diff options
Diffstat (limited to 'doc/device-tree-bindings')
| -rw-r--r-- | doc/device-tree-bindings/gpio/intel,x86-pinctrl.txt | 16 | ||||
| -rw-r--r-- | doc/device-tree-bindings/gpio/nvidia,tegra186-gpio.txt | 161 | ||||
| -rw-r--r-- | doc/device-tree-bindings/reset/reset.txt | 75 |
3 files changed, 244 insertions, 8 deletions
diff --git a/doc/device-tree-bindings/gpio/intel,x86-pinctrl.txt b/doc/device-tree-bindings/gpio/intel,x86-pinctrl.txt index 22d3becb25..8c3a84caf8 100644 --- a/doc/device-tree-bindings/gpio/intel,x86-pinctrl.txt +++ b/doc/device-tree-bindings/gpio/intel,x86-pinctrl.txt @@ -9,7 +9,7 @@ The PINCTRL master node requires the following properties: Pin nodes must be children of the pinctrl master node and can contain the following properties: - pad-offset - (required) offset in the IOBASE for the pin to configure -- gpio-offset - (required) 2 cells +- gpio-offset - (required only when 'mode-gpio' is set) 2 cells - offset in the GPIOBASE for the pin to configure - the bit shift in this register (4 = bit 4) - mode-gpio - (optional) standalone property to force the pin into GPIO mode @@ -18,16 +18,16 @@ contain the following properties: in case of 'mode-gpio' property set: - output-value - (optional) this set the default output value of the GPIO - direction - (optional) this set the direction of the gpio -- pull-str - (optional) this set the pull strength of the pin +- pull-strength - (optional) this set the pull strength of the pin - pull-assign - (optional) this set the pull assignement (up/down) of the pin -- invert - (optional) this input pin is inverted +- invert - (optional) this input pin is inverted Example: pin_usb_host_en0@0 { - gpio-offset = <0x80 8>; - pad-offset = <0x260>; - mode-gpio; - output-value = <1>; - direction = <PIN_OUTPUT>; + gpio-offset = <0x80 8>; + pad-offset = <0x260>; + mode-gpio; + output-value = <1>; + direction = <PIN_OUTPUT>; }; diff --git a/doc/device-tree-bindings/gpio/nvidia,tegra186-gpio.txt b/doc/device-tree-bindings/gpio/nvidia,tegra186-gpio.txt new file mode 100644 index 0000000000..c82a2e221b --- /dev/null +++ b/doc/device-tree-bindings/gpio/nvidia,tegra186-gpio.txt @@ -0,0 +1,161 @@ +NVIDIA Tegra186 GPIO controllers + +Tegra186 contains two GPIO controllers; a main controller and an "AON" +controller. This binding document applies to both controllers. The register +layouts for the controllers share many similarities, but also some significant +differences. Hence, this document describes closely related but different +bindings and compatible values. + +The Tegra186 GPIO controller allows software to set the IO direction of, and +read/write the value of, numerous GPIO signals. Routing of GPIO signals to +package balls is under the control of a separate pin controller HW block. Two +major sets of registers exist: + +a) Security registers, which allow configuration of allowed access to the GPIO +register set. These registers exist in a single contiguous block of physical +address space. The size of this block, and the security features available, +varies between the different GPIO controllers. + +Access to this set of registers is not necessary in all circumstances. Code +that wishes to configure access to the GPIO registers needs access to these +registers to do so. Code which simply wishes to read or write GPIO data does not +need access to these registers. + +b) GPIO registers, which allow manipulation of the GPIO signals. In some GPIO +controllers, these registers are exposed via multiple "physical aliases" in +address space, each of which access the same underlying state. See the hardware +documentation for rationale. Any particular GPIO client is expected to access +just one of these physical aliases. + +Tegra HW documentation describes a unified naming convention for all GPIOs +implemented by the SoC. Each GPIO is assigned to a port, and a port may control +a number of GPIOs. Thus, each GPIO is named according to an alphabetical port +name and an integer GPIO name within the port. For example, GPIO_PA0, GPIO_PN6, +or