diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-03 16:44:15 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-03 16:44:15 -0700 |
commit | 154d6f18a48e00dec2dc84a96914fe1a24669577 (patch) | |
tree | 7b92ac64a00eb173af396752f3bfc72c9eba615c /Documentation | |
parent | 76ca7d1cca761bb9712dfcad9a27d70b520874ae (diff) | |
parent | b22978fc33dec72e5f8e17f90eb63ea9137aafd5 (diff) |
Merge tag 'gpio-v3.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull bulk of gpio updates from Linus Walleij:
"A pretty big chunk of changes this time, but it has all been on
rotation in linux-next and had some testing. Of course there will be
some amount of fixes on top...
- Merged in a branch of irqchip changes from Thomas Gleixner: we need
to have new callbacks from the irqchip to determine if the GPIO
line will be eligible for IRQs, and this callback must be able to
say "no". After some thinking I got the branch from tglx and have
switched all current users over to use this.
- Based on tglx patches, we have added some generic irqchip helpers
in the gpiolib core. These will help centralize code when GPIO
drivers have simple chained/cascaded IRQs. Drivers will still
define their irqchip vtables, but the gpiolib core will take care
of irqdomain set-up, mapping from local offsets to Linux irqs, and
reserve resources by marking the GPIO lines for IRQs.
- Initially the PL061 and Nomadik GPIO/pin control drivers have been
switched over to use the new gpiochip-to-irqchip infrastructure
with more drivers expected for the next kernel cycle. The
factoring of just two drivers still makes it worth it so it is
already a win.
- A new driver for the Synopsys DesignWare APB GPIO block.
- Modify the DaVinci GPIO driver to be reusable also for the new TI
Keystone architecture.
- A new driver for the LSI ZEVIO SoCs.
- Delete the obsolte tnetv107x driver.
- Some incremental work on GPIO descriptors: have
gpiod_direction_output() use a logical level, respecting assertion
polarity through ACTIVE_LOW flags, adding gpiod_direction_output_raw()
for the case where you want to set that very value. Add
gpiochip_get_desc() to fetch a GPIO descriptor from a specific
offset on a certain chip inside driver code.
- Switch ACPI GPIO code over to using gpiochip_get_desc() and get rid
of gpio_to_desc().
- The ACPI GPIO event handling code has been reworked after
encountering an actual real life implementation.
- Support for ACPI GPIO operation regions.
- Generic GPIO chips can now be assigned labels/names from platform
data.
- We now clamp values returned from GPIO drivers to the boolean [0,1]
range.
- Some improved documentation on how to use the polarity flag was
added.
- a large slew of incremental driver updates and non-critical fixes.
Some targeted for stable"
* tag 'gpio-v3.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (80 commits)
gpio: rcar: Add helper variable dev = &pdev->dev
gpio-lynxpoint: force gpio_get() to return "1" and "0" only
gpio: unmap gpio irqs properly
pch_gpio: set value before enabling output direction
gpio: moxart: Actually set output state in moxart_gpio_direction_output()
gpio: moxart: Avoid forward declaration
gpio: mxs: Allow for recursive enable_irq_wake() call
gpio: samsung: Add missing "break" statement
gpio: twl4030: Remove redundant assignment
gpio: dwapb: correct gpio-cells in binding document
gpio: iop: fix devm_ioremap_resource() return value checking
pinctrl: coh901: convert driver to use gpiolib irqchip
pinctrl: nomadik: convert driver to use gpiolib irqchip
gpio: pl061: convert driver to use gpiolib irqchip
gpio: add IRQ chip helpers in gpiolib
pinctrl: nomadik: factor in platform data container
pinctrl: nomadik: rename secondary to latent
gpio: Driver for SYSCON-based GPIOs
gpio: generic: Use platform_device_id->driver_data field for driver flags
pinctrl: coh901: move irq line locking to resource callbacks
