mini2440开发板的一线触摸屏驱动代码的位置在友善之臂提供的linux内核代码中的位置如下：
linux-2.6.32.2\drivers\input\touchscreen\mini2440_1wire_host.c
/*
* mini2440_1wire_host.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* LCD-CPU one wire communication for Mini2440 from
* FriendlyARM Guangzhou CO., LTD.
*
* Copyright (c) 2010 FriendlyARM Guangzhou CO., LTD. <http://www.arm9.net>
*
* ChangeLog
*
*
* 2010-10-14: Russell Guo <russell.grey@gmail.com>
* - Initial version
* -- request touch-screen data
* -- request LCD type, Firmware version
* - Backlight control
*
* the CRC-8 functions is based on web page from http://lfh1986.blogspot.com
*/
#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/miscdevice.h>
#include <linux/timer.h>
#include <linux/param.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <plat/regs-timer.h>
#include <plat/gpio-cfg.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>
#include <mach/gpio.h>
#include <linux/cdev.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/err.h>
#include <linux/io.h>
#include <asm/system.h>
#include <asm/leds.h>
#include <asm/mach-types.h>
#include <asm/irq.h>
#include <mach/map.h>
#include <mach/regs-irq.h>
#include <asm/mach/time.h>
#include <plat/clock.h>
#include <plat/cpu.h>
#undef DEBUG
#define DEBUG
#ifdef DEBUG
#define DPRINTK(x...) {printk("%s(%d): ",__FUNCTION__ ,__LINE__);printk(x);}
#else
#define DPRINTK(x...) (void)(0)
#endif
#define TOUCH_DEVICE_NAME "touchscreen-1wire"
#define BACKLIGHT_DEVICE_NAME "backlight-1wire"
#define SAMPLE_BPS 9600
#define REQ_TS 0x40U
#define REQ_INFO 0x60U
// Touch Screen driver interface
//
static DECLARE_WAIT_QUEUE_HEAD(ts_waitq);
static int ts_ready;
static unsigned ts_status;
static inline void notify_ts_data(unsigned x, unsigned y, unsigned down)
{
if (!down && !(ts_status &(1U << 31))) {
// up repeat, give it up
return;
}
ts_status = ((x << 16) | (y)) | (down << 31);
ts_ready = 1;
wake_up_interruptible(&ts_waitq);
}
static ssize_t ts_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
unsigned long err;
if (!ts_ready) {
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
else
wait_event_interruptible(ts_waitq, ts_ready);
}
ts_ready = 0;
if (count < sizeof ts_status) {
return -EINVAL;
} else {
count = sizeof ts_status;
}
err = copy_to_user((void *)buffer, (const void *)(&ts_status), sizeof ts_status);
return err ? -EFAULT : sizeof ts_status;
}
static unsigned int ts_poll( struct file *file, struct poll_table_struct *wait)
{
unsigned int mask = 0;
poll_wait(file, &ts_waitq, wait);
if (ts_ready)
mask |= POLLIN | POLLRDNORM;
return mask;
}
static struct file_operations ts_fops = {
owner: THIS_MODULE,
read: ts_read,
poll: ts_poll,
};
static struct miscdevice ts_misc = {
.minor = 181,
.name = TOUCH_DEVICE_NAME,
.fops = &ts_fops,
};
static DECLARE_WAIT_QUEUE_HEAD(bl_waitq);
static int bl_ready;
static unsigned char backlight_req = 0;
static unsigned char backlight_init_success;
static inline void notify_bl_data(unsigned char a, unsigned char b, unsigned char c)
{
bl_ready = 1;
backlight_init_success = 1;
wake_up_interruptible(&bl_waitq);
}
static ssize_t bl_write(struct file *file, const char *buffer, size_t count, loff_t * ppos)
{
int ret;
char buf[4] = {0, 0, 0, 0};
unsigned v;
unsigned len;
if (count == 0) {
return -EINVAL;
}
if (count > sizeof buf - 1) {
len = sizeof buf - 1;
} else {
len = count;
}
ret = copy_from_user(buf, buffer, len);
if (ret) {
return -EFAULT;
}
if (sscanf(buf, "%u", &v) != 1) {
return -EINVAL;
}
if (v > 127) {
