mini2440 adc驱动多通道改进版，附带测试程序

#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 <linux/wait.h> #include <linux/sched.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) int converter_channel = 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) { adcdev.channel=converter_channel; 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; OwnADC = 0; up(&ADC_LOCK); } else { value = -1; } if(converter_channel>=3) //通道选择， { converter_channel=1; } else converter_channel++; 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)); static int channel_count; for(channel_count=1;channel_count<4;channel_count++) //连续开三个通道，为通道2 AIN1、3 AIN2、4 AIN3，这里将通道1 AIN0屏蔽了。要开启通道1 只需要将channel_count从0开始 { adcdev.channel=channel_count; adcdev.prescale=0xff; } DPRINTK( "adc opened\n"); converter_channel = 1; 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.");