pcDuino的linux移植五GPIO驱动开发

调试完pcDuino的led裸板程序，再调pcDuino基于linux内核的gpio驱动开发，以前的问题迎刃而解。本文是在pcDuino的linux移植四简单驱动开发的基础上，做GPIO驱动开发。然后写一个应用测试程序，通过敲命令控制pcduino的TX led亮、灭。同时如果你GPIO4、GPIO5接个LED，也会跟着亮、灭。

开发环境：
系统：ubuntu 10.04.4
单板：pcDuino
编译器：arm-2009q3-67-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2

目标：敲命令控制pcDuino上的TX_LED亮、灭

一、硬件介绍

仔细看pcDuino上的原理图和pcDuino的手册，发现二者不是完全对应的，还是以原理图为准。根据原理图知道TX_LED是接到PH15上，可以当做普通IO口用，不需要连跳线

二、编写GPIO驱动代码

主要包括2部分，驱动代码first_drv.c和应用测试程序firstdrvtest.c以及Makefile。

驱动代码first_drv.c

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <mach/gpio.h>
#include <mach/hardware.h>
#include <linux/device.h>

static struct class *firstdrv_class;
static struct class_device *firstdrv_class_dev;

volatile unsigned long *gphcfg1;//0x100 ph9 [6:4]001
volatile unsigned long *gphdat; //0x10c
static int first_drv_open(struct inode *inode, struct file *file)
{
    printk("first_drv_open\n");
    /* 配置GPh9为输出引脚 gpio4*/
    *gphcfg1 |= ((0x1<<4)|(0x1<<8)|(0X1<<28));
    return 0;
}

static ssize_t first_drv_write(struct file *file, const char __user *buf, size_t count,loff_t *ppos)
{
    int val;
    printk("first_drv_write\n");
    copy_from_user(&val, buf, count); //    copy_to_user();

    if (val == 1)
    {
        // 点灯
        *gphdat &= ~((0X1<<9)|(0X1<<10)|(1<<15));
    }
    else
    {
        // 灭灯
        *gphdat |= ((0X1<<9)|(0X1<<10)|(1<<15));
    }

    return 0;
}

static struct file_operations first_drv_fops ={
    .owner = THIS_MODULE,
    .open  = first_drv_open,
    .write = first_drv_write,
};

int major;
static int first_drv_init(void)
{
    major = register_chrdev(0, "first_drv", &first_drv_fops);
    firstdrv_class = class_create(THIS_MODULE, "firstdrv");
    firstdrv_class_dev = device_create(firstdrv_class,NULL,MKDEV(major, 0), NULL, "xyz");
    gphcfg1 = (volatile unsigned long *)ioremap(0x01c20900, 16);
    gphdat = (volatile unsigned long *)ioremap(0x01c2090c, 16);//gphcfg1 + 3;
    return 0;
}

static void first_drv_exit(void)
{
    unregister_chrdev(major,"first_drv");
    device_unregister(firstdrv_class_dev);
    class_destroy(firstdrv_class);
    iounmap(gphcfg1);

    iounmap(gphdat);
}

module_init(first_drv_init);
module_exit(first_drv_exit);

MODULE_LICENSE("GPL");

文件Makefile：

KERN_DIR = /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0

all:
    make -C $(KERN_DIR) M=`pwd` modules

clean:
    make -C $(KERN_DIR) M=`pwd`  modules clean
    rm -rf modules.order

obj-m   += first_drv.o

应用测试程序firstdrvtest.c：

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>

/* firstdrvtest on
  * firstdrvtest off
  */
int main(int argc, char **argv)
{
    int fd;
    int val = 1;
    fd = open("/dev/xyz", O_RDWR);
    if (fd < 0)
    {
        printf("can't open!\n");
    }
    if (argc != 2)
    {
        printf("Usage :\n");
        printf("%s <on|off>\n", argv[0]);
        return 0;
    }

    if (strcmp(argv[1], "on") == 0)
    {
        val  = 1;
    }
    else
    {
        val = 0;
    }

    write(fd, &val, 4);
    return 0;
}

三、编译测试

1.编译驱动first_drv.c

change@change :~/Si/A10/2_led$ cd ../pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/
change@change :~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$ ls
first_drv.c   first_drv.mod.c  first_drv.o   firstdrvtest.c  modules.order
first_drv.ko  first_drv.mod.o  firstdrvtest  Makefile        Module.symvers
change@change:~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$ make clean
make -C /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0 M=`pwd`  modules clean
make[1]: Entering directory `/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0'
  LD      /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/built-in.o
  CC [M]  /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.o
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c: In function 'first_drv_write':
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c:30: warning: ignoring return value of 'copy_from_user', declared with attribute warn_unused_result
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c: In function 'first_drv_init':
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c:57: warning: assignment from incompatible pointer type
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c: In function 'first_drv_exit':
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c:66: warning: passing argument 1 of 'device_unregister' from incompatible pointer type
include/linux/device.h:692: note: expected 'struct device *' but argument is of type 'struct class_device *'
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.mod.o
  LD [M]  /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.ko
  CLEAN   /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/.tmp_versions
  CLEAN   /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/Module.symvers
make[1]: Leaving directory `/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0'
rm -rf modules.order

