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# Copyright (c) 2022, Andriy Gelman <andriy.gelman@gmail.com>
# SPDX-License-Identifier: Apache-2.0
description: |
The Infineon XMC4XXX pin controller is responsible for connecting peripheral outputs
to specific port/pins (also known as alternate functions) and configures pin properties.
The pinctrl settings are referenced in a device tree peripheral node. For example in a UART
node:
&usic1ch1 {
compatible = "infineon,xmc4xxx-uart";
pinctrl-0 = <&uart_tx_p0_1_u1c1 &uart_rx_p0_0_u1c1>;
pinctrl-names = "default";
input-src = "DX0D";
...
};
pinctrl-0 is the phandle that stores the pin settings for two pins: &uart_tx_p0_1_u1c1
and &uart_rx_p0_0_u1c1. These nodes are pre-defined and their naming convention is designed
to help the user select the correct pin settings. Note the use of peripheral type,
pin direction, port/pin number and USIC in the name.
The pre-defined nodes only set the alternate function of the output pin. The
configuration for the pin (i.e. drive strength) should be set in the board setup.
The set of possible configurations are defined in the properties section below (in addition
to the inherited property-allowlist list from pincfg-node.yaml).
To create a new pin configuration, the user may append to the &pinctrl node, for example
#include <zephyr/dt-bindings/pinctrl/xmc4xxx-pinctrl.h>
&pinctrl {
my_node_config: my_node_config {
pinmux = <XMC4XXX_PINMUX_SET(0, 1, 2)>;
drive-push-pull;
... other supported pin configurations ..
};
where XMC4XXX_PINMUX_SET(PORT, PIN, ALTERNATE_FUNCTION) is a helper macro for setting the
alternate function for a given port/pin. Setting ALTERNATE_FUNCTION = 0 means that no
alternate function is selected.
The pinctrl driver only sets the alternate function for output pins. The input mux is
handled by the peripheral drivers. For example the &usic1ch1 node has input-src property for
this purpose. There are no pre-defined nodes for the input mux and this must be properly set
by the user. Refer to the peripheral .yaml file (i.e. infineon,xmc4xxx-uart.yaml) and
XMC4XXX documentation.
compatible: "infineon,xmc4xxx-pinctrl"
include: base.yaml
properties:
"#address-cells":
required: true
const: 1
"#size-cells":
required: true
const: 1
child-binding:
description: Each child node defines the configuration for a particular state.
include:
- name: pincfg-node.yaml
property-allowlist:
- bias-pull-down
- bias-pull-up
- drive-push-pull
- drive-open-drain
- output-high
- output-low
properties:
pinmux:
description: |
Encodes port/pin and alternate function. See helper macro XMC4XX_PINMUX_SET().
Alternate function is only set for output pins; It selects ALT1-ALT4
output line in the GPIO element. The alternate function for input pins is
handled separately by the peripheral. It is upto the peripheral to configure which
input pin to use (For example see parameter input-src in infineon,xmc4xxx-uart.yaml).
required: true
type: int
drive-strength:
description: |
Drive strength of the output pin. Following options as in XMC_GPIO_OUTPUT_STRENGTH
See xmc4_gpio.h. This only has an effect if the pin is in drive-push-pull mode.
required: true
type: string
enum:
- "strong-sharp-edge"
- "strong-medium-edge"
- "strong-soft-edge"
- "strong-slow-edge"
- "medium"
- "medium-unknown1-edge"
- "medium-unknown2-edge"
- "weak"
invert-input:
description: Inverts the input.
type: boolean
hwctrl:
description: Pre-assigns hardware control of the pin to a certain peripheral.
required: true
type: string
enum:
- "disabled"
- "periph1"
- "periph2"