**:1 .1 資料結構
include/linux/i2c.h:
struct i2c_board_info
;drivers/i2c/i2c-core.h:
struct i2c_devinfo
;
drivers/i2c/i2c-core.h:
extern
struct rw_semaphore __i2c_board_lock;
//
extern
struct list_head __i2c_board_list;
// extern
int __i2c_first_dynamic_bus_num;
//全域性變數的初始化,在driver/i2c/i2c-boardinfo.c中
declare_rwsem
(__i2c_board_lock)
;//讀寫鎖
export_symbol_gpl
(__i2c_board_lock)
;list_head
(__i2c_board_list)
;//雙向鍊錶
export_symbol_gpl
(__i2c_board_list)
;int __i2c_first_dynamic_bus_num;
export_symbol_gpl
(__i2c_first_dynamic_bus_num)
;
在arch/arm/mach-s3c64xx/mach-smdk6410.c中,定義了i2c的裝置
static
struct i2c_board_info i2c_devs0[
] __initdata =
,// gjl};
static
struct i2c_board_info i2c_devs1[
] __initdata =
,/* samsung s524ad0xd1 */};
其中 #define i2c_board_info
(dev_type, dev_addr) \
.type = dev_type,
.addr =
(dev_addr)
.type 是name
.addr 是裝置在i2c上的位址
在arch/arm/mach-s3c64xx/mach-smdk6410.c中
static
void __init smdk6410_machine_init
(void
)在driver/i2c/i2c-boardinfo.c中:
int __init i2c_register_board_info
(int busnum,
struct i2c_board_info const
*info,
unsigned len)
up_write
(&__i2c_board_lock)
;return status;
}
s3c24xx_i2c_probe
--> i2c_add_numbered_adapter
--> i2c_register_adapter
--> i2c_scan_static_board_info
--> i2c_new_device
二. i2c裝置驅動的註冊過程
這兒以ov9650為例說明一下,(為什麼呢? 因為ok6410上面沒有其它的i2c裝置了!)
drivers/media/video/samsung/fimc/ov965x.c
static __init int
ov965x_init
(void
)module_init
(ov965x_init)
ov965x_init
--> i2c_add_driver
static
inline
inti2c_add_driver
(struct i2c_driver *driver)
在driver/i2c/i2c-core.c中
inti2c_register_driver
(struct module *owner,
struct i2c_driver *driver)
export_symbol
(i2c_register_driver)
;ov965x_init
--> i2c_add_driver
--> i2c_device_probe
driver/i2c/i2c-core.c
static
inti2c_device_probe
(struct device *dev)
三. i2c裝置驅動的寫過程
i2c_device_probe
--> ov965x_probe
static
intov965x_probe
(struct i2c_client *c,
const
struct i2c_device_id *id)
return0;
}i2c_device_probe
--> ov965x_probe
--> i2c_smbus_write_byte_data
driver/i2c/i2c-core.c
s32 i2c_smbus_write_byte_data
(const
struct i2c_client *client, u8 command, u8 value)
s32 i2c_smbus_xfer
(struct i2c_adapter *adapter, u16 addr,
unsigned
short flags,
char read_write, u8 command,
int protocol,
union i2c_smbus_data *data)
i2c_device_probe
--> ov965x_probe
--> i2c_smbus_write_byte_data
--> i2c_smbus_xfer_emulated
driver/i2c/i2c-core.c
static s32 i2c_smbus_xfer_emulated
(struct i2c_adapter *adapter, u16 addr,
unsigned
short flags,
char read_write, u8 command,
int size,
union i2c_smbus_data *data),}
; msgbuf0[0]
= command;
switch
(size)
status =
i2c_transfer
(adapter, msg, num)
;//把要傳輸的資訊組裝成msg,進行傳輸
//i==0 && i2c_smbus_read
}i2c_device_probe
--> ov965x_probe
--> i2c_smbus_write_byte_data
--> i2c_smbus_xfer_emulated
--> i2c_transfer
driver/i2c/i2c-core.c
inti2c_transfer
(struct i2c_adapter *adap,
struct i2c_msg *msgs,
int num)
else
i2c_lock_adapter
(adap)
;//加把鎖
orig_jiffies = jiffies;
for(ret =
0, try =
0; try <= adap->retries; try++
)i2c_unlock_adapter
(adap)
;//unlock
return ret;
}
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from 目前的arm處理器都支援多種啟動模式，s3c6410和以前的samsung的arm處理器一樣，通過外部管腳om 4 0 的拉高拉低來決定是從哪個儲存裝置上啟動。我認為s3c6410的user manual並沒有說的很清楚，所以我在最開始使用的時候，也對其啟動模式有一些誤解，下面就我個人的理...