1 files changed, 362 insertions, 190 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 566ee2c78709..57b83665e5c3 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -37,7 +37,7 @@ static HLIST_HEAD(clk_root_list);
 static HLIST_HEAD(clk_orphan_list);
 static LIST_HEAD(clk_notifier_list);
 
-static struct hlist_head *all_lists[] = {
+static const struct hlist_head *all_lists[] = {
 	&clk_root_list,
 	&clk_orphan_list,
 	NULL,
@@ -108,17 +108,10 @@ struct clk {
 /***           runtime pm          ***/
 static int clk_pm_runtime_get(struct clk_core *core)
 {
-	int ret;
-
 	if (!core->rpm_enabled)
 		return 0;
 
-	ret = pm_runtime_get_sync(core->dev);
-	if (ret < 0) {
-		pm_runtime_put_noidle(core->dev);
-		return ret;
-	}
-	return 0;
+	return pm_runtime_resume_and_get(core->dev);
 }
 
 static void clk_pm_runtime_put(struct clk_core *core)
@@ -424,19 +417,20 @@ static void clk_core_fill_parent_index(struct clk_core *core, u8 index)
 
 	if (entry->hw) {
 		parent = entry->hw->core;
-		/*
-		 * We have a direct reference but it isn't registered yet?
-		 * Orphan it and let clk_reparent() update the orphan status
-		 * when the parent is registered.
-		 */
-		if (!parent)
-			parent = ERR_PTR(-EPROBE_DEFER);
 	} else {
 		parent = clk_core_get(core, index);
 		if (PTR_ERR(parent) == -ENOENT && entry->name)
 			parent = clk_core_lookup(entry->name);
 	}
 
+	/*
+	 * We have a direct reference but it isn't registered yet?
+	 * Orphan it and let clk_reparent() update the orphan status
+	 * when the parent is registered.
+	 */
+	if (!parent)
+		parent = ERR_PTR(-EPROBE_DEFER);
+
 	/* Only cache it if it's not an error */
 	if (!IS_ERR(parent))
 		entry->core = parent;
@@ -542,6 +536,53 @@ static bool mux_is_better_rate(unsigned long rate, unsigned long now,
 	return now <= rate && now > best;
 }
 
+static void clk_core_init_rate_req(struct clk_core * const core,
+				   struct clk_rate_request *req,
+				   unsigned long rate);
+
+static int clk_core_round_rate_nolock(struct clk_core *core,
+				      struct clk_rate_request *req);
+
+static bool clk_core_has_parent(struct clk_core *core, const struct clk_core *parent)
+{
+	struct clk_core *tmp;
+	unsigned int i;
+
+	/* Optimize for the case where the parent is already the parent. */
+	if (core->parent == parent)
+		return true;
+
+	for (i = 0; i < core->num_parents; i++) {
+		tmp = clk_core_get_parent_by_index(core, i);
+		if (!tmp)
+			continue;
+
+		if (tmp == parent)
+			return true;
+	}
+
+	return false;
+}
+
+static void
+clk_core_forward_rate_req(struct clk_core *core,
+			  const struct clk_rate_request *old_req,
+			  struct clk_core *parent,
+			  struct clk_rate_request *req,
+			  unsigned long parent_rate)
+{
+	if (WARN_ON(!clk_core_has_parent(core, parent)))
+		return;
+
+	clk_core_init_rate_req(parent, req, parent_rate);
+
+	if (req->min_rate < old_req->min_rate)
+		req->min_rate = old_req->min_rate;
+
+	if (req->max_rate > old_req->max_rate)
+		req->max_rate = old_req->max_rate;
+}
+
 int clk_mux_determine_rate_flags(struct clk_hw *hw,
 				 struct clk_rate_request *req,
 				 unsigned long flags)
@@ -549,14 +590,20 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw,
 	struct clk_core *core = hw->core, *parent, *best_parent = NULL;
 	int i, num_parents, ret;
 	unsigned long best = 0;
-	struct clk_rate_request parent_req = *req;
 
