BB Black 入门基础之 Device Tree 常用target(转)

只看该作者 · 2017-10-2 10:30

BB Black 入门基础之 Device Tree 常用target

最近正学习Device Tree，过了这么长一段时间，进展也不是很大。总结下，主要原因还是基础比较薄弱，不太明白DTS这个文件的写法，不清楚哪里去找一些常用的属性值。

补充几个缩写（AM335x TRM Page 1972）
OMAP    Open Multimedia Application Platform
PWMSS    Pulse-Width Modulation Subsystem
ePWM          enhanced PWM
eHRPWM  enhanced high resolution PWM
eCAP             enhanced Capture
eQEP             enhanced Quadrature Encode Pulse

其中PWMSS 包括了 eHRPWM  eCAP eQEP 几个功能模块。所以要使用ehrpwm1 那就必须先使能epwmss1。

fragment@0 {
target = <&am33xx_pinmux>;
...
}

[color=rgb(51, 102, 153) !important]复制代码
以及下面这种

fragment@1 {
target = <&epwmss1>;
__overlay__ {
status = "okay";
};
};

[color=rgb(51, 102, 153) !important]复制代码

fragment@2 {
target = <&ehrpwm1>;
__overlay__ {
status = "okay";
};
};

[color=rgb(51, 102, 153) !important]复制代码

看到了这里target = <&am33xx_pinmux>; 很多时候我们都不知道 am33xx_pinmux 这个东西它究竟是怎么来的。

这里大胆揣测一下，咱们平时常用的target就在下面包括了。

am33xx_pinmux = "/pinmux@44e10800";
user_leds_s0 = "/pinmux@44e10800/user_leds_s0";
i2c0_pins = "/pinmux@44e10800/pinmux_i2c0_pins";
uart0_pins = "/pinmux@44e10800/pinmux_uart0_pins";
clkout2_pin = "/pinmux@44e10800/pinmux_clkout2_pin";
cpsw_default = "/pinmux@44e10800/cpsw_default";
cpsw_sleep = "/pinmux@44e10800/cpsw_sleep";
davinci_mdio_default = "/pinmux@44e10800/davinci_mdio_default";
davinci_mdio_sleep = "/pinmux@44e10800/davinci_mdio_sleep";
i2c2_pins = "/pinmux@44e10800/pinmux_i2c2_pins";
mmc1_pins = "/pinmux@44e10800/pinmux_mmc1_pins";
nxp_hdmi_bonelt_pins = "/pinmux@44e10800/nxp_hdmi_bonelt_pins";
intc = "/ocp/interrupt-controller@48200000";
edma = "/ocp/edma@49000000";
gpio0 = "/ocp/gpio@44e07000";
gpio1 = "/ocp/gpio@4804c000";
gpio2 = "/ocp/gpio@481ac000";
gpio3 = "/ocp/gpio@481ae000";
uart0 = "/ocp/serial@44e09000";
uart1 = "/ocp/serial@48022000";
uart2 = "/ocp/serial@48024000";
uart3 = "/ocp/serial@481a6000";
uart4 = "/ocp/serial@481a8000";
uart5 = "/ocp/serial@481aa000";
i2c0 = "/ocp/i2c@44e0b000";
tps = "/ocp/i2c@44e0b000/tps@24";
dcdc1_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@0";
dcdc2_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@1";
dcdc3_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@2";
ldo1_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@3";
ldo2_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@4";
ldo3_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@5";
ldo4_reg = "/ocp/i2c@44e0b000/tps@24/regulators/regulator@6";
vmmcsd_fixed = "/ocp/i2c@44e0b000/tps@24/fixedregulator@0";
baseboard_eeprom = "/ocp/i2c@44e0b000/baseboard_eeprom@50";
i2c1 = "/ocp/i2c@4802a000";
i2c2 = "/ocp/i2c@4819c000";
cape_eeprom0 = "/ocp/i2c@4819c000/cape_eeprom0@54";
