今天有空去研究camera的上电时序 1.高通平台对于camera的代码组织，大体上还是遵循Android的框架：
即上层应用和HAL层交互，高通平台在HAL层里面实现自己的一套管理策略；
在kernel中实现sensor的底层驱动；
对于最核心的sensor端的底层设置、ISP效果相关等代码则是单独进行了抽离，放在vendor中。 2.vendor中：
vendorqcomproprietarymm-cameramm-camera2media-controllermodulessensorssensor_libsov5648_q5v22e 下面这个结构体便是上电时序 static struct msm_sensor_power_setting ov5648_q5v22e_power_setting[] = { { .seq_type = SENSOR_GPIO, .seq_val = SENSOR_GPIO_STANDBY, .config_val = GPIO_OUT_LOW, .delay = 2, }, { .seq_type = SENSOR_GPIO, .seq_val = SENSOR_GPIO_RESET, .config_val = GPIO_OUT_LOW, .delay = 2, }, { .seq_type = SENSOR_VREG, .seq_val = CAM_VIO, .config_val = 0, .delay = 0, }, { .seq_type = SENSOR_GPIO, .seq_val = SENSOR_GPIO_VANA, .config_val = GPIO_OUT_HIGH, .delay = 1, }, { .seq_type = SENSOR_GPIO, .seq_val = SENSOR_GPIO_VDIG, .config_val = GPIO_OUT_HIGH, .delay = 5, }, { .seq_type = SENSOR_GPIO, .seq_val = SENSOR_GPIO_STANDBY, .config_val = GPIO_OUT_HIGH, .delay = 10, }, { .seq_type = SENSOR_GPIO, .seq_val = SENSOR_GPIO_RESET, .config_val = GPIO_OUT_HIGH, .delay = 5, }, { .seq_type = SENSOR_CLK, .seq_val = SENSOR_CAM_MCLK, .config_val = 23880000,//24000000,//19200000,//23880000, .delay = 5, }, { .seq_type = SENSOR_I2C_MUX, .seq_val = 0, .config_val = 0, .delay = 10, }, }; 它定义在下面的结构体中： static struct msm_camera_sensor_slave_info sensor_slave_info = { ... /* power up / down setting */ .power_setting_array = { .power_setting = ov5648_q5v22e_power_setting, .size = ARRAY_SIZE(ov5648_q5v22e_power_setting), .power_down_setting = power_down_setting, .size_down = ARRAY_SIZE(power_down_setting), }, }; 这些结构体具体在哪里定义呢？在kernel中
/include/media/msm_camsensor_sdk.h中 struct msm_camera_sensor_slave_info { ... struct msm_sensor_power_setting_array power_setting_array; ... }; struct msm_sensor_power_setting { enum msm_sensor_power_seq_type_t seq_type; uint16_t seq_val; long config_val; uint16_t delay; void *data[10]; }; struct msm_sensor_power_setting_array { struct msm_sensor_power_setting power_setting_a[MAX_POWER_CONFIG]; struct msm_sensor_power_setting *power_setting; uint16_t size; struct msm_sensor_power_setting power_down_setting_a[MAX_POWER_CONFIG]; struct msm_sensor_power_setting *power_down_setting; uint16_t size_down; }; 3.从vendor中把时序结构体的内容传递到kernel中的过程如下：
在msm_sensor_init_subdev_ioctl(…,void *arg) —>函数： msm_sensor_driver_cmd(s_init, arg);
—>语句： struct sensor_init_cfg_data cfg = (struct sensor_init_cfg_data )arg;
—>函数：msm_sensor_driver_probe(cfg->cfg.setting,…);
—>语句：copy_from_user((void *)&setting32, setting,sizeof(setting32))将vendor的数据传送到内核空间
—>语句： slave_info->power_setting_array.size =setting32.power_setting_array.size;
slave_info->power_setting_array.power_setting =
compat_ptr(setting32.power_setting_array.power_setting); //把vendor的时序传递完毕
—>语句：rc = msm_sensor_get_power_settings(setting, slave_info,&s_ctrl->sensordata->power_info);
//把slave_info的上电时序传递给s_ctrl结构体
—>语句：msm_camera_fill_vreg_params(…)//校正时序中SENSOR_VREG的seq_val，为设备树的CAM_VIO
