clk: Add set_rate_and_parent() op
Some of Qualcomm's clocks can change their parent and rate at the
same time with a single register write. Add support for this
hardware to the common clock framework by adding a new
set_rate_and_parent() op. When the clock framework determines
that both the parent and the rate are going to change during
clk_set_rate() it will call the .set_rate_and_parent() op if
available and fall back to calling .set_parent() followed by
.set_rate() otherwise.
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index e3e0327..2b38dc9 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1218,10 +1218,9 @@
clk->parent = new_parent;
}
-static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
+static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
{
unsigned long flags;
- int ret = 0;
struct clk *old_parent = clk->parent;
/*
@@ -1252,6 +1251,34 @@
clk_reparent(clk, parent);
clk_enable_unlock(flags);
+ return old_parent;
+}
+
+static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
+ struct clk *old_parent)
+{
+ /*
+ * 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);
+}
+
+static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
+{
+ unsigned long flags;
+ int ret = 0;
+ struct clk *old_parent;
+
+ old_parent = __clk_set_parent_before(clk, parent);
+
/* change clock input source */
if (parent && clk->ops->set_parent)
ret = clk->ops->set_parent(clk->hw, p_index);
@@ -1269,18 +1296,8 @@
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);
- }
+ __clk_set_parent_after(clk, parent, old_parent);
- /* update debugfs with new clk tree topology */
- clk_debug_reparent(clk, parent);
return 0;
}
@@ -1465,17 +1482,32 @@
struct clk *child;
unsigned long old_rate;
unsigned long best_parent_rate = 0;
+ bool skip_set_rate = false;
+ struct clk *old_parent;
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)
+ if (clk->new_parent)
+ best_parent_rate = clk->new_parent->rate;
+ else if (clk->parent)
best_parent_rate = clk->parent->rate;
- if (clk->ops->set_rate)
+ if (clk->new_parent && clk->new_parent != clk->parent) {
+ old_parent = __clk_set_parent_before(clk, clk->new_parent);
+
+ if (clk->ops->set_rate_and_parent) {
+ skip_set_rate = true;
+ clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
+ best_parent_rate,
+ clk->new_parent_index);
+ } else if (clk->ops->set_parent) {
+ clk->ops->set_parent(clk->hw, clk->new_parent_index);
+ }
+
+ __clk_set_parent_after(clk, clk->new_parent, old_parent);
+ }
+
+ if (!skip_set_rate && clk->ops->set_rate)
clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
if (clk->ops->recalc_rate)
@@ -1770,6 +1802,14 @@
goto out;
}
+ if (clk->ops->set_rate_and_parent &&
+ !(clk->ops->set_parent && clk->ops->set_rate)) {
+ pr_warn("%s: %s must implement .set_parent & .set_rate\n",
+ __func__, clk->name);
+ ret = -EINVAL;
+ goto out;
+ }
+
/* throw a WARN if any entries in parent_names are NULL */
for (i = 0; i < clk->num_parents; i++)
WARN(!clk->parent_names[i],