mtk cam_cal eeprom 驱动_camera_eeprom1-程序员宅基地
技术标签： camera
文章目录
前言
一直接触驱动，但没有系统的去学过驱动，对设备驱动的大体架构不是很了解，借着eeprom驱动，大致学习下linux下设备驱动以及i2c驱动。
1.驱动架构
1.1 结构目录
android/kernel-4.19/drivers/misc/mediatek/cam_cal
1.2 内核编译相关
在bringup阶段，会在
android/kernel-4.19/arch/arm64/configs/{project}_debug_defconfig与
android/kernel-4.19/arch/arm64/configs/{project}_defconfig配置
CONFIG_MTK_CAM_CAL=y
最下面mk与Kconfig为
这里相当于指定了obj-y，将生成的目标代码连接到内核。将src/目录列入向下迭代的目录中。
obj-$(CONFIG_MTK_CAM_CAL) += src/
Kconfig
config MTK_CAM_CAL
bool "MTK camera cal driver"
help
CONFIG_MTK_CAM_CAL define if the camera cal driver should be
built in or not. If you want to use EEPROM for sensor. You have
enable CONFIG_MTK_CAM_CAL on ProjectConfig. The kernel space for
EEPROM will be build. It may be like as "/dev/CAM_CAL_DRV".
Use space code will control the driver by open and ioctrl this one.
在上一层的android/kernel-4.19/drivers/misc/mediatek/Kconfig中
引用了此Kconfig
source "drivers/misc/mediatek/cam_cal/Kconfig"
makefile中
obj-$(CONFIG_MTK_CAM_CAL) += cam_cal/
1.3 Makefile
接下来看驱动里面的makefile
android/kernel-4.19/drivers/misc/mediatek/cam_cal/src/Makefile
MTK_PLATFORM := $(subst ",,$(CONFIG_MTK_PLATFORM))
obj-y += $(MTK_PLATFORM)/
适配不同平台
:= 直接赋值 mk :=含义
subst 字符串替换，subst
进入到平台下：这里看mt6765/
MTK_CUSTOM_PATH := $(srctree)/drivers/misc/mediatek
MTK_PLATFORM := $(subst ",,$(CONFIG_MTK_PLATFORM))
CAM_CAL_SRC_PATH := $(MTK_CUSTOM_PATH)/cam_cal/src
CAM_CAL_PLATFORM_SRC_PATH := $(CAM_CAL_SRC_PATH)/$(MTK_PLATFORM)
ARCH_MTK_PROJECT := $(subst ",,$(CONFIG_ARCH_MTK_PROJECT))
COMMON_VERSION := v1
subdir-ccflags-y += -I$(MTK_CUSTOM_PATH)/imgsensor/inc \
-I$(MTK_CUSTOM_PATH)/imgsensor/src/$(CONFIG_MTK_PLATFORM)/camera_hw \
-I$(MTK_CUSTOM_PATH)/cam_cal/inc \
-I$(CAM_CAL_PLATFORM_SRC_PATH) \
-I$(CAM_CAL_SRC_PATH)/common/$(COMMON_VERSION)
subdir-ccflags-y += -I$(srctree)/drivers/i2c/busses/
# Common code
obj-y += ../common/$(COMMON_VERSION)/eeprom_driver.o
obj-y += ../common/$(COMMON_VERSION)/eeprom_i2c_common_driver.o
# Platform code
obj-y += eeprom_i2c_custom_driver.o
define INC_CUSTOM_SRC
ifeq ($(wildcard $(CAM_CAL_PLATFORM_SRC_PATH)/camera_project/$(ARCH_MTK_PROJECT)/$(1).c),)
obj-y += $(1).o
else
obj-y += camera_project/$(ARCH_MTK_PROJECT)/$(1).o
endif
endef
# Project or platform code
CUSTOM_SRC_LIST := cam_cal_list eeprom_i2c_dev
$(foreach src,$(CUSTOM_SRC_LIST),$(eval $(call INC_CUSTOM_SRC,$(src))))
subdir-ccflags-y += -I
意思是ccflags-y，编译时的参数，-I寻找头文件的目录
参考：编译选项
-I选项
此处没有针对项目客制化，camera_project/就不存在了。
此处关注
# Common code
obj-y += ../common/$(COMMON_VERSION)/eeprom_driver.o
obj-y += ../common/$(COMMON_VERSION)/eeprom_i2c_common_driver.o