cape_eeprom1 = "/ocp/i2c@4819c000/cape_eeprom1@55";
cape_eeprom2 = "/ocp/i2c@4819c000/cape_eeprom2@56";
cape_eeprom3 = "/ocp/i2c@4819c000/cape_eeprom3@57";
mmc1 = "/ocp/mmc@48060000";
mmc2 = "/ocp/mmc@481d8000";
mmc3 = "/ocp/mmc@47810000";
wdt2 = "/ocp/wdt@44e35000";
dcan0 = "/ocp/d_can@481cc000";
dcan1 = "/ocp/d_can@481d0000";
timer1 = "/ocp/timer@44e31000";
timer2 = "/ocp/timer@48040000";
timer3 = "/ocp/timer@48042000";
timer4 = "/ocp/timer@48044000";
timer5 = "/ocp/timer@48046000";
timer6 = "/ocp/timer@48048000";
timer7 = "/ocp/timer@4804a000";
spi0 = "/ocp/spi@48030000";
spi1 = "/ocp/spi@481a0000";
musb = "/ocp/usb@47400000";
usb = "/ocp/usb@47400000";
ctrl_mod = "/ocp/usb@47400000/control@44e10000";
usb0_phy = "/ocp/usb@47400000/usb-phy@47401300";
usb0 = "/ocp/usb@47400000/usb@47401000";
usb1_phy = "/ocp/usb@47400000/usb-phy@47401b00";
usb1 = "/ocp/usb@47400000/usb@47401800";
cppi41dma = "/ocp/usb@47400000/dma-controller@07402000";
epwmss0 = "/ocp/epwmss@48300000";
ecap0 = "/ocp/epwmss@48300000/ecap@48300100";
ehrpwm0 = "/ocp/epwmss@48300000/ehrpwm@48300200";
epwmss1 = "/ocp/epwmss@48302000";
ecap1 = "/ocp/epwmss@48302000/ecap@48302100";
ehrpwm1 = "/ocp/epwmss@48302000/ehrpwm@48302200";
epwmss2 = "/ocp/epwmss@48304000";
ecap2 = "/ocp/epwmss@48304000/ecap@48304100";
ehrpwm2 = "/ocp/epwmss@48304000/ehrpwm@48304200";
mac = "/ocp/ethernet@4a100000";
davinci_mdio = "/ocp/ethernet@4a100000/mdio@4a101000";
cpsw_emac0 = "/ocp/ethernet@4a100000/slave@4a100200";
cpsw_emac1 = "/ocp/ethernet@4a100000/slave@4a100300";
ocmcram = "/ocp/ocmcram@40300000";
wkup_m3 = "/ocp/wkup_m3@44d00000";
elm = "/ocp/elm@48080000";
tscadc = "/ocp/tscadc@44e0d000";
am335x_adc = "/ocp/tscadc@44e0d000/adc";
gpmc = "/ocp/gpmc@50000000";
baseboard_beaglebone = "/bone_capemgr/baseboardmaps/board@0";
baseboard_beaglebone_black = "/bone_capemgr/baseboardmaps/board@1";
fb = "/fb@4830e000";
hdmi = "/hdmi";

[color=rgb(51, 102, 153) !important]复制代码
这个能解释得了许多我们已经看到的dts文件的target写法。
但同时，还会遇到如

fragment@3 {
target =
<&ocp>;
...
}

[color=rgb(51, 102, 153) !important]复制代码

这类的target。这里不妨再大胆假设下，OCP即片上外设，如果需要自己定义target，那么就在这个片段里边进行引脚等数据的定义。

gpio-leds-cape-lcd7 {
compatible = "gpio-leds";
pinctrl-names = "default";
pinctrl-0 = <&bone_lcd7_cape_led_00A3_pins>;
lcd7-led0 {
label = "lcd7:green:usr0";
gpios = <&gpio2 28 0>;
linux,default-trigger = "heartbeat";
default-state = "off";
};

[color=rgb(51, 102, 153) !important]复制代码

总结起来就是：
1 常用的target都可用上表给出的 am33xx_pinmux epwmss1 i2c0 这些表示。
2 自定义引脚的意义及配置，通过新建一个包含target = <&ocp> 的节点来实现。

1万 · 2017-10-2 22:33

这个beaglebone功能怎么样？

1万 · 2017-10-2 22:53

嵌入式开发需要准备什么材料？

BB Black 入门基础之 Device Tree 常用target(转)

相关下载

相关帖子