GPIO_PCC3. + +The number of ports implemented by each GPIO controller varies. The number of +implemented GPIOs within each port varies. GPIO registers within a controller +are grouped and laid out according to the port they affect. + +The mapping from port name to the GPIO controller that implements that port, and +the mapping from port name to register offset within a controller, are both +extremely non-linear. The header file <dt-bindings/gpio/tegra186-gpio.h> +describes the port-level mapping. In that file, the naming convention for ports +matches the HW documentation. The values chosen for the names are alphabetically +sorted within a particular controller. Drivers need to map between the DT GPIO +IDs and HW register offsets using a lookup table. + +Each GPIO controller can generate a number of interrupt signals. Each signal +represents the aggregate status for all GPIOs within a set of ports. Thus, the +number of interrupt signals generated by a controller varies as a rough function +of the number of ports it implements. Note that the HW documentation refers to +both the overall controller HW module and the sets-of-ports as "controllers". + +Each GPIO controller in fact generates multiple interrupts signals for each set +of ports. Each GPIO may be configured to feed into a specific one of the +interrupt signals generated by a set-of-ports. The intent is for each generated +signal to be routed to a different CPU, thus allowing different CPUs to each +handle subsets of the interrupts within a port. The status of each of these +per-port-set signals is reported via a separate register. Thus, a driver needs +to know which status register to observe. This binding currently defines no +configuration mechanism for this. By default, drivers should use register +GPIO_${port}_INTERRUPT_STATUS_G1_0. Future revisions to the binding could +define a property to configure this. + +Required properties: +- compatible + Array of strings. + One of: + - "nvidia,tegra186-gpio". + - "nvidia,tegra186-gpio-aon". +- reg-names + Array of strings. + Contains a list of names for the register spaces described by the reg + property. May contain the following entries, in any order: + - "gpio": Mandatory. GPIO control registers. This may cover either: + a) The single physical alias that this OS should use. + b) All physical aliases that exist in the controller. This is + appropriate when the OS is responsible for managing assignment of + the physical aliases. + - "security": Optional. Security configuration registers. + Users of this binding MUST look up entries in the reg property by name, + using this reg-names property to do so. +- reg + Array of (physical base address, length) tuples. + Must contain one entry per entry in the reg-names property, in a matching + order. +- interrupts + Array of interrupt specifiers. + The interrupt outputs from the HW block, one per set of ports, in the + order the HW manual describes them. The number of entries required varies + depending on compatible value: + - "nvidia,tegra186-gpio": 6 entries. + - "nvidia,tegra186-gpio-aon": 1 entry. +- gpio-controller + Boolean. + Marks the device node as a GPIO controller/provider. +- #gpio-cells + Single-cell integer. + Must be <2>. + Indicates how many cells are used in a consumer's GPIO specifier. + In the specifier: + - The first cell is the pin number. + See <dt-bindings/gpio/tegra186-gpio.h>. + - The second cell contains flags: + - Bit 0 specifies polarity + - 0: Active-high (normal). + - 1: Active-low (inverted). +- interrupt-controller + Boolean. + Marks the device node as an interrupt controller/provider. +- #interrupt-cells + Single-cell integer. + Must be <2>. + Indicates how many cells are used in a consumer's interrupt specifier. + In the specifier: + - The first cell is the GPIO number. + See <dt-bindings/gpio/tegra186-gpio.h>. + - The second cell is contains flags: + - Bits [3:0] indicate trigger type and level: + - 1: Low-to-high edge triggered. + - 2: High-to-low edge triggered. + - 4: Active high level-sensitive. + - 8: Active