MTK CAMERA ISP6S Kernel

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我是靠谱客的博主超级紫菜，最近开发中收集的这篇文章主要介绍MTK CAMERA ISP6S Kernel，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

camera的开机上电分两个流程，一个是内核中camera驱动进行挂载，另一个是用户空间通过ioctrl对内核空间camera驱动进行上电。

驱动挂载：
1.module_init(imgsensor_init); module_init用来进行驱动的加载，传入函数指针imgsensor_init调用imgsensor_init()
2.platform_driver_register(&gimgsensor_platform_driver); 注册平台驱动gimgsensor_platform_driver，gimgsensor_platform_driver内部有一个节点.of_match_table:compatible = "mediatek,imgsensor",这里CONFIG_OF成立，将采用设备树的方式进行匹配,对应kd_camera_hw1，匹配到后就会进行probe操作
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
       }
};
kd_camera_hw1:kd_camera_hw1@1a004000 {
   compatible = "mediatek,imgsensor";
};
3.imgsensor_probe(struct platform_device *pplatform_device)
3.1.struct IMGSENSOR *pimgsensor = &gimgsensor; 创建IMGSENSOR资源
struct IMGSENSOR {
   dev_t dev_no;
   struct cdev *pcdev;
   struct class *pclass;

   struct IMGSENSOR_STATUS status;
   struct IMGSENSOR_HW hw;
   struct IMGSENSOR_SENSOR sensor[IMGSENSOR_SENSOR_IDX_MAX_NUM];
   struct IMGSENSOR_SENSOR_LIST *psensor_list[MAX_NUM_OF_SUPPORT_SENSOR];

