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注册时间: 2012-02-21
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楼主发表于: 2012-05-24 14:56

GPF15输出PWM波形，出现问题

参考mini6410_pwm.c后修改让GPF15输出PWM，驱动程序如下：但是GPF15在示波器上没有显示PWM波，请各位大侠指点一下
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <mach/hardware.h>
#include <plat/regs-timer.h>
#include <mach/regs-irq.h>
#include <asm/mach/time.h>
#include <linux/clk.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
//#include <linux/errno.h>
//#include <plat/gpio-cfg.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-f.h>
//#include <mach/gpio-bank-k.h>

#define DEVICE_NAME     "mypwm1"

#define PWM_IOCTL_SET_FREQ      1
#define PWM_IOCTL_STOP          0

static struct semaphore lock;

/* freq:  pclk/50/16/65536 ~ pclk/50/16
  * if pclk = 50MHz, freq is 1Hz to 62500Hz
  * human ear : 20Hz~ 20000Hz
  */
static void PWM_Set_Freq( unsigned long freq )
{
    unsigned long tcon;
    unsigned long tcnt;
    unsigned long tcfg1;
    unsigned long tcfg0;
        //unsigned long cstat;

    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_MUX1_MASK;
    tcfg1 |= S3C_TCFG1_MUX1_DIV16;

    __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));

    //start time1
    tcon &= ~0xf1<<4;
    tcon |= 0xb<<8;        //disable deadzone, auto-reload, inv-off, update TCNTB1&TCMPB1, start timer 1
    __raw_writel(tcon, S3C_TCON);

    tcon &= ~0x2<<8;        //clear manual update bit
    __raw_writel(tcon, S3C_TCON);
}

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)
{
    switch (cmd) {
        case PWM_IOCTL_SET_FREQ:
            if (arg == 0)
                return -EINVAL;
            PWM_Set_Freq(arg);
            break;

        case PWM_IOCTL_STOP:
        default:
            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 ret;

    sema_init(&lock, 1);
    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("FriendlyARM Inc.");
MODULE_DESCRIPTION("S3C6410 PWM Driver");

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