要：
目前，市面上很多6410开发板都存在触摸屏抖动的问题，tiny6410也不例外，友善的解决方法是采用一线触摸，即在LCD板上，用一个单片机控制ADS7846芯片AD转换，再将数据通过单总线的方式与6410通讯。可是，我这里没有一线触摸板，于是就开始移植ADS7846驱动到tiny6410。
介绍：
可能有人会问，6410的触摸屏为什么会抖动呢，是不是滤波没做好，或者是硬件走线的原因？是不是硬件的原因，我无法验证。我尝试过通过滤波来改善，但效果一般。不说别的，我在单独测试AD的时候，发现在输入不变的情况下，AD采样的跳幅最大达到25（0～1024范围），可见，跳动还是很大的，这样的情况下，即使再滤波也只是浪费时间。
mini6410-ts.c触摸屏驱动见：
（原创）6410触摸屏驱动分析（s3c-ts.c）（Linux）（分析）
先说说我的硬件：
TS_PEN ----- GPN9 EINT9
TS_MISO ---- GPC0 MISO0
TS_MOSI ---- GPC2 MOSI0
TS_SCK ----- GPC1 SCK0
TS_CS ----- GPC3 CS0
这些端子在核心板的CON1上可以找到，我这里是用的IO模拟的SPI。
下面的开始介绍移植的过程，代码，我在下面会全部帖出来，里面注释也很详细，一般都能看明白。
1、复制/opt/FriendlyARM/mini6410/linux-2.6.38/drivers/input/touchscreen/mini6410-ts.c为mini6410-ads7846.c。
修改后，如下：
001 |
/*
linux/drivers/input/touchscreen/s3c-ts.c |
002 |
*
|
003 |
* This
program is free software; you can redistribute it and/or modify
|
004 |
* it
under the terms of the GNU General Public License as published by
|
005 |
* the
Free Software Foundation; either version 2 of the License, or
|
006 |
* (at
your option) any later version. |
007 |
*
|
008 |
* This
program is distributed in the hope that it will be useful,
|
009 |
* but
WITHOUT ANY WARRANTY; without even the implied warranty of
|
010 |
*
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
011 |
* GNU
General Public License for more details. |
012 |
*
|
013 |
* You
should have received a copy of the GNU General Public License
|
014 |
* along
with this program; if not, write to the Free Software
|
015 |
*
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
016 |
*
|
017 |
* a misc
driver for mini6410 touch screen |
018 |
* by
FriendlyARM 2010 |
019 |
*
|
020 |
* Based
on following software: |
021 |
*
|
022 |
**
Copyright (c) 2004 Arnaud Patard <arnaud.patard@rtp-net.org>
|
023 |
** iPAQ
H1940 touchscreen support |
024 |
**
|
025 |
**
ChangeLog |
026 |
**
|
027 |
**
2004-09-05: Herbert Potzl <herbert@13thfloor.at>
|
028 |
** -
added clock (de-)allocation code |
029 |
**
|
030 |
**
2005-03-06: Arnaud Patard <arnaud.patard@rtp-net.org>
|
031 |
**
- h1940_ -> s3c24xx (this driver is now also used on the n30
|
032 |
** machines :P)
|
033 |
**
- Debug messages are now enabled with the config option
|
034 |
** TOUCHSCREEN_S3C_DEBUG
|
035 |
**
- Changed the way the value are read |
036 |
**
- Input subsystem should now work |
037 |
**
- Use ioremap and readl/writel |
038 |
**
|
039 |
**
2005-03-23: Arnaud Patard <arnaud.patard@rtp-net.org>
|
040 |
**
- Make use of some undocumented features of the touchscreen
|
041 |
** controller
|
042 |
**
|
043 |
**
2006-09-05: Ryu Euiyoul <ryu.real@gmail.com>
|
044 |
**
- added power management suspend and resume code
|
045 |
*
|
046 |
*
2011-6-23: ADS7846触摸屏驱动程序 by liu_xf |
048 |
*
|
049 |
*
2011-6-29 改进滤波，并将AD连续转换8次的间隔缩小了 |
050 |
*/ |
051 |
|
052 |
#include <linux/errno.h>
|
053 |
#include <linux/kernel.h>
|
054 |
#include <linux/module.h>
|
055 |
#include <linux/slab.h>
|
056 |
#include <linux/input.h>
|
057 |
#include <linux/init.h>
|
058 |
#include <linux/serio.h>
|
059 |
#include <linux/delay.h>
|
060 |
#include
<linux/platform_device.h> |
061 |
#include <linux/clk.h>
|
062 |
