2440觸摸屏驅動程序

                                                2440觸摸屏驅動程序

#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/platform_device.h>
#include <linux/clk.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/plat-s3c24xx/ts.h>
#include <asm/arch/regs-adc.h>
#include <asm/arch/regs-gpio.h>

struct s3c_ts_regs {
unsigned long adccon;
unsigned long adctsc;
unsigned long adcdly;
unsigned long adcdat0;
unsigned long adcdat1;
unsigned long adcupdn;
};

static struct input_dev *s3c_ts_dev;
static volatile struct s3c_ts_regs *s3c_ts_regs;

static void enter_wait_pen_down_mode(void)
{
s3c_ts_regs->adctsc = 0xd3;
}

static void enter_wait_pen_up_mode(void)
{
s3c_ts_regs->adctsc = 0x1d3;
}

static void enter_measure_xy_mode(void)
{
s3c_ts_regs->adctsc = (1<<3)|(1<<2);
}

static void start_adc(void)
{
s3c_ts_regs->adccon |= (1<<0);
}

static irqreturn_t pen_down_up_irq(int irq, void *dev_id)
{
if (s3c_ts_regs->adcdat0 & (1<<15))
{
printk("pen up\n");
enter_wait_pen_down_mode();
}
else
{
//printk("pen down\n");
//enter_wait_pen_up_mode();
enter_measure_xy_mode();
start_adc();
}
return IRQ_HANDLED;
}

static irqreturn_t adc_irq(int irq, void *dev_id)
{
static int cnt = 0;
printk("adc_irq cnt = %d, x = %d, y = %d\n", ++cnt, s3c_ts_regs->adcdat0 & 0x3ff, s3c_ts_regs->adcdat1 & 0x3ff);
enter_wait_pen_up_mode();
return IRQ_HANDLED;
}

static int s3c_ts_init(void)
{
struct clk* clk;
/* 1. 分配一個input_dev結構體 */
s3c_ts_dev = input_allocate_device();

/* 2. 設置 */
/* 2.1 能產生哪類事件 */
set_bit(EV_KEY, s3c_ts_dev->evbit);
set_bit(EV_ABS, s3c_ts_dev->evbit);

/* 2.2 能產生這類事件裏的哪些事件 */
set_bit(BTN_TOUCH, s3c_ts_dev->keybit);

input_set_abs_params(s3c_ts_dev, ABS_X, 0, 0x3FF, 0, 0);
input_set_abs_params(s3c_ts_dev, ABS_Y, 0, 0x3FF, 0, 0);
input_set_abs_params(s3c_ts_dev, ABS_PRESSURE, 0, 1, 0, 0);

/* 3. 註冊 */
input_register_device(s3c_ts_dev);

/* 4. 硬件相關的操作 */
/* 4.1 使能時鐘(CLKCON[15]) */
clk = clk_get(NULL, "adc");
clk_enable(clk);

/* 4.2 設置S3C2440的ADC/TS寄存器 */
s3c_ts_regs = ioremap(0x58000000, sizeof(struct s3c_ts_regs));

/* bit[14]  : 1-A/D converter prescaler enable
* bit[13:6]: A/D converter prescaler value,
*            49, ADCCLK=PCLK/(49+1)=50MHz/(49+1)=1MHz
* bit[0]: A/D conversion starts by enable. 先設爲0
*/
s3c_ts_regs->adccon = (1<<14)|(49<<6);

request_irq(IRQ_TC, pen_down_up_irq, IRQF_SAMPLE_RANDOM, "ts_pen", NULL);
request_irq(IRQ_ADC, adc_irq, IRQF_SAMPLE_RANDOM, "adc", NULL);

enter_wait_pen_down_mode();

return 0;
}

static void s3c_ts_exit(void)
{
free_irq(IRQ_TC, NULL);
iounmap(s3c_ts_regs);
input_unregister_device(s3c_ts_dev);
input_free_device(s3c_ts_dev);

}

module_init(s3c_ts_init);
module_exit(s3c_ts_exit);
MODULE_LICENSE("GPL");

測試：
1. make menuconfig 去掉原來的觸摸屏驅動程序
-> Device Drivers
  -> Input device support
    -> Generic input layer
      -> Touchscreens

      <>   S3C2410/S3C2440 touchscreens

1. ls /dev/event* 
2. insmod s3c_ts.ko
3. ls /dev/event* 
4. hexdump /dev/event0
            秒       微秒   type code    value
0000000 29a4 0000 8625 0008 0003 0000 0172 0000
0000010 29a4 0000 8631 0008 0003 0001 027c 0000
.......................