Device-tree-overlays
Introduction of ROCK Pi Device Tree Overlays
This document describes ROCK Pi device tree overlays provided in kernel packages.
Platform and Chips
rockchip (Rockchip)
- rk3399pro
- rk3328
usage
Kernel provided DT overlay files are in /boot/dtbs/$(uname -r)/rockchip/overlay/
/boot/uEnv.txt contents:
overlays=rk3399pro-i2c2 rk3399pro-console-on-uart2 rk3399pro-pwm0 rk3399pro-w1-gpio rk3399pro-spi-spidev param_spidev_spi_bus=1 param_spidev_max_freq=10000000 param_w1_pin=GPIO2_A2
Add names of overlays you want to activate to overlays= line in /boot/uEnv.txt, separated with spaces.
Add required parameters with their values to /boot/uEnv.txt, one per line.
Add optional parameters with their values to /boot/uEnv.txt if you want to change the default value, one per line.
RK3399PRO Available Overlay
- rk3399pro-i2c2, rk3399pro-i2c6, rk3399pro-i2c7
- rk3399pro-spi-spidev
- rk3399pro-pwm0, rk3399pro-pwm1
- rk3399pro-uart2, rk3399pro-uart4
- rk3399pro-console-on-uart2, rk3399pro-console-on-uart4
- rk3399pro-w1-gpio
rk3399pro-i2c2
Activates I2C bus 2
I2C2 pins (SCL, SDA): GPIO2_A1, GPIO2_A0
Usage: add one line in /boot/uEnv.txt overlays=rk3399pro-i2c2
rk3399pro-i2c6
Activates I2C bus 6
I2C7 pins (SCL, SDA): GPIO2_B2, GPIO2_A1
rk3399pro-i2c7
Activates I2C bus 7
I2C7 pins (SCL, SDA): GPIO2_B0, GPIO2_A7
rk3399pro-spi-spidev
Activates SPIdev device node (/dev/spidevX.Y) for userspace SPI access, where X is the bus number and Y is the CS number
SPI 1 pins (MOSI, MISO, SCK, CS): GPIO1_B0, GPIO1_A7, GPIO1_B1, GPIO1_B2
Parameters:
- param_spidev_spi_bus (int)
- SPI bus to activate SPIdev support on
- Required
- Supported values: 0, 1
- param_spidev_spi_cs (int)
- SPI chip select number
- Optional
- Default: 0
- Supported values: 0, 1
- Using chip select 1 requires using "spi-add-cs1" overlay
- param_spidev_max_freq (int)
- Maximum SPIdev frequency
- Optional
- Default: 10000000
- Range: 3000 - 100000000
rk3399pro-pwm0
Activates PWM0
rk3399pro-pwm1
Activates PWM1
rk3399pro-uart2
Activates serial port 2 (/dev/ttyS2)
UART2 pins (RXD, TXD): GPIO4_C3, GPIO4_C4
Notice: rk3399pro-uart2 and rk3399pro-console-on-uart2 cannnot be added together in /boot/uEnv.txt.
rk3399pro-uart4
Activates serial port 4 (/dev/ttyS4)
UART4 pins (RXD, TXD): GPIO1_A7, GPIO1_B0
Notice: UART4 cannot be activated together with SPI1 since they share the same pins. Also, rk3399pro-uart4 and rk3399pro-console-on-uart4 cannnot be added together in /boot/uEnv.txt.
rk3399pro-console-on-uart2
Activates debug console on UART2
console pins (RXD, TXD): GPIO4_C3, GPIO4_C4
Notice: rk3399pro-console-on-uart2 and rk3399pro-uart2 cannnot be added together in /boot/uEnv.txt.
rk3399pro-console-on-uart4
Activates debug console on UART4
console pins (RXD, TXD): GPIO1_A7, GPIO1_B0
Notice: rk3399pro-console-on-uart4 and rk3399pro-uart4 cannnot be added together in /boot/uEnv.txt.
rk3399pro-w1-gpio
Activates 1-Wire GPIO master
Requires an external pull-up resistor on the data pin
Parameters:
- param_w1_pin (pin)
- Data pin for 1-Wire master
- Optional
- Default: GPIO2_A2
rk3399pro-raspberrypi-7-inch-lcd
Activates Raspberry Pi 7-inch LCD
Notice: In term of hardware, use a 15-pin FPC cable to connect RPI LCD to ROCK Pi N10.
For power supply, both 5V pin and GND pin on 5-pin connector on RPI LCD are connected to the 40-pin connector on ROCK Pi N10.
rk3399pro-pcie-gen2
Activates PCIe Gen2 Mode