Hi!
> My implementation has two primary goals:
>
> 1.) To help device drivers track and control their device's power state
>
> 2.) To bubble power state dependency changes from a leaf node to the
> last affected parent node in the chain.
>
> The basic unit of the tree is referred to as a "pm_node". Each
> "pm_node" has a list of states it supports, a current state, and a
> driver to handle state transitions. Any "pm_node" can have children and
> therefore act as a power container.
>
> struct pm_state {
> char *name;
> unsigned long index;
> unsigned long link_req;
> void *link_data;
> };
>
> "index" is a driver specific value that indicates the state. "link_req"
> is a set of flags that indicate requirements from the parent "pm_node".
> "link_data" provides additional requirement information.
>
> struct pm_node {
> struct semaphore sem;
> struct list_head children;
> struct list_head child_list;
> struct pm_node *parent;
> struct pm_node *tmp_path;
> struct device *dev;
>
> struct pm_node_driver *drv;
> unsigned int current_state;
> unsigned int target_state;
Would not it be cleaner to have struct pm_state *current_state, target state?
> "states" is a list of power states sorted from most functional to least
> functional. "current_state" and "target_state" are index values for
> that list.
>
> struct pm_node_driver {
> int (*set_state) (struct pm_node *node);
> int (*raise_event) (struct pm_node *domain,
> struct pm_node *child,
> unsigned long *new_state);
struct pm_state here, too?
> void (*lower_event) (struct pm_node *domain);
> };
>
> "raise_event" notifies the power domain when a child has increased its
"Increase" == went more power hungry?
> I apologize for the unpolished/untested state of the code as it's
> primarily intended to illustrate a concept. I'll need to look over the
> problem more carefully if we decide this is the right direction. Power
Seems ok to me.
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