#include <linux/fs.h>
|
063 |
#include <linux/poll.h>
|
064 |
#include <linux/irq.h>
|
065 |
#include
<linux/interrupt.h> |
066 |
#include <linux/cdev.h>
|
067 |
#include
<linux/miscdevice.h> |
068 |
|
069 |
#include <asm/uaccess.h>
|
070 |
#include <asm/io.h>
|
071 |
#include <asm/irq.h>
|
072 |
#include
<mach/hardware.h> |
073 |
|
074 |
|
075 |
//#include <mach/irqs.h>
|
076 |
#include <mach/map.h>
|
077 |
#include
<mach/regs-clock.h> |
078 |
#include
<mach/regs-gpio.h> |
079 |
#include
<plat/gpio-cfg.h> |
080 |
#include
<mach/gpio-bank-n.h> |
081 |
#include
<mach/gpio-bank-c.h> |
082 |
|
083 |
|
084 |
#define
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
085 |
#undef
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
086 |
#define DEBUG_LVL
KERN_DEBUG |
087 |
|
088 |
|
089 |
/*
|
090 |
*
Definitions & global arrays. |
091 |
*/ |
092 |
#define DEVICE_NAME
"touchscreen" |
093 |
static DECLARE_WAIT_QUEUE_HEAD(ts_waitq); //定义并初始化一个等待队列 |
094 |
|
095 |
typedef unsigned TS_EVENT;
|
096 |
#define NR_EVENTS 64
//触摸屏fifo大小 |
097 |
|
098 |
|
099 |
static TS_EVENT events[NR_EVENTS];
|
100 |
static int evt_head, evt_tail; //fifo的头的尾 |
101 |
//驱动写fifo时evt_head++，应用读fifo时 evt_tail++
|
102 |
|
103 |
#define ts_evt_pending()
((volatile u8)(evt_head != evt_tail)) //相等就表示满了
|
104 |
#define ts_evt_get()
(events + evt_tail) |
105 |
#define ts_evt_pull()
(evt_tail = (evt_tail + 1) & (NR_EVENTS - 1))
|
106 |
#define ts_evt_clear()
(evt_head = evt_tail = 0) |
107 |
|
108 |
#define ADS7846_CNV_NBR 8
//ADC连续转换的次数 |
109 |
struct ads7846_ts_info { |
110 |
|
111 |
struct input_dev *dev;
|
112 |
|
113 |
unsigned
int xp;
//x方向位置
|
114 |
unsigned
int yp;
//y方向位置
|
115 |
unsigned
int count;
//adc转换次数
|
116 |
unsigned
int cnv_nbr;
|
117 |
unsigned
int x_buf[ADS7846_CNV_NBR]; //ad转换buf |
118 |
unsigned
int y_buf[ADS7846_CNV_NBR];
|
119 |
|
120 |
};
|
121 |
|
122 |
static struct ads7846_ts_info
*ts; |
123 |
|
124 |
|
125 |
|
126 |
|
127 |
//ADS7846底层操作========================================================================
|
128 |
#define ADS7846_GPIO_MISO 0
//gpc0 |
129 |
#define ADS7846_GPIO_MOSI
2 //gpc2 |
130 |
#define ADS7846_GPIO_CLK
1 //gpc1 |
131 |
#define ADS7846_GPIO_CS
3 //gpc3 |
132 |
|
133 |
// ADS7846 Control Byte bit defines
|
134 |
#define ADS7846_CMD_START
0x0080 |
135 |
#define ADS7846_ADDR_BIT 4
|
136 |
#define ADS7846_ADDR_MASK
(0x7<<ADS7846_ADDR_BIT) |
137 |
#define ADS7846_MEASURE_X
(0x5<<ADS7846_ADDR_BIT) |
138 |
#define ADS7846_MEASURE_Y
(0x1<<ADS7846_ADDR_BIT) |
139 |
#define ADS7846_MEASURE_Z1
(0x3<<ADS7846_ADDR_BIT) |
140 |
#define ADS7846_MEASURE_Z2
(0x4<<ADS7846_ADDR_BIT) |
141 |
#define ADS7846_8BITS
(1<<3) |
142 |
#define ADS7846_12BITS 0
|
143 |
#define ADS7846_SER
(1<<2) |
144 |
#define ADS7846_DFR 0
|
145 |
#define ADS7846_PWR_BIT 0
|
146 |
#define ADS7846_PD 0
|
147 |
#define ADS7846_ADC_ON
(0x1<<ADS7846_PWR_BIT) |
148 |
#define ADS7846_REF_ON
(0x2<<ADS7846_PWR_BIT) |
149 |
#define ADS7846_REF_ADC_ON
(0x3<<ADS7846_PWR_BIT) |
150 |
|
151 |
#define MEASURE_8BIT_X\
|
152 |
(unsigned short)(ADS7846_CMD_START
| ADS7846_MEASURE_X | ADS7846_8BITS | ADS7846_DFR | ADS7846_PD)