# Platform code
obj-y += eeprom_i2c_custom_driver.o
这三个对应的.c文件
2.driver
参考字符驱动架构
2.1 init
android/kernel-4.19/drivers/misc/mediatek/cam_cal/src/common/v1/eeprom_driver.c
首先，模块加载方法与卸载方法
static int __init EEPROM_drv_init(void)
{
pr_debug("%s Start!\n", __func__);
if (platform_driver_register(&g_stEEPROM_HW_Driver)) {
pr_debug("failed to register EEPROM driver i2C main\n");
return -ENODEV;
}
if (platform_device_register(&g_platDev)) {
pr_debug("failed to register EEPROM device");
return -ENODEV;
}
EEPROM_chrdev_register();
pr_debug("%s End!\n", __func__);
return 0;
}
static void __exit EEPROM_drv_exit(void)
{
platform_device_unregister(&g_platDev);
platform_driver_unregister(&g_stEEPROM_HW_Driver);
EEPROM_chrdev_unregister();
}
module_init(EEPROM_drv_init);
module_exit(EEPROM_drv_exit);
platform_driver_register可参考
其中：g_stEEPROM_HW_Driver 对应
static struct platform_driver g_stEEPROM_HW_Driver = {
.probe = EEPROM_HW_probe,
.remove = EEPROM_HW_remove,
.driver = {
.name = CAM_CAL_DRV_NAME,
.owner = THIS_MODULE,
}
};
EEPROM_chrdev_register()进行分配设备号等操作：
关键是g_charDrv，是一个cdev类型的结构体参考：cdev
static struct cdev *g_charDrv;
#define CAM_CAL_DYNAMIC_ALLOCATE_DEVNO 1
static inline int EEPROM_chrdev_register(void)
{
struct device *device = NULL;
pr_debug("%s Start\n", __func__);
#if CAM_CAL_DYNAMIC_ALLOCATE_DEVNO
if (alloc_chrdev_region(&g_devNum, 0, 1, CAM_CAL_DRV_NAME)) {
//动态分配主次设备号
pr_debug("Allocate device no failed\n");
return -EAGAIN;
}
#else
if (register_chrdev_region(g_devNum, 1, CAM_CAL_DRV_NAME)) {
pr_debug("Register device no failed\n");
return -EAGAIN;
}
#endif
g_charDrv = cdev_alloc();//空间的申请
if (g_charDrv == NULL) {
unregister_chrdev_region(g_devNum, 1);
pr_debug("Allocate mem for kobject failed\n");
return -ENOMEM;
}
cdev_init(g_charDrv, &g_stCAM_CAL_fops1);//对空间清零并赋值ops
g_charDrv->owner = THIS_MODULE;
if (cdev_add(g_charDrv, g_devNum, 1)) {
//注册字符设备对象cdev到内核
pr_debug("Attatch file operation failed\n");
unregister_chrdev_region(g_devNum, 1);
return -EAGAIN;
}
g_drvClass = class_create(THIS_MODULE, "CAM_CALdrv1");
// 以CLASS_NAME创建一个class结构，这个动作将会在/sys/class目录创建一个名为CLASS_NAME的目录
if (IS_ERR(g_drvClass)) {
int ret = PTR_ERR(g_drvClass);
pr_debug("Unable to create class, err = %d\n", ret);
return ret;
}
device = device_create(g_drvClass, NULL, g_devNum, NULL,
CAM_CAL_DRV_NAME);
//以DEVICE_NAME为名，参考/sys/class/CLASS_NAME在/dev目录下创建一个设备：/dev/DEVICE_NAME
pr_debug("%s End\n", __func__);
return 0;
}
alloc_chrdev_region(&g_devNum, 0, 1, CAM_CAL_DRV_NAME)// 为字符设备动态申请第一个设备号
CAM_CAL_DRV_NAME定义为，也就是设备节点，在/dev下面可以看到
