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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-13 07:54:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-13 07:54:57 -0800
commit061ad5038ca5ac75419204b216bddc2806008ead (patch)
treeedd48af16a121d6a457f5e29119cac91b3a9c61c /Documentation
parente7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba (diff)
parentacf1fcf77247efa01d7213f53082451f6c9c8f3b (diff)
Merge tag 'gpio-v4.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO updates from Luinus Walleij: "Bulk GPIO changes for the v4.10 kernel cycle: Core changes: - Simplify threaded interrupt handling: instead of passing numbed parameters to gpiochip_irqchip_add_chained() we create a new call: gpiochip_irqchip_add_nested() so the two types are clearly semantically different. Also make sure that all nested chips call gpiochip_set_nested_irqchip() which is necessary for IRQ resend to work properly if it happens. - Return error on seek operations for the chardev. - Clamp values set as part of gpio[d]_direction_output() so that anything != 0 will be send down to the driver as "1" not the value passed in. - ACPI can now support naming of GPIO lines, hogs and holes in the GPIO lists. New drivers: - The SX150x driver was deemed unfit for the GPIO subsystem and was moved over to a combined GPIO+pinctrl driver in the pinctrl subsystem. New features: - Various cleanups to various drivers" * tag 'gpio-v4.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (49 commits) gpio: merrifield: Implement gpio_get_direction callback gpio: merrifield: Add support for hardware debouncer gpio: chardev: Return error for seek operations gpio: arizona: Tidy up probe error path gpio: arizona: Remove pointless set of platform drvdata gpio: pl061: delete platform data handling gpio: pl061: move platform data into driver gpio: pl061: rename variable from chip to pl061 gpio: pl061: rename state container struct gpio: pl061: use local state for parent IRQ storage gpio: set explicit nesting on drivers gpio: simplify adding threaded interrupts gpio: vf610: use builtin_platform_driver gpio: axp209: use correct register for GPIO input status gpio: stmpe: fix interrupt handling bug gpio: em: depnd on ARCH_SHMOBILE gpio: zx: depend on ARCH_ZX gpio: x86: update config dependencies for x86 specific hardware gpio: mb86s7x: use builtin_platform_driver gpio: etraxfs: use builtin_platform_driver ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/acpi/gpio-properties.txt62
-rw-r--r--Documentation/devicetree/bindings/gpio/gpio-sx150x.txt41
-rw-r--r--Documentation/devicetree/bindings/pinctrl/pinctrl-sx150x.txt69
-rw-r--r--Documentation/gpio/driver.txt62
4 files changed, 167 insertions, 67 deletions
diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt
index 5aafe0b351a1..2aff0349facd 100644
--- a/Documentation/acpi/gpio-properties.txt
+++ b/Documentation/acpi/gpio-properties.txt
@@ -51,6 +51,68 @@ it to 1 marks the GPIO as active low.
In our Bluetooth example the "reset-gpios" refers to the second GpioIo()
resource, second pin in that resource with the GPIO number of 31.
+It is possible to leave holes in the array of GPIOs. This is useful in
+cases like with SPI host controllers where some chip selects may be
+implemented as GPIOs and some as native signals. For example a SPI host
+controller can have chip selects 0 and 2 implemented as GPIOs and 1 as
+native:
+
+ Package () {
+ "cs-gpios",
+ Package () {
+ ^GPIO, 19, 0, 0, // chip select 0: GPIO
+ 0, // chip select 1: native signal
+ ^GPIO, 20, 0, 0, // chip select 2: GPIO
+ }
+ }
+
+Other supported properties
+--------------------------
+
+Following Device Tree compatible device properties are also supported by
+_DSD device properties for GPIO controllers:
+
+- gpio-hog
+- output-high
+- output-low
+- input
+- line-name
+
+Example:
+
+ Name (_DSD, Package () {
+ // _DSD Hierarchical Properties Extension UUID
+ ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+ Package () {
+ Package () {"hog-gpio8", "G8PU"}
+ }
+ })
+
+ Name (G8PU, Package () {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package () {
+ Package () {"gpio-hog", 1},
+ Package () {"gpios", Package () {8, 0}},
+ Package () {"output-high", 1},
+ Package () {"line-name", "gpio8-pullup"},
+ }
+ })
+
+- gpio-line-names
+
+Example:
+
+ Package () {
+ "gpio-line-names",
+ Package () {
+ "SPI0_CS_N", "EXP2_INT", "MUX6_IO", "UART0_RXD", "MUX7_IO",
+ "LVL_C_A1", "MUX0_IO", "SPI1_MISO"
+ }
+ }
+
+See Documentation/devicetree/bindings/gpio/gpio.txt for more information
+about these properties.