|
153 |
#define MEASURE_8BIT_Y\
|
154 |
(unsigned short)(ADS7846_CMD_START
| ADS7846_MEASURE_Y | ADS7846_8BITS | ADS7846_DFR | ADS7846_PD)
|
155 |
|
156 |
#define MEASURE_12BIT_X \
|
157 |
(unsigned short)(ADS7846_CMD_START
| ADS7846_MEASURE_X | ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)
|
158 |
#define MEASURE_12BIT_Y \
|
159 |
(unsigned short)(ADS7846_CMD_START
| ADS7846_MEASURE_Y | ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)
|
160 |
#define MEASURE_12BIT_Z1 \
|
161 |
(unsigned char)(ADS7846_MEASURE_Z1
| ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)
|
162 |
#define MEASURE_12BIT_Z2 \
|
163 |
(unsigned char)(ADS7846_MEASURE_Z2
| ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)
|
164 |
|
165 |
// Pin access
|
166 |
//
|
167 |
static inline void set_miso_as_up(void)//gpc0 |
168 |
{
|
169 |
unsigned
long tmp;
|
170 |
tmp =
readl(S3C64XX_GPCPUD); |
171 |
tmp
&= ~(3U <<0); |
172 |
tmp |=
(2U << 0); |
173 |
writel(tmp, S3C64XX_GPCPUD);
|
174 |
}
|
175 |
|
176 |
static inline void set_miso_as_input(void)//gpc0 |
177 |
{
|
178 |
unsigned
long tmp;
|
179 |
tmp =
readl(S3C64XX_GPCCON); |
180 |
tmp
&= ~(0xf << 0); |
181 |
writel(tmp, S3C64XX_GPCCON);
|
182 |
}
|
183 |
|
184 |
static inline void set_cs_mosi_clk_as_output(void)//gpc1 2 3 |
185 |
{
|
186 |
unsigned
long tmp;
|
187 |
tmp =
readl(S3C64XX_GPCCON); |
188 |
tmp =
(tmp & ~0xfff0) | (0x1110); |
189 |
writel(tmp, S3C64XX_GPCCON);
|
190 |
}
|
191 |
|
192 |
static inline void set_cs_mosi_clk_as_up(void)//gpc1 2 3 |
193 |
{
|
194 |
unsigned
long tmp;
|
195 |
tmp =
readl(S3C64XX_GPCPUD); |
196 |
tmp
&= ~((3U <<2)|(3U <<4)|(3U <<6));
|
197 |
tmp |=
(2U << 2) | (2U << 4) | (2U << 6);
|
198 |
writel(tmp, S3C64XX_GPCPUD);
|
199 |
}
|
200 |
|
201 |
|
202 |
static inline void set_gpcx_value(int
pinx ,int
v) |
203 |
{
|
204 |
unsigned
long tmp;
|
205 |
tmp =
readl(S3C64XX_GPCDAT); |
206 |
if (v) {
|
207 |
tmp
|= (1 << pinx); |
208 |
}
else {
|
209 |
tmp
&= ~(1<<pinx); |
210 |
}
|
211 |
writel(tmp, S3C64XX_GPCDAT);
|
212 |
}
|
213 |
|
214 |
static inline int
get_gpcx_value(int pinx)
|
215 |
{
|
216 |
int v;
|
217 |
unsigned
long tmp;
|
218 |
tmp =
readl(S3C64XX_GPCDAT); |
219 |
v =
!!(tmp & (1<<pinx)); |
220 |
return v;
|
221 |
}
|
222 |
|
223 |
//读12bit
|
224 |
static unsigned int ads7846_Read_Data(void)
|
225 |
{
|
226 |
unsigned
int i,temp=0x00; |
227 |
for(i=0;i<12;i++)
|
228 |
{
|
229 |
temp
<<=1; |
230 |
set_gpcx_value(ADS7846_GPIO_CLK, 1); udelay(10);
|
231 |
set_gpcx_value(ADS7846_GPIO_CLK, 0); udelay(10);
|
232 |
if(get_gpcx_value(ADS7846_GPIO_MISO) != 0)temp++;
|
233 |
}
|
234 |
return (temp);
|
235 |
}
|
236 |
//写8bit
|
237 |
static void ads7846_Write_Data(unsigned int n)
|
238 |
{
|
239 |
unsigned
char i;
|
240 |
set_gpcx_value(ADS7846_GPIO_CLK, 0);
|
241 |
for(i=0;i<8;i++)
|
242 |
{
|
243 |
if((n&0x80)==0x80)
|
244 |
set_gpcx_value(ADS7846_GPIO_MOSI, 1);
|
245 |
else |
246 |
set_gpcx_value(ADS7846_GPIO_MOSI, 0);
|
247 |
|
248 |
n
<<= 1; |
249 |
set_gpcx_value(ADS7846_GPIO_CLK, 1); udelay(10);
|
250 |
set_gpcx_value(ADS7846_GPIO_CLK, 0); udelay(10);
|
251 |
}