#define CAM_CAL_DRV_NAME "CAM_CAL_DRV"
alloc_chrdev_region动态分配主次设备号，详细参考
&g_devNum为
#define CAM_CAL_DEV_MAJOR_NUMBER 226
static dev_t g_devNum = MKDEV(CAM_CAL_DEV_MAJOR_NUMBER, 0);
MKDEV是将主设备号和次设备号转换成dev_t类型的一个内核函数。参考
cdev_alloc与cdev_init参考
cdev_add 注册字符设备对象cdev到内核,
这里的g_stCAM_CAL_fops1，可参考
对应：
static const struct file_operations g_stCAM_CAL_fops1 = {
.owner = THIS_MODULE,
.open = EEPROM_drv_open,
.release = EEPROM_drv_release,
/*.ioctl = CAM_CAL_Ioctl */
#ifdef CONFIG_COMPAT
.compat_ioctl = EEPROM_drv_compat_ioctl,
#endif
.unlocked_ioctl = EEPROM_drv_ioctl
};
CONFIG_COMPAT是用来兼容64位与32位的，
2.1 EEPROM_drv_ioctl
接下来看ioctl实现，先看两个重要的机构体
stCAM_CAL_INFO_STRUCT
struct stCAM_CAL_INFO_STRUCT {
u32 u4Offset;
u32 u4Length;
u32 sensorID;
/*
* MAIN = 0x01,
* SUB = 0x02,
* MAIN_2 = 0x04,
* SUB_2 = 0x08,
* MAIN_3 = 0x10,
*/
u32 deviceID;
u8 *pu1Params;
};
stCAM_CAL_CMD_INFO_STRUCT
struct stCAM_CAL_CMD_INFO_STRUCT {
unsigned int sensorID;
unsigned int deviceID;
unsigned int i2cAddr;
struct i2c_client *client;
cam_cal_cmd_func readCMDFunc;
cam_cal_cmd_func writeCMDFunc;
unsigned int maxEepromSize;
};
ioctl实现
static long EEPROM_drv_ioctl(struct file *file,
unsigned int a_u4Command, unsigned long a_u4Param)
{
int i4RetValue = 0;
u8 *pBuff = NULL;
u8 *pu1Params = NULL;
/*u8 *tempP = NULL; */
struct stCAM_CAL_INFO_STRUCT *ptempbuf = NULL;
struct stCAM_CAL_CMD_INFO_STRUCT *pcmdInf = NULL;//初始化
if (_IOC_DIR(a_u4Command) != _IOC_NONE) {
//判断传送到设备驱动程序的 cmd 命令的读写状态
pBuff = kmalloc(sizeof(struct stCAM_CAL_INFO_STRUCT),
GFP_KERNEL);//分配内存，GFP_KERNEL是内核内存分配时最常用的，无内存可用时可引起休眠
if (pBuff == NULL) {
pr_debug("ioctl allocate pBuff mem failed\n");
return -ENOMEM;
}
if (copy_from_user
((u8 *) pBuff, (u8 *) a_u4Param,
sizeof(struct stCAM_CAL_INFO_STRUCT))) {
//将用户空间a_u4Param拷贝到pBuff
/*get input structure address */
kfree(pBuff);
pr_debug("ioctl copy from user failed\n");
return -EFAULT;
}
ptempbuf = (struct stCAM_CAL_INFO_STRUCT *)pBuff;
if ((ptempbuf->u4Length <= 0) ||
(ptempbuf->u4Length > CAM_CAL_MAX_BUF_SIZE)) {
//防止上层传下来的参数过大或过小
kfree(pBuff);
pr_debug("Buffer Length Error!\n");
return -EFAULT;
}
pu1Params = kmalloc(ptempbuf->u4Length, GFP_KERNEL);//为u4Length分配空间
if (pu1Params == NULL) {
kfree(pBuff);
pr_debug("ioctl allocate pu1Params mem failed\n");
return -ENOMEM;
}
if (copy_from_user
((u8 *) pu1Params, (u8 *) ptempbuf->pu1Params,
ptempbuf->u4Length)) {
//拿到参数
kfree(pBuff);
kfree(pu1Params);
pr_debug("ioctl copy from user failed\n");
return -EFAULT;
}
}
if (ptempbuf == NULL) {
/*It have to add */
pr_debug("ptempbuf is Null !!!");
return -EFAULT;
}
switch (a_u4Command) {
