Linux 内核clk 添加clk provider

内核把所有的clk  provider管理维护起来，这些存放在of_clk_providers链表当中， 这个provider定义如下：

struct of_clk_provider {  struct list_head link;

 struct device_node *node;  struct clk *(*get)(struct of_phandle_args *clkspec, void *data);  struct clk_hw *(*get_hw)(struct of_phandle_args *clkspec, void *data);  void *data; };

static LIST_HEAD(of_clk_providers); static DEFINE_MUTEX(of_clk_lock);   添加函数：

/**  * of_clk_add_provider() - Register a clock provider for a node  * @np: Device node pointer associated with clock provider  * @clk_src_get: callback for decoding clock  * @data: context pointer for @clk_src_get callback.  */ int of_clk_add_provider(struct device_node *np,    struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,          void *data),    void *data) {  struct of_clk_provider *cp;

 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);  if (!cp)   return -ENOMEM;

 cp->node = of_node_get(np);  cp->data = data;  cp->get = clk_src_get;

 mutex_lock(&of_clk_lock);  list_add(&cp->link, &of_clk_providers);  mutex_unlock(&of_clk_lock);  pr_debug("Added clock from %s\n", np->full_name);

 return 0; }

删除操作 /**  * of_clk_del_provider() - Remove a previously registered clock provider  * @np: Device node pointer associated with clock provider  */ void of_clk_del_provider(struct device_node *np) {  struct of_clk_provider *cp;

 mutex_lock(&of_clk_lock);  list_for_each_entry(cp, &of_clk_providers, link) {   if (cp->node == np) {    list_del(&cp->link);    of_node_put(cp->node);    kfree(cp);    break;   }  }  mutex_unlock(&of_clk_lock); }

获取clk：

struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) {  struct of_clk_provider *provider;  struct clk *clk = ERR_PTR(-ENOENT);

 /* Check if we have such a provider in our array */  mutex_lock(&of_clk_lock);  list_for_each_entry(provider, &of_clk_providers, link) {   if (provider->node == clkspec->np)    clk = provider->get(clkspec, provider->data);   if (!IS_ERR(clk))    break;  }  mutex_unlock(&of_clk_lock);

 return clk; }