mypwm.c
- linux内核为3.0.1
- 头文件包括的比较多，有很多确实没用，就是以后开发的时候可以直接复制这些头文件，妈妈再也不用担心我的头文件丢失了
- 飞凌自带的内核中由于定时器中断已经占用，我有自己编译了一个内核，中断都没有用，这样才能用
- 关于各种中断的定义，具体在arch/arm/s3c64xx/mach/irqs.h 中，好像是，仔细看看
- 使用的是杂项字符设备，框架是别人的，修改出来的，不用mknod，省事了
</pre><pre code_snippet_id="367118" snippet_file_name="blog_20140528_1_4053757" name="code" class="cpp">/*程序利用timer1输出pwm波到引脚（根据底板和核心板原理图可以察看）；
并将始终中断功能也加入到功能*/
/*****************************************************************/
#include <linux/clk.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/mach/time.h>
#include <asm/uaccess.h>
#include <mach/hardware.h>
#include <mach/regs-irq.h>
#include <mach/map.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>
#include <mach/gpio-bank-e.h>
#include <mach/gpio-bank-f.h>
#include <mach/gpio-bank-k.h>
#include <plat/regs-timer.h>
#include <plat/gpio-cfg.h>
#include "pwm.h"
static struct semaphore lock;
/* freq: pclk/50/16/65536 ~ pclk/50/16
* if pclk = 50MHz, freq is 1Hz to 62500Hz
* human ear : 20Hz~ 20000Hz
*/
/*中断处理函数*/
static irqreturn_t timer_function(int irq, void *dev_id)
{
printk(KERN_INFO"the first irq is OK\n");
return IRQ_RETVAL(IRQ_HANDLED);
}
/*pwm frequency set program*/
static void PWM_Set_Freq( unsigned long freq )
{
unsigned long tcon;
unsigned long tcnt;
unsigned long tcfg1;
unsigned long tcfg0;
struct clk *clk_p;
unsigned long pclk;
unsigned tmp;
tmp = readl(S3C64XX_GPFCON);
tmp &= ~(0x3U << 30); //
tmp |= (0x2U << 30); //
writel(tmp, S3C64XX_GPFCON);
tcon = __raw_readl(S3C_TCON);
tcfg1 = __raw_readl(S3C_TCFG1);
tcfg0 = __raw_readl(S3C_TCFG0);
//prescaler = 50
tcfg0 &= ~S3C_TCFG_PRESCALER0_MASK;
tcfg0 |= (50 - 1);
//mux = 1/16
tcfg1 &= ~(S3C_TCFG1_MUX0_MASK | S3C_TCFG1_MUX1_MASK);
tcfg1 |= S3C_TCFG1_MUX0_DIV16 | S3C_TCFG1_MUX1_DIV16; //timer1ÉèÖÃΪ16·ÖƵ
__raw_writel(tcfg1, S3C_TCFG1);
__raw_writel(tcfg0, S3C_TCFG0);
clk_p = clk_get(NULL, "pclk");
pclk = clk_get_rate(clk_p);
tcnt = (pclk/50/16)/freq;
__raw_writel(tcnt, S3C_TCNTB(1)); //
__raw_writel(tcnt/2, S3C_TCMPB(1)); //
tcon &= ~(0x1f<<8);
tcon |= (0xb<<8); //disable deadzone, auto-reload, inv-off, update TCNTB0&TCMPB0, start timer 0
__raw_writel(tcon, S3C_TCON);
tcon &= ~(2<<8); //clear manual update bit
__raw_writel(tcon, S3C_TCON);
}
/*stop pwm*/
void PWM_Stop( void )
{
unsigned tmp;
tmp = readl(S3C64XX_GPFCON);
tmp &= ~(0x3U << 30);
writel(tmp, S3C64XX_GPFCON);
}
static int s3c64xx_pwm_open(struct inode *inode, struct file *file)
{
if (!down_trylock(&lock))
return 0;
else
return -EBUSY;
}
static int s3c64xx_pwm_close(struct inode *inode, struct file *file)
{
up(&lock);
return 0;
}
static long s3c64xx_pwm_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
int ioarg;
switch (cmd)
{
case PWM_IOCTL_SET_FREQ:
if (arg == 0)
{
printk ("<1>"DEVICE_NAME"\tfrequency is zero\n");
return -EINVAL;
}
get_user(ioarg,(int*)arg);
printk ("<1>"DEVICE_NAME"\tset frequency%d\n",ioarg);
PWM_Set_Freq(ioarg);
break;
case PWM_IOCTL_STOP:
default:
printk ("<1>"DEVICE_NAME"\tstop pwm\n");
PWM_Stop();
break;
}
return 0;
}
static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.open = s3c64xx_pwm_open,
.release = s3c64xx_pwm_close,
.unlocked_ioctl = s3c64xx_pwm_ioctl,
};
static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};
static int __init dev_init(void)
{
int ret1,ret2;
sema_init(&lock, 1);
ret1 = misc_register(&misc);
PWM_Set_Freq(1);
printk ("<1>"DEVICE_NAME"\tinitialized\n");
/*申请定时器中断 */
enable_irq(IRQ_TIMER1);
ret2 = request_irq(IRQ_TIMER1, timer_function, IRQ_TYPE_LEVEL_HIGH, DEVICE_NAME, NULL);
if(0 != ret2)
{
printk(KERN_INFO"request the irq is err\n");
return -1;
}
printk(KERN_INFO"request the irq is well\n");
return ret1;
}
static void __exit dev_exit(void)
{
misc_deregister(&misc);
}
module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");
MODULE_DESCRIPTION("S3C6410 PWM Driver");
pwm.h
#ifndef __PWM_H__
#define __PWM_H__
#include <linux/ioctl.h>
#define DEVICE_NAME "mypwm"
/*»ÃÊý*/
#define PWM_IOC_MAGIC 'l'
/*PWMÃüÁî*/
#define PWM_IOCTL_SET_FREQ _IOW(PWM_IOC_MAGIC, 1, int)
#define PWM_IOCTL_STOP _IO(PWM_IOC_MAGIC, 2)
#define PWM_IOC_MAXNR 2
#endif /* __PWM_H__ */
做个好人，送上app
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "pwm.h"
#define DEV_NAME "/dev/" DEVICE_NAME
int main(int argc, char *argv[])
{
if (argc > 2) {
printf("Usage: %s <binary code>\n"
" eg. %s 1001 -- will turn on pwm 0 and 3,"
" and turn off pwm 1 and 2\n", argv[0], argv[0]);
_exit(EXIT_FAILURE);
}
int fd, ioarg;
if (-1==(fd=open (DEV_NAME, O_RDWR)))
{
printf("open dev error\n");
_exit(EXIT_FAILURE);
}
if (1==argc)
{
ioctl(fd, PWM_IOCTL_STOP);
printf("pwm STOP\n");
}
else if((ioarg = atoi(argv[1]))<=0)
{
ioctl(fd, PWM_IOCTL_STOP);
printf("pwm STOP\n");
}
else
{
printf("ioarg=%d\n", ioarg);
ioctl(fd, PWM_IOCTL_SET_FREQ, (int *)&ioarg);
}
_exit(EXIT_SUCCESS);
}
makefile
obj-m := mypwm.o
KDIR := /forlinx/OK6410/linux-ok6410/
all:
make -C $(KDIR) M=$(PWD) modules CROSS_COMPILE=arm-linux- ARCH=arm
clean:
rm -f *.ko *.o *.mod.o *.mod.c *.symvers *.bak *.order