alif,pinctrl
Description
Alif Semiconductor pin controller
The Alif pin controller manages pin multiplexing and pad configuration for
Alif SoCs. Each I/O pin can be assigned to one of up to eight alternate
functions (peripheral signals). Additionally, pad configuration settings
control electrical properties such as input enable, drive strength, and
slew rate.
I/O pins are organized into ports, with each port containing up to 8 pins.
Pin multiplexing configurations are specified using predefined macros from
the SoC-specific pinctrl header (e.g., alif-ensemble-pinctrl.h). These macros
encode the port, pin number, and alternate function.
For example, PIN_P0_0__UART0_RX_A represents port 0, pin 0, configured for the
UART0 RX alternate function.
Pad configuration is specified using standard pinctrl properties.
Example:
#include <dt-bindings/pinctrl/alif-ensemble-pinctrl.h>
&pinctrl {
uart4_default: uart4_default {
group0 {
pinmux = <PIN_P12_1__UART4_RX_B>;
input-enable;
};
group1 {
pinmux = <PIN_P12_2__UART4_TX_B>;
};
};
};
In the example above:
- "&pinctrl" references the pin controller node defined in the SoC devicetree.
- "uart4_default" is a user-defined state node that groups all pin configurations
for UART4's default operating state.
- "group0" and "group1" are pin group nodes. Pins within a group share the same
pad configuration properties. The RX pin needs input-enable, while the TX pin
uses default settings, so they are placed in separate groups.
- "pinmux = <PIN_P12_1__UART4_RX_B>" specifies the pin function. The macro
PIN_P12_1__UART4_RX_B selects port 12, pin 1, configured for UART4 RX function.
These macros are defined in alif-ensemble-pinctrl.h.
- "input-enable" enables the input buffer for the RX pin. Other pad
configuration properties are supported as defined in the property-allowlist.
To link the pin configuration to a device:
&uart4 {
pinctrl-0 = <&uart4_default>;
pinctrl-names = "default";
};
Properties
Top level properties
These property descriptions apply to “alif,pinctrl” nodes themselves. This page also describes child node properties in the following sections.
Properties not inherited from the base binding file.
(None)
Deprecated properties not inherited from the base binding file.
(None)
Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “alif,pinctrl” compatible.
Name |
Type |
Details |
|---|---|---|
|
|
Pin controller register regions. Two regions are required:
1. Main pinctrl registers for GPIO ports P0-P14
2. LPGPIO pinctrl registers for low-power GPIO
This property is required. See Important properties for more information. |
|
|
Names for the register regions:
- "pinctrl": Main GPIO pin control registers
- "lpgpio_pinctrl": Low-power GPIO pin control registers
This property is required. |
|
|
Indicates the operational status of the hardware or other
resource that the node represents. In particular:
- "okay" means the resource is operational and, for example,
can be used by device drivers
- "disabled" means the resource is not operational and the system
should treat it as if it is not present
For details, see "2.3.4 status" in Devicetree Specification v0.4.
Legal values: See Important properties for more information. |
|
|
This property is a list of strings that essentially define what
type of hardware or other resource this devicetree node
represents. Each device driver checks for specific compatible
property values to find the devicetree nodes that represent
resources that the driver should manage.
The recommended format is "vendor,device", The "vendor" part is
an abbreviated name of the vendor. The "device" is usually from
the datasheet.
The compatible property can have multiple values, ordered from
most- to least-specific. Having additional values is useful when the
device is a specific instance of a more general family, to allow the
system to match the most specific driver available.
For details, see "2.3.1 compatible" in Devicetree Specification v0.4.
This property is required. See Important properties for more information. |
|
|
Information about interrupts generated by the device, encoded as an array
of one or more interrupt specifiers. The format of the data in this property
varies by where the device appears in the interrupt tree. Devices with the same
"interrupt-parent" will use the same format in their interrupts properties.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
See Important properties for more information. |
|
|
Extended interrupt specifier for device, used as an alternative to
the "interrupts" property.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
|
|
|
Optional names given to each interrupt generated by a device.
The interrupts themselves are defined in either "interrupts" or
"interrupts-extended" properties.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
|
|
|
If present, this refers to the node which handles interrupts generated
by this device.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
|
|
|
Human readable string describing the device. Use of this property is
deprecated except as needed on a case-by-case basis.
For details, see "4.1.2 Miscellaneous Properties" in Devicetree
Specification v0.4.
See Important properties for more information. |
|
|
Information about the device's clock providers. In general, this property
should follow conventions established in the dt-schema binding:
https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/clock/clock.yaml
|
|
|
Optional names given to each clock provider in the "clocks" property.
|
|
|
This property encodes the number of <u32> cells used by address fields
in "reg" properties in this node's children.
For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.
|
|
|
This property encodes the number of <u32> cells used by size fields in
"reg" properties in this node's children.
For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.
|
|
|
DMA channel specifiers relevant to the device.
|
|
|
Optional names given to the DMA channel specifiers in the "dmas" property.
|
|
|
IO channel specifiers relevant to the device.
|
|
|
Optional names given to the IO channel specifiers in the "io-channels" property.
|
|
|
Mailbox / IPM channel specifiers relevant to the device.
|
|
|
Optional names given to the mbox specifiers in the "mboxes" property.
|
|
|
Power domain specifiers relevant to the device.
|
|
|
Optional names given to the power domain specifiers in the "power-domains" property.
|
|
|
Number of cells in power-domains property
|
|
|
HW spinlock id relevant to the device.
|
|
|
Optional names given to the hwlock specifiers in the "hwlocks" property.
|
|
|
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
|
|
|
Property to identify that a device can be used as wake up source.
When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.
Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.
|
|
|
Automatically configure the device for runtime power management after the
init function runs.
|
|
|
List of power states that will disable this device power.
|
Grandchild node properties
Name |
Type |
Details |
|---|---|---|
|
|
Array of pin function selections. Each element is a 32-bit value
encoding port, pin, and alternate function using ALIF_PINMUX() or
predefined macros from alif-ensemble-pinctrl.h (e.g., PIN_P0_0__UART0_RX_A).
This property is required. |
|
|
Output drive strength in milliamps.
- 2: 2 mA
- 4: 4 mA (default)
- 8: 8 mA
- 12: 12 mA
Default value: Legal values: |
|
|
Output slew rate control.
- slow: Slow slew rate (default)
- fast: Fast slew rate
Default value: Legal values: |
|
|
high impedance mode ("third-state", "floating")
|
|
|
latch weakly
|
|
|
enable pull-up resistor
|
|
|
enable pull-down resistor
|
|
|
drive actively high and low
|
|
|
drive with open drain (hardware AND)
|
|
|
enable input on pin (e.g. enable an input buffer, no effect on output)
|
|
|
disable input on pin (e.g. disable an input buffer, no effect on output)
|
|
|
enable schmitt-trigger mode
|
|
|
disable schmitt-trigger mode
|