一:設備模型建立流程圖
二:重要函數分析
(1)新適配器加入內核:
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
int id;
int status;
{
int id;
int status;
if (adap->nr & ~MAX_ID_MASK)
return -EINVAL;
return -EINVAL;
retry://爲i2c_adapter_idr分配內存
if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
return -ENOMEM;
if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
return -ENOMEM;
mutex_lock(&core_lock);
/* "above" here means "above or equal to", sigh;
* we need the "equal to" result to force the result
*///讓指針adap關聯一個ID,這個ID值從adap->nr開始
status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
if (status == 0 && id != adap->nr) {
status = -EBUSY;//分配的ID值必須與adap->nr相等
idr_remove(&i2c_adapter_idr, id);
}
mutex_unlock(&core_lock);
if (status == -EAGAIN)
goto retry;
/* "above" here means "above or equal to", sigh;
* we need the "equal to" result to force the result
*///讓指針adap關聯一個ID,這個ID值從adap->nr開始
status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
if (status == 0 && id != adap->nr) {
status = -EBUSY;//分配的ID值必須與adap->nr相等
idr_remove(&i2c_adapter_idr, id);
}
mutex_unlock(&core_lock);
if (status == -EAGAIN)
goto retry;
if (status == 0)//表示ID分配成功。
status = i2c_register_adapter(adap);//註冊一個適配器。
return status;
}
status = i2c_register_adapter(adap);//註冊一個適配器。
return status;
}
static int i2c_register_adapter(struct i2c_adapter *adap)
{
int res = 0, dummy;
{
int res = 0, dummy;
/* Can't register until after driver model init */
if (unlikely(WARN_ON(!i2c_bus_type.p)))
return -EAGAIN;
if (unlikely(WARN_ON(!i2c_bus_type.p)))
return -EAGAIN;
mutex_init(&adap->bus_lock);
mutex_init(&adap->clist_lock);
INIT_LIST_HEAD(&adap->clients);
mutex_init(&adap->clist_lock);
INIT_LIST_HEAD(&adap->clients);
mutex_lock(&core_lock);
/* Add the adapter to the driver core.
* If the parent pointer is not set up,
* we add this adapter to the host bus.
*/
if (adap->dev.parent == NULL) {
adap->dev.parent = &platform_bus;
pr_debug("I2C adapter driver [%s] forgot to specify "
"physical device\n", adap->name);
}
* If the parent pointer is not set up,
* we add this adapter to the host bus.
*/
if (adap->dev.parent == NULL) {
adap->dev.parent = &platform_bus;
pr_debug("I2C adapter driver [%s] forgot to specify "
"physical device\n", adap->name);
}
/* Set default timeout to 1 second if not already set */
if (adap->timeout == 0)
adap->timeout = HZ;
//設置適配器的名
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
adap->dev.release = &i2c_adapter_dev_release;
////將適配器設備歸類,在驅動註冊的時候會根據這個類找尋
//這個類中匹配的適配器。
//這個類表示該設備是一個適配器,而adap->class表示該設備支持的設備類型
adap->dev.class = &i2c_adapter_class;
res = device_register(&adap->dev);//註冊該設備
//到此適配器設備已被完全註冊到了內核。
if (res)
goto out_list;
if (adap->timeout == 0)
adap->timeout = HZ;
//設置適配器的名
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
adap->dev.release = &i2c_adapter_dev_release;
////將適配器設備歸類,在驅動註冊的時候會根據這個類找尋
//這個類中匹配的適配器。
//這個類表示該設備是一個適配器,而adap->class表示該設備支持的設備類型
adap->dev.class = &i2c_adapter_class;
res = device_register(&adap->dev);//註冊該設備
//到此適配器設備已被完全註冊到了內核。
if (res)
goto out_list;
dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
/* create pre-declared device nodes for new-style drivers */
/*
結構體board_info包含了一些平臺信息,和I2C設備地址。該結構
由函數i2c_register_board_info()加到鏈表__i2c_board_list上。
函數i2c_scan_static_board_info在該鏈表上找一個滿足這樣條件的
devinfo->busnum == adapter->nr的結構體,然後根據board_info中的
client->flags = info->flags;
client->addr = info->addr;
client->irq = info->irq;
註冊一個client(它代表一個具體的設備),並且
client->dev.parent = &client->adapter->dev;最終將將client->dev
掛到鏈表adapter->dev->p->klist_children上。
函數device_for_each_child就是根據該鏈表來找出適配器上的每一個client的。
*/
if (adap->nr < __i2c_first_dynamic_bus_num)
i2c_scan_static_board_info(adap);
/*
結構體board_info包含了一些平臺信息,和I2C設備地址。該結構
由函數i2c_register_board_info()加到鏈表__i2c_board_list上。
函數i2c_scan_static_board_info在該鏈表上找一個滿足這樣條件的
devinfo->busnum == adapter->nr的結構體,然後根據board_info中的
client->flags = info->flags;
client->addr = info->addr;
client->irq = info->irq;
註冊一個client(它代表一個具體的設備),並且
client->dev.parent = &client->adapter->dev;最終將將client->dev
掛到鏈表adapter->dev->p->klist_children上。
函數device_for_each_child就是根據該鏈表來找出適配器上的每一個client的。
*/
if (adap->nr < __i2c_first_dynamic_bus_num)
i2c_scan_static_board_info(adap);
/* Notify drivers */
/*
尋找每一個總線類型爲i2c_bus_type的驅動,這些驅動都被包裝爲i2c_driver.