case CAM_CALIOC_S_WRITE: /*Note: Write Command is Unverified! */
pr_debug("CAM_CALIOC_S_WRITE start!\n");
pcmdInf = EEPROM_get_cmd_info_ex(ptempbuf->sensorID,
ptempbuf->deviceID);//根据id,拿到i2c地址，读写函数
/* Check the max size if specified */
if (pcmdInf != NULL &&
(pcmdInf->maxEepromSize != 0) &&
(pcmdInf->maxEepromSize <
(ptempbuf->u4Offset + ptempbuf->u4Length))) {
pr_debug("Error!! not support address >= 0x%x!!\n",
pcmdInf->maxEepromSize);
kfree(pBuff);
kfree(pu1Params);
return -EFAULT;
}
if (pcmdInf != NULL && g_lastDevID != ptempbuf->deviceID) {
if (EEPROM_set_i2c_bus(ptempbuf->deviceID,//设置i2c
pcmdInf) != 0) {
pr_debug("deviceID Error!\n");
kfree(pBuff);
kfree(pu1Params);
return -EFAULT;
}
g_lastDevID = ptempbuf->deviceID;
}
if (pcmdInf != NULL) {
if (pcmdInf->writeCMDFunc != NULL) {
i4RetValue = pcmdInf->writeCMDFunc(//执行写函数
pcmdInf->client,
ptempbuf->u4Offset, pu1Params,
ptempbuf->u4Length);
} else
pr_debug("pcmdInf->writeCMDFunc == NULL\n");
} else
pr_debug("pcmdInf == NULL\n");
pr_debug("CAM_CALIOC_S_WRITE End!\n");
break;
case CAM_CALIOC_G_READ:
pr_debug("CAM_CALIOC_G_READ start! offset=%d, length=%d\n",
ptempbuf->u4Offset, ptempbuf->u4Length);
pr_debug("SensorID=%x DeviceID=%x\n",
ptempbuf->sensorID, ptempbuf->deviceID);
pcmdInf = EEPROM_get_cmd_info_ex(
ptempbuf->sensorID,
ptempbuf->deviceID);
/* Check the max size if specified */
if (pcmdInf != NULL &&
(pcmdInf->maxEepromSize != 0) &&
(pcmdInf->maxEepromSize <
(ptempbuf->u4Offset + ptempbuf->u4Length))) {
pr_debug("Error!! not support address >= 0x%x!!\n",
pcmdInf->maxEepromSize);
kfree(pBuff);
kfree(pu1Params);
return -EFAULT;
}
if (pcmdInf != NULL && g_lastDevID != ptempbuf->deviceID) {
if (EEPROM_set_i2c_bus(ptempbuf->deviceID,
pcmdInf) != 0) {
pr_debug("deviceID Error!\n");
kfree(pBuff);
kfree(pu1Params);
return -EFAULT;
}
g_lastDevID = ptempbuf->deviceID;
}
if (pcmdInf != NULL) {
if (pcmdInf->readCMDFunc != NULL)
i4RetValue =
pcmdInf->readCMDFunc(pcmdInf->client,
ptempbuf->u4Offset,
pu1Params,
ptempbuf->u4Length);
else {
pr_debug("pcmdInf->readCMDFunc == NULL\n");
kfree(pBuff);
kfree(pu1Params);
return -EFAULT;
}
}
break;
default:
pr_debug("No CMD\n");
i4RetValue = -EPERM;
break;
}
if (_IOC_READ & _IOC_DIR(a_u4Command)) {
if (copy_to_user
((u8 __user *) ptempbuf->pu1Params, (u8 *) pu1Params,
ptempbuf->u4Length)) {
kfree(pBuff);
kfree(pu1Params);
pr_debug("ioctl copy to user failed\n");
return -EFAULT;
}
}
kfree(pBuff);
kfree(pu1Params);
return i4RetValue;
}
_IO, _IOR, _IOW, _IOWR 宏的用法与解析参考
CAM_CALIOC_G_READ定义
hal定义在/vendor/mediatek/proprietary/custom/mt6765/kernel/cam_cal/inc/cam_cal.h