|
252 |
}
|
253 |
|
254 |
|
255 |
//ADS7846转换==
|
256 |
//保存在ts->buf 当中
|
257 |
static void ads7846_conver_start(void)
|
258 |
{
|
259 |
int i;
|
260 |
unsigned
int cmd[2];
|
261 |
unsigned
int data[2];
|
262 |
|
263 |
set_gpcx_value(ADS7846_GPIO_CS, 0);
|
264 |
//开读 |
265 |
cmd[0] =
MEASURE_12BIT_X; |
266 |
cmd[1] =
MEASURE_12BIT_Y; |
267 |
|
268 |
/*
CS# Low */ |
269 |
set_gpcx_value(ADS7846_GPIO_CS, 0);
|
270 |
|
271 |
//连续转换 |
272 |
for(ts->count=0;
ts->count<ts->cnv_nbr;) |
273 |
{
|
274 |
//分别读出x y坐标＝＝ |
275 |
for(i=0; i<2; i++){
|
276 |
ads7846_Write_Data(cmd[i]);
|
277 |
udelay(40); |
278 |
data[i] = ads7846_Read_Data();
|
279 |
}
|
280 |
|
281 |
|
282 |
|
283 |
//保存转换结果 |
284 |
ts->x_buf[ts->count]= data[0];
|
285 |
ts->y_buf[ts->count]= data[1];
|
286 |
ts->count++; |
287 |
}
|
288 |
/*
CS# High */ |
289 |
set_gpcx_value(ADS7846_GPIO_CS, 1);
|
290 |
|
291 |
#ifdef
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
292 |
//printk("ts read pos: x = %d, y = %d\n", data[0],
data[1]); |
293 |
#endif
|
294 |
|
295 |
}
|
296 |
|
297 |
|
298 |
//-----------------------------------------------------------------------------
|
299 |
|
300 |
//触摸屏数据滤波算法
|
301 |
//触摸屏AD连续转换N次后，按升序排列，再取中间几位值求平均
|
302 |
#define TS_AD_NBR_PJ
4 //取中间4位求平均值 |
303 |
#define TS_AD_NBR_MAX_CZ
10 //最大与最小的差值 |
304 |
static inline bool
touch_ad_data_filter(unsigned int *buf0, unsigned
int *buf1)
|
305 |
{
|
306 |
unsigned
int i,j,k,temp,temp1,nbr=(ADS7846_CNV_NBR);
|
307 |
//将转换结果升序排列 |
308 |
//buf0
|
309 |
for (j= 0; j< nbr;
j++) |
310 |
for (i = 0; i < nbr;
i++) |
311 |
{ |
312 |
if(buf0[i]>buf0[i+1])//升序排列
|
313 |
{
|
314 |
temp=buf0[i+1]; |
315 |
buf0[i+1]=buf0[i]; |
316 |
buf0[i]=temp; |
317 |
}
|
318 |
}
|
319 |
|
320 |
//buf1 |
321 |
for (j= 0; j< nbr;
j++) |
322 |
for (i = 0; i < nbr;
i++) |
323 |
{ |
324 |
if(buf1[i]>buf1[i+1])//升序排列
|
325 |
{
|
326 |
temp=buf1[i+1]; |
327 |
buf1[i+1]=buf1[i]; |
328 |
buf1[i]=temp; |
329 |
}
|
330 |
}
|
331 |
|
332 |
//串口调试查看结果 |
333 |
//for
(j= 0; j< nbr; j++) |
334 |
//
printk("buf0[%2d]=%4d, buf1[%2d]=%4d,\r\n",j,buf0[j],j,buf1[j]);
|
335 |
//取中间值求平均== |
336 |
k=((nbr-TS_AD_NBR_PJ)>>1);
|
337 |
temp =
0;temp1 = 0; |
338 |
//检查值是否有效== |
339 |
if((buf0[k+TS_AD_NBR_PJ-1]-buf0[k]>TS_AD_NBR_MAX_CZ)||(buf1[k+TS_AD_NBR_PJ-1]-buf1[k]>TS_AD_NBR_MAX_CZ))
//无效值 |
340 |
{
|
341 |
|
342 |
return 0;
|
343 |
}
|
344 |
//--
|
345 |
//将中间指定位数累加 |
346 |
for(i=0;i<TS_AD_NBR_PJ;i++)
|
347 |
{
|
348 |
temp
+= buf0[k+i]; |
349 |
temp1
+= buf1[k+i]; |
350 |
}
|
351 |
//求平均值,将结果保存在最低位 |
352 |
buf0[0]=temp/TS_AD_NBR_PJ;
|
353 |
buf1[0] =
temp1/TS_AD_NBR_PJ; |
354 |
//--
|
355 |
return 1;
|
356 |
|
357 |
}
|
358 |
|
359 |
|
360 |
//将AD转换的值放入FIFO
|
361 |
//这里是一个先进先出的fifo
|
362 |
//只要有数据被添加进来，就会唤醒ts_waitq进程
|
363 |
static void ts_evt_add(unsigned
x, unsigned y, unsigned down) { |
364 |
unsigned
ts_event; |
365 |
int next_head;
|
366 |
|
367 |
ts_event
= ((x << 16) | (y)) | (down << 31);
|
368 |
next_head = (evt_head + 1) & (NR_EVENTS - 1);
|
369 |
//没满就装入 |
370 |
if (next_head !=
evt_tail) { |
371 |
events[evt_head] = ts_event;
|
372 |
evt_head = next_head; |
373 |