如果驅動類型i2c_driver->class和適配器類型adapter->class匹配,並且
驅動支持的設備地址driver->address_data在適配器中沒有被佔用。就會根據
這個地址註冊一個client掛到這個適配器上。
/*
尋找每一個總線類型爲i2c_bus_type的驅動,這些驅動都被包裝爲i2c_driver.
如果驅動類型i2c_driver->class和適配器類型adapter->class匹配,並且
驅動支持的設備地址driver->address_data在適配器中沒有被佔用。就會根據
這個地址註冊一個client掛到這個適配器上。
另一個任務是調用函數driver->attach_adapter,註冊一個有設備號的設備
並將這個適配器與這個設備關聯。該driver是i2c_driver並不是所有的driver
都有爲一個適配器創建設備節點的能力即有函數driver->attach_adapter。。。。
並將這個適配器與這個設備關聯。該driver是i2c_driver並不是所有的driver
都有爲一個適配器創建設備節點的能力即有函數driver->attach_adapter。。。。
*/
dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
i2c_do_add_adapter);
dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
i2c_do_add_adapter);
out_unlock:
mutex_unlock(&core_lock);
return res;
mutex_unlock(&core_lock);
return res;
out_list:
idr_remove(&i2c_adapter_idr, adap->nr);
goto out_unlock;
}
idr_remove(&i2c_adapter_idr, adap->nr);
goto out_unlock;
}
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
struct i2c_devinfo *devinfo;
{
struct i2c_devinfo *devinfo;
mutex_lock(&__i2c_board_lock);
/*
devinfo被函數i2c_register_board_info掛到鏈表__i2c_board_list上。
本函數是在鏈表__i2c_board_list上找一個結構體devinfo,該結構體滿足
devinfo->busnum == adapter->nr。
devinfo中包含了地址,flags,type等信息,可用於初始化一個client
並註冊到內核。
結構體devinfo中的信息與平臺相關。因此該結構的註冊應該是在平臺
的初始化時進行。
*/
list_for_each_entry(devinfo, &__i2c_board_list, list) {
if (devinfo->busnum == adapter->nr
&& !i2c_new_device(adapter,
&devinfo->board_info))
dev_err(&adapter->dev,
"Can't create device at 0x%02x\n",
devinfo->board_info.addr);
}
mutex_unlock(&__i2c_board_lock);
}
/*
devinfo被函數i2c_register_board_info掛到鏈表__i2c_board_list上。
本函數是在鏈表__i2c_board_list上找一個結構體devinfo,該結構體滿足
devinfo->busnum == adapter->nr。
devinfo中包含了地址,flags,type等信息,可用於初始化一個client
並註冊到內核。
結構體devinfo中的信息與平臺相關。因此該結構的註冊應該是在平臺
的初始化時進行。
*/
list_for_each_entry(devinfo, &__i2c_board_list, list) {
if (devinfo->busnum == adapter->nr
&& !i2c_new_device(adapter,
&devinfo->board_info))
dev_err(&adapter->dev,
"Can't create device at 0x%02x\n",
devinfo->board_info.addr);
}
mutex_unlock(&__i2c_board_lock);
}
(2)一個新的驅動加入內核:
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
{
int res;
{
int res;
/* Can't register until after driver model init */
if (unlikely(WARN_ON(!i2c_bus_type.p)))
return -EAGAIN;
if (unlikely(WARN_ON(!i2c_bus_type.p)))
return -EAGAIN;
/* new style driver methods can't mix with legacy ones */
/*
"new style" driver:
is_newstyle_driver(d) ((d)->probe || (d)->remove || (d)->detect)
"legacy"driver:
driver->detach_adapter || driver->detach_client
attach_adapter和detach_adapter;detach_client和attach_client是兩對
操作相反的函數,必須成對出現。
這兩類驅動的區別就是他們所擁有的函數不一樣。
不能出現這兩類驅動的混合體,即兼有這兩類驅動的標誌函數的驅動。
*/
if (is_newstyle_driver(driver)) {
if (driver->detach_adapter || driver->detach_client) {
printk(KERN_WARNING
"i2c-core: driver [%s] is confused\n",
driver->driver.name);
return -EINVAL;
}
}
/*
"new style" driver:
is_newstyle_driver(d) ((d)->probe || (d)->remove || (d)->detect)
"legacy"driver:
driver->detach_adapter || driver->detach_client
attach_adapter和detach_adapter;detach_client和attach_client是兩對
操作相反的函數,必須成對出現。
這兩類驅動的區別就是他們所擁有的函數不一樣。
不能出現這兩類驅動的混合體,即兼有這兩類驅動的標誌函數的驅動。
*/
if (is_newstyle_driver(driver)) {
if (driver->detach_adapter || driver->detach_client) {
printk(KERN_WARNING
"i2c-core: driver [%s] is confused\n",
driver->driver.name);
