linux adc駆動

5914 ワード

フレンドリーな開発ボードが提供する駆動はmisc形式に書かれています.
#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_MINI6410
extern int mini6410_adc_acquire_io(void);
extern void mini6410_adc_release_io(void);
#else
static inline int mini6410_adc_acquire_io(void) {
	return 0;
}
static inline void mini6410_adc_release_io(void) {
	/* Nothing */
}
#endif

static 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
", 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
", 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
"); return 0; } static int s3c2410_adc_release(struct inode *inode, struct file *filp) { DPRINTK("adc closed
"); 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
"); return -ENOMEM; } adc_clock = clk_get(NULL, "adc"); if (!adc_clock) { printk(KERN_ERR "failed to get adc clock source
"); 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
"); 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("FriendlyARM Inc.");