+
ACPI GPIO Mappings Provided by Drivers
--------------------------------------
diff --git a/Documentation/devicetree/bindings/gpio/gpio-sx150x.txt b/Documentation/devicetree/bindings/gpio/gpio-sx150x.txt
deleted file mode 100644
index c809acb9c71b..000000000000
--- a/Documentation/devicetree/bindings/gpio/gpio-sx150x.txt
+++ /dev/null
@@ -1,41 +0,0 @@
-SEMTECH SX150x GPIO expander bindings
-
-
-Required properties:
-
-- compatible: should be "semtech,sx1506q",
- "semtech,sx1508q",
- "semtech,sx1509q",
- "semtech,sx1502q".
-
-- reg: The I2C slave address for this device.
-
-- interrupt-parent: phandle of the parent interrupt controller.
-
-- interrupts: Interrupt specifier for the controllers interrupt.
-
-- #gpio-cells: Should be 2. The first cell is the GPIO number and the
- second cell is used to specify optional parameters:
- bit 0: polarity (0: normal, 1: inverted)
-
-- gpio-controller: Marks the device as a GPIO controller.
-
-- interrupt-controller: Marks the device as a interrupt controller.
-
-The GPIO expander can optionally be used as an interrupt controller, in
-which case it uses the default two cell specifier as described in
-Documentation/devicetree/bindings/interrupt-controller/interrupts.txt.
-
-Example:
-
- i2c_gpio_expander@20{
- #gpio-cells = <2>;
- #interrupt-cells = <2>;
- compatible = "semtech,sx1506q";
- reg = <0x20>;
- interrupt-parent = <&gpio_1>;
- interrupts = <16 0>;
-
- gpio-controller;
- interrupt-controller;
- };
diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-sx150x.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-sx150x.txt
new file mode 100644
index 000000000000..c293c8aaac73
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-sx150x.txt
@@ -0,0 +1,69 @@
+SEMTECH SX150x GPIO expander bindings
+
+Please refer to pinctrl-bindings.txt, ../gpio/gpio.txt, and
+../interrupt-controller/interrupts.txt for generic information regarding
+pin controller, GPIO, and interrupt bindings.
+
+Required properties:
+- compatible: should be one of :
+ "semtech,sx1506q",
+ "semtech,sx1508q",
+ "semtech,sx1509q",
+ "semtech,sx1502q".
+
+- reg: The I2C slave address for this device.
+
+- #gpio-cells: Should be 2. The first cell is the GPIO number and the
+ second cell is used to specify optional parameters:
+ bit 0: polarity (0: normal, 1: inverted)
+
+- gpio-controller: Marks the device as a GPIO controller.
+
+Optional properties :
+- interrupt-parent: phandle of the parent interrupt controller.
+
+- interrupts: Interrupt specifier for the controllers interrupt.
+
+- interrupt-controller: Marks the device as a interrupt controller.
+
+- semtech,probe-reset: Will trigger a reset of the GPIO expander on probe,
+ only for sx1508q and sx1509q
+
+The GPIO expander can optionally be used as an interrupt controller, in
+which case it uses the default two cell specifier.
