在linux设备驱动学习中，在参考别人的源码，会达到很好的学习效果。在这篇文章中我列出了友善之臂中的驱动程序和自己写的注释。
在后续的章节中会有本人muge0913驱动程序发放，简单易懂的程序，帮大家向嵌入式步步靠近。
仅供技术交流请勿商用。
#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/input.h>#include <linux/init.h>#include <linux/errno.h>#include <linux/serio.h>#include <linux/delay.h>#include <linux/clk.h>#include <linux/wait.h>#include <linux/sched.h>#include <linux/cdev.h>#include <linux/miscdevice.h>#include <asm/io.h>#include <asm/irq.h>#include <asm/uaccess.h>#include <mach/map.h>#include <mach/regs-clock.h>#include <mach/regs-gpio.h>#include <plat/regs-timer.h>#include <plat/regs-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;#ifdef CONFIG_TOUCHSCREEN_MINI6410extern int mini6410_adc_acquire_io(void);extern void mini6410_adc_release_io(void);#elsestatic inline int mini6410_adc_acquire_io(void) {return 0;}static inline void mini6410_adc_release_io(void) {/* Nothing */}#endifstatic int __ADC_locked = 0;static ADC_DEV adcdev;static volatile int ev_adc = 0;static int adc_data;static struct clk*adc_clock;#define __ADCREG(name)(*(volatile unsigned long *)(base_addr + name))#define ADCCON__ADCREG(S3C_ADCCON)// ADC control#define ADCTSC__ADCREG(S3C_ADCTSC)// ADC touch screen control#define ADCDLY__ADCREG(S3C_ADCDLY)// ADC start or Interval Delay#define ADCDAT0__ADCREG(S3C_ADCDAT0)// ADC conversion data 0#define ADCDAT1__ADCREG(S3C_ADCDAT1)// ADC conversion data 1#define ADCUPDN__ADCREG(S3C_ADCUPDN)// 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 (__ADC_locked) {adc_data = ADCDAT0 & 0x3ff;ev_adc = 1;wake_up_interruptible(&adcdev.wait);/* clear interrupt */__raw_writel(0x0, base_addr + S3C_ADCCLRINT);}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 (mini6410_adc_acquire_io() == 0) {__ADC_locked = 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;__ADC_locked = 0;mini6410_adc_release_io();} 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(SAMSUNG_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);}module_init(dev_init);module_exit(dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("muge0913");
那些无法讲述的悲伤和苍凉，
