Mni2440 linux PWM 驱动代码修改支持频率，占空比修改--XiaoLin.Peng

作者：XiaoLin.Peng

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#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 <linux/interrupt.h>
#include <linux/gpio.h>

#include <asm/irq.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <mach/regs-gpio.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>

#define DEVICE_NAME "pwm"

#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_Duty( unsigned long freq,unsigned long duty)
{
   unsigned long tcon;
   unsigned long tcnt;
   unsigned long tcfg1;
   unsigned long tcfg0;

//for test added byXiaolin.Peng
   unsigned long TCNTB_saver = 0;
    unsigned long TCMPB_saver = 0;

   struct clk *clk_p;
   unsigned long pclk;

//for test added by Xiaolin.Peng
printk("freq: %ld\n", freq);

//set GPB0 as tout0, pwm output
s3c2410_gpio_cfgpin(S3C2410_GPB(0), S3C2410_GPB0_TOUT0);

tcon = __raw_readl(S3C2410_TCON);
tcfg1 = __raw_readl(S3C2410_TCFG1);
tcfg0 = __raw_readl(S3C2410_TCFG0);

//prescaler = 50
tcfg0 &= ~S3C2410_TCFG_PRESCALER0_MASK;
tcfg0 |= (50 - 1);

//mux = 1/16
tcfg1 &= ~S3C2410_TCFG1_MUX0_MASK;
tcfg1 |= S3C2410_TCFG1_MUX0_DIV16;

__raw_writel(tcfg1, S3C2410_TCFG1);
__raw_writel(tcfg0, S3C2410_TCFG0);

clk_p = clk_get(NULL, "pclk");
   pclk = clk_get_rate(clk_p);
   tcnt = (pclk/(tcfg0+1)/16)/freq;

   __raw_writel(tcnt, S3C2410_TCNTB(0));
   __raw_writel((tcnt*duty)/100, S3C2410_TCMPB(0));

//for test add by Xiaolin.Peng
   TCNTB_saver = __raw_readl(S3C2410_TCNTB(0));
   TCMPB_saver = __raw_readl(S3C2410_TCMPB(0));
   printk("TCNTB: %ld\n", TCNTB_saver);
   printk("TCMPB: %ld\n", TCMPB_saver);

   tcon &= ~0x1f;
   tcon |= 0xb;       //disable deadzone, auto-reload, inv-off, update TCNTB0&TCMPB0, start timer 0
   __raw_writel(tcon, S3C2410_TCON);

   tcon &= ~2;           //clear manual update bit
   __raw_writel(tcon, S3C2410_TCON);
}

static void PWM_Stop(void)
{
s3c2410_gpio_cfgpin(S3C2410_GPB(0), S3C2410_GPIO_OUTPUT);
s3c2410_gpio_setpin(S3C2410_GPB(0), 0);
}

static int s3c24xx_pwm_open(struct inode *inode, struct file *file)
{
   if (!down_trylock(&lock))
   {
       return 0;
   }
   else
       return -EBUSY;
}

static int s3c24xx_pwm_close(struct inode *inode, struct file *file)
{
   PWM_Stop();
   up(&lock);
    return 0;
}
//cmd =1,open pwm function. = 0, close pwm function
//pwm frquency = (arg & 0xff00)>>8,
//pwm duty = (arm & 0x00ff)
//
static int s3c24xx_pwm_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
   printk("ioctl pwm: %d %ld\n", cmd, arg);
   switch (cmd) {
   case PWM_IOCTL_SET_FREQ:
       if (arg == 0)
           return -EINVAL;
       PWM_Set_Freq_Duty((arg>>8),(arg&0xff));
       break;

case PWM_IOCTL_STOP:
       PWM_Stop();
       break;
   }

return 0;
}

static struct file_operations dev_fops = {
    .owner   =   THIS_MODULE,
    .open    =   s3c24xx_pwm_open,
    .release =   s3c24xx_pwm_close,
    .ioctl   =   s3c24xx_pwm_ioctl,
};

static struct miscdevice misc = {
   .minor = MISC_DYNAMIC_MINOR,
   .name = DEVICE_NAME,
   .fops = &dev_fops,
};

static int __init dev_init(void)
{
int ret;

init_MUTEX(&lock);//init semaphore
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("S3C2410/S3C2440 PWM Driver");

下面是用于测试驱动的代码：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>

int main(int argc, char **argv)
{
   int on = 1;
        unsigned long frq_duty = 0;;
   int fd;

fprintf(stderr, "PWM APP starting...\n");

fd = open("/dev/pwm", 0);
   if (fd < 0) {
       fprintf(stderr, "error:open device pwm failed\n   ");
       exit(1);
   }
   else {
       fprintf(stderr, "PWM devie open success\n");
   }
        frq_duty = ((200<<8)|80);
   ioctl(fd, on, frq_duty);
        while(1);
   close(fd);
   return 0;
}

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Mni2440 linux PWM 驱动代码修改支持频率，占空比修改--XiaoLin.Peng

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