mini6410 adc驅動程序

mini6410 adc驅動程序:

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <mach/regs-clock.h>
#include <plat/regs-timer.h>
 
#include <plat/regs-adc.h>
#include <mach/regs-gpio.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>

#include "s3c24xx-adc.h"

#undef DEBUG
//#define DEBUG
#ifdef DEBUG
#define DPRINTK(x...) {printk(__FUNCTION__"(%d): ",__LINE__);printk(##x);}
#else
#define DPRINTK(x...) (void)(0)
#endif

#define DEVICE_NAME "adc"

static void __iomem *base_addr;

typedef struct {
 wait_queue_head_t wait;
 int channel;
 int prescale;
}ADC_DEV;

DECLARE_MUTEX(ADC_LOCK);
static int OwnADC = 0;

static ADC_DEV adcdev;
static volatile int ev_adc = 0;
static int adc_data;

static struct clk *adc_clock;

#define ADCCON      (*(volatile unsigned long *)(base_addr + S3C2410_ADCCON)) //ADC control
#define ADCTSC      (*(volatile unsigned long *)(base_addr + S3C2410_ADCTSC)) //ADC touch screen control
#define ADCDLY      (*(volatile unsigned long *)(base_addr + S3C2410_ADCDLY)) //ADC start or Interval Delay
#define ADCDAT0     (*(volatile unsigned long *)(base_addr + S3C2410_ADCDAT0)) //ADC conversion data 0
#define ADCDAT1     (*(volatile unsigned long *)(base_addr + S3C2410_ADCDAT1)) //ADC conversion data 1
#define ADCUPDN     (*(volatile unsigned long *)(base_addr + 0x14)) //Stylus Up/Down interrupt status

#define PRESCALE_DIS        (0 << 14)
#define PRESCALE_EN         (1 << 14)
#define PRSCVL(x)           ((x) << 6)
#define ADC_INPUT(x)        ((x) << 3)
#define ADC_START           (1 << 0)
#define ADC_ENDCVT          (1 << 15)

#define START_ADC_AIN(ch, prescale) \
 do{ \
  ADCCON = PRESCALE_EN | PRSCVL(prescale) | ADC_INPUT((ch)) ; \
  ADCCON |= ADC_START; \
 }while(0)

static irqreturn_t adcdone_int_handler(int irq, void *dev_id)
{
 if (OwnADC) {
  adc_data = ADCDAT0 & 0x3ff;

  ev_adc = 1;
  wake_up_interruptible(&adcdev.wait);
 }

 return IRQ_HANDLED;
}

static ssize_t s3c2410_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
 char str[20];
 int value;
 size_t len;
 if (down_trylock(&ADC_LOCK) == 0) {
  OwnADC = 1;
  START_ADC_AIN(adcdev.channel, adcdev.prescale);
  wait_event_interruptible(adcdev.wait, ev_adc);

  ev_adc = 0;

  DPRINTK("AIN[%d] = 0x%04x, %d\n", adcdev.channel, adc_data, ADCCON & 0x80 ? 1:0);

  value = adc_data;
  sprintf(str,"%5d", adc_data);
  copy_to_user(buffer, (char *)&adc_data, sizeof(adc_data));

  OwnADC = 0;
  up(&ADC_LOCK);
 } else {
  value = -1;
 }

 len = sprintf(str, "%d\n", value);
 if (count >= len) {
  int r = copy_to_user(buffer, str, len);
  return r ? r : len;
 } else {
  return -EINVAL;
 }
}

static int s3c2410_adc_open(struct inode *inode, struct file *filp)
{
 init_waitqueue_head(&(adcdev.wait));

 adcdev.channel=0;
 adcdev.prescale=0xff;

 DPRINTK( "adc opened\n");
 return 0;
}

static int s3c2410_adc_release(struct inode *inode, struct file *filp)
{
 DPRINTK( "adc closed\n");
 return 0;
}

static struct file_operations dev_fops = {
 owner: THIS_MODULE,
 open: s3c2410_adc_open,
 read: s3c2410_adc_read,
 release: s3c2410_adc_release,
};

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

static int __init dev_init(void)
{
 int ret;

 base_addr=ioremap(S3C2410_PA_ADC,0x20);
 if (base_addr == NULL) {
  printk(KERN_ERR "Failed to remap register block\n");
  return -ENOMEM;
 }

 adc_clock = clk_get(NULL, "adc");
 if (!adc_clock) {
  printk(KERN_ERR "failed to get adc clock source\n");
  return -ENOENT;
 }
 clk_enable(adc_clock);
 
 /* normal ADC */
 ADCTSC = 0;

 ret = request_irq(IRQ_ADC, adcdone_int_handler, IRQF_SHARED, DEVICE_NAME, &adcdev);
 if (ret) {
  iounmap(base_addr);
  return ret;
 }

 ret = misc_register(&misc);

 printk (DEVICE_NAME"\tinitialized\n");
 return ret;
}

static void __exit dev_exit(void)
{
 free_irq(IRQ_ADC, &adcdev);
 iounmap(base_addr);

 if (adc_clock) {
  clk_disable(adc_clock);
  clk_put(adc_clock);
  adc_clock = NULL;
 }

 misc_deregister(&misc);
}

EXPORT_SYMBOL(ADC_LOCK);
module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");