#ifdef
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
374 |
printk("====>Add ... [
%4d, %4d ]%s\n", x, y, down ? "":" ~~~");
|
375 |
#endif
|
376 |
/* wake up any read call
*/ |
377 |
if (waitqueue_active(&ts_waitq)) { //判斷等待隊列是否有進程睡眠 |
378 |
wake_up_interruptible(&ts_waitq); //唤醒ts_waitq等待队列中所有interruptible类型的进程
|
379 |
}
|
380 |
}
else {
|
381 |
/* drop the event and try to wakeup readers
*/ |
382 |
printk(KERN_WARNING "mini6410-ads7846: touch event buffer full"); |
383 |
wake_up_interruptible(&ts_waitq);
|
384 |
}
|
385 |
}
|
386 |
|
387 |
static unsigned int ads7846_ts_poll( struct file *file,
struct poll_table_struct *wait)
|
388 |
{
|
389 |
unsigned
int mask =
0; |
390 |
|
391 |
//将ts_waitq等待队列添加到poll_table里去
|
392 |
poll_wait(file, &ts_waitq, wait);
|
393 |
//返回掩码
|
394 |
if (ts_evt_pending())
|
395 |
mask
|= POLLIN | POLLRDNORM; //返回设备可读
|
396 |
|
397 |
return mask;
|
398 |
}
|
399 |
|
400 |
//读 系统调用==
|
401 |
static int ads7846_ts_read(struct file *filp,
char __user
*buff, size_t count, loff_t *offp) |
402 |
{
|
403 |
DECLARE_WAITQUEUE(wait, current); //把当前进程加到定义的等待队列头wait中
|
404 |
char *ptr = buff;
|
405 |
int err = 0;
|
406 |
|
407 |
add_wait_queue(&ts_waitq, &wait); //把wait入到等待队列头中。该队列会在进程等待的条件满足时唤醒它。
|
408 |
//我们必须在其他地方写相关代码，在事件发生时，对等的队列执行wake_up()操作。
|
409 |
//这里是在ts_evt_add里wake_up
|
410 |
while (count >=
sizeof(TS_EVENT)) { |
411 |
err
= -ERESTARTSYS; |
412 |
if (signal_pending(current)) //如果是信号唤醒 参考http://www.360doc.com/content/10/1009/17/1317564_59632874.shtml
|
413 |
break;
|
414 |
|
415 |
if (ts_evt_pending()) {
|
416 |
TS_EVENT *evt = ts_evt_get();
|
417 |
|
418 |
err = copy_to_user(ptr, evt, sizeof(TS_EVENT));
|
419 |
ts_evt_pull(); |
420 |
|
421 |
if (err)
|
422 |
break;
|
423 |
|
424 |
ptr += sizeof(TS_EVENT);
|
425 |
count -= sizeof(TS_EVENT);
|
426 |
continue;
|
427 |
}
|
428 |
|
429 |
set_current_state(TASK_INTERRUPTIBLE); //改变进程状态为可中断的睡眠 |
430 |
err
= -EAGAIN; |
431 |
if (filp->f_flags
& O_NONBLOCK) //如果上层调用是非阻塞方式，则不阻塞该进程，直接返回EAGAIN
|
432 |
break;
|
433 |
schedule(); //本进程在此处交出CPU控制权，等待被唤醒
|
434 |
//进程调度的意思侧重于把当前任务从CPU拿掉，再从就绪队列中按照调度算法取一就绪进程占用CPU
|
435 |
}
|
436 |
current->state = TASK_RUNNING;
|
437 |
remove_wait_queue(&ts_waitq, &wait);
|
438 |
|
439 |
return ptr == buff ? err
: ptr - buff; |
440 |
}
|
441 |
//--
|
442 |
|
443 |
static int ads7846_ts_open(struct inode *inode,
struct file
*filp) { |
444 |
/*
flush event queue */ |
445 |
ts_evt_clear(); |
446 |
|
447 |
return 0;
|
448 |
}
|
449 |
|
450 |
//当应用程序操作设备文件时调用的open
read等函数，最终会调用这个结构体中对应的函数 |
451 |
static struct file_operations
dev_fops = { |
452 |
.owner = THIS_MODULE,
|
453 |
.read = ads7846_ts_read,
|
454 |
.poll = ads7846_ts_poll, //select系统调用 |
455 |
.open = ads7846_ts_open,
|
456 |
};
|
457 |
|
458 |
//设备号，设备名，注册的时候用到这个数组
|
459 |
//混杂设备主设备号为10
|
460 |
static struct miscdevice misc =
{ |
461 |
.minor = MISC_DYNAMIC_MINOR, //自动分配次设置号 |
462 |
//.minor = 180,
|
463 |
.name = DEVICE_NAME,
|
464 |
.fops = &dev_fops,
|
465 |
};
|
466 |
|
467 |
|
468 |
|
469 |
|
470 |
|
471 |
|
472 |
/**
|
473 |
*
get_down - return the down state of the pen
|
474 |
*
获取pen引脚状态，为0表示down |