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/devicetree/bindings/gpio/cirrus,clps711x-mctrl-gpio.txt | 17 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-davinci.txt | 25 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-zevio.txt | 16 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio.txt | 60 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt | 60 | ||||
-rw-r--r-- | Documentation/gpio/consumer.txt | 1 | ||||
-rw-r--r-- | Documentation/gpio/driver.txt | 35 |
7 files changed, 204 insertions, 10 deletions
diff --git a/Documentation/devicetree/bindings/gpio/cirrus,clps711x-mctrl-gpio.txt b/Documentation/devicetree/bindings/gpio/cirrus,clps711x-mctrl-gpio.txt new file mode 100644 index 000000000000..94ae9f82dcf8 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/cirrus,clps711x-mctrl-gpio.txt @@ -0,0 +1,17 @@ +* ARM Cirrus Logic CLPS711X SYSFLG1 MCTRL GPIOs + +Required properties: +- compatible: Should contain "cirrus,clps711x-mctrl-gpio". +- gpio-controller: Marks the device node as a gpio controller. +- #gpio-cells: Should be two. The first cell is the pin number and + the second cell is used to specify the gpio polarity: + 0 = Active high, + 1 = Active low. + +Example: + sysgpio: sysgpio { + compatible = "cirrus,ep7312-mctrl-gpio", + "cirrus,clps711x-mctrl-gpio"; + gpio-controller; + #gpio-cells = <2>; + }; diff --git a/Documentation/devicetree/bindings/gpio/gpio-davinci.txt b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt index a2e839d6e338..5079ba7d6568 100644 --- a/Documentation/devicetree/bindings/gpio/gpio-davinci.txt +++ b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt @@ -1,13 +1,17 @@ -Davinci GPIO controller bindings +Davinci/Keystone GPIO controller bindings Required Properties: -- compatible: should be "ti,dm6441-gpio" +- compatible: should be "ti,dm6441-gpio", "ti,keystone-gpio" - reg: Physical base address of the controller and the size of memory mapped registers. - gpio-controller : Marks the device node as a gpio controller. +- #gpio-cells : Should be two. + - first cell is the pin number + - second cell is used to specify optional parameters (unused) + - interrupt-parent: phandle of the parent interrupt controller. - interrupts: Array of GPIO interrupt number. Only banked or unbanked IRQs are @@ -27,6 +31,7 @@ Example: gpio: gpio@1e26000 { compatible = "ti,dm6441-gpio"; gpio-controller; + #gpio-cells = <2>; reg = <0x226000 0x1000>; interrupt-parent = <&intc>; interrupts = <42 IRQ_TYPE_EDGE_BOTH 43 IRQ_TYPE_EDGE_BOTH @@ -39,3 +44,19 @@ gpio: gpio@1e26000 { interrupt-controller; #interrupt-cells = <2>; }; + +leds { + compatible = "gpio-leds"; + + led1 { + label = "davinci:green:usr1"; + gpios = <&gpio 10 GPIO_ACTIVE_HIGH>; + ... + }; + + led2 { + label = "davinci:red:debug1"; + gpios = <&gpio 11 GPIO_ACTIVE_HIGH>; + ... + }; +}; diff --git a/Documentation/devicetree/bindings/gpio/gpio-zevio.txt b/Documentation/devicetree/bindings/gpio/gpio-zevio.txt new file mode 100644 index 000000000000..a37bd9ae2730 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-zevio.txt @@ -0,0 +1,16 @@ +Zevio GPIO controller + +Required properties: +- compatible: Should be "lsi,zevio-gpio" +- reg: Address and length of the register set for the device +- #gpio-cells: Should be two. The first cell is the pin number and the + second cell is used to specify optional parameters (currently unused). +- gpio-controller: Marks the device node as a GPIO controller. + +Example: + gpio: gpio@90000000 { + compatible = "lsi,zevio-gpio"; + reg = <0x90000000 0x1000>; + gpio-controller; + #gpio-cells = <2>; + }; diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt index 0c85bb6e3a80..3fb8f53071b8 100644 --- a/Documentation/devicetree/bindings/gpio/gpio.txt +++ b/Documentation/devicetree/bindings/gpio/gpio.txt @@ -13,11 +13,11 @@ properties, each containing a 'gpio-list': gpio-specifier : Array of #gpio-cells specifying specific gpio (controller specific) -GPIO properties should be named "[<name>-]gpios". Exact +GPIO properties should be named "[<name>-]gpios". The exact meaning of each gpios property must be documented in the device tree binding for