在目录下ampa53_linuxdrvextdrvtouchpadft6236下可以看到ft6236.c的文件
1. init函数
代码语言：javascript复制static int __init ft_init(void)
{
int ret = 0;
hi_gpio_groupbit_info stIntInfo;
hi_gpio_groupbit_info stRstInfo;
stIntInfo.group_num = INT_GPIO_CHIP;
stIntInfo.bit_num = INT_GPIO_OFFSET;
stIntInfo.value = 0;
stRstInfo.group_num = RST_GPIO_CHIP;
stRstInfo.bit_num = RST_GPIO_OFFSET;
stRstInfo.value = 1;
ret = i2cdev_init();
if (ret)
{
dev_err(NULL, " i2cdev_init fail!n");
goto error_end;
}
hi_gpio_set_dir(&stIntInfo);
hi_gpio_set_dir(&stRstInfo);
ret = ft_reset(&stRstInfo);
if (ret)
{
dev_err(NULL, " ft_reset fail!n");
goto error_end;
}
ret = devinput_init();
if (ret)
{
dev_err(NULL, " devinput_init fail!n");
goto error_end;
}
return 0;
error_end:
return -1;
}INT_GPIO_CHIP和INT_GPIO_OFFSET都是在宏定义
#elif (defined(BOARD_DEMB) && (defined(HI3556AV100) || defined(HI3519AV100)))下定义的
#define RST_GPIO_CHIP (2)
#define RST_GPIO_OFFSET (6)
#define INT_GPIO_CHIP (2)
#define INT_GPIO_OFFSET (5)这些管脚可以在这里《Hi3556AV100 Demo 单板使用指南.pdf》中看到，分别得出触摸屏的中断和复位管脚
1.1 对触摸屏进行复位
代码语言：javascript复制static int ft_reset(hi_gpio_groupbit_info* pstRstInfo)
{
pstRstInfo->value = 1;
hi_gpio_write_bit(pstRstInfo);
pstRstInfo->value = 0;
hi_gpio_write_bit(pstRstInfo);
msleep(5);
pstRstInfo->value = 1;
hi_gpio_write_bit(pstRstInfo);
return 0;
}对触摸屏进行复位；
1.2 input系统初始化
代码语言：javascript复制static int devinput_init(void)
{
int error = 0;
/* 1. distribution a "input_dev" structure */
ft_ts_dev = input_allocate_device();
if (ft_ts_dev == NULL)
{
printk(" func:%s line:%d rn", __FUNCTION__, __LINE__);
return -1;
}
ft_ts_dev->evbit[0] = BIT_MASK(EV_SYN) | BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
set_bit(EV_SYN, ft_ts_dev->evbit);
set_bit(EV_KEY, ft_ts_dev->evbit);
set_bit(EV_ABS, ft_ts_dev->evbit);
set_bit(INPUT_PROP_DIRECT, ft_ts_dev->propbit);
input_set_abs_params(ft_ts_dev, ABS_MT_POSITION_X, 0 , FT_SCREEN_WIDTH_NUM, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_POSITION_Y, 0, FT_SCREEN_HEIGHT_NUM, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_TOUCH_MAJOR,
0, 0xff, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_PRESSURE,
0, 0xff, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_TRACKING_ID,
0, 0xff, 0, 0);
error = input_mt_init_slots(ft_ts_dev, FT_MAX_TOUCH_POINTS,
INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
if (error)
{ return error; }
ft_ts_dev->name = "ft";
ft_ts_dev->id.bustype = BUS_I2C;
error = input_register_device(ft_ts_dev);
if (error)
{
dev_err(NULL, "failed to register input device: %dn", error);
return error;
}
/**request_threaded_irq(unsigned int irq,irq_handler_t handler,irq_handler_t thread_fn,unsigned long irqflags,const char * devname,void * dev_id)*/
error = fts_irq_register();
if(error)
{
dev_err(NULL, "failed to register input device: %dn", error);
return error;
}
/**Clear INT*/
touch_set_reg(0x045f241C, 0x20);
return 0;
}- set_bit()告诉input输入子系统支持哪些按键
evbit： 事件类型（包括EV_RST,EV_REL,EV_MSC,EV_KEY,EV_ABS,EV_REP等） propbit： set_bit(INPUT_PROP_DIRECT,dev->propbit);//表明设备的坐标直接和屏幕坐标向对应
- input_set_abs_params
给设备的input_dev结构体初始化，这些input_dev如果想被当成多点屏处理的话，只需要给input_dev额外增加以下几个参数：
