip
+ is cascaded, set the handler to handle_level_irq() and/or handle_edge_irq()
+ in the irqchip .set_type() callback depending on what your controller
+ supports and what is requested by the consumer.
Locking IRQ usage