each device. -For example, the following could be used to describe gpios pins to use +For example, the following could be used to describe GPIO pins used as chip select lines; with chip selects 0, 1 and 3 populated, and chip select 2 left empty: @@ -44,35 +44,79 @@ whether pin is open-drain and whether pin is logically inverted. Exact meaning of each specifier cell is controller specific, and must be documented in the device tree binding for the device. -Example of the node using GPIOs: +Example of a node using GPIOs: node { gpios = <&qe_pio_e 18 0>; }; In this example gpio-specifier is "18 0" and encodes GPIO pin number, -and empty GPIO flags as accepted by the "qe_pio_e" gpio-controller. +and GPIO flags as accepted by the "qe_pio_e" gpio-controller. + +1.1) GPIO specifier best practices +---------------------------------- + +A gpio-specifier should contain a flag indicating the GPIO polarity; active- +high or active-low. If it does, the follow best practices should be followed: + +The gpio-specifier's polarity flag should represent the physical level at the +GPIO controller that achieves (or represents, for inputs) a logically asserted +value at the device. The exact definition of logically asserted should be +defined by the binding for the device. If the board inverts the signal between +the GPIO controller and the device, then the gpio-specifier will represent the +opposite physical level than the signal at the device's pin. + +When the device's signal polarity is configurable, the binding for the +device must either: + +a) Define a single static polarity for the signal, with the expectation that +any software using that binding would statically program the device to use +that signal polarity. + +The static choice of polarity may be either: + +a1) (Preferred) Dictated by a binding-specific DT property. + +or: + +a2) Defined statically by the DT binding itself. + +In particular, the polarity cannot be derived from the gpio-specifier, since +that would prevent the DT from separately representing the two orthogonal +concepts of configurable signal polarity in the device, and possible board- +level signal inversion. + +or: + +b) Pick a single option for device signal polarity, and document this choice +in the binding. The gpio-specifier should represent the polarity of the signal +(at the GPIO controller) assuming that the device is configured for this +particular signal polarity choice. If software chooses to program the device +to generate or receive a signal of the opposite polarity, software will be +responsible for correctly interpreting (inverting) the GPIO signal at the GPIO +controller. 2) gpio-controller nodes ------------------------ -Every GPIO controller node must both an empty "gpio-controller" -property, and have #gpio-cells contain the size of the gpio-specifier. +Every GPIO controller node must contain both an empty "gpio-controller" +property, and a #gpio-cells integer property, which indicates the number of +cells in a gpio-specifier. Example of two SOC GPIO banks defined as gpio-controller nodes: qe_pio_a: gpio-controller@1400 { - #gpio-cells = <2>; compatible = "fsl,qe-pario-bank-a", "fsl,qe-pario-bank"; reg = <0x1400 0x18>; gpio-controller; + #gpio-cells = <2>; }; qe_pio_e: gpio-controller@1460 { - #gpio-cells = <2>; compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank"; reg = <0x1460 0x18>; gpio-controller; + #gpio-cells = <2>; }; 2.1) gpio- and pin-controller interaction diff --git a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt new file mode 100644 index 000000000000..dd5d2c0394b1 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt @@ -0,0 +1,60 @@ +* Synopsys DesignWare APB GPIO controller + +Required properties: +- compatible : Should contain "snps,dw-apb-gpio" +- reg : Address and length of the register set for the device. +- #address-cells : should be 1 (for addressing port subnodes). +- #size-cells : should be 0 (port subnodes). + +The GPIO controller has a configurable number of ports, each of which