海思35xx通过gpio模拟i2c实现GT911触摸功能
1.遇到的问题
- 地址选配后一直不对,首先检测硬件问题,然后通过调试驱动部分,打印调试从设备给的ack(没有逻辑分析仪);发现寄存器地址一直为FF或00,检查发现GT911地址均为16bit,而读写i2c接口是8位的;
- 成功后点击触摸板点击位置与实际不一致;可以进行坐标转换;
2.网上下载
GT91xx编程指南文件
电容触摸芯片GT911 Datasheet 文件
3.Datasheet 重点部分
(1) gpio模拟时,可能需要注意这个延时时间;
(2) 选择地址为0x28/0x29或0xBA/0xBB时序
4.部分代码
(1) 部分寄存器定义
#define GT_CMD_WR 0x28 //写地址
//#define GT_CMD_RD 0x29 //读命令 我的驱动内部逻辑已处理,仅需要写地址就可以了//GT91xx 部分寄存器定义
#define GT_CTRL_REG 0X8040 //GT911控制寄存器
#define GT_CFGS_REG 0X8047 //GT911配置起始地址寄存器
#define GT_CHECK_REG 0X80FF //GT911校验和寄存器
#define GT_FRESH_REG 0X8100 //配置已更新标志
#define GT_PID_REG 0X8140 //GT911产品ID寄存器
#define GT_FIRMVERSION_REG 0x8144 //固件版本#define GT_GSTID_REG 0X814E //GT911当前检测到的触摸情况
#define GT_TP1_REG 0X8150 //第一个触摸点数据地址
#define GT_TP2_REG 0X8158 //第二个触摸点数据地址
#define GT_TP3_REG 0X8160 //第三个触摸点数据地址
#define GT_TP4_REG 0X8168 //第四个触摸点数据地址
#define GT_TP5_REG 0X8170 //第五个触摸点数据地址const u32 GT911_TPX_TBL[5]={GT_TP1_REG,GT_TP2_REG,GT_TP3_REG,GT_TP4_REG,GT_TP5_REG};
(2) 配置GT911从设备地址0x28/0x29或0xBB/0xBA
void TouchScreen::GT911_INT(u8 cmd)
{if(cmd){CGpio::Instance()->SetGpio(13,5,1,1);}else{CGpio::Instance()->SetGpio(13,5,1,0);}
}void TouchScreen::GT911_RST(u8 cmd)
{if(cmd){CGpio::Instance()->SetGpio(6,3,1,1);}else{CGpio::Instance()->SetGpio(6,3,1,0);}
}//我选的是0x28/0x29
void TouchScreen::goodix_init()
{ GT911_RST(0);GT911_INT(0);msleep(50);GT911_INT(1);usleep(200);GT911_RST(1);msleep(10);GT911_INT(0);msleep(80);Hi_Gpio_SetDir(13,5,0);//GPIO13_5设为输入msleep(60);return;
}
(3) i2c写接口及驱动接口参考
// gpio_i2c2_read 、 gpio_i2c2_write驱动部分参考如下:EXPORT_SYMBOL(gpio_i2c2_read);unsigned int gpio_i2c2_read(unsigned char devaddress, unsigned short address, int num_bytes){unsigned char rxdata;unsigned int ret = 0x00;int i;i2c_start_bit(); //gpio模拟i2c 略i2c_send_byte((unsigned char)(devaddress));i2c_receive_ack();i2c_send_byte((unsigned char)((address >> 8) & 0xff));i2c_receive_ack();i2c_send_byte((unsigned char)(address & 0xff));i2c_receive_ack(); i2c_start_bit();i2c_send_byte((unsigned char)(devaddress) | 1); //只需要写地址的原因在这里,完全可以其他处理;i2c_receive_ack();for (i=0; i<num_bytes-1; i++) {rxdata = i2c_receive_byte();//i2c_send_ack();ret |= rxdata;ret <<= 8;}rxdata = i2c_receive_byte();// i2c_send_ack();i2c_stop_bit();ret |= rxdata;// printk("dev=%x, reg =%x, rxd=%x\n", devaddress, address, ret);return ret;}EXPORT_SYMBOL(gpio_i2c2_write);void gpio_i2c2_write(unsigned char devaddress, unsigned short address, unsigned int data, int num_bytes){int i;i2c_start_bit();i2c_send_byte((unsigned char)(devaddress));i2c_receive_ack();i2c_send_byte((unsigned char)((address >> 8) & 0xff));i2c_receive_ack();i2c_send_byte((unsigned char)(address & 0xff));i2c_receive_ack();for (i=0; i<num_bytes; i++) {i2c_send_byte((unsigned char)((data >> (i*8)) & 0xff)); i2c_receive_ack();}// i2c_send_byte((unsigned char)((data >> (i*8)) & 0xff)); i2c_stop_bit();}// ioctl 操作对应的驱动接口如下:long gpioi2c_ioctl(struct file *file, unsigned int cmd, unsigned long arg){...case GPIO_I2C_READ_SHORT: val = *(unsigned int *)arg;device_addr = (val&0xff000000)>>24;reg_addr = (val&0xffff00)>>8;reg_val = gpio_i2c2_read(device_addr, reg_addr, 2);*(unsigned int *)arg = reg_val; break; case GPIO_I2C_WRITE_SHORT:val = *(unsigned int *)arg;device_addr = (val&0xff000000)>>24;reg_addr = (val&0xffff00)>>8;reg_val = val&0xffff;gpio_i2c2_write(device_addr, reg_addr, reg_val, 2);break; }//读写16位寄存器的接口;int xxx::writeI2c16(int devaddr, int reg, int data){int fd = -1;int ret =0;int value;fd = open("/dev/gpioi2c", 0);if(fd<0){printf("Open gpioi2c error!\n");return -1;}value = ((devaddr&0xff)<<24) | ((reg&0xffff)<<8) | (data&0xffff);ret = ioctl(fd, GPIO_I2C_WRITE_SHORT, &value);close(fd);return ret;}
