From 3fa2252b7a78a8057017471a28f47b306e95ee26 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Wed, 15 Jan 2014 10:47:22 -0800 Subject: [PATCH] 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 Signed-off-by: Stephen Boyd Signed-off-by: Mike Turquette --- Documentation/clk.txt | 3 ++ drivers/clk/clk.c | 78 +++++++++++++++++++++++++++--------- include/linux/clk-provider.h | 15 +++++++ 3 files changed, 77 insertions(+), 19 deletions(-) diff --git a/Documentation/clk.txt b/Documentation/clk.txt index eb20198783cd..699ef2a323b1 100644 --- a/Documentation/clk.txt +++ b/Documentation/clk.txt @@ -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); diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index e3e03270b95e..2b38dc99063f 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -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], diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 5429f5db5037..999b28ba38f7 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -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); -- GitLab