are +represented as child nodes with the following properties: + +Required properties: +- compatible : "snps,dw-apb-gpio-port" +- gpio-controller : Marks the device node as a gpio controller. +- #gpio-cells : Should be two. The first cell is the pin number and + the second cell is used to specify the gpio polarity: + 0 = active high + 1 = active low +- reg : The integer port index of the port, a single cell. + +Optional properties: +- interrupt-controller : The first port may be configured to be an interrupt +controller. +- #interrupt-cells : Specifies the number of cells needed to encode an + interrupt. Shall be set to 2. The first cell defines the interrupt number, + the second encodes the triger flags encoded as described in + Documentation/devicetree/bindings/interrupts.txt +- interrupt-parent : The parent interrupt controller. +- interrupts : The interrupt to the parent controller raised when GPIOs + generate the interrupts. +- snps,nr-gpios : The number of pins in the port, a single cell. + +Example: + +gpio: gpio@20000 { + compatible = "snps,dw-apb-gpio"; + reg = <0x20000 0x1000>; + #address-cells = <1>; + #size-cells = <0>; + + porta: gpio-controller@0 { + compatible = "snps,dw-apb-gpio-port"; + gpio-controller; + #gpio-cells = <2>; + snps,nr-gpios = <8>; + reg = <0>; + interrupt-controller; + #interrupt-cells = <2>; + interrupt-parent = <&vic1>; + interrupts = <0>; + }; + + portb: gpio-controller@1 { + compatible = "snps,dw-apb-gpio-port"; + gpio-controller; + #gpio-cells = <2>; + snps,nr-gpios = <8>; + reg = <1>; + }; +}; diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index e42f77d8d4ca..09854fe59307 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -154,6 +154,7 @@ raw line value: void gpiod_set_raw_value(struct gpio_desc *desc, int value) int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) 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: diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt index 9da0bfa74781..f73cc7b5dc85 100644 --- a/Documentation/gpio/driver.txt +++ b/Documentation/gpio/driver.txt @@ -62,6 +62,37 @@ Any debugfs dump method should normally ignore signals which haven't been requested as GPIOs. They can use gpiochip_is_requested(), which returns either NULL or the label associated with that GPIO when it was requested. + +GPIO drivers providing IRQs +--------------------------- +It is custom that GPIO drivers (GPIO chips) are also providing interrupts, +most often cascaded off a parent interrupt controller, and in some special +cases the GPIO logic is melded with a SoC's primary interrupt controller. + +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. + +It is legal for any IRQ consumer to request an IRQ from any irqchip no matter +if that is a combined GPIO+IRQ driver. The basic premise is that gpio_chip and +irq_chip are orthogonal, and offering their services independent of each +other. + +gpiod_to_irq() is just a convenience function to figure out the IRQ for a +certain GPIO line and should not be relied upon to have been called before +the IRQ is used. + +So always prepare the hardware and make it ready for action in respective +callbacks from the GPIO and irqchip APIs. Do not rely on gpiod_to_irq() having +been called first. + +This orthogonality leads to ambiguities that we need to solve: if there is +competition inside the subsystem which side is using the resource (a certain +GPIO line and register for example) it needs to deny certain operations and +keep track of usage inside of the gpiolib subsystem. This is why the API +below exists. + + Locking IRQ usage ----------------- Input GPIOs can be used as IRQ signals. When this happens, a driver is requested @@ -73,3 +104,7 @@ This will prevent the use of non-irq related GPIO APIs until the GPIO IRQ lock is released: void gpiod_unlock_as_irq(struct gpio_desc *desc) + +When implementing an irqchip inside a GPIO driver, these two functions should +typically be called in the .startup() and .shutdown() callbacks from the +irqchip. |