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基于Tiny6410的LED驱动程序

 
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从电路图中看出,GPIO低电平有效(LED亮)。GPK共有16个端口,每个端口由三个寄存器控制——控制寄存器(GPKCON)、数据寄存器(GPKDAT)和上拉寄存器(GPKPUD),每个寄存器都是32位,如下图所示。


GPK的控制寄存器分为两个,GPKCON0控制0~8好端口,GPKCON1控制9~15号端口。控制寄存器连续的4位控制一个端口,如下图中LED对应的控制寄存器。


驱动程序

/*

*===========================================================================

* Filename: tiny6410_leds.c

* Description: led drivers for Tiny6410

*

* Created: xhzuoxin 05/07/2013

* Compiler: gcc

*===========================================================================

*/

#include<linux/module.h>

#include<linux/init.h>

//#include <linux/mm.h>

#include<linux/fs.h>

//#include <linux/types.h>

//#include <linux/delay.h>

//#include <linux/slab.h>

//#include <linux/cdev.h>

#include<linux/miscdevice.h>

#include<linux/errno.h>

#include<linux/ioctl.h>

//#include <linux/string.h>

//#include <linux/list.h>

#include<linux/pci.h>

#include<asm/uaccess.h>

//#include <asm/atomic.h>

//#include <asm/unistd.h>

//#include <asm/irq.h>

#include<mach/regs-gpio.h>

#include<mach/hardware.h>

#include<mach/map.h>

#include<mach/regs-clock.h>

#include<mach/regs-gpio.h>

#include<plat/gpio-cfg.h>

#include<mach/gpio-bank-e.h>

#include<mach/gpio-bank-k.h>

#defineLED4 GPK7

#defineLED3 GPK6

#defineLED2 GPK5

#defineLED1 GPK4

#defineDEBUG 0

#defineDEVICE_NAME "tiny6410_leds"

static long tiny6410_leds_ioctl(structfile *flip,unsignedintcmd, unsigned longarg)

{

/* arg:which led */

switch(cmd) {

unsigned tmp;

case 0:

case 1:

if (arg > 4) {

return -EINVAL;

}

tmp =readl(S3C64XX_GPKDAT); // read data register

tmp&= ~(1 << (4+arg)); // clear bit

tmp |=((!cmd) << (4+arg)); // set bitwith cmd

writel(tmp,S3C64XX_GPKDAT); // write data register

#ifDEBUG

printk(DEVICE_NAME":%ld %d\n", arg, cmd);

#endif

return 0;

default:

return -EINVAL;

}

}

static struct file_operations dev_fops = {

.owner =THIS_MODULE,

.unlocked_ioctl= tiny6410_leds_ioctl,

};

static struct miscdevice misc = {

.minor =MISC_DYNAMIC_MINOR,

.name =DEVICE_NAME,

.fops =&dev_fops,

};

static int __init dev_init(void)

{

int ret;

unsigned tmp;

/*configure config register : 0001 output */

tmp =readl(S3C64XX_GPKCON);

tmp = (tmp&~ (0xffffU<<16)) | (0x1111U<<16);

writel(tmp,S3C64XX_GPKCON);

/*configure data register : init dark */

tmp =readl(S3C64XX_GPKDAT);

tmp |=(0xF << 4);

writel(tmp,S3C64XX_GPKDAT);

ret =misc_register(&misc);

printk(DEVICE_NAME"\tinitialized\n");

return ret;

}

static void __exit dev_exit(void)

{

misc_deregister(&misc);

}

module_init(dev_init);

module_exit(dev_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("zx");

Makefile文件如下:

ARCH=arm

COMPILE=arm-linux-

ifneq ($(KERNELRELEASE),)

obj-m:=tiny6410_leds.o

else

KDIR ?= /mnt/HappyStudy/Tiny6410/linux-2.6.38

PWD := $(shell pwd)

endif

all:

make -C$(KDIR) M=$(PWD) modules ARCH=$(ARCH) CROSS_COMPILE=$(COMPILE)

clean:

rm -f *.ko*.o *.mod.o *.od.c *.symvers

用户空间测试文件为led.c如下,

#include<stdio.h>

#include<stdlib.h>

#include<unistd.h>

#include<sys/ioctl.h>

#include<sys/types.h>

#include<sys/stat.h>

#include<fcntl.h>

#defineDEVICE_NAME"/dev/tiny6410_leds"

intmain(int argc,char**argv)

{

int on;

int led_no;

int fd;

if (argc != 3 || sscanf(argv[1], "%d",&led_no) != 1 || sscanf(argv[2],"%d", &on) != 1 || on < 0|| on > 1 || led_no < 0 || led_no > 3) {

fprintf(stderr,"Usage: leds led_no 0|1\n");

exit(1);

}

fd =open(DEVICE_NAME, 0);

if (fd < 0) {

perror("opendevice leds");

exit(1);

}

ioctl(fd,on, led_no);

close(fd);

return 0;

}

使用arm-linux编译,友善提供了一个编译led.c的Makefile文件,我们关注其中的install目标,该目标能将编译后的程序安装到系统中。

ifndef DESTDIR

DESTDIR ?=/tmp/FriendlyARM/mini6410/rootfs

endif

CFLAGS =-Wall -O2

CC =arm-linux-gcc

INSTALL =install

TARGET =led

all: $(TARGET)

led: led.c

$(CC)$(CFLAGS) $< -o $@

install: $(TARGET)

$(INSTALL)$^ $(DESTDIR)/usr/bin

clean distclean:

rm -rf *.o$(TARGET)

.PHONY: $(PHONY) install clean distclean

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