kernel定义在/kernel-4.9/drivers/misc/mediatek/cam_cal/inc/
/*CAM_CAL write*/
#define CAM_CALIOC_S_WRITE _IOW(CAM_CALAGIC, 0, struct stCAM_CAL_INFO_STRUCT)
/*CAM_CAL read*/
#define CAM_CALIOC_G_READ _IOWR(CAM_CALAGIC, 5, struct stCAM_CAL_INFO_STRUCT)
ioctol函数重点关注三个部分：
EEPROM_get_cmd_info
EEPROM_set_i2c_bus
pcmdInf->readCMDFunc
这三个函数
2.2 EEPROM_get_cmd_info
EEPROM_get_cmd_info_ex会去校验配置的读写函数：
static struct stCAM_CAL_CMD_INFO_STRUCT *EEPROM_get_cmd_info_ex
(unsigned int sensorID, unsigned int deviceID)
{
int i = 0;
/* To check device ID */
for (i = 0; i < IMGSENSOR_SENSOR_IDX_MAX_NUM; i++) {
if (g_camCalDrvInfo[i].deviceID == deviceID)
break;
}
/* To check cmd from Sensor ID */
if (i == IMGSENSOR_SENSOR_IDX_MAX_NUM) {
for (i = 0; i < IMGSENSOR_SENSOR_IDX_MAX_NUM; i++) {
/* To Set Client */
if (g_camCalDrvInfo[i].sensorID == 0) {
pr_debug("Start get_cmd_info!\n");
EEPROM_get_cmd_info(sensorID,
&g_camCalDrvInfo[i]);
if (g_camCalDrvInfo[i].readCMDFunc != NULL) {
g_camCalDrvInfo[i].sensorID = sensorID;
g_camCalDrvInfo[i].deviceID = deviceID;
pr_debug("deviceID=%d, SensorID=%x\n",
deviceID, sensorID);
}
break;
}
}
}
if (i == IMGSENSOR_SENSOR_IDX_MAX_NUM) {
/*g_camCalDrvInfo is full */
return NULL;
} else {
return &g_camCalDrvInfo[i];
}
}
接着调用到EEPROM_get_cmd_info,根据sensor_id去拿到相应的配置
static int EEPROM_get_cmd_info(unsigned int sensorID,
struct stCAM_CAL_CMD_INFO_STRUCT *cmdInfo)
{
struct stCAM_CAL_LIST_STRUCT *pCamCalList = NULL;
int i = 0;
cam_cal_get_sensor_list(&pCamCalList);
if (pCamCalList != NULL) {
pr_debug("pCamCalList!=NULL && pCamCalFunc!= NULL\n");
for (i = 0; pCamCalList[i].sensorID != 0; i++) {
if (pCamCalList[i].sensorID == sensorID) {
pr_debug("pCamCalList[%d].sensorID==%x\n", i,
pCamCalList[i].sensorID);
cmdInfo->i2cAddr = pCamCalList[i].slaveID >> 1;
cmdInfo->readCMDFunc =
pCamCalList[i].readCamCalData;
//add for dual camera write cal data begin
cmdInfo->writeCMDFunc = pCamCalList[i].writeCamCalData;
//add for dual camera write cal data end
cmdInfo->maxEepromSize =
pCamCalList[i].maxEepromSize;
/*
* Default 8K for Common_read_region driver
* 0 for others
*/
if (cmdInfo->readCMDFunc == Common_read_region
&& cmdInfo->maxEepromSize == 0) {
cmdInfo->maxEepromSize =
DEFAULT_MAX_EEPROM_SIZE_8K;
}
return 1;
}
}
}
return 0;
}
cam_cal_get_sensor_list(&pCamCalList);会去拿到
struct stCAM_CAL_LIST_STRUCT g_camCalList[] = {
{
S5K3L6_SUNWIN_SENSOR_ID, 0xA0, Common_read_region,Common_write_region},
{
S5K3L6_TSP_SENSOR_ID, 0xA0, Common_read_region,Common_write_region},
/* ADD before this line */
{
0, 0, 0} /*end of list */
};