475 |
* GPN9
EINT9 TS_PEN |
476 |
*/ |
477 |
static inline bool
get_down(void)
|
478 |
{
|
479 |
int tmp,down;
|
480 |
tmp =
readl(S3C64XX_GPNDAT); |
481 |
down =
!(tmp & (1<<9)); |
482 |
return (down);
|
483 |
}
|
484 |
|
485 |
|
486 |
/*===========================================================================================
|
487 |
touch_timer_get_value这个函数的调用：
|
488 |
|
489 |
1、
触摸笔开始点击的时候， 在中断函数touch_down里面被调用，不是直接调用，而是设置定时器超时后调用
|
490 |
这样是为了去抖动 |
491 |
|
492 |
2、
touch_timer_get_value被调用一次后，如果pendown信号有效，则touch_timer_get_value会被持续调用
|
493 |
也是通过定时器实现的 |
494 |
|
495 |
touch_timer_get_value这个函数的功能：
|
496 |
启动7846转换，直到连续转换8次后，再滤波处理，获得有效值，并向上报告触摸屏事件
|
497 |
|
498 |
============================================================================================*/ |
499 |
static void touch_timer_get_value(unsigned long data);
|
500 |
|
501 |
static DEFINE_TIMER(touch_timer, touch_timer_get_value, 0, 0);
|
502 |
|
503 |
static void touch_timer_get_value(unsigned long data) {
|
504 |
|
505 |
int pendown;
|
506 |
|
507 |
pendown
= get_down(); |
508 |
|
509 |
#ifdef
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
510 |
// if(pendown)
|
511 |
// {
|
512 |
// printk("touch is down!\n");
|
513 |
// }
|
514 |
// else
|
515 |
// printk("touch is up!\n");
|
516 |
#endif
|
517 |
|
518 |
if (pendown) {
|
519 |
|
520 |
//关中断=== |
521 |
disable_irq(IRQ_EINT(9));
|
522 |
//-- |
523 |
//启动ADS7846转换== |
524 |
ads7846_conver_start();
|
525 |
//开中断== |
526 |
enable_irq(IRQ_EINT(9));
|
527 |
//-- |
528 |
//如果转换了8次，就写入FIFO保存 |
529 |
//if (ts->count == ( ts->cnv_nbr)) {
|
530 |
if(touch_ad_data_filter(ts->x_buf,ts->y_buf)) //滤波处理 |
531 |
{ |
532 |
|
533 |
ts->xp = ts->x_buf[0];
|
534 |
ts->yp = ts->y_buf[0];
|
535 |
|
536 |
ts_evt_add(ts->xp, ts->yp, 1); //向上报告触摸屏事件 |
537 |
} |
538 |
|
539 |
|
540 |
ts->xp = 0; |
541 |
ts->yp = 0; |
542 |
ts->count = 0; |
543 |
//} |
544 |
//-- |
545 |
|
546 |
mod_timer(&touch_timer, jiffies + 2); //重新设置系统定时器，超时后，又会调用touch_timer_get_value
|
547 |
//jiffies变量记录了系统启动以来，系统定时器已经触发的次数。内核每秒钟将jiffies变量增加HZ次。
|
548 |
//因此，对于HZ值为100的系统，1个jiffy等于10ms，而对于HZ为1000的系统，1个jiffy仅为1ms
|
549 |
//这里系统配置提HZ是100 |
550 |
|
551 |
}
else {
//如果是松开，报告其触摸笔状态
|
552 |
ts->xp = 0; |
553 |
ts->yp = 0; |
554 |
ts->count = 0; |
555 |
|
556 |
ts_evt_add(0, 0, 0); |
557 |
|
558 |
|
559 |
}
|
560 |
|
561 |
}
|
562 |
|
563 |
|
564 |
|
565 |
//触摸屏按下中断服务==
|
566 |
//双边沿中断
|
567 |
static irqreturn_t touch_down(int irqno, void *param)
|
568 |
{
|
569 |
|
570 |
|
571 |
/*
Clear interrupt */ |
572 |
//__raw_writel(0x0, ts_base + S3C_ADCCLRWK);
|
573 |
//__raw_writel(0x0, ts_base + S3C_ADCCLRINT);
|
574 |
|
575 |
//稍后调用touch_timer_get_value，去抖动
|
576 |
mod_timer(&touch_timer, jiffies + 2); //等ADS7846转换完成了再读 |
577 |
//同时还可以防抖动，如果定时器没有超时的这段时间里，发生了抬起和按下中断，则定时器的值会被重设，不会超时
|
578 |
//内核配置时HZ值设为100，即1个jiffy等于10ms，
|
579 |
//touch_timer_get_value(1); //直接调用会有抖动
|
580 |
|
581 |
return IRQ_RETVAL(IRQ_HANDLED);
|
582 |
}
|
583 |
|
584 |
|
585 |
|
586 |
|
587 |
//-------------------------------------------
|
588 |
|
589 |
|
590 |
/*
|
591 |
* The
functions for inserting/removing us as a module.