return -EINVAL;
}
}
/* add the driver to the list of i2c drivers in the driver core */
driver->driver.owner = owner;
driver->driver.bus = &i2c_bus_type;//設置它的總線類型
driver->driver.owner = owner;
driver->driver.bus = &i2c_bus_type;//設置它的總線類型
/* for new style drivers, when registration returns the driver core
* will have called probe() for all matching-but-unbound devices.
*/
res = driver_register(&driver->driver);//註冊驅動
if (res)
return res;
* will have called probe() for all matching-but-unbound devices.
*/
res = driver_register(&driver->driver);//註冊驅動
if (res)
return res;
/*
到這裏該驅動已被完全註冊到了內核。它可以去匹配內核中已存在的
client而後執行probe函數了。
但是一個i2c_driver還有着其他的使命。如果該驅動是一個攜帶地址信息的
"new style" driver,則它要把這些每一個地址對應一個client註冊到內核。
如果是一個"legacy"driver,則它要用它的driver->attach_adapter函數
去處理每一個adapter->nr空閒的適配器。
每一個函數driver->attach_adapter的操作都跟adapter->nr有關,在這些函數
中都會對adapter->nr進行判斷,所以driver->attach_adapter並不是,一個驅動
的函數attach_adapter對每一個適配器都會成功執行。
到這裏該驅動已被完全註冊到了內核。它可以去匹配內核中已存在的
client而後執行probe函數了。
但是一個i2c_driver還有着其他的使命。如果該驅動是一個攜帶地址信息的
"new style" driver,則它要把這些每一個地址對應一個client註冊到內核。
如果是一個"legacy"driver,則它要用它的driver->attach_adapter函數
去處理每一個adapter->nr空閒的適配器。
每一個函數driver->attach_adapter的操作都跟adapter->nr有關,在這些函數
中都會對adapter->nr進行判斷,所以driver->attach_adapter並不是,一個驅動
的函數attach_adapter對每一個適配器都會成功執行。
比如在驅動i2cdev_driver中函數attach_adapter的執行會創建一個設備節點,
但是對同一個適配器兩次執行函數attach_adapter就不會產生兩個設備節點,
因爲產生設備節點的次設備號是由adapter->nr來決定的。內核是不會允許
對同一個設備號註冊兩次的。
*/
mutex_lock(&core_lock);
pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
INIT_LIST_HEAD(&driver->clients);//初始化鏈表頭用於掛接client
/* Walk the adapters that are already present */
/*
尋找類型爲i2c_adapter_class的所有設備,即適配器。
如果驅動爲"new style" driver將在函數__attach_adapter中
執行函數i2c_detect,如果當前找到的適配器所支持的設備類型
與驅動所支持的設備類型相匹配,就將驅動所攜帶的地址信息
driver->address_data,對應着client註冊到內核,並插入該適配器。
適配器所支持的設備類型由adapter->class決定,而不是
adapter->dev->class,adapter->dev->class的類型應爲i2c_adapter_class。
驅動所支持的設備類型爲driver->class。
如果該驅動爲"legacy"driver,則在函數__attach_adapter中將執行
函數driver->attach_adapter,將在類i2c_adapter_class上找到的
所有適配器都執行一遍本驅動的driver->attach_adapter函數。
當然並不是所有驅動都能成功執行該函數。該函數的執行會判斷
adapter->nr。
*/
class_for_each_device(&i2c_adapter_class, NULL, driver,
__attach_adapter);
/* Walk the adapters that are already present */
/*
尋找類型爲i2c_adapter_class的所有設備,即適配器。
如果驅動爲"new style" driver將在函數__attach_adapter中
執行函數i2c_detect,如果當前找到的適配器所支持的設備類型
與驅動所支持的設備類型相匹配,就將驅動所攜帶的地址信息
driver->address_data,對應着client註冊到內核,並插入該適配器。
適配器所支持的設備類型由adapter->class決定,而不是
adapter->dev->class,adapter->dev->class的類型應爲i2c_adapter_class。
驅動所支持的設備類型爲driver->class。
如果該驅動爲"legacy"driver,則在函數__attach_adapter中將執行
函數driver->attach_adapter,將在類i2c_adapter_class上找到的
所有適配器都執行一遍本驅動的driver->attach_adapter函數。
當然並不是所有驅動都能成功執行該函數。該函數的執行會判斷
adapter->nr。
*/
class_for_each_device(&i2c_adapter_class, NULL, driver,
__attach_adapter);
mutex_unlock(&core_lock);
return 0;
}
return 0;
}
(3)適配器與設備進行類型匹配,探測驅動中的可用地址,並將地址對應於一個client註冊到內核
在適配器設備和驅動註冊到內核後調用了兩個相似的函數如下:
在適配器設備註冊到內核後調用函數:
static int i2c_do_add_adapter(struct device_driver *d, void *data)
{
struct i2c_driver *driver = to_i2c_driver(d);
struct i2c_adapter *adap = data;
{
struct i2c_driver *driver = to_i2c_driver(d);
struct i2c_adapter *adap = data;
/* Detect supported devices on that bus, and instantiate them */
//如果驅動的類與適配器的類相匹配,則將驅動支持的設備插入適配器。
i2c_detect(adap, driver);
