Camera5 MTK camera驱动框架介绍

一、概序：

　　前文已经介绍了camera驱动部分的内容Camera４ MTK camera驱动结构介绍，这里在回顾下之前的框架图，

这篇主要介绍红框部分的内容：
　　　　

　　imgsensor起到承上启下的作用，在系统起来时会创建整个camera驱动运行的环境，其中主要的

文件和函数如下框图所示，先设备挂载时会调用注册platform设备platform_driver_register，在匹配成

功后会调用probe函数进行初始相关的设备：

　　其中camera的三路电压的上电方式可以通过GPIO来控制，也可以通过PMIC(REGULATOR)的方式来

进行控制，在imgsensor_hw中通过不同的pdev信息，调用不同的set函数。涉及的文件路径：

　　kernel-4.9/drivers/misc/mediatek/imgsensor/src/common/v1/imgsensor.c

　　kernel-4.9/drivers/misc/mediatek/imgsensor/src/common/v1/imgsensor_hw.c

　　kernel-4.9/drivers/misc/mediatek/imgsensor/src/mt6765/camera_hw/regulator/regulator.c

　　kernel-4.9/drivers/misc/mediatek/imgsensor/src/mt6765/camera_hw/gpio/gpio.c

二、上电相关的结构体之间的联系：

（1）IMGSENSOR_HW结构体：

　　IMGSENSOR_HW结构体包含了pdev(gpio/regulator)的设备结构体和上电时序相关的结构体：

（2）上电时序控制相关：

　　上电方式控制：GPIO?REGULATOR?

　　上电时序控制结构体：

三、系统初始化：

１、设备加载：

　　imgsensor和其他的驱动模块相同，也是通过module_init来初始化模块，在init中注册platform总线驱动，

从而需要对应的platform_driver结构体信息：

static const struct of_device_id gimgsensor_of_device_id[] = {{ .compatible = "mediatek,camera_hw", },{}
};static struct platform_driver gimgsensor_platform_driver = {.probe      = imgsensor_probe,.remove     = imgsensor_remove,.suspend    = imgsensor_suspend,.resume     = imgsensor_resume,.driver     = {.name   = "image_sensor",.owner  = THIS_MODULE,
#ifdef CONFIG_OF.of_match_table = gimgsensor_of_device_id,
#endif}
};

　　当gimgsensor_of_device_id的信息在dts中match上以后回执行到对应的probe函数，probe中主要注册

了sensordrv的字符设备和初始化imgsensor的硬件信息(时钟及上电)：

static int imgsensor_probe(struct platform_device *pdev)
{/* Register char driver */imgsensor_driver_register();gpimgsensor_hw_platform_device = pdev;imgsensor_clk_init(&pgimgsensor->clk);imgsensor_hw_init(&pgimgsensor->hw);imgsensor_i2c_create();imgsensor_proc_init();atomic_set(&pgimgsensor->imgsensor_open_cnt, 0);return 0;
}

2、imgsensor_driver_register创建字符设备：

//字符设备的file_operation结构体
static const struct file_operations gimgsensor_file_operations = {.owner = THIS_MODULE,.open = imgsensor_open,.release = imgsensor_release,.unlocked_ioctl = imgsensor_ioctl,
#ifdef CONFIG_COMPAT.compat_ioctl = imgsensor_compat_ioctl
#endif
};static inline int imgsensor_driver_register(void){//分配一个设备号和nanmealloc_chrdev_region(&dev_no, 0, 1, IMGSENSOR_DEV_NAME)/* Allocate driver */gpimgsensor_cdev = cdev_alloc();/* Attatch file operation. */cdev_init(gpimgsensor_cdev, &gimgsensor_file_operations);/* Add to system */cdev_add(gpimgsensor_cdev, dev_no, 1);gpimgsensor_class = class_create(THIS_MODULE, "sensordrv");device_create(gpimgsensor_class, NULL, dev_no, NULL, IMGSENSOR_DEV_NAME);
}

3、imgsensor_clk_init 时钟初始化：

enum IMGSENSOR_RETURN imgsensor_clk_init(struct IMGSENSOR_CLK *pclk)
{int i;struct platform_device *pplatform_dev = gpimgsensor_hw_platform_device;/* get all possible using clocks */for (i = 0; i < IMGSENSOR_CCF_MAX_NUM; i++)pclk->imgsensor_ccf[i] =devm_clk_get(&pplatform_dev->dev, gimgsensor_mclk_name[i]);return IMGSENSOR_RETURN_SUCCESS;
}