 	/* if NO_REPARENT flag set, pass through to current parent */
 	if (core->flags & CLK_SET_RATE_NO_REPARENT) {
 		parent = core->parent;
 		if (core->flags & CLK_SET_RATE_PARENT) {
-			ret = __clk_determine_rate(parent ? parent->hw : NULL,
-						   &parent_req);
+			struct clk_rate_request parent_req;
+
+			if (!parent) {
+				req->rate = 0;
+				return 0;
+			}
+
+			clk_core_forward_rate_req(core, req, parent, &parent_req, req->rate);
+			ret = clk_core_round_rate_nolock(parent, &parent_req);
 			if (ret)
 				return ret;
 
@@ -573,23 +620,29 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw,
 	/* find the parent that can provide the fastest rate <= rate */
 	num_parents = core->num_parents;
 	for (i = 0; i < num_parents; i++) {
+		unsigned long parent_rate;
+
 		parent = clk_core_get_parent_by_index(core, i);
 		if (!parent)
 			continue;
 
 		if (core->flags & CLK_SET_RATE_PARENT) {
-			parent_req = *req;
-			ret = __clk_determine_rate(parent->hw, &parent_req);
+			struct clk_rate_request parent_req;
+
+			clk_core_forward_rate_req(core, req, parent, &parent_req, req->rate);
+			ret = clk_core_round_rate_nolock(parent, &parent_req);
 			if (ret)
 				continue;
+
+			parent_rate = parent_req.rate;
 		} else {
-			parent_req.rate = clk_core_get_rate_nolock(parent);
+			parent_rate = clk_core_get_rate_nolock(parent);
 		}
 
-		if (mux_is_better_rate(req->rate, parent_req.rate,
+		if (mux_is_better_rate(req->rate, parent_rate,
 				       best, flags)) {
 			best_parent = parent;
-			best = parent_req.rate;
+			best = parent_rate;
 		}
 	}
 
@@ -631,6 +684,40 @@ static void clk_core_get_boundaries(struct clk_core *core,
 		*max_rate = min(*max_rate, clk_user->max_rate);
 }
 
+/*
+ * clk_hw_get_rate_range() - returns the clock rate range for a hw clk
+ * @hw: the hw clk we want to get the range from
+ * @min_rate: pointer to the variable that will hold the minimum
+ * @max_rate: pointer to the variable that will hold the maximum
+ *
+ * Fills the @min_rate and @max_rate variables with the minimum and
+ * maximum that clock can reach.
+ */
+void clk_hw_get_rate_range(struct clk_hw *hw, unsigned long *min_rate,
+			   unsigned long *max_rate)
+{
+	clk_core_get_boundaries(hw->core, min_rate, max_rate);
+}
+EXPORT_SYMBOL_GPL(clk_hw_get_rate_range);
+
+static bool clk_core_check_boundaries(struct clk_core *core,
+				      unsigned long min_rate,
+				      unsigned long max_rate)
+{
+	struct clk *user;
+
+	lockdep_assert_held(&prepare_lock);
+
+	if (min_rate > core->max_rate || max_rate < core->min_rate)
+		return false;
+
+	hlist_for_each_entry(user, &core->clks, clks_node)
+		if (min_rate > user->max_rate || max_rate < user->min_rate)
+			return false;
+
+	return true;
+}
+
 void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate,
 			   unsigned long max_rate)
 {
@@ -828,10 +915,9 @@ static void clk_core_unprepare(struct clk_core *core)
 	if (core->ops->unprepare)
 		core->ops->unprepare(core->hw);
 
-	clk_pm_runtime_put(core);
-
 	trace_clk_unprepare_complete(core);
 	clk_core_unprepare(core->parent);
+	clk_pm_runtime_put(core);
 }
 
 static void clk_core_unprepare_lock(struct clk_core *core)
@@ -1330,6 +1416,20 @@ static int clk_core_determine_round_nolock(struct clk_core *core,
 		return 0;
 
 	/*
+	 * Some clock providers hand-craft their clk_rate_requests and
+	 * might not fill min_rate and max_rate.
+	 *
+	 * If it's the case, clamping the rate is equivalent to setting
+	 * the rate to 0 which is bad. Skip the clamping but complain so
+	 * that it gets fixed, hopefully.
+	 */
+	if (!req->min_rate && !req->max_rate)
+		pr_warn("%s: %s: clk_rate_request has initialized min or max rate.\n",
+			__func__, core->name);
+	else
+		req->rate = clamp(req->rate, req->min_rate, req->max_rate);
+
+	/*
 	 * At this point, core protection will be disabled
 	 * - if the provider is not protected at all
 	 * - if the calling consumer is the only one which has exclusivity
@@ -1354,13 +1454,23 @@ static int clk_core_determine_round_nolock(struct clk_core *core,
 }
 
 static void clk_core_init_rate_req(struct clk_core * const core,
-				   struct clk_rate_request *req)
+				   struct clk_rate_request *req,
+				   unsigned long rate)
 {
 	struct clk_core *parent;
 
