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1、在linux-2.6.32.2/drivers/char/目录下，增加一个驱动程序文件mini2440_pwm.c，内容如下：#include#include#include#include#include#include#include#include#include#include
2、#include#include#include#include#include#include#include#include#include#include#defineDEVICE_NAME
3、"pwm"//设备名#definePWM_IOCTL_SET_FREQ1//定义宏变量，用于后面的ioctl中的switchcase#definePWM_IOCTL_STOP0//定义信号量lockstaticstructsemaphorelock;/*freq:pclk/50/16/65536~pclk/50/16*ifpclk=50MHz,freqis1Hzto62500Hz*humanear:20Hz~20000Hz*/staticvoidPWM_Set_Freq(unsignedlongfreq)//设置pwm的频率，配置各个寄存器{
4、unsignedlongtcon;unsignedlongtcnt;unsignedlongtcfg1;unsignedlongtcfg0;structclk*clk_p;unsignedlongpclk;//setGPB0astout0,pwmoutput设置GPB0为tout0,pwm输出s3c2410_gpio_cfgpin(S3C2410_GPB(0),S3C2410_GPB0_TOUT0);tcon=__raw_readl(S3C2410_TCON);//读取寄存器TCON到tcontcfg1=__raw_readl(S3C2410
5、_TCFG1);//读取寄存器TCFG1到tcfg1tcfg0=__raw_readl(S3C2410_TCFG0);//读取寄存器TCFG0到tcfg0//prescaler=50tcfg0&=~S3C2410_TCFG_PRESCALER0_MASK;//S3C2410_TCFG_PRESCALER0_MASK定时器0和1的预分频值的掩码，TCFG[0~8]tcfg0
6、=(50-1);//预分频为50//mux=1/16tcfg1&=~S3C2410_TCFG1_MUX0_MASK;//S3C2410_TCFG1_MUX0_MASK定时器
7、0分割值的掩码：TCFG1[0~3]tcfg1
8、=S3C2410_TCFG1_MUX0_DIV16;//定时器0进行16分割__raw_writel(tcfg1,S3C2410_TCFG1);//把tcfg1的值写到分割寄存器S3C2410_TCFG1中__raw_writel(tcfg0,S3C2410_TCFG0);//把tcfg0的值写到预分频寄存器S3C2410_TCFG0中clk_p=clk_get(NULL,"pclk");//得到pclkpclk=clk_get_rate(clk_p);tcnt=(pclk/50/16)/fre
9、q;//得到定时器的输入时钟，进而设置PWM的调制频率__raw_writel(tcnt,S3C2410_TCNTB(0));//PWM脉宽调制的频率等于定时器的输入时钟__raw_writel(tcnt/2,S3C2410_TCMPB(0));//占空比是50%tcon&=~0x1f;tcon
10、=0xb;//disabledeadzone,auto-reload,inv-off,updateTCNTB0&TCMPB0,starttimer0__raw_writel(tcon,S3C2410_TCON);//把tcon写到计数器控制寄存器S3
11、C2410_TCON中tcon&=~2;//clearmanualupdatebit__raw_writel(tcon,S3C2410_TCON);}staticv