//如果驅動的類與適配器的類相匹配,則將驅動支持的設備插入適配器。
i2c_detect(adap, driver);
/* Let legacy drivers scan this bus for matching devices */
if (driver->attach_adapter) {//使適配器關聯一個設備號或者。。。。。。
/* We ignore the return code; if it fails, too bad */
driver->attach_adapter(adap);
}
return 0;
}
if (driver->attach_adapter) {//使適配器關聯一個設備號或者。。。。。。
/* We ignore the return code; if it fails, too bad */
driver->attach_adapter(adap);
}
return 0;
}
驅動註冊到內核後調用函數:
static int __attach_adapter(struct device *dev, void *data)
{
struct i2c_adapter *adapter = to_i2c_adapter(dev);
struct i2c_driver *driver = data;
{
struct i2c_adapter *adapter = to_i2c_adapter(dev);
struct i2c_driver *driver = data;
//如果驅動的類與適配器的類相匹配,則將驅動支持的設備插入適配器。
i2c_detect(adapter, driver);
/* Legacy drivers scan i2c busses directly */
if (driver->attach_adapter)//使適配器關聯一個設備號或者。。。。。。
driver->attach_adapter(adapter);
if (driver->attach_adapter)//使適配器關聯一個設備號或者。。。。。。
driver->attach_adapter(adapter);
return 0;
}
}
兩函數的對比:
static int __attach_adapter(struct device *dev, void *data)
與
static int i2c_do_add_adapter(struct device_driver *d, void *data)
前者是在新的驅動加入內核時調用函數class_for_each_device時調用的函數。
函數class_for_each_device是在類i2c_adapter_class中找一個適配器設備
與新驅動匹配。該函數變化的是設備不變的是加入的新的驅動(void *data)
後者是在新的適配器加入內核時調用函數 bus_for_each_drv時調用的函數。
函數bus_for_each_drv是在總線類型爲i2c_bus_type的驅動中找到一個驅動
與新加入的適配器匹配。該函數變化的是驅動,不變的是新加入的適配器
(void *data)。
相同點都是執行函數i2c_detect和函數driver->attach_adapter。
其實在bus_for_each_drv和class_for_each_device並不執行匹配的操作。
只是簡單的取出所有的驅動或是適配器,執行函數i2c_detect和attach_adapter。
真正的匹配是在函數i2c_detect和attach_adapter中進行的。
函數i2c_detect中會去判斷驅動支持的設備類和適配器所支持的設備類
是否匹配。
函數driver->attach_adapter中會判斷adapter->nr是不是自己需要處理的
適配器,或者是是不是該適配器已被處理過了。
當然函數i2c_detect和函數driver->attach_adapter是絕不會同時執行的。
因爲函數i2c_detect的執行需要用到函數driver->detect而該函數是
"new style" drivers的標誌函數。而函數driver->attach_adapter是
"legacy" drivers的標誌函數。i2c_driver中是沒有兼有這兩種驅動的混合體
驅動的。
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
{
const struct i2c_client_address_data *address_data;
struct i2c_client *temp_client;
int i, err = 0;
int adap_id = i2c_adapter_id(adapter);
{
const struct i2c_client_address_data *address_data;
struct i2c_client *temp_client;
int i, err = 0;
int adap_id = i2c_adapter_id(adapter);
address_data = driver->address_data;
/*
因爲註冊一個client要調用函數i2c_new_device(adapter, &info);
該函數要用結構體info爲client提供必要的信息。所以函數
driver->detect的主要作用是填充結構體info。
client代表一個具體設備而每個設備都有它的地址address_data。
所以driver->detect和address_data都是必不可少。
*/
if (!driver->detect || !address_data)
return 0;
/*
因爲註冊一個client要調用函數i2c_new_device(adapter, &info);
該函數要用結構體info爲client提供必要的信息。所以函數
driver->detect的主要作用是填充結構體info。
client代表一個具體設備而每個設備都有它的地址address_data。
所以driver->detect和address_data都是必不可少。
*/
if (!driver->detect || !address_data)
return 0;
/* Set up a temporary client to help detect callback */
/*
分配一個臨時的temp_client,因爲temp_client得設備並沒有被註冊,
也沒有被插入適配器,它只是暫存了一些client信息。
*/
temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
if (!temp_client)
return -ENOMEM;
temp_client->adapter = adapter;
/*
分配一個臨時的temp_client,因爲temp_client得設備並沒有被註冊,
也沒有被插入適配器,它只是暫存了一些client信息。
*/
temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
if (!temp_client)
return -ENOMEM;
temp_client->adapter = adapter;
/* Force entries are done first, and are not affected by ignore
entries */
/*
爲什麼是forces?