(4) 触摸屏初始化
void TouchScreen::I2C_init()
{//system("himm 0x120F08E0 0x230"); //SDA 上拉,高速//system("himm 0x120F08E4 0x230"); //SCLSetGpio(12,7,1,1);SetGpio(12,6,1,1);
}//下面的goodix_send_cfg如下:我没用到,不知道正确与否
int TouchScreen::goodix_send_cfg()
{u8 sum[2] = {0};static unsigned char imps2_param [] ={0x69,0x00,0x04,0x58,0x02,0x05,0x0D,0x00,0x01,0x0A,0x1E,0x0F,0x64,0x46,0x03,0x05,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x8C,0x2E,0x0E,0x3C,0x3E,0x61,0x07,0x00,0x00,0x00,0x02,0x02,0x1D,0x00,0x01,0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x00,0x00,0x28,0x62,0x94,0xC5,0x02,0x07,0x00,0x00,0x04,0xA1,0x2B,0x00,0x8C,0x34,0x00,0x7D,0x3E,0x00,0x6F,0x4B,0x00,0x66,0x59,0x00,0x66,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x1C,0x1A,0x18,0x16,0x14,0x12,0x10,0x0E,0x0C,0x0A,0x08,0x06,0x04,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x02,0x04,0x06,0x08,0x0A,0x0C,0x0F,0x10,0x12,0x13,0x14,0x16,0x18,0x1C,0x1D,0x1E,0x1F,0x20,0x21,0x22,0x24,0x26,0x28,0x29,0x2A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x38,0x01};//厂家初始化序列for(int i = 0; i < sizeof(imps2_param); i++){writeI2c16(GT_CMD_WR,GT_CFGS_REG+i,imps2_param[i]);//写入配置 0x8047~0x8100 共186个sum[0] += imps2_param[i];readI2c16(GT_CMD_WR,GT_CFGS_REG+i);}sum[0] = (~sum[0])+1;//校验和为补码,看手册sum[1]=1;writeI2c16(GT_CMD_WR,GT_CHECK_REG,sum[0]);//写入校验和writeI2c16(GT_CMD_WR,GT_FRESH_REG,sum[1]);//配置更新标记msleep(10);return 0;
}void TouchScreen::TouchScreenInit()
{SetGpio(6,3,1,0); //rst init 具体看硬件io口SetGpio(13,5,1,0); //INT init//system("himm 0x120F09B4 0x330");I2C_init(); //好像没用处goodix_init(); // IIC地址选择writeI2c16(GT_CMD_WR,GT_CTRL_REG,0x02);//软复位GT911writeI2c16(GT_CMD_WR,GT_GSTID_REG,0);u32 id = readI2c16(GT_CMD_WR,GT_CFGS_REG);if((id & 0xff) < 0x69) //0x69为配置中的首位{//更新GT911寄存器配置goodix_send_cfg();//厂家提供,没有不要乱配,可能导致不能用;}writeI2c16(GT_CMD_WR,GT_CTRL_REG,0x00);//结束软复位writeI2c16(GT_CMD_WR,GT_GSTID_REG,0);//多写几次无所谓
}
(4) 主循环
void TouchScreen::PthreadProc()
{ unsigned int t = 0 ;int touchStatus = 0;u8 buf[5];time_t tim, last_monitor_tim = 0;memset(&keyInfo,0,sizeof(keyInfo));while(1) //轮询方式{if(0 == (t++)%50){ if(touchStatus & 0x80) //&& (((touchStatus & 0xF) > 0) && ((touchStatus & 0xF) < 6)))//数据准备好可读{if(touchStatus & 0x0F)//触摸点数大于1{for(int i = 0; i < 1; i++){ for(int j = 0; j < 5; j++){buf[j] = readI2c16(GT_CMD_WR,GT911_TPX_TBL[i]+j);}}if((touchStatus & 0xff) == 0x81) //单击{msleep(140);//延时去抖//do something}else if((touchStatus & 0xff) == 0x82) //双击{msleep(100);//延时去抖//do something}//逻辑与物理坐标转换touchPos.s32XPos = (buf[0] + (buf[1] << 8)) * m_TmpWidth / m_phyWidth;touchPos.s32YPos = (buf[2] + (buf[3] << 8)) * m_TmpHeight / m_phyHeight;//处理坐标 ... }writeI2c16(GT_CMD_WR,GT_GSTID_REG,0x00);//将此标志清零}else{msleep(150); }}}
}
5.说明
(1) 本文为记录所用,代码仅供参考,错误地方欢迎指正;
(2) 主循环可以用轮询或中断方式
(3) 代码中gpio具体看硬件手册
6. 参考
https://blog.csdn.net/qlexcel/article/details/99696108
https://www.cnblogs.com/DarkBright/p/10730346.html