代码语言：javascript复制input_set_abs_params(ft_ts_dev, ABS_MT_POSITION_X, 0 , FT_SCREEN_WIDTH_NUM, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_POSITION_Y, 0, FT_SCREEN_HEIGHT_NUM, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_TOUCH_MAJOR,
0, 0xff, 0, 0);
//相当于单点屏的ABX_PRESSURE
input_set_abs_params(ft_ts_dev, ABS_MT_PRESSURE,
0, 0xff, 0, 0);
input_set_abs_params(ft_ts_dev, ABS_MT_TRACKING_ID,
0, 0xff, 0, 0);
//确定第几手指来上报的数据input_set_abs_params(idev, ABS_X, -64, 64, 4, 0); 对于X轴范围是-64到 64，数据误差是-4到 4，中心平滑位置是0
- input_mt_init_slots
报告最大支持的点数
- input_register_device
注册input子系统
- 通过注册中断管脚
fts_irq_register注册中断
2. 中断函数处理
代码语言：javascript复制static irqreturn_t ftint_irq(int irq, void *data)
{
int i;
bool act;
struct input_dev* input = ft_ts_dev;
ts_event event;
int ret = touch_event_handler(&event);
if(ret)
printk( "n buffer_read failed n");
if(event.point_num != 0)
{
for(i = 0; i < event.touch_point; i )
{
input_mt_slot(input, i);
act = (event.au8_touch_event[i] == FT_EVENT_PRESS_DOWN || event.au8_touch_event[i] == FT_EVENT_CONTACT);
input_mt_report_slot_state(input, MT_TOOL_FINGER, act);
if (!act)
continue;
input_report_abs(input, ABS_MT_POSITION_X, event.au16_x[i]);
input_report_abs(input, ABS_MT_POSITION_Y, event.au16_y[i]);
}
}
input_mt_sync_frame(input);
input_sync(input);
return IRQ_HANDLED;
}- touch_event_handler函数
ret = hi_i2c_read(0x0, buf, FT_MAX_BUFUSED_NUM);在这里，使用了hi_i2c_read，在文件i2cdev.c中，注意i2c_board_info的一般是8位从地址；
一般来说，触摸屏有固件的，然后每一个固件都代表类似的协议，由于我们没有相应的协议，所以按照下面的来看：
代码语言：javascript复制for (i = 0; i < FT_MAX_TOUCH_POINTS; i )
{
event->touch_point ;
/**Notice the array bound !!*/
/* 获取x坐标 */
event->au16_x[i] =
(s16) (buf[FT_TOUCH_X_H_POS 6 * i] & 0x0F) << 8 | (s16) buf[FT_TOUCH_X_L_POS 6 * i];
/* 获取y坐标 */
event->au16_y[i] =
(s16) (buf[FT_TOUCH_Y_H_POS 6 * i] & 0x0F) << 8 | (s16) buf[FT_TOUCH_Y_L_POS 6 * i];
/* 按下，松开，触摸 */
event->au8_touch_event[i] =
buf[FT_TOUCH_EVENT_POS 6 * i] >> 6;
event->au8_finger_id[i] =
(buf[FT_TOUCH_FINGER_POS 6 * i]) >> 4;
/**pressure and area not used !!*/
#if 0
event->area[i] =
(buf[FT_TOUCH_AREA_POS 6 * i]) >> 4;
event->pressure[i] =
(s16) buf[FTS_TOUCH_PRE_POS 6 * i];
if (0 == event->area[i])
event->area[i] = 0x09;
if (0 == event->pressure[i])
event->pressure[i] = 0x3f;
#endif
if ((event->au8_touch_event[i]==0 || event->au8_touch_event[i]==2)&&(event->point_num==0))
{
printk("abnormal touch data from fw");
return -1;
}
}- 中断函数：
static irqreturn_t ftint_irq(int irq, void *data)
{
int i;
bool act;
struct input_dev* input = ft_ts_dev;
ts_event event;
int ret = touch_event_handler(&event);
if(ret)
printk( "n buffer_read failed n");
if(event.point_num != 0)
{
for(i = 0; i < event.touch_point; i )
{
input_mt_slot(input, i);
act = (event.au8_touch_event[i] == FT_EVENT_PRESS_DOWN || event.au8_touch_event[i] == FT_EVENT_CONTACT);
input_mt_report_slot_state(input, MT_TOOL_FINGER, act);
if (!act)
continue;
input_report_abs(input, ABS_MT_POSITION_X, event.au16_x[i]);
input_report_abs(input, ABS_MT_POSITION_Y, event.au16_y[i]);
}
}
input_mt_sync_frame(input);
input_sync(input);
return IRQ_HANDLED;
}
