1、由原理图可知4G模块用到GPIO39 GPIO40 GPIO41：

 该模块用的是usb 连接，我们已经配置好USB，我们只要开启对应GPIO即可。

#############hub_usb4_4g_power_h#############
 echo 39 > /sys/class/gpio/export
 echo out > /sys/class/gpio/gpio39/direction
 echo 1 > /sys/class/gpio/gpio39/value
#############hub_usb4_4g_power_on############
 echo 40 > /sys/class/gpio/export
 echo out > /sys/class/gpio/gpio40/direction
 echo 1 > /sys/class/gpio/gpio40/value
#############hub_usb4_4g_reset_N##################
 echo 41 > /sys/class/gpio/export
 echo out > /sys/class/gpio/gpio41/direction
 echo 0 > /sys/class/gpio/gpio41/value
 sleep 0.1
 echo 1 > /sys/class/gpio/gpio41/value

2、移植4G驱动

修改驱动源码

# vi kernel/drivers/usb/serial/option.c

3、添加内核配置

CONFIG_USB_SERIAL=y

CONFIG_USB_SERIAL_OPTION=y

2、lsub可以看到识别该模块

上电后可看到如下打印。

3、配置 ppp 

CONFIG_PPP=y 

CONFIG_PPP_MULTILINK=y

CONFIG_PPP_FILTER=y 

CONFIG_PPP_ASYNC=y 

CONFIG_PPP_SYNC_TTY=y

CONFIG_PPP_DEFLATE=y

CONFIG_PPP_BSDCOMP=y

6、编辑拨号脚本

# vi /etc/ppp/peers/modem_L610 

nodetach
lock
/dev/ttyUSB0
115200
nocrtscts
debug
logfile /tmp/logfile
modem
hide-password
usepeerdns
noauth
noipdefault
novj
novjccomp
noccp
defaultroute
ipcp-accept-local
ipcp-accept-remote
connect '/usr/sbin/chat -s -v -f /etc/ppp/peers/chat-modem-connect'
disconnect '/usr/sbin/chat -s -v -f /etc/ppp/peers/chat-modem-disconnect'

# vi /etc/ppp/peers/chat-modem-connect 

ABORT 'NOCARRIER'
ABORT 'ERROR'
ABORT 'NODIALTONE'
ABORT 'BUSY'
ABORT 'NOANSWER'
'' AT
OK AT+GTRAT?
OK AT+CMEE=2
OK AT+CSQ
OK AT+CPIN?
OK AT+COPS?
OK AT+CGDCONT=1,\"IP\",\"cmnet\"
OK ATDT*99#
CONNECT''

# vi /etc/ppp/peers/chat-modem-disconnect 

ABORT OK
ABORT BUSY
ABORT DELAYED
ABORT "NO ANSWER"
ABORT "NO CARRIER"
ABORT "NO DIALTONE"
ABORT VOICE
ABORT ERROR
ABORT RINGING
TIMEOUT 12
""\K
""\K
""\K
""+++ATH
""+++ATH
""+++ATH
#""ATZ
SAY"\nGoodbay\n"

7、ppp拨号

pppd call modem_L610 &

尝试ping 114.114.114.114，验证网络是否通畅。

成功连通