Milk-V Duo开发板免费体验 硬件使用-GPIO

随便看看

启动系统后板子上的LED灯就开始闪烁了，具体是什么灯呢，这个还不知道，正常有LED设备的话可以查看LED的所代表的行为，但是经过查找一番，没找到LED设备，那么就先看看有什么任务吧

[root@milkv]/sys/class/gpio# ps
PID   USER     COMMAND
    1 root     init
    2 root     [kthreadd]
    3 root     [rcu_gp]
    4 root     [rcu_par_gp]
    7 root     [kworker/u2:0-ev]
    8 root     [mm_percpu_wq]
    9 root     [ksoftirqd/0]
   10 root     [rcu_preempt]
   11 root     [kdevtmpfs]
   12 root     [rcu_tasks_kthre]
   13 root     [oom_reaper]
   14 root     [writeback]
   15 root     [kcompactd0]
   24 root     [kblockd]
   25 root     [watchdogd]
   27 root     [kworker/0:1H-kb]
   28 root     [rpciod]
   29 root     [kworker/u3:0]
   30 root     [xprtiod]
   31 root     [cfg80211]
   32 root     [kswapd0]
   33 root     [nfsiod]
   34 root     [stmmac_wq]
   35 root     [kworker/u2:1]
   68 root     [irq/43-cviusb-o]
   69 root     [irq/44-cd-gpio-]
   70 root     [sdhci]
   71 root     [irq/21-mmc0]
   73 root     [ion_system_heap]
   74 root     [mmc_complete]
   79 root     [jbd2/mmcblk0p2-]
   80 root     [ext4-rsv-conver]
   96 root     /sbin/syslogd -n
  100 root     /sbin/klogd -n
  128 root     [kworker/0:3-eve]
  146 root     /usr/sbin/dropbear -R
  151 nobody   /usr/sbin/dnsmasq
  161 root     [cvitask_isp_pre]
  162 root     [cvitask_isp_bla]
  163 root     [cvitask_isp_err]
  165 root     [cvitask_vpss_0]
  166 root     [cvitask_vpss_1]
  168 root     [gdc_work]
  173 root     [cvitask_tpu_wor]
  178 root     {S99user} /bin/sh /etc/init.d/S99user start
  183 root     [kworker/0:2H]
  187 root     -sh
  268 root     /usr/sbin/dropbear -R
  282 root     -sh
 2390 root     [kworker/0:0-eve]
 3097 root     [kworker/0:1-eve]
 3650 root     ps
 3651 root     sleep 0.5

在里面看到了一个S99user的启动脚本，那么看看内容是什么呢？

[root@milkv]/sys/class/gpio# cat /etc/init.d/S99user
#!/bin/sh
${CVI_SHOPTS}
#
# Start firmware
#
export USERDATAPATH=/mnt/data/
export SYSTEMPATH=/mnt/system/

case "$1" in
  start)
        echo "init mpp system..."
        if [ -d $SYSTEMPATH/ko ]; then
                sh $SYSTEMPATH/ko/loadsystemko.sh
        fi

        echo "Starting app..."

        if [ -f $SYSTEMPATH/blink.sh ]; then
                . $SYSTEMPATH/blink.sh &
        fi

        if [ -f $SYSTEMPATH/rndis.sh ]; then
                . $SYSTEMPATH/rndis.sh &
        fi

        if [ -f $USERDATAPATH/auto.sh ]; then
                usleep 30000
                . $USERDATAPATH/auto.sh &
                exit 1
        fi
        if [ -f $SYSTEMPATH/auto.sh ]; then
                usleep 30000
                . $SYSTEMPATH/auto.sh &
        fi
        ;;
  stop)
        ;;
  restart|reload)
        ;;
  *)
        echo "Usage: $0 {start|stop|restart}"
        exit 1
esac

exit $?

通过查看脚本可以看到/mnt/data/下面会检测auto.sh，/mnt/system/下面会检测ko/loadsystemko.sh，blink.sh，rndis.sh，auto.sh

分别看看这些文件都有什么东西：

[root@milkv]/mnt# ls
system
[root@milkv]/mnt# cat system/ko/loadsystemko.sh
#!/bin/sh
${CVI_SHOPTS}
#
# Start to insert kernel modules
#
insmod /mnt/system/ko/cv180x_sys.ko
insmod /mnt/system/ko/cv180x_base.ko
insmod /mnt/system/ko/cv180x_rtos_cmdqu.ko
insmod /mnt/system/ko/cv180x_fast_image.ko
insmod /mnt/system/ko/cvi_mipi_rx.ko
insmod /mnt/system/ko/snsr_i2c.ko
insmod /mnt/system/ko/cv180x_vi.ko
insmod /mnt/system/ko/cv180x_vpss.ko
insmod /mnt/system/ko/cv180x_dwa.ko
#insmod /mnt/system/ko/cv180x_vo.ko
#insmod /mnt/system/ko/cv180x_mipi_tx.ko
insmod /mnt/system/ko/cv180x_rgn.ko

