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-rw-r--r--Documentation/clk.txt46
-rw-r--r--drivers/clk/clk.c142
-rw-r--r--include/linux/clk-private.h3
-rw-r--r--include/linux/clk-provider.h7
4 files changed, 132 insertions, 66 deletions
diff --git a/Documentation/clk.txt b/Documentation/clk.txt
index 6f68ba0d1e01..3aeb5c440442 100644
--- a/Documentation/clk.txt
+++ b/Documentation/clk.txt
@@ -70,6 +70,10 @@ the operations defined in clk.h:
unsigned long parent_rate);
long (*round_rate)(struct clk_hw *hw, unsigned long,
unsigned long *);
+ long (*determine_rate)(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk **best_parent_clk);
int (*set_parent)(struct clk_hw *hw, u8 index);
u8 (*get_parent)(struct clk_hw *hw);
int (*set_rate)(struct clk_hw *hw, unsigned long);
@@ -179,26 +183,28 @@ mandatory, a cell marked as "n" implies that either including that
callback is invalid or otherwise unnecessary. Empty cells are either
optional or must be evaluated on a case-by-case basis.
- clock hardware characteristics
- -----------------------------------------------------------
- | gate | change rate | single parent | multiplexer | root |
- |------|-------------|---------------|-------------|------|
-.prepare | | | | | |
-.unprepare | | | | | |
- | | | | | |
-.enable | y | | | | |
-.disable | y | | | | |
-.is_enabled | y | | | | |
- | | | | | |
-.recalc_rate | | y | | | |
-.round_rate | | y | | | |
-.set_rate | | y | | | |
- | | | | | |
-.set_parent | | | n | y | n |
-.get_parent | | | n | y | n |
- | | | | | |
-.init | | | | | |
- -----------------------------------------------------------
+ clock hardware characteristics
+ -----------------------------------------------------------
+ | gate | change rate | single parent | multiplexer | root |
+ |------|-------------|---------------|-------------|------|
+.prepare | | | | | |
+.unprepare | | | | | |
+ | | | | | |
+.enable | y | | | | |
+.disable | y | | | | |
+.is_enabled | y | | | | |
+ | | | | | |
+.recalc_rate | | y | | | |
+.round_rate | | y [1] | | | |
+.determine_rate | | y [1] | | | |
+.set_rate | | y | | | |
+ | | | | | |
+.set_parent | | | n | y | n |
+.get_parent | | | n | y | n |
+ | | | | | |
+.init | | | | | |
+ -----------------------------------------------------------
+[1] either one of round_rate or determine_rate is required.
Finally, register your clock at run-time with a hardware-specific
registration function. This function simply populates struct clk_foo's
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 3d57cf64c9e7..f33f1ccf1b2f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -889,21 +889,24 @@ EXPORT_SYMBOL_GPL(clk_enable);
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;
}
/**
@@ -1056,6 +1059,10 @@ static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
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)
@@ -1176,18 +1183,25 @@ out:
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);
}
}
@@ -1198,50 +1212,63 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
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;
}
@@ -1253,7 +1280,7 @@ out:
*/
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)
@@ -1266,9 +1293,19 @@ static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long even
}
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;
@@ -1286,6 +1323,10 @@ static void clk_change_rate(struct clk *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;
@@ -1300,8 +1341,16 @@ static void clk_change_rate(struct clk *clk)
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);
}
/**
@@ -1552,8 +1601,9 @@ int __clk_init(struct device *dev, struct clk *clk)
/* 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;
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index dd7adff76e81..8138c94409f3 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -33,8 +33,11 @@ struct clk {
const char **parent_names;
struct clk **parents;
u8 num_parents;
+ u8 new_parent_index;
unsigned long rate;
unsigned long new_rate;
+ struct clk *new_parent;
+ struct clk *new_child;
unsigned long flags;
unsigned int enable_count;
unsigned int prepare_count;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index a83409285a7f..4f525b37c6fd 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -79,6 +79,10 @@ struct clk_hw;
* @round_rate: Given a target rate as input, returns the closest rate actually
* supported by the clock.
*
+ * @determine_rate: Given a target rate as input, returns the closest rate
+ * actually supported by the clock, and optionally the parent clock
+ * that should be used to provide the clock rate.
+ *
* @get_parent: Queries the hardware to determine the parent of a clock. The
* return value is a u8 which specifies the index corresponding to
* the parent clock. This index can be applied to either the
@@ -126,6 +130,9 @@ struct clk_ops {
unsigned long parent_rate);
long (*round_rate)(struct clk_hw *hw, unsigned long,
unsigned long *);
+ long (*determine_rate)(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk **best_parent_clk);
int (*set_parent)(struct clk_hw *hw, u8 index);
u8 (*get_parent)(struct clk_hw *hw);
int (*set_rate)(struct clk_hw *hw, unsigned long,