   atomic_t imgsensor_open_cnt;
   enum IMGSENSOR_RETURN (*mclk_set_drive_current)
       (void *pinstance,
       enum IMGSENSOR_SENSOR_IDX sensor_idx,
       enum ISP_DRIVING_CURRENT_ENUM drive_current);
3.2.struct IMGSENSOR_HW *phw = &pimgsensor->hw;
struct IMGSENSOR_HW {
   struct IMGSENSOR_HW_DEVICE_COMMON common;   平台设备
   struct IMGSENSOR_HW_DEVICE *pdev[IMGSENSOR_HW_ID_MAX_NUM];   上电方式，对应regulator/gpio等
   struct IMGSENSOR_HW_SENSOR_POWER
               sensor_pwr[IMGSENSOR_SENSOR_IDX_MAX_NUM];
               {
                   struct IMGSENSOR_HW_POWER_INFO *ppwr_info;   哪路供电及供电电压和时序
                   enum IMGSENSOR_HW_ID id[IMGSENSOR_HW_PIN_MAX_NUM]; 哪路供电
               };   上电方式及上电时序
   const char *enable_sensor_by_index[IMGSENSOR_SENSOR_IDX_MAX_NUM];
};
};
3.3.
3.4.alloc_chrdev_region(&pimgsensor->dev_no, 0, 1, IMGSENSOR_DEV_NAME) 动态分配设备号，IMGSENSOR_DEV_NAME:kd_camera_hw
3.5.pimgsensor->pcdev = cdev_alloc();   动态申请并分配一个新的字符设备
3.6.cdev_init(pimgsensor->pcdev, &gimgsensor_file_operations);   绑定字符设备及其操作函数
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
};
3.7.cdev_add(pimgsensor->pcdev, pimgsensor->dev_no, 1)   绑定了字符设备及其设备号并注册进系统中
3.8.pimgsensor->pclass = class_create(THIS_MODULE, "sensordrv");   态创建设备的逻辑类，在/sys/class/目录下创建一个名为"sensordrv"的文件夹
3.9.pdevice = device_create(pimgsensor->pclass, NULL, pimgsensor->dev_no, NULL, IMGSENSOR_DEV_NAME);   创建设备文件kd_camera_hw，在/dev目录下，通过这个设备文件可以进行读写操作
3.10.pdevice->of_node = of_find_compatible_node(NULL, NULL, "mediatek,imgsensor");   从根节点在设备树中查找"mediatek,imgsensor"，返回要查找的节点
3.11.phw->common.pplatform_device = pplatform_device;   pplatform_device为probe传入参数，平台设备
3.12.imgsensor_hw_init(phw);   上电模块初始化
3.12.1.
struct IMGSENSOR_HW_SENSOR_POWER *psensor_pwr;
struct IMGSENSOR_HW_CFG *pcust_pwr_cfg;
struct IMGSENSOR_HW_CFG imgsensor_custom_config[] = {
   {
       IMGSENSOR_SENSOR_IDX_MAIN,
       IMGSENSOR_I2C_DEV_0,
       {
           {IMGSENSOR_HW_PIN_MCLK, IMGSENSOR_HW_ID_MCLK},   ppwr_info{IMGSENSOR_HW_PIN, IMGSENSOR_HW_ID}
           {IMGSENSOR_HW_PIN_AVDD, IMGSENSOR_HW_ID_GPIO},
           {IMGSENSOR_HW_PIN_DOVDD, IMGSENSOR_HW_ID_REGULATOR},
           {IMGSENSOR_HW_PIN_DVDD, IMGSENSOR_HW_ID_GPIO},
           {IMGSENSOR_HW_PIN_PDN, IMGSENSOR_HW_ID_GPIO},
           {IMGSENSOR_HW_PIN_RST, IMGSENSOR_HW_ID_GPIO},
           {IMGSENSOR_HW_PIN_NONE, IMGSENSOR_HW_ID_NONE},
       }
   {
   ...
}
struct IMGSENSOR_HW_CUSTOM_POWER_INFO *ppwr_info;
   {IMGSENSOR_HW_PIN_MCLK, IMGSENSOR_HW_ID_MCLK}
struct device_node *of_node = of_find_compatible_node(NULL, NULL, "mediatek,imgsensor");
3.12.2.遍历设置的IMGSENSOR_SENSOR_IDX_MAX_NUM，根据cameraidx依次进行上电结构体的匹配赋值
pcust_pwr_cfg = imgsensor_custom_config;   拿到imgsensor_cfg_table.c中填入的pcust_pwr_cfg = imgsensor_custom_config的地址/*这里是bringup需要客制化的地方*/，就是平台提供的各路供电接口及其上电方式，比如上面的IMGSENSOR_SENSOR_IDX_MAIN使用i2c为IMGSENSOR_I2C_DEV_0，avdd使用gpio进行供电，iovdd使用regulator进行供电。通过pcust_pwr_cfg地址+1的方式拿取第二第三颗sensor。
snprintf(str_prop_name, izeof(str_prop_name), "cam%d_pin_%s", i, imgsensor_hw_pin_names[ppwr_info->pin]);   根据ppwr_info->pin比如上面定义的IMGSENSOR_HW_PIN_AVDD得到str_prop_name="cam0_pin_vcama"。
of_property_read_string(of_node, str_prop_name, &pin_hw_id_name)   在设备树中寻找cam0_pin_vcama并返回对应的pin_hw_id_name:gpio
再循环IMGSENSOR_HW_ID_MAX_NUM(mclk/regulator/gpio),如果上面返回的pin_hw_id_name==这个检索(mclk/regulator/gpio)，ppwr_info->id = 这个检索，ppwr_info->pin=3(avdd),ppwr_info->id=2(gpio)
具体没懂3.12.2.这个操作的意义是什么，相比v1多了个对dts的检索操作，本来imgsensor_custom_config这个表格就已经将avdd和gpio匹配了
3.12.3.遍历IMGSENSOR_HW_ID_MAX_NUM(mclk/regulator/gpio)调用各自init
3.12.4.遍历设置的IMGSENSOR_SENSOR_IDX_MAX_NUM
***psensor_pwr = &phw->sensor_pwr[i];   将IMGSENSOR_HW_SENSOR_POWER赋给psensor_pwr，这个结构体实际就是将imgsensor_custom_config的每路的供电方式和这路供电的电压/延时绑定在了一起
struct IMGSENSOR_HW_SENSOR_POWER {
   struct IMGSENSOR_HW_POWER_INFO *ppwr_info;   {哪路供电,电压,延时}
   enum IMGSENSOR_HW_ID id[IMGSENSOR_HW_PIN_MAX_NUM];   供电方式
};
pcust_pwr_cfg = imgsensor_custom_config;   根据cameraidx依次进行上电结构体的匹配赋值
ppwr_info = pcust_pwr_cfg->pwr_info;   拿到imgsensor_custom_config中IMGSENSOR_HW_PIN和IMGSENSOR_HW_ID的匹配关系(avdd通过gpio上电)
while (ppwr_info->pin != IMGSENSOR_HW_PIN_NONE) {
   for (j = 0; j < IMGSENSOR_HW_ID_MAX_NUM && ppwr_info->id != phw->pdev[j]->id; j++) {}   遍历IMGSENSOR_HW_ID(mclk/regulator/gpio)
           psensor_pwr->id[ppwr_info->pin] = j;   ***这里保存了每一路的供电方式和这路供电的电压/延时给到&phw->sensor_pwr[i]供后续上电使用
           ppwr_info++;
}