v = 127;
}
bl_ready = 0;
backlight_req = v + 0x80U;
ret = wait_event_interruptible_timeout(bl_waitq, bl_ready, HZ / 10);
if (ret < 0) {
return ret;
}
if (ret == 0) {
return -ETIMEDOUT;
}
return count;
}
static struct file_operations bl_fops = {
owner: THIS_MODULE,
write: bl_write,
};
static struct miscdevice bl_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = BACKLIGHT_DEVICE_NAME,
.fops = &bl_fops,
};
// for query base info
//
static unsigned lcd_type, firmware_ver;
static inline void notify_info_data(unsigned char _lcd_type, unsigned char ver_year, unsigned char week)
{
if (_lcd_type != 0xFF) {
lcd_type = _lcd_type;
firmware_ver = ver_year * 100 + week;
}
}
// Pin access
//
static inline void set_pin_up(void)
{
s3c2410_gpio_pullup(S3C2410_GPB(1), 0);
}
static inline void set_pin_as_input(void)
{
s3c2410_gpio_cfgpin(S3C2410_GPB(1), S3C2410_GPIO_INPUT);
}
static inline void set_pin_as_output(void)
{
s3c2410_gpio_cfgpin(S3C2410_GPB(1), S3C2410_GPIO_OUTPUT);
}
static inline void set_pin_value(int v)
{
s3c2410_gpio_setpin(S3C2410_GPB(1), !!v);
}
static inline int get_pin_value(void)
{
int v = !!s3c2410_gpio_getpin(S3C2410_GPB(1));
return v;
}
// CRC
//
static const unsigned char crc8_tab[] = {
0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3,
};
#define crc8_init(crc) ((crc) = 0XACU)
#define crc8(crc, v) ( (crc) = crc8_tab[(crc) ^(v)])
// once a session complete
static unsigned total_received, total_error;
static unsigned last_req, last_res;
static void one_wire_session_complete(unsigned char req, unsigned int res)
{
unsigned char crc;
const unsigned char *p = (const unsigned char*)&res;
total_received ++;
last_res = res;
crc8_init(crc);
crc8(crc, p[3]);
crc8(crc, p[2]);
crc8(crc, p[1]);
if (crc != p[0]) {
// CRC dismatch
if (total_received > 100) {
total_error++;
}
return;
}
switch(req) {
case REQ_TS:
{
unsigned short x,y;
unsigned pressed;
x = ((p[3] >> 4U) << 8U) + p[2];
y = ((p[3] & 0xFU) << 8U) + p[1];
pressed = (x != 0xFFFU) && (y != 0xFFFU);
notify_ts_data(x, y, pressed);
}
break;
case REQ_INFO:
notify_info_data(p[3], p[2], p[1]);
break;
default:
notify_bl_data(p[3], p[2], p[1]);
break;
}
}
// one-wire protocol core
static unsigned long TCNT_FOR_SAMPLE_BIT;
static int init_timer_for_1wire(void)
{
unsigned long tcfg1;
unsigned long tcfg0;
unsigned prescale1_value;
unsigned long pclk;
struct clk *clk;
// get pclk
clk = clk_get(NULL, "timers");
if (IS_ERR(clk)) {
DPRINTK("ERROR to get PCLK\n");
return -EIO;
}
pclk = clk_get_rate(clk);
// get prescaler
tcfg0 = __raw_readl(S3C2410_TCFG0);
// we use system prescaler value because timer 4 uses same one
prescale1_value = (tcfg0 >> 8) & 0xFF;
// calc the TCNT_FOR_SAMPLE_BIT, that is one of the goal
TCNT_FOR_SAMPLE_BIT = pclk / 2 / (prescale1_value + 1) / SAMPLE_BPS - 1;
// select timer 3, the 2rd goal
tcfg1 = __raw_readl(S3C2410_TCFG1);
tcfg1 &= ~S3C2410_TCFG1_MUX3_MASK;
writel(tcfg1, S3C2410_TCFG1);
return 0;
}
static inline void stop_timer_for_1wire(void)
{
unsigned long tcon;
tcon = __raw_readl(S3C2410_TCON);
tcon &= ~S3C2410_TCON_T3START;
writel(tcon, S3C2410_TCON);
}
enum {
IDLE,
START,
REQUEST,
WAITING,
RESPONSE,
STOPING,
} one_wire_status = IDLE;
static volatile unsigned int io_bit_count;
static volatile unsigned int io_data;
static volatile unsigned char one_wire_request;
static irqreturn_t timer_for_1wire_interrupt(int irq, void *dev_id)
{
io_bit_count--;
switch(one_wire_status) {
case START:
if (io_bit_count == 0) {
io_bit_count = 16;