因爲跳過了適配器支持的設備類和驅動支持的設備類匹配判斷
if (!(adapter->class & driver->class))
goto exit_free;
也就是說即使不匹配,這些設備地址只要滿足某些條件也要將其插入適配器。
*/
if (address_data->forces) {
const unsigned short * const *forces = address_data->forces;
int kind;
entries */
/*
爲什麼是forces?
因爲跳過了適配器支持的設備類和驅動支持的設備類匹配判斷
if (!(adapter->class & driver->class))
goto exit_free;
也就是說即使不匹配,這些設備地址只要滿足某些條件也要將其插入適配器。
*/
if (address_data->forces) {
const unsigned short * const *forces = address_data->forces;
int kind;
for (kind = 0; forces[kind]; kind++) {
for (i = 0; forces[kind][i] != I2C_CLIENT_END;
i += 2) {//adap_id即是分配的與結構體adapter相關聯的ID
if (forces[kind][i] == adap_id
|| forces[kind][i] == ANY_I2C_BUS) {
dev_dbg(&adapter->dev, "found force "
"parameter for adapter %d, "
"addr 0x%02x, kind %d\n",
adap_id, forces[kind][i + 1],
kind);
temp_client->addr = forces[kind][i + 1];
//將這個地址的設備插入適配器。
err = i2c_detect_address(temp_client,
kind, driver);
if (err)
goto exit_free;
}
}
}
}
for (i = 0; forces[kind][i] != I2C_CLIENT_END;
i += 2) {//adap_id即是分配的與結構體adapter相關聯的ID
if (forces[kind][i] == adap_id
|| forces[kind][i] == ANY_I2C_BUS) {
dev_dbg(&adapter->dev, "found force "
"parameter for adapter %d, "
"addr 0x%02x, kind %d\n",
adap_id, forces[kind][i + 1],
kind);
temp_client->addr = forces[kind][i + 1];
//將這個地址的設備插入適配器。
err = i2c_detect_address(temp_client,
kind, driver);
if (err)
goto exit_free;
}
}
}
}
/* Stop here if the classes do not match */
//適配器和驅動的類型要匹配此處的驅動爲i2c_driver
if (!(adapter->class & driver->class))
goto exit_free;
//適配器和驅動的類型要匹配此處的驅動爲i2c_driver
if (!(adapter->class & driver->class))
goto exit_free;
/* Stop here if we can't use SMBUS_QUICK */
//如果該適配器不支持I2C_FUNC_SMBUS_QUICK功能則就此結束。
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
if (address_data->probe[0] == I2C_CLIENT_END
&& address_data->normal_i2c[0] == I2C_CLIENT_END)
goto exit_free;
//如果該適配器不支持I2C_FUNC_SMBUS_QUICK功能則就此結束。
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
if (address_data->probe[0] == I2C_CLIENT_END
&& address_data->normal_i2c[0] == I2C_CLIENT_END)
goto exit_free;
dev_warn(&adapter->dev, "SMBus Quick command not supported, "
"can't probe for chips\n");
err = -EOPNOTSUPP;
goto exit_free;
}
"can't probe for chips\n");
err = -EOPNOTSUPP;
goto exit_free;
}
/* Probe entries are done second, and are not affected by ignore
entries either */
//address_data->probe支持的設備地址不受
//address_data->ignore(忽略某些地址)的影響
//而address_data->normal_i2c[i]中的地址就要受到ignore的影響
entries either */
//address_data->probe支持的設備地址不受
//address_data->ignore(忽略某些地址)的影響
//而address_data->normal_i2c[i]中的地址就要受到ignore的影響
for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
if (address_data->probe[i] == adap_id
|| address_data->probe[i] == ANY_I2C_BUS) {
dev_dbg(&adapter->dev, "found probe parameter for "
"adapter %d, addr 0x%02x\n", adap_id,
address_data->probe[i + 1]);
temp_client->addr = address_data->probe[i + 1];
//將這個地址對應的設備插入適配器。
err = i2c_detect_address(temp_client, -1, driver);
if (err)
goto exit_free;
}
}
if (address_data->probe[i] == adap_id
|| address_data->probe[i] == ANY_I2C_BUS) {
dev_dbg(&adapter->dev, "found probe parameter for "
"adapter %d, addr 0x%02x\n", adap_id,
address_data->probe[i + 1]);
temp_client->addr = address_data->probe[i + 1];
//將這個地址對應的設備插入適配器。
err = i2c_detect_address(temp_client, -1, driver);
