return !clk ? NULL : clk->parent;
}
+struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
+{
+ if (!clk || index >= clk->num_parents)
+ return NULL;
+ else if (!clk->parents)
+ return __clk_lookup(clk->parent_names[index]);
+ else if (!clk->parents[index])
+ return clk->parents[index] =
+ __clk_lookup(clk->parent_names[index]);
+ else
+ return clk->parents[index];
+}
+
unsigned int __clk_get_enable_count(struct clk *clk)
{
return !clk ? 0 : clk->enable_count;
return NULL;
}
+/*
+ * Helper for finding best parent to provide a given frequency. This can be used
+ * directly as a determine_rate callback (e.g. for a mux), or from a more
+ * complex clock that may combine a mux with other operations.
+ */
+long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk **best_parent_p)
+{
+ struct clk *clk = hw->clk, *parent, *best_parent = NULL;
+ int i, num_parents;
+ unsigned long parent_rate, best = 0;
+
+ /* if NO_REPARENT flag set, pass through to current parent */
+ if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
+ parent = clk->parent;
+ if (clk->flags & CLK_SET_RATE_PARENT)
+ best = __clk_round_rate(parent, rate);
+ else if (parent)
+ best = __clk_get_rate(parent);
+ else
+ best = __clk_get_rate(clk);
+ goto out;
+ }
+
+ /* find the parent that can provide the fastest rate <= rate */
+ num_parents = clk->num_parents;
+ for (i = 0; i < num_parents; i++) {
+ parent = clk_get_parent_by_index(clk, i);
+ if (!parent)
+ continue;
+ if (clk->flags & CLK_SET_RATE_PARENT)
+ parent_rate = __clk_round_rate(parent, rate);
+ else
+ parent_rate = __clk_get_rate(parent);
+ if (parent_rate <= rate && parent_rate > best) {
+ best_parent = parent;
+ best = parent_rate;
+ }
+ }
+
+out:
+ if (best_parent)
+ *best_parent_p = best_parent;
+ *best_parent_rate = best;
+
+ return best;
+}
+
/*** clk api ***/
void __clk_unprepare(struct clk *clk)
/**
* clk_unprepare - undo preparation of a clock source
- * @clk: the clk being unprepare
+ * @clk: the clk being unprepared
*
* clk_unprepare may sleep, which differentiates it from clk_disable. In a
* simple case, clk_unprepare can be used instead of clk_disable to gate a clk
/**
* __clk_round_rate - round the given rate for a clk
* @clk: round the rate of this clock
+ * @rate: the rate which is to be rounded
*
* Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
*/
unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
{
unsigned long parent_rate = 0;
+ struct clk *parent;
if (!clk)
return 0;
- if (!clk->ops->round_rate) {
- if (clk->flags & CLK_SET_RATE_PARENT)
- return __clk_round_rate(clk->parent, rate);
- else
- return clk->rate;
- }
-
- if (clk->parent)
- parent_rate = clk->parent->rate;
-
- return clk->ops->round_rate(clk->hw, rate, &parent_rate);
+ parent = clk->parent;
+ if (parent)
+ parent_rate = parent->rate;
+
+ if (clk->ops->determine_rate)
+ return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
+ &parent);
+ else if (clk->ops->round_rate)
+ return clk->ops->round_rate(clk->hw, rate, &parent_rate);
+ else if (clk->flags & CLK_SET_RATE_PARENT)
+ return __clk_round_rate(clk->parent, rate);
+ else
+ return clk->rate;
}
/**
*
* Walks the subtree of clks starting with clk and recalculates rates as it
* goes. Note that if a clk does not implement the .recalc_rate callback then
- * it is assumed that the clock will take on the rate of it's parent.
+ * it is assumed that the clock will take on the rate of its parent.
*
* clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
* if necessary.
}
EXPORT_SYMBOL_GPL(clk_get_rate);
+static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
+{
+ u8 i;
+
+ if (!clk->parents)
+ clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
+ GFP_KERNEL);
+
+ /*
+ * find index of new parent clock using cached parent ptrs,
+ * or if not yet cached, use string name comparison and cache
+ * them now to avoid future calls to __clk_lookup.