change@change:~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$ make
make -C /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0 M=`pwd` modules
make[1]: Entering directory `/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0'
  CC [M]  /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.o
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c: In function 'first_drv_write':
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c:30: warning: ignoring return value of 'copy_from_user', declared with attribute warn_unused_result
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c: In function 'first_drv_init':
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c:57: warning: assignment from incompatible pointer type
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c: In function 'first_drv_exit':
/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.c:66: warning: passing argument 1 of 'device_unregister' from incompatible pointer type
include/linux/device.h:692: note: expected 'struct device *' but argument is of type 'struct class_device *'
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.mod.o
  LD [M]  /home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv/first_drv.ko
make[1]: Leaving directory `/home/change/Si/A10/pcduino/linux-sunxi-sunxi-3.0'

2.编译应用测试程序firstdrvtest.c

change@change:~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$  /home/change/tools/arm-2009q3/bin/arm-none-linux-gnueabi-gcc -o firstdrvtest firstdrvtest.c

其中/home/change/tools/arm-2009q3/bin/arm-none-linux-gnueabi-gcc是我的交叉编译路径，根据自己情况修改。

change@change:~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$ ls
first_drv.c   first_drv.mod.c  first_drv.o   firstdrvtest.c  modules.order
first_drv.ko  first_drv.mod.o  firstdrvtest  Makefile        Module.symvers
change@change:~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$ cp first_drv.ko firstdrvtest /home/change/work/rootfs_dir/fs_mini/home/linux-3.0.62/pcduino/
change@change:~/Si/A10/pcduino/linux-sunxi-sunxi-3.0/drivers/mydrv/led_drv$

其中/home/change/work/rootfs_dir/fs_mini是我的NFS共享目录，详细配置见我的ubuntu 开发环境配置。程序比较简单，就不分析了，有问题直接留言吧，开始测试吧。

3.测试

启动前面pcDuino的linux移植一、二、三、四搭建的驱动开发平台，上电进入pcDuino启动控制台，串口输出如下

/ # ifconfig eth0 172.16.1.111
<4>wemac wemac.0: WARNING: no IRQ resource flags set.
[   18.250000] wemac wemac.0: WARNING: no IRQ resource flags set.
<6>wemac wemac.0: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
[   18.400000] wemac wemac.0: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
/ # ping 172.16.1<7>eth0: no IPv6 routers present
[   28.860000] eth0: no IPv6 routers present

PING 172.16.1 (172.16.0.1): 56 data bytes
^C
--- 172.16.1 ping statistics ---
4 packets transmitted, 0 packets received, 100% packet loss
/ # ping 172.16.1.137
PING 172.16.1.137 (172.16.1.137): 56 data bytes
64 bytes from 172.16.1.137: seq=0 ttl=64 time=10.015 ms
64 bytes from 172.16.1.137: seq=1 ttl=64 time=1.013 ms
64 bytes from 172.16.1.137: seq=2 ttl=64 time=1.735 ms
64 bytes from 172.16.1.137: seq=3 ttl=64 time=0.814 ms
^C
--- 172.16.1.137 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 0.814/3.394/10.015 ms
/ # ls
bin      etc      lib      mnt      run      sys      usr
dev      home     linuxrc  proc     sbin     tmp      var
/ # mount -t nfs -o nolock 172.16.1.137:/home/change/work/rootfs_dir/fs_mini /mn
t/
/ # ls /mnt/
bin      etc      lib      mnt      root     sys      usr
dev      home     linuxrc  proc     sbin     tmp
/ # cd /mnt/home/linux-3.0.62/pcduino/
/mnt/home/linux-3.0.62/pcduino # ls
first_drv.ko  firstdrvtest  gpio_drv.ko   gpiodrvtest
/mnt/home/linux-3.0.62/pcduino # insmod first_drv.ko 
/mnt/home/linux-3.0.62/pcduino # lsmod 
first_drv 1768 0 - Live 0xbf000000
/mnt/home/linux-3.0.62/pcduino # ./firstdrvtest off
first_drv_open
[  303.610000] first_drv_open
first_drv_write
[  303.610000] first_drv_write
/mnt/home/linux-3.0.62/pcduino # ./firstdrvtest on
first_drv_open
[  309.510000] first_drv_open
first_drv_write
[  309.510000] first_drv_write
/mnt/home/linux-3.0.62/pcduino #

可以看到执行./firstdrvtest off ,pcDuino上的TX LED就灭，执行./firstdrvtest on,pcDuino上的TX LED就亮。测试基本正常，卸载刚刚加载的驱动如下;

/mnt/home/linux-3.0.62/pcduino # rmmod first_drv
/mnt/home/linux-3.0.62/pcduino # lsmod 
/mnt/home/linux-3.0.62/pcduino #

基本OK了，下一步继续完善驱动。