From f3a5dd7a1a00473e9fff98ab8176c2b96b5b0d38 Mon Sep 17 00:00:00 2001 From: stephen Date: Tue, 26 Feb 2019 20:32:24 +0800 Subject: [PATCH 37/97] overlays: add README Signed-off-by: stephen --- arch/arm64/boot/dts/rockchip/overlays/README | 121 +++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 arch/arm64/boot/dts/rockchip/overlays/README diff --git a/arch/arm64/boot/dts/rockchip/overlays/README b/arch/arm64/boot/dts/rockchip/overlays/README new file mode 100644 index 000000000000..93c4c42029a8 --- /dev/null +++ b/arch/arm64/boot/dts/rockchip/overlays/README @@ -0,0 +1,121 @@ +Introduction +============= + +This directory contains Device Tree overlays. Device Tree makes it possible +to support many hardware configurations with a single kernel and without the +need to explicitly load or blacklisr kernel modules. + +On Rock Pi, you will find a .dtb for each base platform in /boot. This +describes the hardware that is part of the Rock Pi board. The loader selects +the .dtb file appropriate for the platform by name and pass it to the kernel. + +Device Tree Overlays usage is controlled from /boot/hw_intfc.conf. You can do +the settings for Rock Pi in your hw_intfc.conf, which should cause your +Rock Pi to do your wanted things after a reboot. + +In /boot/overlays you will find many .dtbo files. The loader will merge the +selected .dtbo files by reading file /boot/hw_intfc.conf. + + +Using Overlays +=============== + +Overlays are loaded using "intfc:" directive. As an example, consider the +at24c02 module. Add one line in hw_intfc.conf: + + intfc:dtoverlay=at24c02 + +This causes the file /boot/overlays/at24c02.dtbo to be loaded. + + +The Overlay and Parameter Reference +===================================== + +N.B. When editing this file, please preserve the indentation levels to make it +simple to parse programmatically. NO HARD TABS. + +Name: pwm0 +Info: Overlay for BUS PWM0 +Load: intfc:pwm0= +Value: + on Set to "on" to enable the pwm0 interface (default "off") + off Set to "off" to disable the pwm0 interface + + +Name: pwm1 +Info: Overlay for BUS PWM1 +Load: intfc:pwm1= +Value: + on Set to "on" to enable the pwm1 interface (default "off") + off Set to "off" to disable the pwm2 interface + + +Name: uart2 +Info: Overlay for BUS UART2 +Load: intfc:uart2= +Value: + on Set to "on" to enable the uart2 interface (default "off") + off Set to "off" to disable the uart2 interface + + +Name: uart4 +Info: Overlay for BUS UART4 +Load: intfc:uart4= +Value: + on Set to "on" to enable the uart4 interface (default "off") + off Set to "off" to disable the uart4 interface + + +Name: spi1 +Info: Overlay for BUS SPI1 +Load: intfc:spi1= +Value: + on Set to "on" to enable the spi1 interface (default "off") + off Set to "off" to disable the spi1 interface + + +Name: spi2 +Info: Overlay for BUS SPI2 +Load: intfc:spi2= +Value: + on Set to "on" to enable the spi2 interface (default "off") + off Set to "off" to disable the spi2 interface + + +Name: i2c2 +Info: Overlay for BUS I2C2 +Load: intfc:i2c2= +Value: + on Set to "on" to enable the i2c2 interface (default "off") + off Set to "off" to disable the i2c2 interface + + +Name: i2c6 +Info: Overlay for BUS I2C6 +Load: intfc:i2c6= +Value: + on Set to "on" to enable the i2c6 interface (default "off") + off Set to "off" to disable the i2c6 interface + + +Name: i2c7 +Info: Overlay for BUS I2C7 +Load: intfc:i2c7= +Value: + on Set to "on" to enable the i2c7 interface (default "off") + off Set to "off" to disable the i2c7 interface + + +N.B. It is recommended to only ebable those bus interfaces that are needed. +Leaving all interfaces enabled can lead to unwanted behaviour. + + +Name: at24c02 +Info: Overlay for activation of Atmel AT24C02 over I2C +Load: intfc:dtoverlay=at24c02 + + +Name: two-color-led +Info: Overlay for activation of two color led module. +Load: intfc:dtoverlay=two-color-led + -- 2.25.1