+
+Required properties for pin configuration sub-nodes:
+ - pins: List of pins to which the configuration applies.
+
+Optional properties for pin configuration sub-nodes:
+----------------------------------------------------
+ - bias-disable: disable any pin bias, except the OSCIO pin
+ - bias-pull-up: pull up the pin, except the OSCIO pin
+ - bias-pull-down: pull down the pin, except the OSCIO pin
+ - bias-pull-pin-default: use pin-default pull state, except the OSCIO pin
+ - drive-push-pull: drive actively high and low
+ - drive-open-drain: drive with open drain only for sx1508q and sx1509q and except the OSCIO pin
+ - output-low: set the pin to output mode with low level
+ - output-high: set the pin to output mode with high level
+
+Example:
+
+ i2c0gpio-expander@20{
+ #gpio-cells = <2>;
+ #interrupt-cells = <2>;
+ compatible = "semtech,sx1506q";
+ reg = <0x20>;
+ interrupt-parent = <&gpio_1>;
+ interrupts = <16 0>;
+
+ gpio-controller;
+ interrupt-controller;
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&gpio1_cfg_pins>;
+
+ gpio1_cfg_pins: gpio1-cfg {
+ pins = "gpio1";
+ bias-pull-up;
+ };
+ };
diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt
index 368d5a294d89..747c721776ed 100644
--- a/Documentation/gpio/driver.txt
+++ b/Documentation/gpio/driver.txt
@@ -175,8 +175,8 @@ The IRQ portions of the GPIO block are implemented using an irqchip, using
the header <linux/irq.h>. So basically such a driver is utilizing two sub-
systems simultaneously: gpio and irq.
-RT_FULL: GPIO driver should not use spinlock_t or any sleepable APIs
-(like PM runtime) as part of its irq_chip implementation on -RT.
+RT_FULL: a realtime compliant GPIO driver should not use spinlock_t or any
+sleepable APIs (like PM runtime) as part of its irq_chip implementation.
- spinlock_t should be replaced with raw_spinlock_t [1].
- If sleepable APIs have to be used, these can be done from the .irq_bus_lock()
and .irq_bus_unlock() callbacks, as these are the only slowpath callbacks
@@ -185,33 +185,32 @@ RT_FULL: GPIO driver should not use spinlock_t or any sleepable APIs
GPIO irqchips usually fall in one of two categories:
* CHAINED GPIO irqchips: these are usually the type that is embedded on
- an SoC. This means that there is a fast IRQ handler for the GPIOs that
+ an SoC. This means that there is a fast IRQ flow handler for the GPIOs that
gets called in a chain from the parent IRQ handler, most typically the
- system interrupt controller. This means the GPIO irqchip is registered
- using irq_set_chained_handler() or the corresponding
- gpiochip_set_chained_irqchip() helper function, and the GPIO irqchip
- handler will be called immediately from the parent irqchip, while
- holding the IRQs disabled. The GPIO irqchip will then end up calling
- something like this sequence in its interrupt handler:
-
- static irqreturn_t tc3589x_gpio_irq(int irq, void *data)
+ system interrupt controller. This means that the GPIO irqchip handler will
+ be called immediately from the parent irqchip, while holding the IRQs
+ disabled. The GPIO irqchip will then end up calling something like this
+ sequence in its interrupt handler:
+
+ static irqreturn_t foo_gpio_irq(int irq, void *data)
chained_irq_enter(...);
generic_handle_irq(...);
chained_irq_exit(...);
Chained GPIO irqchips typically can NOT set the .can_sleep flag on
- struct gpio_chip, as everything happens directly in the callbacks.
+ struct gpio_chip, as everything happens directly in the callbacks: no
+ slow bus traffic like I2C can be used.
RT_FULL: Note, chained IRQ handlers will not be forced threaded on -RT.
As result, spinlock_t or any sleepable APIs (like PM runtime) can't be used
in chained IRQ handler.