one_wire_status = REQUEST;
}
break;
case REQUEST:
// Send a bit
set_pin_value(io_data & (1U << 31));
io_data <<= 1;
if (io_bit_count == 0) {
io_bit_count = 2;
one_wire_status = WAITING;
}
break;
case WAITING:
if (io_bit_count == 0) {
io_bit_count = 32;
one_wire_status = RESPONSE;
}
if (io_bit_count == 1) {
set_pin_as_input();
set_pin_value(1);
}
break;
case RESPONSE:
// Get a bit
io_data = (io_data << 1) | get_pin_value();
if (io_bit_count == 0) {
io_bit_count = 2;
one_wire_status = STOPING;
set_pin_value(1);
set_pin_as_output();
one_wire_session_complete(one_wire_request, io_data);
}
break;
case STOPING:
if (io_bit_count == 0) {
one_wire_status = IDLE;
stop_timer_for_1wire();
}
break;
default:
stop_timer_for_1wire();
}
return IRQ_HANDLED;
}
static struct irqaction timer_for_1wire_irq = {
.name = "1-wire Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = timer_for_1wire_interrupt,
.dev_id = &timer_for_1wire_irq,
};
static void start_one_wire_session(unsigned char req)
{
unsigned long tcon;
unsigned long flags;
if (one_wire_status != IDLE) {
printk("one_wire_status: %d\n", one_wire_status);
return;
}
one_wire_status = START;
set_pin_value(1);
set_pin_as_output();
// IDLE to START
{
unsigned char crc;
crc8_init(crc);
crc8(crc, req);
io_data = (req << 8) + crc;
io_data <<= 16;
}
last_req = (io_data >> 16);
one_wire_request = req;
io_bit_count = 1;
set_pin_as_output();
writel(TCNT_FOR_SAMPLE_BIT, S3C2410_TCNTB(3));
// init tranfer and start timer
tcon = __raw_readl(S3C2410_TCON);
tcon &= ~(0xF << 16);
tcon |= S3C2410_TCON_T3MANUALUPD;
writel(tcon, S3C2410_TCON);
tcon |= S3C2410_TCON_T3START;
tcon |= S3C2410_TCON_T3RELOAD;
tcon &= ~S3C2410_TCON_T3MANUALUPD;
local_irq_save(flags);
writel(tcon, S3C2410_TCON);
set_pin_value(0);
local_irq_restore(flags);
}
// poll the device
// following is Linux timer not HW timer
static int exitting;
static struct timer_list one_wire_timer;
void one_wire_timer_proc(unsigned long v)
{
unsigned char req;
if (exitting) {
return;
}
one_wire_timer.expires = jiffies + HZ / 50;
add_timer(&one_wire_timer);
if (lcd_type == 0) {
req = REQ_INFO;
} else if (!backlight_init_success) {
req = 127;
} else if (backlight_req) {
req = backlight_req;
backlight_req = 0;
} else {
req = REQ_TS;
}
start_one_wire_session(req);
}
static struct timer_list one_wire_timer = {
.function = one_wire_timer_proc,
};
static int read_proc(char *buf, char **start, off_t offset, int count, int *eof, void *data)
{
int len;
len = sprintf(buf, "%u %u %u %u %04X %08X\n", lcd_type, firmware_ver, total_received, total_error, last_req, last_res);
*eof = 1;
return len;
}
static int __init dev_init(void)
{
int ret;
ret = misc_register(&ts_misc) | misc_register(&bl_misc) ;
set_pin_up();
set_pin_value(1);
set_pin_as_output();
if (ret == 0) {
setup_irq(IRQ_TIMER3, &timer_for_1wire_irq);
ret = init_timer_for_1wire();
init_timer(&one_wire_timer);
one_wire_timer_proc(0);
create_proc_read_entry("driver/one-wire-info", 0, NULL, read_proc, NULL);
}
if (ret == 0) {
printk (TOUCH_DEVICE_NAME"\tinitialized\n");
printk (BACKLIGHT_DEVICE_NAME"\tinitialized\n");
}
return ret;
}
static void __exit dev_exit(void)
{
exitting = 1;
remove_proc_entry("driver/one-wire-info", NULL);
del_timer_sync(&one_wire_timer);
free_irq(IRQ_TIMER3, &timer_for_1wire_irq);
misc_deregister(&ts_misc);
misc_deregister(&bl_misc);
}
module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");
MODULE_DESCRIPTION("Mini2440 one-wire host and Touch Screen Driver");