+ */
+ for (i = 0; i < clk->num_parents; i++) {
+ if (clk->parents && clk->parents[i] == parent)
+ break;
+ else if (!strcmp(clk->parent_names[i], parent->name)) {
+ if (clk->parents)
+ clk->parents[i] = __clk_lookup(parent->name);
+ break;
+ }
+ }
+
+ return i;
+}
+
+static void clk_reparent(struct clk *clk, struct clk *new_parent)
+{
+ /* avoid duplicate POST_RATE_CHANGE notifications */
+ if (new_parent->new_child == clk)
+ new_parent->new_child = NULL;
+
+ hlist_del(&clk->child_node);
+
+ if (new_parent)
+ hlist_add_head(&clk->child_node, &new_parent->children);
+ else
+ hlist_add_head(&clk->child_node, &clk_orphan_list);
+
+ clk->parent = new_parent;
+}
+
+static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
+{
+ unsigned long flags;
+ int ret = 0;
+ struct clk *old_parent = clk->parent;
+
+ /*
+ * Migrate prepare state between parents and prevent race with
+ * clk_enable().
+ *
+ * If the clock is not prepared, then a race with
+ * clk_enable/disable() is impossible since we already have the
+ * prepare lock (future calls to clk_enable() need to be preceded by
+ * a clk_prepare()).
+ *
+ * If the clock is prepared, migrate the prepared state to the new
+ * parent and also protect against a race with clk_enable() by
+ * forcing the clock and the new parent on. This ensures that all
+ * future calls to clk_enable() are practically NOPs with respect to
+ * hardware and software states.
+ *
+ * See also: Comment for clk_set_parent() below.
+ */
+ if (clk->prepare_count) {
+ __clk_prepare(parent);
+ clk_enable(parent);
+ clk_enable(clk);
+ }
+
+ /* update the clk tree topology */
+ flags = clk_enable_lock();
+ clk_reparent(clk, parent);
+ clk_enable_unlock(flags);
+
+ /* change clock input source */
+ if (parent && clk->ops->set_parent)
+ ret = clk->ops->set_parent(clk->hw, p_index);
+
+ if (ret) {
+ flags = clk_enable_lock();
+ clk_reparent(clk, old_parent);
+ clk_enable_unlock(flags);
+
+ if (clk->prepare_count) {
+ clk_disable(clk);
+ clk_disable(parent);
+ __clk_unprepare(parent);
+ }
+ return ret;
+ }
+
+ /*
+ * Finish the migration of prepare state and undo the changes done
+ * for preventing a race with clk_enable().
+ */
+ if (clk->prepare_count) {
+ clk_disable(clk);
+ clk_disable(old_parent);
+ __clk_unprepare(old_parent);
+ }
+
+ /* update debugfs with new clk tree topology */
+ clk_debug_reparent(clk, parent);
+ return 0;
+}
+
/**
* __clk_speculate_rates
* @clk: first clk in the subtree
* pre-rate change notifications and returns early if no clks in the
* subtree have subscribed to the notifications. Note that if a clk does not
* implement the .recalc_rate callback then it is assumed that the clock will
- * take on the rate of it's parent.
+ * take on the rate of its parent.
*
* Caller must hold prepare_lock.
*/
return ret;
}
-static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
+static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
+ struct clk *new_parent, u8 p_index)
{
struct clk *child;
clk->new_rate = new_rate;
+ clk->new_parent = new_parent;
+ clk->new_parent_index = p_index;
+ /* include clk in new parent's PRE_RATE_CHANGE notifications */
+ clk->new_child = NULL;
+ if (new_parent && new_parent != clk->parent)
+ new_parent->new_child = clk;
hlist_for_each_entry(child, &clk->children, child_node) {
if (child->ops->recalc_rate)
child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
else
child->new_rate = new_rate;
- clk_calc_subtree(child, child->new_rate);
+ clk_calc_subtree(child, child->new_rate, NULL, 0);
}
}
static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
{
struct clk *top = clk;
+ struct clk *old_parent, *parent;
unsigned long best_parent_rate = 0;
unsigned long new_rate;
+ u8 p_index = 0;
/* sanity */
if (IS_ERR_OR_NULL(clk))
return NULL;
/* save parent rate, if it exists */
- if (clk->parent)
- best_parent_rate = clk->parent->rate;
-
- /* never propagate up to the parent */
- if (!(clk->flags & CLK_SET_RATE_PARENT)) {
- if (!clk->ops->round_rate) {
- clk->new_rate = clk->rate;
- return NULL;
- }
- new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
+ parent = old_parent = clk->parent;
+ if (parent)
+ best_parent_rate = parent->rate;
+
+ /* find the closest rate and parent clk/rate */
+ if (clk->ops->determine_rate) {
+ new_rate = clk->ops->determine_rate(clk->hw, rate,
+ &best_parent_rate,
+ &parent);
+ } else if (clk->ops->round_rate) {
+ new_rate = clk->ops->round_rate(clk->hw, rate,
+ &best_parent_rate);
+ } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
+ /* pass-through clock without adjustable parent */
+ clk->new_rate = clk->rate;