low level-sensitive. + Valid combinations are 1, 2, 3, 4, 8. + +Example: + +#include <dt-bindings/interrupt-controller/irq.h> + +gpio@2200000 { + compatible = "nvidia,tegra186-gpio"; + reg-names = "security", "gpio"; + reg = + <0x0 0x2200000 0x0 0x10000>, + <0x0 0x2210000 0x0 0x10000>; + interrupts = + <0 47 IRQ_TYPE_LEVEL_HIGH>, + <0 50 IRQ_TYPE_LEVEL_HIGH>, + <0 53 IRQ_TYPE_LEVEL_HIGH>, + <0 56 IRQ_TYPE_LEVEL_HIGH>, + <0 59 IRQ_TYPE_LEVEL_HIGH>, + <0 180 IRQ_TYPE_LEVEL_HIGH>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; +}; + +gpio@c2f0000 { + compatible = "nvidia,tegra186-gpio-aon"; + reg-names = "security", "gpio"; + reg = + <0x0 0xc2f0000 0x0 0x1000>, + <0x0 0xc2f1000 0x0 0x1000>; + interrupts = + <0 60 IRQ_TYPE_LEVEL_HIGH>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; +}; diff --git a/doc/device-tree-bindings/reset/reset.txt b/doc/device-tree-bindings/reset/reset.txt new file mode 100644 index 0000000000..31db6ff849 --- /dev/null +++ b/doc/device-tree-bindings/reset/reset.txt @@ -0,0 +1,75 @@ += Reset Signal Device Tree Bindings = + +This binding is intended to represent the hardware reset signals present +internally in most IC (SoC, FPGA, ...) designs. Reset signals for whole +standalone chips are most likely better represented as GPIOs, although there +are likely to be exceptions to this rule. + +Hardware blocks typically receive a reset signal. This signal is generated by +a reset provider (e.g. power management or clock module) and received by a +reset consumer (the module being reset, or a module managing when a sub- +ordinate module is reset). This binding exists to represent the provider and +consumer, and provide a way to couple the two together. + +A reset signal is represented by the phandle of the provider, plus a reset +specifier - a list of DT cells that represents the reset signal within the +provider. The length (number of cells) and semantics of the reset specifier +are dictated by the binding of the reset provider, although common schemes +are described below. + +A word on where to place reset signal consumers in device tree: It is possible +in hardware for a reset signal to affect multiple logically separate HW blocks +at once. In this case, it would be unwise to represent this reset signal in +the DT node of each affected HW block, since if activated, an unrelated block +may be reset. Instead, reset signals should be represented in the DT node +where it makes most sense to control it; this may be a bus node if all +children of the bus are affected by the reset signal, or an individual HW +block node for dedicated reset signals. The intent of this binding is to give +appropriate software access to the reset signals in order to manage the HW, +rather than to slavishly enumerate the reset signal that affects each HW +block. + += Reset providers = + +Required properties: +#reset-cells: Number of cells in a reset specifier; Typically 0 for nodes + with a single reset output and 1 for nodes with multiple + reset outputs. + +For example: + + rst: reset-controller { + #reset-cells = <1>; + }; + += Reset consumers = + +Required properties: +resets: List of phandle and reset specifier pairs, one pair + for each reset signal that affects the device, or that the + device manages. Note: if the reset provider specifies '0' for + #reset-cells, then only the phandle portion of the pair will + appear. + +Optional properties: +reset-names: List of reset signal name strings sorted in the same order as + the resets property. Consumers drivers will use reset-names to + match reset signal names with reset specifiers. + +For example: + + device { + resets = <&rst 20>; + reset-names = "reset"; + }; + +This represents a device with a single reset signal named "reset". + + bus { + resets = <&rst 10> <&rst 11> <&rst 12> <&rst 11>; + reset-names = "i2s1", "i2s2", "dma", "mixer"; + }; + +This represents a bus that controls the reset signal of each of four sub- +ordinate devices. Consider for example a bus that fails to operate unless no +child device has reset asserted. |
