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# Copyright (c) 2022 NXP
# SPDX-License-Identifier: Apache-2.0
description: |
The node has the 'pinctrl' node label set in MCUX SoC's devicetree. These
nodes can be autogenerated using the MCUXpresso config tools combined with
the imx_dts_gen.py script in NXP's HAL. The mux, mode, input, daisy, and cfg
fields in a group select the pins to be configured, and the remaining
devicetree properties set configuration values for those pins
for example, here is an group configuring LPUART1 pins:
group0 {
pinmux = <&iomuxc_uart4_rxd_uart_rx_uart4_rx:,
&iomuxc_uart4_txd_uart_tx_uart4_tx>;
bias-pull-up;
slew-rate = "slow";
drive-strength = "x1";
};
This will select UART4_RXD as UART4 rx, and UART4_TXD as UART4 tx.
Both pins will be configured with a slow slew rate, and minimum drive
strength.
Note that the soc level iomuxc dts file can be examined to find the possible
pinmux options. Here are the affects of each property on the
IOMUXC SW_PAD_CTL register:
input-schmitt-enable: HYS=1
bias-pull-up: PUE=1, PE=1
bias-pull-down: PUE=0, PE=1
drive-open-drain: ODE=1
slew-rate: FSEL=<enum_idx>
drive-strength: DSE=<enum_idx>
input-enable: SION=1 (in SW_MUX_CTL_PAD register)
If only required properties are supplied, the pin will have the following
configuration:
HYS=0,
PE=0
PUE=0
ODE=0,
SRE=<slew-rate>,
DSE=<drive-strength>,
SION=0,
compatible: "nxp,imx8mp-pinctrl"
include: base.yaml
child-binding:
description: iMX pin controller pin group
child-binding:
description: |
iMX pin controller pin configuration node.
include:
- name: pincfg-node.yaml
property-allowlist:
- input-schmitt-enable
- drive-open-drain
- input-enable
- bias-pull-up
- bias-pull-down
properties:
pinmux:
required: true
type: phandles
description: |
Pin mux selections for this group. See the soc level iomuxc DTSI file
for a defined list of these options.
drive-strength:
required: true
type: string
enum:
- "x1"
- "x4"
- "x2"
- "x6"
description: |
Pin output drive strength. Sets the DSE field in the IOMUXC peripheral.
00 X1- low drive strength
01 X4- high drive strength
10 X2- medium drive strength
11 X6- max drive strength
slew-rate:
required: true
type: string
enum:
- "slow"
- "fast"
description: |
Select slew rate for pin. Corresponds to SRE field in IOMUXC peripheral
0 SLOW — Slow Frequency Slew Rate
1 FAST — Fast Frequency Slew Rate