4、imgsensor_hw_init电压初始化：

（１）依次调用GPIO/REGULATOR/MCLK的init接口；

（2）解析出imgsensor_custom_config，获取到对应sensor的对应管脚(DVDD/AVDD...)的上电方式（GPIO/REGULATOR）;

enum IMGSENSOR_RETURN imgsensor_hw_init(struct IMGSENSOR_HW *phw)
{struct IMGSENSOR_HW_SENSOR_POWER      *psensor_pwr;struct IMGSENSOR_HW_CFG               *pcust_pwr_cfg;struct IMGSENSOR_HW_CUSTOM_POWER_INFO *ppwr_info;int i, j;char str_prop_name[LENGTH_FOR_SNPRINTF];struct device_node *of_node= of_find_compatible_node(NULL, NULL, "mediatek,camera_hw");//依次调用GPIO/REGULATOR/MCLK的init接口；for (i = 0; i < IMGSENSOR_HW_ID_MAX_NUM; i++) {if (hw_open[i] != NULL)(hw_open[i])(&phw->pdev[i]);if (phw->pdev[i]->init != NULL)(phw->pdev[i]->init)(phw->pdev[i]->pinstance);}//解析出imgsensor_custom_configfor (i = 0; i < IMGSENSOR_SENSOR_IDX_MAX_NUM; i++) {psensor_pwr = &phw->sensor_pwr[i];pcust_pwr_cfg = imgsensor_custom_config;//上电时序while (pcust_pwr_cfg->sensor_idx != i)pcust_pwr_cfg++;//退出循环if (pcust_pwr_cfg->sensor_idx == IMGSENSOR_SENSOR_IDX_NONE)continue;//ppwr_info对应{IMGSENSOR_HW_ID_GPIO, IMGSENSOR_HW_PIN_AVDD}ppwr_info = pcust_pwr_cfg->pwr_info;while (ppwr_info->pin != IMGSENSOR_HW_PIN_NONE) {//查询imgsensor_custom_config中ID_PIN 是否在GPIO/REGULATOR/Mclk中?for (j = 0; j < IMGSENSOR_HW_ID_MAX_NUM; j++){if (ppwr_info->id == phw->pdev[j]->id)break;}//将对应sensor的对应PIN(DVDD/AVDD...)设置为系统的ID_PIN(GPIO/REGULATOR/MCKL)psensor_pwr->id[ppwr_info->pin] = j;ppwr_info++;}}//判断dts中是否设定对应的index为对应的name,如:cam3_enable_sensor = "gc2375hmain3_mipi_raw";for (i = 0; i < IMGSENSOR_SENSOR_IDX_MAX_NUM; i++) {memset(str_prop_name, 0, sizeof(str_prop_name));snprintf(str_prop_name,sizeof(str_prop_name),"cam%d_%s",i,"enable_sensor");if (of_property_read_string(of_node,str_prop_name,&phw->enable_sensor_by_index[i]) < 0) {pr_info("Property cust-sensor not defined\n");phw->enable_sensor_by_index[i] = NULL;}}return IMGSENSOR_RETURN_SUCCESS;
}

5、imgsensor_i2c_create I2C设备初始化：

enum IMGSENSOR_RETURN imgsensor_i2c_create(void)
{int i;for (i = 0; i < IMGSENSOR_I2C_DEV_MAX_NUM; i++)i2c_add_driver(&gi2c_driver[i]);return IMGSENSOR_RETURN_SUCCESS;
}

6、具体类型的上电介绍（以pmic控制的regulator方式为例）

　　前面imgsensor_hw_init中有去调用imgsensor_hw_regulator_open和regulator_init：

（1）传入对应的设备的device结构体：

static struct IMGSENSOR_HW_DEVICE device = {.pinstance = (void *)&reg_instance,.init      = regulator_init,//开机初始化时调用.set       = regulator_set,//在上电设置电压时会调用.release   = regulator_release,.id        = IMGSENSOR_HW_ID_REGULATOR
};enum IMGSENSOR_RETURN imgsensor_hw_regulator_open(struct IMGSENSOR_HW_DEVICE **pdevice)
{*pdevice = &device;return IMGSENSOR_RETURN_SUCCESS;
}

（2）调用对应的init进行初始化：

　　因为MTK 平台的PMIC上电是通过统一的REGULATOR进行统一管理的，每一种上电方式需要申请对应type

的regulator控制的结构体，才可以来进行设置：

enum REGULATOR_TYPE {REGULATOR_TYPE_VCAMA,REGULATOR_TYPE_VCAMD,REGULATOR_TYPE_VCAMIO,REGULATOR_TYPE_MAX_NUM
};static enum IMGSENSOR_RETURN regulator_init(void *pinstance)
{struct REGULATOR *preg = (struct REGULATOR *)pinstance;struct device            *pdevice;struct device_node       *pof_node;int j, i;char str_regulator_name[LENGTH_FOR_SNPRINTF];pdevice  = gimgsensor_device;for (j = IMGSENSOR_SENSOR_IDX_MIN_NUM;j < IMGSENSOR_SENSOR_IDX_MAX_NUM;j++) {for (i = 0; i < REGULATOR_TYPE_MAX_NUM; i++) {snprintf(str_regulator_name,sizeof(str_regulator_name),"cam%d_%s", j,regulator_control[i].pregulator_type);preg->pregulator[j][i] =regulator_get(pdevice, str_regulator_name);if (preg->pregulator[j][i] == NULL)pr_err("regulator[%d][%d]  %s fail!\n",j, i, str_regulator_name);atomic_set(&preg->enable_cnt[j][i], 0);}}pdevice->of_node = pof_node;imgsensor_oc_init();return IMGSENSOR_RETURN_SUCCESS;
}

　　到这里imgsensor部分的内容还有对上(hal层)承接的ioctl相关的内容没有介绍，这部分的内容会在后续的

整个系统调用流程中进行梳理。

作者：frank_zyp
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