diff options
author | Linus Torvalds | 2016-12-13 07:54:57 -0800 |
---|---|---|
committer | Linus Torvalds | 2016-12-13 07:54:57 -0800 |
commit | 061ad5038ca5ac75419204b216bddc2806008ead (patch) | |
tree | edd48af16a121d6a457f5e29119cac91b3a9c61c /Documentation | |
parent | e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba (diff) | |
parent | acf1fcf77247efa01d7213f53082451f6c9c8f3b (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.txt | 62 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-sx150x.txt | 41 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/pinctrl/pinctrl-sx150x.txt | 69 | ||||
-rw-r--r-- | Documentation/gpio/driver.txt | 62 |
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 --------------------------------------- |