#insmod /mnt/system/ko/cv180x_wdt.ko
insmod /mnt/system/ko/cv180x_thermal.ko
insmod /mnt/system/ko/cv180x_clock_cooling.ko

insmod /mnt/system/ko/cv180x_tpu.ko
insmod /mnt/system/ko/cv180x_vcodec.ko
insmod /mnt/system/ko/cv180x_jpeg.ko
insmod /mnt/system/ko/cvi_vc_driver.ko MaxVencChnNum=9 MaxVdecChnNum=9
#insmod /mnt/system/ko/cv180x_rtc.ko
#insmod /mnt/system/ko/cv180x_ive.ko

echo 3 > /proc/sys/vm/drop_caches
dmesg -n 4

#usb hub control
#/etc/uhubon.sh host

exit $?
[root@milkv]/mnt# cat system/blink.sh
#!/bin/sh

LED_GPIO=/sys/class/gpio/gpio440

if test -d $LED_GPIO; then
    echo "GPIO440 already exported"
else
    echo 440 > /sys/class/gpio/export
fi

echo out > $LED_GPIO/direction

while true; do
    echo 0 > $LED_GPIO/value
    sleep 0.5
    echo 1 > $LED_GPIO/value
    sleep 0.5
done
[root@milkv]/mnt# cat system/rndis.sh
#!/bin/sh

/etc/uhubon.sh device > > /tmp/rndis.log 2 >&1
/etc/run_usb.sh probe rndis > > /tmp/rndis.log 2 >&1
/etc/run_usb.sh start rndis > > /tmp/rndis.log 2 >&1

sleep 0.5
ifconfig usb0 192.168.42.1

count=`ps | grep dnsmasq | grep -v grep | wc -l`
if [ ${count} -lt 1 ] ;then
  echo "/etc/init.d/S80dnsmasq start" > > /tmp/rndis.log 2 >&1
  /etc/init.d/S80dnsmasq start > > /tmp/rndis.log 2 >&1
fi
[root@milkv]/mnt# cat system/auto.sh
#!/bin/sh
${CVI_SHOPTS}

export LD_LIBRARY_PATH="/lib:/lib/3rd:/lib/arm-linux-gnueabihf:/usr/lib:/usr/local/lib:/mnt/system/lib:/mnt/system/usr/lib:/mnt/system/usr/lib/3rd:/mnt/data/lib"
export PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/mnt/system/usr/bin:/mnt/system/usr/sbin:/mnt/data/bin:/mnt/data/sbin"


if [ ! -f "/tmp/evb_init" ];then
   echo 1 > /tmp/evb_init
else
   exit 1
fi

GPIO

通过查看脚本看到了LED是通过脚本来控制的功能是周期1S的闪烁，RNDIS是在脚本里面设置的IP地址，直接设置为192.168.42.1

关于LED引脚，原理图上面写的是XGPIOC[24]

而教程里面是用GPIOx（x=0，1，2…）来表示的，通过测试GPIOA=GPIO0,GPIOB=GPIO1以此类推，GPIOC[24]=416+24=440，与脚本的引脚号一致，所以把blink.sh脚本干掉之后手动控制一下试试，发现输出结果符合预期，但是输出模式好像不能读取电平，读到的电平一直是0。

[root@milkv]/sys/class/gpio# ls
export       gpiochip352  gpiochip384  gpiochip416  gpiochip448  gpiochip480  unexport
[root@milkv]/sys/class/gpio# echo 440 > export
[root@milkv]/sys/class/gpio# ls
export       gpio440      gpiochip352  gpiochip384  gpiochip416  gpiochip448  gpiochip480  unexport
[root@milkv]/sys/class/gpio# cd gpio440/
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# ls
active_low  device      direction   edge        subsystem   uevent      value
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# cat direction
in
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# echo out >direction
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# cat value
0
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# echo 1 > value
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# cat value
0
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# echo 0 > value
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440# cat value
0
[root@milkv]/sys/devices/platform/3022000.gpio/gpiochip2/gpio/gpio440#

然后测试其他引脚，比如说GPIO14(GPIOA[14])和GPIO15(GPIOA[15])，即494和495

结果与LED引脚不一样，电平不受控制，原因未知，可能是受其他模块影响吧，换GPIO6(GPIOA[23])和GPIO17(GPIOA[24])，即503和504试试，结果是符合预期的。

至此GPIO的测试就完成了


　　审核编辑：汤梓红