if (err)
goto exit_free;
}
}
/* Normal entries are done last, unless shadowed by an ignore entry */
//驅動中所支持的地址一般都存於address_data->normal_i2c中
for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
int j, ignore;
//驅動中所支持的地址一般都存於address_data->normal_i2c中
for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
int j, ignore;
ignore = 0;
for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
j += 2) {
if ((address_data->ignore[j] == adap_id ||
address_data->ignore[j] == ANY_I2C_BUS)
&& address_data->ignore[j + 1]
== address_data->normal_i2c[i]) {
dev_dbg(&adapter->dev, "found ignore "
"parameter for adapter %d, "
"addr 0x%02x\n", adap_id,
address_data->ignore[j + 1]);
ignore = 1;
break;
}
}
if (ignore)
continue;
for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
j += 2) {
if ((address_data->ignore[j] == adap_id ||
address_data->ignore[j] == ANY_I2C_BUS)
&& address_data->ignore[j + 1]
== address_data->normal_i2c[i]) {
dev_dbg(&adapter->dev, "found ignore "
"parameter for adapter %d, "
"addr 0x%02x\n", adap_id,
address_data->ignore[j + 1]);
ignore = 1;
break;
}
}
if (ignore)
continue;
dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
"addr 0x%02x\n", adap_id,
address_data->normal_i2c[i]);
temp_client->addr = address_data->normal_i2c[i];
//將這個地址對應的設備插入適配器。
err = i2c_detect_address(temp_client, -1, driver);
if (err)
goto exit_free;
}
"addr 0x%02x\n", adap_id,
address_data->normal_i2c[i]);
temp_client->addr = address_data->normal_i2c[i];
//將這個地址對應的設備插入適配器。
err = i2c_detect_address(temp_client, -1, driver);
if (err)
goto exit_free;
}
exit_free:
kfree(temp_client);
return err;
}
kfree(temp_client);
return err;
}
static int i2c_detect_address(struct i2c_client *temp_client, int kind,
struct i2c_driver *driver)
{
struct i2c_board_info info;
struct i2c_adapter *adapter = temp_client->adapter;
int addr = temp_client->addr;
int err;
//有效地設備地址必須在這個範圍內
/* Make sure the address is valid */
if (addr < 0x03 || addr > 0x77) {
dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
addr);
return -EINVAL;
}
struct i2c_driver *driver)
{
struct i2c_board_info info;
struct i2c_adapter *adapter = temp_client->adapter;
int addr = temp_client->addr;
int err;
//有效地設備地址必須在這個範圍內
/* Make sure the address is valid */
if (addr < 0x03 || addr > 0x77) {
dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
addr);
return -EINVAL;
}
/* Skip if already in use */
//檢測這個地址在適配器adapter中是否被佔用。
if (i2c_check_addr(adapter, addr))
return 0;
//檢測這個地址在適配器adapter中是否被佔用。
if (i2c_check_addr(adapter, addr))
return 0;
/* Make sure there is something at this address, unless forced */
if (kind < 0) {
if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
I2C_SMBUS_QUICK, NULL) < 0)
return 0;
if (kind < 0) {
if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
I2C_SMBUS_QUICK, NULL) < 0)
return 0;
/* prevent 24RF08 corruption */
if ((addr & ~0x0f) == 0x50)
i2c_smbus_xfer(adapter, addr, 0, 0, 0,
I2C_SMBUS_QUICK, NULL);
}
if ((addr & ~0x0f) == 0x50)
i2c_smbus_xfer(adapter, addr, 0, 0, 0,
I2C_SMBUS_QUICK, NULL);
}
/* Finally call the custom detection function */
//清空構體info準備存放信息
memset(&info, 0, sizeof(struct i2c_board_info));
info.addr = addr;
//該函數爲結構體info填充一些信息。
err = driver->detect(temp_client, kind, &info);
if (err) {
