mini6410 PWM驱动程序

mini6410 PWM驱动程序:

#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 <plat/gpio-cfg.h>
#include <plat/regs-clock.h>
#include <plat/regs-gpio.h>

#include <plat/gpio-bank-e.h>
#include <plat/gpio-bank-f.h>
#include <plat/gpio-bank-k.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( 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 << 28);
 tmp |=  (0x2U << 28);
 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;
 tcfg1 |= S3C_TCFG1_MUX0_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(0));
 __raw_writel(tcnt/2, S3C_TCMPB(0));
   
 tcon &= ~0x1f;
 tcon |= 0xb;  //disable deadzone, auto-reload, inv-off, update TCNTB0&TCMPB0, start timer 0
 __raw_writel(tcon, S3C_TCON);
 
 tcon &= ~2;   //clear manual update bit
 __raw_writel(tcon, S3C_TCON);
}

void PWM_Stop( void )
{
 unsigned tmp;
 tmp = readl(S3C64XX_GPFCON);
 tmp &= ~(0x3U << 28);
 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 int s3c64xx_pwm_ioctl(struct inode *inode, struct file *file, 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,
    .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;

 init_MUTEX(&lock);
 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");