3.12.5.在dts中读取cam0_enable_sensor返回给phw->enable_sensor_by_index 就是sensor name

3.13.imgsensor_i2c_create();   各sensor i2c注册
i2c_add_driver(&gi2c_driver[i]);
static struct i2c_driver gi2c_driver[IMGSENSOR_I2C_DEV_MAX_NUM] = {
   {
       .probe = imgsensor_i2c_probe_0,
       .remove = imgsensor_i2c_remove,
       .driver = {
       .name = IMGSENSOR_I2C_DRV_NAME_0,
       .owner = THIS_MODULE,
#ifdef CONFIG_OF
       .of_match_table = gof_device_id_0,   匹配dws中IMGSENSOR_I2C_OF_DRV_NAME_0("mediatek,camera_main"),dws中配置了camera_main的i2c地址
#endif
       },
       .id_table = gi2c_dev_id,
   },
   ...
}
3.14.imgsensor_proc_init();   创建一个proc虚拟文件，应用层通过读写该文件，即可实现与内核的交互
3.15.imgsensor_init_sensor_list();
struct IMGSENSOR *pimgsensor = &gimgsensor;
struct IMGSENSOR_SENSOR_LIST *psensor_list = gimgsensor_sensor_list;   获取sensorlist，客制化地方，加入需要的sensor
of_property_read_string(of_node, "cust-sensor", &penable_sensor);   在of_node("mediatek,imgsensor")节点中寻找cust-sensor返回给penable_sensor,在gimgsensor_sensor_list中找到与penable_sensor一致的sensor，由于gimgsensor是全局的引用，所以最终一致的sensor会存在gimgsensor.psensor_list中
至此，camera驱动挂载与初始化完成

上电
camera的上电是在开机时cameraprovider起来时通过searchSensor调用的，kernel的调用从imgsensor_ioctl()开始
1.adopt_CAMERA_HW_FeatureControl()
struct IMGSENSOR_SENSOR *psensor;   包含SENSOR_INST和SENSOR_FUNCTION
psensor = imgsensor_sensor_get_inst(pFeatureCtrl->InvokeCamera);   根据上层传下来的cameraid返回底层的psensor
psensor->inst.sensor_idx = pFeatureCtrl->InvokeCamera;   拿到底层的cameraid
v1通过这里遍历去给各sensoridx上电
1.1.imgsensor_set_driver()
struct IMGSENSOR *pimgsensor = &gimgsensor;
struct IMGSENSOR_SENSOR_INST *psensor_inst = &psensor->inst;
v1_1通过这里遍历MAX_NUM_OF_SUPPORT_SENSOR给各sensor上电
pimgsensor->psensor_list[i]->init(&psensor->pfunc);   拿到sensor的函数指针
psensor_inst->psensor_list = pimgsensor->psensor_list[i];   将gimgsensor之前在imgsensor_init_sensor_list()拿到的sensorlist赋给psensor_inst->psensor_list
2.imgsensor_check_is_alive(psensor)
struct IMGSENSOR *pimgsensor = &gimgsensor;
struct IMGSENSOR_SENSOR_INST *psensor_inst = &psensor->inst;
2.1.imgsensor_hw_power(&pimgsensor->hw, psensor, IMGSENSOR_HW_POWER_STATUS_ON);   传入IMGSENSOR_HW_POWER_STATUS_ON为上电
2.1.1.imgsensor_hw_power_sequence(phw, sensor_idx, pwr_status, sensor_power_sequence, curr_sensor_name);   sensor_power_sequence是客制化的上电时序
struct IMGSENSOR_HW_SENSOR_POWER *psensor_pwr = &phw->sensor_pwr[sensor_idx];   获取之前拿到的上电配置(哪路电使用哪种上电方式，上电电压是多少，上电延时)
struct IMGSENSOR_HW_POWER_SEQ *ppwr_seq = ppower_sequence;
strcmp(ppwr_seq->name, pcurr_idx)   遍历上电时序表ppower_sequence，根据传入的sensor的name，匹配一致拿取这个sensor的时序表
ppwr_info = ppwr_seq->pwr_info;
遍历需要上电模组的上电时序表ppower_sequence里的ppwr_info->pin
pdev = phw->pdev[psensor_pwr->id[ppwr_info->pin]];   拿到之前init时保存的这个pin所对应的上电方式(id:mclk/regulator/mclk)的dev
pdev->set(pdev->pinstance, sensor_idx, ppwr_info->pin/*pin脚*/, ppwr_info->pin_state_on/*上电电压*/);   到各自上电模块dev中进行set上电
mdelay(ppwr_info->pin_on_delay);   delay延时
至此完成上电
2.2.imgsensor_sensor_feature_control(psensor, SENSOR_FEATURE_CHECK_SENSOR_ID, (MUINT8 *) &sensorID, &retLen);   调用sensor驱动get_imgsensor_id接口获取sensor id
2.3.mgsensor_hw_power(&pimgsensor->hw, psensor, IMGSENSOR_HW_POWER_STATUS_OFF);   下电