+ return NULL;
+ } else {
+ /* pass-through clock with adjustable parent */
+ top = clk_calc_new_rates(parent, rate);
+ new_rate = parent->new_rate;
goto out;
}
- /* need clk->parent from here on out */
- if (!clk->parent) {
- pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
+ /* some clocks must be gated to change parent */
+ if (parent != old_parent &&
+ (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
+ pr_debug("%s: %s not gated but wants to reparent\n",
+ __func__, clk->name);
return NULL;
}
- if (!clk->ops->round_rate) {
- top = clk_calc_new_rates(clk->parent, rate);
- new_rate = clk->parent->new_rate;
-
- goto out;
+ /* try finding the new parent index */
+ if (parent) {
+ p_index = clk_fetch_parent_index(clk, parent);
+ if (p_index == clk->num_parents) {
+ pr_debug("%s: clk %s can not be parent of clk %s\n",
+ __func__, parent->name, clk->name);
+ return NULL;
+ }
}
- new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
-
- if (best_parent_rate != clk->parent->rate) {
- top = clk_calc_new_rates(clk->parent, best_parent_rate);
-
- goto out;
- }
+ if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
+ best_parent_rate != parent->rate)
+ top = clk_calc_new_rates(parent, best_parent_rate);
out:
- clk_calc_subtree(clk, new_rate);
+ clk_calc_subtree(clk, new_rate, parent, p_index);
return top;
}
*/
static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
{
- struct clk *child, *fail_clk = NULL;
+ struct clk *child, *tmp_clk, *fail_clk = NULL;
int ret = NOTIFY_DONE;
if (clk->rate == clk->new_rate)
}
hlist_for_each_entry(child, &clk->children, child_node) {
- clk = clk_propagate_rate_change(child, event);
- if (clk)
- fail_clk = clk;
+ /* Skip children who will be reparented to another clock */
+ if (child->new_parent && child->new_parent != clk)
+ continue;
+ tmp_clk = clk_propagate_rate_change(child, event);
+ if (tmp_clk)
+ fail_clk = tmp_clk;
+ }
+
+ /* handle the new child who might not be in clk->children yet */
+ if (clk->new_child) {
+ tmp_clk = clk_propagate_rate_change(clk->new_child, event);
+ if (tmp_clk)
+ fail_clk = tmp_clk;
}
return fail_clk;
old_rate = clk->rate;
+ /* set parent */
+ if (clk->new_parent && clk->new_parent != clk->parent)
+ __clk_set_parent(clk, clk->new_parent, clk->new_parent_index);
+
if (clk->parent)
best_parent_rate = clk->parent->rate;
if (clk->notifier_count && old_rate != clk->rate)
__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
- hlist_for_each_entry(child, &clk->children, child_node)
+ hlist_for_each_entry(child, &clk->children, child_node) {
+ /* Skip children who will be reparented to another clock */
+ if (child->new_parent && child->new_parent != clk)
+ continue;
clk_change_rate(child);
+ }
+
+ /* handle the new child who might not be in clk->children yet */
+ if (clk->new_child)
+ clk_change_rate(clk->new_child);
}
/**
* outcome of clk's .round_rate implementation. If *parent_rate is unchanged
* after calling .round_rate then upstream parent propagation is ignored. If
* *parent_rate comes back with a new rate for clk's parent then we propagate
- * up to clk's parent and set it's rate. Upward propagation will continue
+ * up to clk's parent and set its rate. Upward propagation will continue
* until either a clk does not support the CLK_SET_RATE_PARENT flag or
* .round_rate stops requesting changes to clk's parent_rate.
*
struct clk *top, *fail_clk;
int ret = 0;
+ if (!clk)
+ return 0;
+
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
kzalloc((sizeof(struct clk*) * clk->num_parents),
GFP_KERNEL);
- if (!clk->parents)
- ret = __clk_lookup(clk->parent_names[index]);
- else if (!clk->parents[index])
- ret = clk->parents[index] =
- __clk_lookup(clk->parent_names[index]);
- else
- ret = clk->parents[index];
+ ret = clk_get_parent_by_index(clk, index);
out:
return ret;
}
-static void clk_reparent(struct clk *clk, struct clk *new_parent)
-{
- hlist_del(&clk->child_node);
-
- if (new_parent)
- hlist_add_head(&clk->child_node, &new_parent->children);
- else
- hlist_add_head(&clk->child_node, &clk_orphan_list);
-
- clk->parent = new_parent;
-}
-
void __clk_reparent(struct clk *clk, struct clk *new_parent)
{
clk_reparent(clk, new_parent);
__clk_recalc_rates(clk, POST_RATE_CHANGE);
}
-static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
-{
- u8 i;
-
- if (!clk->parents)
- clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
- GFP_KERNEL);
-
- /*
- * find index of new parent clock using cached parent ptrs,
- * or if not yet cached, use string name comparison and cache
- * them now to avoid future calls to __clk_lookup.
