diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/acpi/enumeration.txt | 26 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-bcm-kona.txt | 52 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt | 71 |
3 files changed, 145 insertions, 4 deletions
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt index aca4e69121b7..b994bcb32b92 100644 --- a/Documentation/acpi/enumeration.txt +++ b/Documentation/acpi/enumeration.txt @@ -295,10 +295,6 @@ These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0" specifies the path to the controller. In order to use these GPIOs in Linux we need to translate them to the Linux GPIO numbers. -The driver can do this by including <linux/acpi_gpio.h> and then calling -acpi_get_gpio(path, gpio). This will return the Linux GPIO number or -negative errno if there was no translation found. - In a simple case of just getting the Linux GPIO number from device resources one can use acpi_get_gpio_by_index() helper function. It takes pointer to the device and index of the GpioIo/GpioInt descriptor in the @@ -322,3 +318,25 @@ suitable to the gpiolib before passing them. In case of GpioInt resource an additional call to gpio_to_irq() must be done before calling request_irq(). + +Note that the above API is ACPI specific and not recommended for drivers +that need to support non-ACPI systems. The recommended way is to use +the descriptor based GPIO interfaces. The above example looks like this +when converted to the GPIO desc: + + #include <linux/gpio/consumer.h> + ... + + struct gpio_desc *irq_desc, *power_desc; + + irq_desc = gpiod_get_index(dev, NULL, 1); + if (IS_ERR(irq_desc)) + /* handle error */ + + power_desc = gpiod_get_index(dev, NULL, 0); + if (IS_ERR(power_desc)) + /* handle error */ + + /* Now we can use the GPIO descriptors */ + +See also Documentation/gpio.txt. diff --git a/Documentation/devicetree/bindings/gpio/gpio-bcm-kona.txt b/Documentation/devicetree/bindings/gpio/gpio-bcm-kona.txt new file mode 100644 index 000000000000..4a63bc96b687 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-bcm-kona.txt @@ -0,0 +1,52 @@ +Broadcom Kona Family GPIO +========================= + +This GPIO driver is used in the following Broadcom SoCs: + BCM11130, BCM11140, BCM11351, BCM28145, BCM28155 + +The Broadcom GPIO Controller IP can be configured prior to synthesis to +support up to 8 banks of 32 GPIOs where each bank has its own IRQ. The +GPIO controller only supports edge, not level, triggering of interrupts. + +Required properties +------------------- + +- compatible: "brcm,bcm11351-gpio", "brcm,kona-gpio" +- reg: Physical base address and length of the controller's registers. +- interrupts: The interrupt outputs from the controller. There is one GPIO + interrupt per GPIO bank. The number of interrupts listed depends on the + number of GPIO banks on the SoC. The interrupts must be ordered by bank, + starting with bank 0. There is always a 1:1 mapping between banks and + IRQs. +- #gpio-cells: Should be <2>. The first cell is the pin number, the second + cell is used to specify optional parameters: + - bit 0 specifies polarity (0 for normal, 1 for inverted) + See also "gpio-specifier" in .../devicetree/bindings/gpio/gpio.txt. +- #interrupt-cells: Should be <2>. The first cell is the GPIO number. The + second cell is used to specify flags. The following subset of flags is + supported: + - trigger type (bits[1:0]): + 1 = low-to-high edge triggered. + 2 = high-to-low edge triggered. + 3 = low-to-high or high-to-low edge triggered + Valid values are 1, 2, 3 + See also .../devicetree/bindings/interrupt-controller/interrupts.txt. +- gpio-controller: Marks the device node as a GPIO controller. +- interrupt-controller: Marks the device node as an interrupt controller. + +Example: + gpio: gpio@35003000 { + compatible = "brcm,bcm11351-gpio", "brcm,kona-gpio"; + reg = <0x35003000 0x800>; + interrupts = + <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH + GIC_SPI 115 IRQ_TYPE_LEVEL_HIGH + GIC_SPI 114 IRQ_TYPE_LEVEL_HIGH + GIC_SPI 113 IRQ_TYPE_LEVEL_HIGH + GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH + GIC_SPI 111 IRQ_TYPE_LEVEL_HIGH>; + #gpio-cells = <2>; + #interrupt-cells = <2>; + gpio-controller; + interrupt-controller; + }; diff --git a/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt new file mode 100644 index 000000000000..d63194a2c848 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt @@ -0,0 +1,71 @@ +* PCF857x-compatible I/O expanders + +The PCF857x-compatible chips have "quasi-bidirectional" I/O lines that can be +driven high by a pull-up current source or driven low to ground. This combines +the direction and output level into a single bit per line, which can't be read +back. We can't actually know at initialization time whether a line is configured +(a) as output and driving the signal low/high, or (b) as input and reporting a +low/high value, without knowing the last value written since the chip came out +of reset (if any). The only reliable solution for setting up line direction is +thus to do it explicitly. + +Required Properties: + + - compatible: should be one of the following. + - "maxim,max7328": For the Maxim MAX7378 + - "maxim,max7329": For the Maxim MAX7329 + - "nxp,pca8574": For the NXP PCA8574 + - "nxp,pca8575": For the NXP PCA8575 + - "nxp,pca9670": For the NXP PCA9670 + - "nxp,pca9671": For the NXP PCA9671 + - "nxp,pca9672": For the NXP PCA9672 + - "nxp,pca9673": For the NXP PCA9673 + - "nxp,pca9674": For the NXP PCA9674 + - "nxp,pca9675": For the NXP PCA9675 + - "nxp,pcf8574": For the NXP PCF8574 + - "nxp,pcf8574a": For the NXP PCF8574A + - "nxp,pcf8575": For the NXP PCF8575 + - "ti,tca9554": For the TI TCA9554 + + - reg: I2C slave address. + + - gpio-controller: Marks the device node as a gpio controller. + - #gpio-cells: Should be 2. The first cell is the GPIO number and the second + cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>. Only the + GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW flags are supported. + +Optional Properties: + + - lines-initial-states: Bitmask that specifies the initial state of each + line. When a bit is set to zero, the corresponding line will be initialized to + the input (pulled-up) state. When the bit is set to one, the line will be + initialized the the low-level output state. If the property is not specified + all lines will be initialized to the input state. + + The I/O expander can detect input state changes, and thus optionally act as + an interrupt controller. When the expander interrupt line is connected all the + following properties must be set. For more information please see the + interrupt controller device tree bindings documentation available at + Documentation/devicetree/bindings/interrupt-controller/interrupts.txt. + + - interrupt-controller: Identifies the node as an interrupt controller. + - #interrupt-cells: Number of cells to encode an interrupt source, shall be 2. + - interrupt-parent: phandle of the parent interrupt controller. + - interrupts: Interrupt specifier for the controllers interrupt. + + +Please refer to gpio.txt in this directory for details of the common GPIO +bindings used by client devices. + +Example: PCF8575 I/O expander node + + pcf8575: gpio@20 { + compatible = "nxp,pcf8575"; + reg = <0x20>; + interrupt-parent = <&irqpin2>; + interrupts = <3 0>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + }; |