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>
This commit is contained in:
Stephen Boyd 2014-01-15 10:47:22 -08:00 committed by Mike Turquette
parent d0d44dd4ac
commit 3fa2252b7a
3 changed files with 77 additions and 19 deletions

View File

@ -77,6 +77,9 @@ the operations defined in clk.h:
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);
int (*set_rate_and_parent)(struct clk_hw *hw,
unsigned long rate,
unsigned long parent_rate, u8 index);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
void (*init)(struct clk_hw *hw);

View File

@ -1218,10 +1218,9 @@ static void clk_reparent(struct clk *clk, struct clk *new_parent)
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 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
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 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
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 @@ static void clk_change_rate(struct clk *clk)
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 @@ int __clk_init(struct device *dev, struct clk *clk)
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],

View File

@ -116,6 +116,18 @@ struct clk_hw;
* set then clock accuracy will be initialized to parent accuracy
* or 0 (perfect clock) if clock has no parent.
*
* @set_rate_and_parent: Change the rate and the parent of this clock. The
* requested rate is specified by the second argument, which
* should typically be the return of .round_rate call. The
* third argument gives the parent rate which is likely helpful
* for most .set_rate_and_parent implementation. The fourth
* argument gives the parent index. This callback is optional (and
* unnecessary) for clocks with 0 or 1 parents as well as
* for clocks that can tolerate switching the rate and the parent
* separately via calls to .set_parent and .set_rate.
* Returns 0 on success, -EERROR otherwise.
*
*
* The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
* implementations to split any work between atomic (enable) and sleepable
* (prepare) contexts. If enabling a clock requires code that might sleep,
@ -147,6 +159,9 @@ struct clk_ops {
u8 (*get_parent)(struct clk_hw *hw);
int (*set_rate)(struct clk_hw *hw, unsigned long,
unsigned long);
int (*set_rate_and_parent)(struct clk_hw *hw,
unsigned long rate,
unsigned long parent_rate, u8 index);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
void (*init)(struct clk_hw *hw);