一种调试i2c、spi器件寄存器的方法

 

        在调试芯片驱动的调试阶段，经常会碰到寄存器值不确定，需要不断更改寄存器的值来调试芯片驱动的效果到最佳状态，从而出现要不停的编译驱动代码，这样浪费了很多的时间，下面介绍一种调试的方法，通过创建节点，通过echo和cat来写和读设备寄存器的值，从而达到快速调试的效果。

        首先要创建节点，在驱动的探测函数中，创建节点：device_create_file(devices*, device_attribute*)；

        在驱动的卸载函数中，删除节点： device_remove_file(devices*, device_attribute*)；

        具体的实现如下代码

        

#define tw9912_TEST 1//Harvey add for tw9912 test#if tw9912_TEST#define tp_major 555#endif#if  tw9912_TESTstatic u8 tw9912REG;static u8 tw9912VAL;static u8 cameramode;static u8 camerafmt;static ssize_t TEST_mode_show(struct device *dev,struct device_attribute *attr, char *_buf)//(struct class *cls, char *_buf){    int count;    count = sprintf(_buf,"tw9912Mode:%d\n",                                        cameramode);printk(KERN_INFO "tw9912_data.CameraDispMode %d\n",cameramode);return count;}static ssize_t TEST_mode_store(struct device *dev,struct device_attribute *attr, char *_buf,size_t _count)//(struct class *cls, const char *_buf, size_t _count){     int tmp_get_android = 0;    tmp_get_android = simple_strtol(_buf, NULL, 10);     printk(KERN_INFO "cameramode %d\n",tmp_get_android);    cameramode=tmp_get_android;    tw9912_init_Disp_mode(cameramode,camerafmt);    return _count; }static ssize_t TEST_FMT_show(struct device *dev,struct device_attribute *attr, char *_buf)//(struct class *cls, char *_buf){    int count;    count = sprintf(_buf,"tw9912FMT:%d\n",                                        camerafmt);printk(KERN_INFO "tw9912_data.CameraDispFMT %d\n",camerafmt);return count;}static ssize_t TEST_FMT_store(struct device *dev,struct device_attribute *attr, char *_buf,size_t _count)//(struct class *cls, const char *_buf, size_t _count){     int tmp_get_android = 0;    tmp_get_android = simple_strtol(_buf, NULL, 10);     printk(KERN_INFO "tw9912_data.CameraDispFMT %d\n",tmp_get_android);    camerafmt=tmp_get_android;    tw9912_init_Disp_mode(cameramode,camerafmt);    return _count; }static ssize_t TEST_REG_show(struct device *dev,struct device_attribute *attr, char *_buf)//(struct class *cls, char *_buf){    int count;    count = sprintf(_buf,"tw9912REG:0x%x\n",                                         tw9912REG);printk(KERN_INFO "tw9912REG 0x%x\n",tw9912REG);return count;}static ssize_t TEST_REG_store(struct device *dev,struct device_attribute *attr, char *_buf,size_t _count)//(struct class *cls, const char *_buf, size_t _count){   //  int tmp_get_android = 0;    tw9912REG = simple_strtol(_buf, NULL, 16);     printk(KERN_INFO "tw9912REG %x\n",tw9912REG);    return _count; }static ssize_t TEST_VAL_show(struct device *dev,struct device_attribute *attr, char *_buf)//(struct class *cls, char *_buf){    int count;tw9912VAL=tw9912_read(tw9912REG);//   printk(KERN_INFO "tw9912Read ERROR\n");   count = sprintf(_buf,"tw9912VAL:0x%x\n",                                         tw9912VAL);printk(KERN_INFO "tw9912VAL 0x%x\n",tw9912VAL);return count;}static ssize_t TEST_VAL_store(struct device *dev,struct device_attribute *attr, char *_buf,size_t _count)//(struct class *cls, const char *_buf, size_t _count){   //  int tmp_get_android = 0;    tw9912VAL = simple_strtol(_buf, NULL, 16);     printk(KERN_INFO "tw9912VAL %x\n",tw9912VAL);       if(tw9912_write_reg(tw9912REG,tw9912VAL)<0)    printk(KERN_INFO "tw9912Write ERROR\n");    return _count; }static struct class *tw9912_TEST_class = NULL;static struct device *tw9912_TEST_dev=NULL;static DEVICE_ATTR(TESTMODE, 0666, TEST_mode_show, TEST_mode_store);static DEVICE_ATTR(TESTFMT, 0666, TEST_FMT_show, TEST_FMT_store);static DEVICE_ATTR(TESTREG, 0666, TEST_REG_show, TEST_REG_store);static DEVICE_ATTR(TESTVAL, 0666, TEST_VAL_show, TEST_VAL_store);#endifstatic int tw9912_probe(struct i2c_client *client, const struct i2c_device_id *id){        ……     #if tw9912_TEST    tw9912_TEST_class= class_create(THIS_MODULE, "tw9912Testclass");     tw9912_TEST_dev= device_create(tw9912_TEST_class, NULL, MKDEV(tp_major, 0), NULL, "tw9912Testdev");        device_create_file(tw9912_TEST_dev, &dev_attr_TESTMODE);        device_create_file(tw9912_TEST_dev, &dev_attr_TESTFMT);        device_create_file(tw9912_TEST_dev, &dev_attr_TESTREG);        device_create_file(tw9912_TEST_dev, &dev_attr_TESTVAL);#endif        ……}static int tw9912_remove(struct i2c_client *client){        ……#if tw9912_TEST    device_remove_file(tw9912_TEST_dev, &dev_attr_TESTMODE);    device_remove_file(tw9912_TEST_dev, &dev_attr_TESTFMT);    device_remove_file(tw9912_TEST_dev, &dev_attr_TESTREG);    device_remove_file(tw9912_TEST_dev, &dev_attr_TESTVAL);     device_destroy(tw9912_TEST_dev, MKDEV(tp_major, 0));         class_destroy(tw9912_TEST_class);#endif      ……}