/* -ENODEV is returned if the detection fails. We catch it
here as this isn't an error. */
return err == -ENODEV ? 0 : err;
}
//清空構體info準備存放信息
memset(&info, 0, sizeof(struct i2c_board_info));
info.addr = addr;
//該函數爲結構體info填充一些信息。
err = driver->detect(temp_client, kind, &info);
if (err) {
/* -ENODEV is returned if the detection fails. We catch it
here as this isn't an error. */
return err == -ENODEV ? 0 : err;
}
/* Consistency check */
/*
info.type在函數driver->detect中將把driver->name拷給它。
info.type最終將在函數i2c_new_device中
strlcpy(client->name, info->type, sizeof(client->name));
client代表一個具體的設備,驅動對應着設備,當驅動與設備
相匹配時執行初始化函數函數probe。
在總線i2c_bus_type上驅動與設備匹配的條件是,name相同。
*/
if (info.type[0] == '\0') {
dev_err(&adapter->dev, "%s detection function provided "
"no name for 0x%x\n", driver->driver.name,
addr);
} else {
struct i2c_client *client;
/*
info.type在函數driver->detect中將把driver->name拷給它。
info.type最終將在函數i2c_new_device中
strlcpy(client->name, info->type, sizeof(client->name));
client代表一個具體的設備,驅動對應着設備,當驅動與設備
相匹配時執行初始化函數函數probe。
在總線i2c_bus_type上驅動與設備匹配的條件是,name相同。
*/
if (info.type[0] == '\0') {
dev_err(&adapter->dev, "%s detection function provided "
"no name for 0x%x\n", driver->driver.name,
addr);
} else {
struct i2c_client *client;
/* Detection succeeded, instantiate the device */
dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
info.type, info.addr);
//獲取了足夠的建立client的信息(info)則註冊client,並插入適配器
client = i2c_new_device(adapter, &info);
if (client)//這些設備都是driver所支持的,所以要掛到driver->clients上。
list_add_tail(&client->detected, &driver->clients);
else
dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
info.type, info.addr);
}
return 0;
}
dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
info.type, info.addr);
//獲取了足夠的建立client的信息(info)則註冊client,並插入適配器
client = i2c_new_device(adapter, &info);
if (client)//這些設備都是driver所支持的,所以要掛到driver->clients上。
list_add_tail(&client->detected, &driver->clients);
else
dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
info.type, info.addr);
}
return 0;
}
struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
struct i2c_client *client;
int status;
//將結構體info中存儲的各種信息用來初始化client。
//函數driver->detect(temp_client, kind, &info);
//是用來填充info中的值的,由此可見該函數的重要性。
client = kzalloc(sizeof *client, GFP_KERNEL);
if (!client)
return NULL;
//
client->adapter = adap;
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
struct i2c_client *client;
int status;
//將結構體info中存儲的各種信息用來初始化client。
//函數driver->detect(temp_client, kind, &info);
//是用來填充info中的值的,由此可見該函數的重要性。
client = kzalloc(sizeof *client, GFP_KERNEL);
if (!client)
return NULL;
//
client->adapter = adap;
client->dev.platform_data = info->platform_data;
if (info->archdata)
client->dev.archdata = *info->archdata;
client->dev.archdata = *info->archdata;
client->flags = info->flags;
client->addr = info->addr;
client->irq = info->irq;
//爲結構體client命名該名來至攜帶client地址信息的驅動
strlcpy(client->name, info->type, sizeof(client->name));
client->addr = info->addr;
client->irq = info->irq;
//爲結構體client命名該名來至攜帶client地址信息的驅動
strlcpy(client->name, info->type, sizeof(client->name));
/* a new style driver may be bound to this device when we
* return from this function, or any later moment (e.g. maybe
* hotplugging will load the driver module). and the device
* refcount model is the standard driver model one.