|
592 |
*/ |
593 |
static int __init
ads7846_ts_probe(struct platform_device *pdev) |
594 |
{
|
595 |
struct device *dev;
|
596 |
int ret = 0;
|
597 |
|
598 |
dev =
&pdev->dev; |
599 |
#ifdef
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
600 |
printk("ads7846_ts_probe
start!\n");
|
601 |
#endif
|
602 |
//给ads7846_ts_info指针分配内存==
|
603 |
ts =
kzalloc(sizeof(struct ads7846_ts_info), GFP_KERNEL);
|
604 |
ts->cnv_nbr = ADS7846_CNV_NBR;
|
605 |
ts->xp = 0; |
606 |
ts->yp = 0; |
607 |
ts->count = 0; |
608 |
|
609 |
|
610 |
//申请中断== |
611 |
//TS_PEN双边沿触发 EINT9 GPN9
|
612 |
ret =
request_irq(IRQ_EINT(9), touch_down,IRQ_TYPE_EDGE_BOTH,
|
613 |
"ads7864_touch", ts);
|
614 |
|
615 |
if (ret != 0) {
|
616 |
dev_err(dev,"ads7846_ts.c:
Could not allocate ts IRQ_EINT !\n");
|
617 |
ret
= -EIO; |
618 |
goto fail;
|
619 |
}
|
620 |
|
621 |
|
622 |
|
623 |
|
624 |
ret =
misc_register(&misc); //注册这混杂字符设备
|
625 |
if (ret) {
|
626 |
dev_err(dev, "ads7846_ts.c:
Could not register device(mini6410 touchscreen)!\n"); |
627 |
ret
= -EIO; |
628 |
goto fail;
|
629 |
}
|
630 |
//初始化GPIO== |
631 |
set_miso_as_up(); |
632 |
set_miso_as_input(); |
633 |
set_cs_mosi_clk_as_up();
|
634 |
set_cs_mosi_clk_as_output();
|
635 |
set_gpcx_value(ADS7846_GPIO_MOSI ,1);
|
636 |
set_gpcx_value(ADS7846_GPIO_CS ,1);
|
637 |
set_gpcx_value(ADS7846_GPIO_CLK ,1);
|
638 |
//--
|
639 |
|
640 |
#ifdef
CONFIG_TOUCHSCREEN_ADS7846_DEBUG |
641 |
printk("ads7846_ts_probe
end!\n"); |
642 |
#endif
|
643 |
|
644 |
return 0;
|
645 |
|
646 |
fail:
|
647 |
disable_irq(IRQ_EINT(9));
|
648 |
free_irq(IRQ_EINT(9), ts);
|
649 |
|
650 |
return ret;
|
651 |
|
652 |
}
|
653 |
|
654 |
static int ads7846_ts_remove(struct platform_device
*dev) |
655 |
{
|
656 |
printk(KERN_INFO "ads7846_ts_remove() of TS called !\n"); |
657 |
|
658 |
disable_irq(IRQ_EINT(9));
|
659 |
free_irq(IRQ_EINT(9), ts);
|
660 |
return 0;
|
661 |
}
|
662 |
|
663 |
#ifdef CONFIG_PM
|
664 |
static unsigned int adccon, adctsc, adcdly;
|
665 |
|
666 |
static int ads7846_ts_suspend(struct platform_device
*dev, pm_message_t state) |
667 |
{
|
668 |
|
669 |
return 0;
|
670 |
}
|
671 |
|
672 |
static int ads7846_ts_resume(struct platform_device
*pdev) |
673 |
{
|
674 |
return 0;
|
675 |
}
|
676 |
#else
|
677 |
#define ads7846_ts_suspend
NULL |
678 |
#define ads7846_ts_resume
NULL |
679 |
#endif
|
680 |
|
681 |
static struct platform_driver
ads7846_ts_driver = { |
682 |
.probe = ads7846_ts_probe,
|
683 |
.remove
= ads7846_ts_remove,
|
684 |
.suspend = ads7846_ts_suspend,
|
685 |
.resume = ads7846_ts_resume,
|
686 |
.driver = { |
687 |
.owner = THIS_MODULE,
|
688 |
.name = "ads7846-ts",
|
689 |
},
|
690 |
};
|
691 |
|
692 |
static char banner[] __initdata
= KERN_INFO "mini6410 ads7846 Touchscreen
driver,by liu_xf 20110622,\n";
|
693 |
|
694 |
static int __init
ads7846_ts_init(void) |
695 |
{
|
696 |
printk(banner); |
697 |
return platform_driver_register(&ads7846_ts_driver);
|
698 |
}
|
699 |
|
700 |
static void __exit
ads7846_ts_exit(void) |
701 |
{
|
702 |
platform_driver_unregister(&ads7846_ts_driver);
|
703 |
}
|
704 |
|
705 |
module_init(ads7846_ts_init);
|
706 |
module_exit(ads7846_ts_exit);
|
707 |
|
708 |
MODULE_AUTHOR("Hunan Create Inc.");
|
709 |
MODULE_LICENSE("GPL"); |
2、修改当前目录下的Kconfig和makefile，让它在menuconfig里可见，并能被编译。
在 Kconfig里添加：
01 |
config TOUCHSCREEN_MINI6410_ADS7846
|
02 |
tristate
"ADS7846 touchscreen driver for
Mini6410" |
03 |
depends
on MACH_MINI6410 |
04 |
default y
|
05 |
help
|
06 |
Say Y
here to enable the driver for the ADS7846 touchscreen on the
|
07 |
FriendlyARM Mini6410 development board.