- */
- for (i = 0; i < clk->num_parents; i++) {
- if (clk->parents && clk->parents[i] == parent)
- break;
- else if (!strcmp(clk->parent_names[i], parent->name)) {
- if (clk->parents)
- clk->parents[i] = __clk_lookup(parent->name);
- break;
- }
- }
-
- return i;
-}
-
-static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
-{
- unsigned long flags;
- int ret = 0;
- struct clk *old_parent = clk->parent;
-
- /*
- * Migrate prepare state between parents and prevent race with
- * clk_enable().
- *
- * If the clock is not prepared, then a race with
- * clk_enable/disable() is impossible since we already have the
- * prepare lock (future calls to clk_enable() need to be preceded by
- * a clk_prepare()).
- *
- * If the clock is prepared, migrate the prepared state to the new
- * parent and also protect against a race with clk_enable() by
- * forcing the clock and the new parent on. This ensures that all
- * future calls to clk_enable() are practically NOPs with respect to
- * hardware and software states.
- *
- * See also: Comment for clk_set_parent() below.
- */
- if (clk->prepare_count) {
- __clk_prepare(parent);
- clk_enable(parent);
- clk_enable(clk);
- }
-
- /* update the clk tree topology */
- flags = clk_enable_lock();
- clk_reparent(clk, parent);
- clk_enable_unlock(flags);
-
- /* change clock input source */
- if (parent && clk->ops->set_parent)
- ret = clk->ops->set_parent(clk->hw, p_index);
-
- if (ret) {
- flags = clk_enable_lock();
- clk_reparent(clk, old_parent);
- clk_enable_unlock(flags);
-
- if (clk->prepare_count) {
- clk_disable(clk);
- clk_disable(parent);
- __clk_unprepare(parent);
- }
- return ret;
- }
-
- /*
- * Finish the migration of prepare state and undo the changes done
- * for preventing a race with clk_enable().
- */
- if (clk->prepare_count) {
- clk_disable(clk);
- clk_disable(old_parent);
- __clk_unprepare(old_parent);
- }
-
- /* update debugfs with new clk tree topology */
- clk_debug_reparent(clk, parent);
- return 0;
-}
-
/**
* clk_set_parent - switch the parent of a mux clk
* @clk: the mux clk whose input we are switching
u8 p_index = 0;
unsigned long p_rate = 0;
- if (!clk || !clk->ops)
+ if (!clk)
+ return 0;
+
+ if (!clk->ops)
return -EINVAL;
/* verify ops for for multi-parent clks */
/* check that clk_ops are sane. See Documentation/clk.txt */
if (clk->ops->set_rate &&
- !(clk->ops->round_rate && clk->ops->recalc_rate)) {
- pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
+ !((clk->ops->round_rate || clk->ops->determine_rate) &&
+ clk->ops->recalc_rate)) {
+ pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
__func__, clk->name);
ret = -EINVAL;
goto out;
* The .init callback is not used by any of the basic clock types, but
* exists for weird hardware that must perform initialization magic.
* Please consider other ways of solving initialization problems before
- * using this callback, as it's use is discouraged.
+ * using this callback, as its use is discouraged.
*/
if (clk->ops->init)
clk->ops->init(clk->hw);
* very large numbers of clocks that need to be statically initialized. It is
* a layering violation to include clk-private.h from any code which implements
* a clock's .ops; as such any statically initialized clock data MUST be in a
- * separate C file from the logic that implements it's operations. Returns 0
+ * separate C file from the logic that implements its operations. Returns 0
* on success, otherwise an error code.
*/
struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
*/
void __init of_clk_init(const struct of_device_id *matches)
{
+ const struct of_device_id *match;
struct device_node *np;
if (!matches)
matches = __clk_of_table;
- for_each_matching_node(np, matches) {
- const struct of_device_id *match = of_match_node(matches, np);
+ for_each_matching_node_and_match(np, matches, &match) {
of_clk_init_cb_t clk_init_cb = match->data;
clk_init_cb(np);
}
projects / ~andy / linux / blobdiff