*/
//device_register(&client->dev);註冊設備並
//client->dev.parent = &client->adapter->dev;
//以上設置很重要是函數device_for_each_child實現的基礎。
status = i2c_attach_client(client);
if (status < 0) {
kfree(client);
client = NULL;
}
return client;
}
* return from this function, or any later moment (e.g. maybe
* hotplugging will load the driver module). and the device
* refcount model is the standard driver model one.
*/
//device_register(&client->dev);註冊設備並
//client->dev.parent = &client->adapter->dev;
//以上設置很重要是函數device_for_each_child實現的基礎。
status = i2c_attach_client(client);
if (status < 0) {
kfree(client);
client = NULL;
}
return client;
}
int i2c_attach_client(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
int res;
{
struct i2c_adapter *adapter = client->adapter;
int res;
/* Check for address business */
//檢測地址client->addr在適配器adapter中是否已被佔據
res = i2c_check_addr(adapter, client->addr);
if (res)
return res;
//該適配器是所有它支持的設備的父設備
client->dev.parent = &client->adapter->dev;
client->dev.bus = &i2c_bus_type;
//檢測地址client->addr在適配器adapter中是否已被佔據
res = i2c_check_addr(adapter, client->addr);
if (res)
return res;
//該適配器是所有它支持的設備的父設備
client->dev.parent = &client->adapter->dev;
client->dev.bus = &i2c_bus_type;
if (client->driver)
client->dev.driver = &client->driver->driver;
/*
有兩種驅動new-style drivers 和"legacy" drivers前者只註冊
client,匹配相應驅動,執行函數probe()。後者是添加適配器
創建設備節點。
*/
if (client->driver && !is_newstyle_driver(client->driver)) {
/*
在函數i2c_client_release中調用complete(&client->released);
通知完成released。在函數i2c_detach_client中有
wait_for_completion(&client->released);
*/
client->dev.release = i2c_client_release;
dev_set_uevent_suppress(&client->dev, 1);
} else
client->dev.release = i2c_client_dev_release;
//注意client->dev->name與client->name的區分
dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adapter),
client->addr);
res = device_register(&client->dev);//註冊設備
if (res)
goto out_err;
client->dev.driver = &client->driver->driver;
/*
有兩種驅動new-style drivers 和"legacy" drivers前者只註冊
client,匹配相應驅動,執行函數probe()。後者是添加適配器
創建設備節點。
*/
if (client->driver && !is_newstyle_driver(client->driver)) {
/*
在函數i2c_client_release中調用complete(&client->released);
通知完成released。在函數i2c_detach_client中有
wait_for_completion(&client->released);
*/
client->dev.release = i2c_client_release;
dev_set_uevent_suppress(&client->dev, 1);
} else
client->dev.release = i2c_client_dev_release;
//注意client->dev->name與client->name的區分
dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adapter),
client->addr);
res = device_register(&client->dev);//註冊設備
if (res)
goto out_err;
mutex_lock(&adapter->clist_lock);
//將適配器支持的設備插入適配器
list_add_tail(&client->list, &adapter->clients);
mutex_unlock(&adapter->clist_lock);
//將適配器支持的設備插入適配器
list_add_tail(&client->list, &adapter->clients);
mutex_unlock(&adapter->clist_lock);
dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n",
client->name, dev_name(&client->dev));
//好像該做的都做完了,函數adapter->client_register或許
//在某些特定的場合有着它特定的作用
if (adapter->client_register) {
if (adapter->client_register(client)) {
dev_dbg(&adapter->dev, "client_register "
"failed for client [%s] at 0x%02x\n",
client->name, client->addr);
}
}
client->name, dev_name(&client->dev));
//好像該做的都做完了,函數adapter->client_register或許
//在某些特定的場合有着它特定的作用
if (adapter->client_register) {
if (adapter->client_register(client)) {
dev_dbg(&adapter->dev, "client_register "
"failed for client [%s] at 0x%02x\n",
client->name, client->addr);
}
}
return 0;
out_err:
dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "
"(%d)\n", client->name, client->addr, res);
return res;
}
dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "
"(%d)\n", client->name, client->addr, res);
return res;
}