|
08 |
|
09 |
If
unsure, say N. |
10 |
|
11 |
To
compile this driver as a module, choose M here: the
|
12 |
module
will be called
mini6410-ads7846. |
makefile里添加
obj-$(CONFIG_TOUCHSCREEN_MINI6410_ADS7846) +=
mini6410-ads7846.o<BR> |
3、 ads7846_device_ts设备定义
复制 /opt/FriendlyARM/mini6410/linux-2.6.38/arch/arm/mach-s3c64xx/dev-ts-mini6410.c为dev-ads7846-mini6410.c，更改代码为
01 |
/*
linux/arch/arm/mach-s3c64xx/dev-ts-mini6410.c
|
02 |
*
|
03 |
*
Copyright (c) 2008 Simtec Electronics |
04 |
* Ben
Dooks <ben@simtec.co.uk> |
06 |
*
|
07 |
* S3C
series device definition for touchscreen devices
|
08 |
*
|
09 |
* This
program is free software; you can redistribute it and/or modify
|
10 |
* it
under the terms of the GNU General Public License version 2 as
|
11 |
*
published by the Free Software Foundation.
|
12 |
*/ |
13 |
|
14 |
#include <linux/kernel.h>
|
15 |
#include
<linux/platform_device.h> |
16 |
|
17 |
#include <mach/map.h>
|
18 |
#include <mach/irqs.h>
|
19 |
#include <plat/devs.h>
|
20 |
#include <plat/cpu.h>
|
21 |
#include <mach/ts.h>
|
22 |
|
23 |
/* Touch srcreen
*/ |
24 |
//resource没有用，先留在这，不管它
|
25 |
static struct resource
ads7846_ts_resource[] = { |
26 |
[0] = {
|
27 |
.start = SAMSUNG_PA_ADC,
|
28 |
.end = SAMSUNG_PA_ADC + SZ_256 - 1,
|
29 |
.flags = IORESOURCE_MEM,
|
30 |
},
|
31 |
[1] = {
|
32 |
.start = IRQ_PENDN, |
33 |
.end = IRQ_PENDN, |
34 |
.flags = IORESOURCE_IRQ,
|
35 |
},
|
36 |
[2] = {
|
37 |
.start = IRQ_ADC, |
38 |
.end = IRQ_ADC, |
39 |
.flags = IORESOURCE_IRQ,
|
40 |
}
|
41 |
};
|
42 |
|
43 |
struct platform_device ads7846_device_ts = {
|
44 |
.name = "ads7846-ts",
|
45 |
.id = -1, |
46 |
.num_resources = ARRAY_SIZE(ads7846_ts_resource),
|
47 |
.resource = ads7846_ts_resource,
|
48 |
};
|
49 |
/*
|
50 |
void __init
ads7846_ts_set_platdata(struct s3c_ts_mach_info *pd)
|
51 |
{
|
52 |
printk(KERN_ERR "%s: no platform data\n", __func__);
|
53 |
|
54 |
}
|
55 |
*/ |
4、在/opt/FriendlyARM/mini6410/linux-2.6.38/arch/arm/mach-s3c64xx/mach-mini6410.c的platform_device添加ads7846_device_ts设备（s3c_device_ts附近），注册设备时要用到它
#ifdef
CONFIG_TOUCHSCREEN_MINI6410_ADS7846 |
&ads7846_device_ts,
|
#endif |
5、添加设备声明
mach-mini6410里注册ads7846_device_ts设备，但在哪里mach-mini6410并不知道，需要在devs.h里声明，打开当前目录下的devs.h，添加如下代码：
extern struct platform_device
ads7846_device_ts;<BR> |
6、然后再make，放到SD卡里运行
make menuconfig，在device drives－> input device support -> touch screens选择ADS7846 touchscreen driver for Mini6410 ,然后再make zImage。
完成后，再放到SD卡里运行，怎么样，一点也不抖动了吧！
结语：
这个驱动是由mini6410-ts.c修改而来的，那些系统调用的函数都没有改，只是将获取触摸屏数据的方式变了，可以直接用原来的tslib。经测试，效果良好。但是在移植的过程中，有一个问题还是没搞明白，之前，我是将TS_PEN接在EINT6上在的，但一接上去，就一直中断，把系统都弄死了，要按下触摸屏才能停止中断，不知道是什么原因，可能是EINT6被其它地方设置了，还是怎么回事，后来换成EINT9就好了，正好两个端子相邻。知道的大侠还请告诉我一声。