—>语句：rc = s_ctrl->func_tbl->sensor_power_up(s_ctrl); //真正执行上电时序 因为.sensor_power_up = msm_sensor_power_up,所以真正的上电函数为：msm_sensor_power_up(struct msm_sensor_ctrl_t *s_ctrl)
–>语句：power_info = &s_ctrl->sensordata->power_info; //把s_ctrl的上电信息传递给power_info
–>函数：msm_camera_power_up(power_info, s_ctrl->sensor_device_type,sensor_i2c_client);//上电
ps：vendor中的addr_type、camera_id、slave_addr等信息也是按照这样的方法从vendor中传递到kernel中的，可以加打印调试信息看这些值正确与否。 4.下面解析这个上电函数： int msm_camera_power_up(struct msm_camera_power_ctrl_t *ctrl, enum msm_camera_device_type_t device_type, struct msm_camera_i2c_client *sensor_i2c_client) { struct msm_sensor_power_setting *power_setting = NULL; ... rc = msm_camera_request_gpio_table( //申请gpio ctrl->gpio_conf->cam_gpio_req_tbl, ctrl->gpio_conf->cam_gpio_req_tbl_size, 1); ... index = 0; index < ctrl->power_setting_size; index++) { power_setting = &ctrl->power_setting[index]; //把时序的节点一个一个取下来解析 switch (power_setting->seq_type) { //判断类型 case SENSOR_CLK: if (power_setting->config_val) ctrl->clk_info[power_setting->seq_val].clk_rate = power_setting->config_val; rc = msm_cam_clk_enable(...1); //camera频率使能 ... case SENSOR_GPIO: ... gpio_set_value_cansleep(ctrl->gpio_conf->gpio_num_info->gpio_num[power_setting->seq_val], (int) power_setting->config_val); //拉高拉低gpio口 ... case SENSOR_VREG: if (power_setting->seq_val < ctrl->num_vreg) msm_camera_config_single_vreg(...,1); //函数里面打开reg_ptr的电源控制器regulator_enable，下面再解析 ... case SENSOR_I2C_MUX: if (ctrl->i2c_conf && ctrl->i2c_conf->use_i2c_mux) msm_camera_enable_i2c_mux(ctrl->i2c_conf); //打开使能i2c_mux break; default: ... } //以下是每个时序节点解析完毕后，进行的延迟，可以没有 if (power_setting->delay > 20) { msleep(power_setting->delay); } else if (power_setting->delay) { usleep_range(power_setting->delay * 1000,(power_setting->delay * 1000) + 1000); } } ... return 0; } 最后两个节点比较特殊：
第一个SENSOR_VREG:
在解析设备树节点的时候： //从中有一路电vio为0V qcom,cam-vreg-name = "cam_vdig", "cam_vio", "cam_vana";//"cam_vaf"; qcom,cam-vreg-min-voltage = <1800000 0 2850000 >;//2800000>; qcom,cam-vreg-max-voltage = <1800000 0 2850000 >;//2800000>; qcom,cam-vreg-op-mode = <200000 0 80000 100000>; //在kernel中对设备树节点解析的时候 for (i = 0; i < count; i++) { vreg[i].min_voltage = vreg_array[i];}//存入结构体中 在msm_sensor_driver_probe函数中调用msm_camera_fill_vreg_params 在里面遍历上电时序节点： for (i = 0; i < power_setting_size; i++) { if (power_setting[i].seq_type != SENSOR_VREG) continue; switch (power_setting[i].seq_val) { case CAM_VDIG: ... case CAM_VIO: for (j = 0; j < num_vreg; j++) { if (!strcmp(cam_vreg[j].reg_name, "cam_vio")) { power_setting[i].seq_val = j; //让seq_val 对准设备树的seq_val break; } } break; case CAM_VANA: ... case CAM_VAF: ... case CAM_V_CUSTOM1: ... } } //再进入此节点上电的时候有 msm_camera_config_single_vreg(..&ctrl->cam_vreg[power_setting->seq_val],..); 中间的参数就是设备树上的电压。 第二个节点SENSOR_I2C_MUX：
执行函数msm_camera_enable_i2c_mux—>可能是申请锁和一帧的内存空间 解析完毕后，最后两个节点是打开时序和I2C_MUX，如果成功上电便完成了。
对照规格书：
把DOVDD上电后，AVDD,DVDD,PWDNB的上电时序都大于图中规定时间。 回到msm_sensor_driver_probe函数中。