unsigned int cam_cal_get_sensor_list(
struct stCAM_CAL_LIST_STRUCT **ppCamcalList)
{
if (ppCamcalList == NULL)
return 1;
*ppCamcalList = &g_camCalList[0];
return 0;
}
2.3 EEPROM_set_i2c_bus
之前，在init时，当检测到匹配的device - driver，调用probe()函数
static struct platform_driver g_stEEPROM_HW_Driver = {
.probe = EEPROM_HW_probe,
.remove = EEPROM_HW_remove,
.driver = {
.name = CAM_CAL_DRV_NAME,
.owner = THIS_MODULE,
}
};
即：i2c_add_driver参考：i2c设备驱动
static int EEPROM_HW_probe(struct platform_device *pdev)
{
i2c_add_driver(&EEPROM_HW_i2c_driver2);
i2c_add_driver(&EEPROM_HW_i2c_driver3);
return i2c_add_driver(&EEPROM_HW_i2c_driver);
}
EEPROM_HW_i2c_driver就对应i2c_driver结构体
struct i2c_driver EEPROM_HW_i2c_driver = {
.probe = EEPROM_HW_i2c_probe,
.remove = EEPROM_HW_i2c_remove,
.driver = {
.name = CAM_CAL_DRV_NAME,
.owner = THIS_MODULE,
#ifdef CONFIG_OF
.of_match_table = EEPROM_HW_i2c_of_ids,//对应设备树节点：{.compatible = "mediatek,camera_main_eeprom",},
#endif
},
.id_table = EEPROM_HW_i2c_id,//对应宏CAM_CAL_DRV_NAME，存储driver名称，作为bus匹配时的识别
};
设备树节点，此处会匹配camera_main_eeprom，老平台，需在dws中去配置。
mtk 新的5g平台，直接在cust_${Project}_camera.dtsi中配置。
EEPROM_HW_i2c_probe为： 此处对client，addr等信息进行赋值
static int EEPROM_HW_i2c_probe
(struct i2c_client *client, const struct i2c_device_id *id)
{
/* get sensor i2c client */
spin_lock(&g_spinLock);
g_pstI2Cclients[I2C_DEV_IDX_1] = client;
/* set I2C clock rate */
#ifdef CONFIG_MTK_I2C_EXTENSION
g_pstI2Cclients[I2C_DEV_IDX_1]->timing = gi2c_dev_timing[I2C_DEV_IDX_1];
g_pstI2Cclients[I2C_DEV_IDX_1]->ext_flag &= ~I2C_POLLING_FLAG;
#endif
/* Default EEPROM Slave Address Main= 0xa0 */
g_pstI2Cclients[I2C_DEV_IDX_1]->addr = 0x50;
spin_unlock(&g_spinLock);
return 0;
}
接下来回到ioctol中，在ioctol中调用
if (EEPROM_set_i2c_bus(ptempbuf->deviceID,
pcmdInf) != 0)
来到：设置client与addr,addr就是从cmdInfo，即配置的结构体中拿到的
将client放到cmdInfo这个结构体中
static int EEPROM_set_i2c_bus(unsigned int deviceID,
struct stCAM_CAL_CMD_INFO_STRUCT *cmdInfo)
{
enum IMGSENSOR_SENSOR_IDX idx;
enum EEPROM_I2C_DEV_IDX i2c_idx;
struct i2c_client *client;
idx = IMGSENSOR_SENSOR_IDX_MAP(deviceID);
i2c_idx = get_i2c_dev_sel(idx);
if (idx == IMGSENSOR_SENSOR_IDX_NONE)
return -EFAULT;
if (i2c_idx < I2C_DEV_IDX_1 || i2c_idx >= I2C_DEV_IDX_MAX)
return -EFAULT;
client = g_pstI2Cclients[i2c_idx];
pr_debug("%s end! deviceID=%d index=%u client=%p\n",
__func__, deviceID, idx, client);
if (client == NULL) {
pr_err("i2c client is NULL");
return -EFAULT;
}
if (cmdInfo != NULL) {
client->addr = cmdInfo->i2cAddr;
cmdInfo->client = client;
}
return 0;
}
2.4 readCMDFunc
接下来看ioctol read中的
pcmdInf->readCMDFunc(pcmdInf->client,