1.2.psensor_list->id = psensor->inst.psensor_list->id;
memcpy(psensor_list->name, psensor->inst.psensor_list->name, 32);

Regulator
regulator_init()
1.struct REGULATOR *preg //创建 REGULATOR，其中包含其regulator设备以及原子锁count
struct regulator {
   struct device *dev;
   struct list_head list;
   unsigned int always_on:1;
   unsigned int bypass:1;
   int uA_load;
   int min_uV;
   int max_uV;
   const char *supply_name;
   struct device_attribute dev_attr;
   struct regulator_dev *rdev;
   struct dentry *debugfs;
};
2.根据底层IMGSENSOR_SENSOR_IDX以及自身定义的regulator_control(vcama/vcamd/vcamio)获取所有的cam和三路电的排列组合，组合成str_regulator_name(cam0_vcama),regulator_get_optional通过dev以及str_regulator_name获取regulator资源regulator[idx][type]供后续上下电使用，cam0_vcama对应dtsi中的kd_camera_hw1，kd_camera_hw1将其各路电和引脚绑定,这里cam0_vcamio是regulator供电,cam0_vcamio-supply = <&mt_pmic_vcamio_ldo_reg>;其他的都是gpio供电

regulator_set()
1.imgsensor_hw.c的imgsensor_hw_power_sequence()将sensor_idx,pin哪路电和电压传入regulator_set()
2.regulator中只定义了vcama(0)，vcamd(1)，vcamio(2)三路电，但是在cfg_table中除了regulator上电还会有其他上电方式的enum，所以传入的上电方式enum和regulator的上电方式enum存在偏移量IMGSENSOR_HW_PIN_AVDD
reg_type_offset = REGULATOR_TYPE_VCAMA;//REGULATOR_TYPE_VCAMA为0，不知道具体作用？
pregulator = preg->pregulator[(unsigned int)sensor_idx][reg_type_offset + pin - IMGSENSOR_HW_PIN_AVDD];

regulator的上电enum:
enum REGULATOR_TYPE {
   REGULATOR_TYPE_VCAMA,
   REGULATOR_TYPE_VCAMD,
   REGULATOR_TYPE_VCAMIO,
   REGULATOR_TYPE_MAX_NUM
}
cfg_table的上电enum:
前三个对于regulator是无用的，所以偏移就为IMGSENSOR_HW_PIN_AVDD 3
enum IMGSENSOR_HW_PIN {
   IMGSENSOR_HW_PIN_NONE = 0,
   IMGSENSOR_HW_PIN_PDN,
   IMGSENSOR_HW_PIN_RST,
   IMGSENSOR_HW_PIN_AVDD,
   IMGSENSOR_HW_PIN_DVDD,
   IMGSENSOR_HW_PIN_DOVDD,
}
3.绑定了regulator后regulator_set_voltage(regulator, min voltage, max voltage),regulator_enable(pregulator)完成上电

gpio
gpio_init()
1.同样创建gpio设备
2.devm_pinctrl_get通过dev获取pinctrl资源节点
3.根据IMGSENSOR_SENSOR_IDX和gpio_pinctrl_list_cam(ldo_vcama_1)获取所有排列组合组合成str_pinctrl_name(cam0_ldo_vcama_1)
4.pinctrl_lookup_state根据pinctrl资源和str_pinctrl_name获取gpio资源gpio->ppinctrl_state_cam[j][i]供后续上下电使用,同样也是在kd_camera_hw1中

gpio_set()
1.获取传下来的电压值gpio_state，非0为GPIO_STATE_H, 0为GPIO_STATE_L
2.ppinctrl_state = pgpio->ppinctrl_state_cam[sensor_idx][((pin - IMGSENSOR_HW_PIN_PDN) << 1) + gpio_state]; //gpio的enum相较于cfg_table的多了low和high，所以会有这个移位操作？
上下电取决于gpio_state，上电获取ppinctrl_state_cam[0]的GPIO_CTRL_STATE_RST_L,下电为GPIO_CTRL_STATE_RST_H
3.pinctrl_select_state(pgpio->ppinctrl, ppinctrl_state); pinctrl_select_state通过pinctrl资源和ppinctrl_state进行状态的选择