- if required (and if it can't be converted to the nested threaded GPIO irqchip)
- - chained IRQ handler can be converted to generic irq handler and this way
- it will be threaded IRQ handler on -RT and hard IRQ handler on non-RT
+ If required (and if it can't be converted to the nested threaded GPIO irqchip)
+ a chained IRQ handler can be converted to generic irq handler and this way
+ it will be a threaded IRQ handler on -RT and a hard IRQ handler on non-RT
(for example, see [3]).
Know W/A: The generic_handle_irq() is expected to be called with IRQ disabled,
- so IRQ core will complain if it will be called from IRQ handler which is
- forced thread. The "fake?" raw lock can be used to W/A this problem:
+ so the IRQ core will complain if it is called from an IRQ handler which is
+ forced to a thread. The "fake?" raw lock can be used to W/A this problem:
raw_spinlock_t wa_lock;
static irqreturn_t omap_gpio_irq_handler(int irq, void *gpiobank)
@@ -243,7 +242,7 @@ GPIO irqchips usually fall in one of two categories:
by the driver. The hallmark of this driver is to call something like
this in its interrupt handler:
- static irqreturn_t tc3589x_gpio_irq(int irq, void *data)
+ static irqreturn_t foo_gpio_irq(int irq, void *data)
...
handle_nested_irq(irq);
@@ -256,23 +255,31 @@ associated irqdomain and resource allocation callbacks, the gpiolib has
some helpers that can be enabled by selecting the GPIOLIB_IRQCHIP Kconfig
symbol:
-* gpiochip_irqchip_add(): adds an irqchip to a gpiochip. It will pass
+* gpiochip_irqchip_add(): adds a chained irqchip to a gpiochip. It will pass
the struct gpio_chip* for the chip to all IRQ callbacks, so the callbacks
need to embed the gpio_chip in its state container and obtain a pointer
to the container using container_of().
(See Documentation/driver-model/design-patterns.txt)
- If there is a need to exclude certain GPIOs from the IRQ domain, one can
- set .irq_need_valid_mask of the gpiochip before gpiochip_add_data() is
- called. This allocates .irq_valid_mask with as many bits set as there are
- GPIOs in the chip. Drivers can exclude GPIOs by clearing bits from this
- mask. The mask must be filled in before gpiochip_irqchip_add() is called.
+* gpiochip_irqchip_add_nested(): adds a nested irqchip to a gpiochip.
+ Apart from that it works exactly like the chained irqchip.
* gpiochip_set_chained_irqchip(): sets up a chained irq handler for a
gpio_chip from a parent IRQ and passes the struct gpio_chip* as handler
data. (Notice handler data, since the irqchip data is likely used by the
- parent irqchip!) This is for the chained type of chip. This is also used
- to set up a nested irqchip if NULL is passed as handler.
+ parent irqchip!).
+
+* gpiochip_set_nested_irqchip(): sets up a nested irq handler for a
+ gpio_chip from a parent IRQ. As the parent IRQ has usually been
+ explicitly requested by the driver, this does very little more than
+ mark all the child IRQs as having the other IRQ as parent.
+
+If there is a need to exclude certain GPIOs from the IRQ domain, you can
+set .irq_need_valid_mask of the gpiochip before gpiochip_add_data() is
+called. This allocates an .irq_valid_mask with as many bits set as there
+are GPIOs in the chip. Drivers can exclude GPIOs by clearing bits from this
+mask. The mask must be filled in before gpiochip_irqchip_add() or
+gpiochip_irqchip_add_nested() is called.
To use the helpers please keep the following in mind:
@@ -323,6 +330,9 @@ When implementing an irqchip inside a GPIO driver, these two functions should
typically be called in the .startup() and .shutdown() callbacks from the
irqchip.
+When using the gpiolib irqchip helpers, these callback are automatically
+assigned.
+
Real-Time compliance for GPIO IRQ chips
---------------------------------------