ptempbuf->u4Offset,
pu1Params,
ptempbuf->u4Length);
即为：
unsigned int Common_read_region(struct i2c_client *client, unsigned int addr,
unsigned char *data, unsigned int size)
{
g_pstI2CclientG = client;
if (iReadData_CAM_CAL(addr, size, data) == 0)
return size;
else
return 0;
}
再调用到
int iReadData_CAM_CAL(unsigned int ui4_offset,
unsigned int ui4_length, unsigned char *pinputdata)
{
int i4RetValue = 0;
int i4ResidueDataLength;
u32 u4IncOffset = 0;
u32 u4CurrentOffset;
u8 *pBuff;
i4ResidueDataLength = (int)ui4_length;
u4CurrentOffset = ui4_offset;
pBuff = pinputdata;
do {
if (i4ResidueDataLength >= EEPROM_I2C_READ_MSG_LENGTH_MAX) {
i4RetValue = Read_I2C_CAM_CAL(
(u16) u4CurrentOffset,
EEPROM_I2C_READ_MSG_LENGTH_MAX, pBuff);
if (i4RetValue != 0) {
pr_debug("I2C iReadData failed!!\n");
return -1;
}
u4IncOffset += EEPROM_I2C_READ_MSG_LENGTH_MAX;
i4ResidueDataLength -= EEPROM_I2C_READ_MSG_LENGTH_MAX;
u4CurrentOffset = ui4_offset + u4IncOffset;
pBuff = pinputdata + u4IncOffset;
} else {
i4RetValue =
Read_I2C_CAM_CAL(
(u16) u4CurrentOffset, i4ResidueDataLength, pBuff);
if (i4RetValue != 0) {
pr_debug("I2C iReadData failed!!\n");
return -1;
}
u4IncOffset += i4ResidueDataLength;
i4ResidueDataLength = 0;
u4CurrentOffset = ui4_offset + u4IncOffset;
pBuff = pinputdata + u4IncOffset;
/* break; */
}
} while (i4ResidueDataLength > 0);
return 0;
}
EEPROM_I2C_READ_MSG_LENGTH_MAX
一次读多少，如果没设置，默认为一次读32次。
接下来Read_I2C_CAM_CAL，就是构建read函数：
static int Read_I2C_CAM_CAL(u16 a_u2Addr, u32 ui4_length, u8 *a_puBuff)
{
int i4RetValue = 0;
char puReadCmd[2] = {
(char)(a_u2Addr >> 8), (char)(a_u2Addr & 0xFF) };
struct i2c_msg msg[EEPROM_I2C_MSG_SIZE_READ];
if (ui4_length > EEPROM_I2C_READ_MSG_LENGTH_MAX) {
pr_debug("exceed one transition %d bytes limitation\n",
EEPROM_I2C_READ_MSG_LENGTH_MAX);
return -1;
}
spin_lock(&g_spinLock);
g_pstI2CclientG->addr =
g_pstI2CclientG->addr & (I2C_MASK_FLAG | I2C_WR_FLAG);
spin_unlock(&g_spinLock);
msg[0].addr = g_pstI2CclientG->addr;
msg[0].flags = g_pstI2CclientG->flags & I2C_M_TEN;
msg[0].len = 2;
msg[0].buf = puReadCmd;
msg[1].addr = g_pstI2CclientG->addr;
msg[1].flags = g_pstI2CclientG->flags & I2C_M_TEN;
msg[1].flags |= I2C_M_RD;
msg[1].len = ui4_length;
msg[1].buf = a_puBuff;
i4RetValue = i2c_transfer(g_pstI2CclientG->adapter,
msg,
EEPROM_I2C_MSG_SIZE_READ);
spin_lock(&g_spinLock);
g_pstI2CclientG->addr = g_pstI2CclientG->addr & I2C_MASK_FLAG;
spin_unlock(&g_spinLock);
if (i4RetValue != EEPROM_I2C_MSG_SIZE_READ) {
pr_debug("I2C read data failed!!\n");
return -1;
}
return 0;
}
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