-	if (WARN_ON(!core || !req))
+	if (WARN_ON(!req))
+		return;
+
+	memset(req, 0, sizeof(*req));
+	req->max_rate = ULONG_MAX;
+
+	if (!core)
 		return;
 
+	req->rate = rate;
+	clk_core_get_boundaries(core, &req->min_rate, &req->max_rate);
+
 	parent = core->parent;
 	if (parent) {
 		req->best_parent_hw = parent->hw;
@@ -1371,6 +1481,51 @@ static void clk_core_init_rate_req(struct clk_core * const core,
 	}
 }
 
+/**
+ * clk_hw_init_rate_request - Initializes a clk_rate_request
+ * @hw: the clk for which we want to submit a rate request
+ * @req: the clk_rate_request structure we want to initialise
+ * @rate: the rate which is to be requested
+ *
+ * Initializes a clk_rate_request structure to submit to
+ * __clk_determine_rate() or similar functions.
+ */
+void clk_hw_init_rate_request(const struct clk_hw *hw,
+			      struct clk_rate_request *req,
+			      unsigned long rate)
+{
+	if (WARN_ON(!hw || !req))
+		return;
+
+	clk_core_init_rate_req(hw->core, req, rate);
+}
+EXPORT_SYMBOL_GPL(clk_hw_init_rate_request);
+
+/**
+ * clk_hw_forward_rate_request - Forwards a clk_rate_request to a clock's parent
+ * @hw: the original clock that got the rate request
+ * @old_req: the original clk_rate_request structure we want to forward
+ * @parent: the clk we want to forward @old_req to
+ * @req: the clk_rate_request structure we want to initialise
+ * @parent_rate: The rate which is to be requested to @parent
+ *
+ * Initializes a clk_rate_request structure to submit to a clock parent
+ * in __clk_determine_rate() or similar functions.
+ */
+void clk_hw_forward_rate_request(const struct clk_hw *hw,
+				 const struct clk_rate_request *old_req,
+				 const struct clk_hw *parent,
+				 struct clk_rate_request *req,
+				 unsigned long parent_rate)
+{
+	if (WARN_ON(!hw || !old_req || !parent || !req))
+		return;
+
+	clk_core_forward_rate_req(hw->core, old_req,
+				  parent->core, req,
+				  parent_rate);
+}
+
 static bool clk_core_can_round(struct clk_core * const core)
 {
 	return core->ops->determine_rate || core->ops->round_rate;
@@ -1379,6 +1534,8 @@ static bool clk_core_can_round(struct clk_core * const core)
 static int clk_core_round_rate_nolock(struct clk_core *core,
 				      struct clk_rate_request *req)
 {
+	int ret;
+
 	lockdep_assert_held(&prepare_lock);
 
 	if (!core) {
@@ -1386,12 +1543,22 @@ static int clk_core_round_rate_nolock(struct clk_core *core,
 		return 0;
 	}
 
-	clk_core_init_rate_req(core, req);
-
 	if (clk_core_can_round(core))
 		return clk_core_determine_round_nolock(core, req);
-	else if (core->flags & CLK_SET_RATE_PARENT)
-		return clk_core_round_rate_nolock(core->parent, req);
+
+	if (core->flags & CLK_SET_RATE_PARENT) {
+		struct clk_rate_request parent_req;
+
+		clk_core_forward_rate_req(core, req, core->parent, &parent_req, req->rate);
+		ret = clk_core_round_rate_nolock(core->parent, &parent_req);
+		if (ret)
+			return ret;
+
+		req->best_parent_rate = parent_req.rate;
+		req->rate = parent_req.rate;
+
+		return 0;
+	}
 
 	req->rate = core->rate;
 	return 0;
@@ -1435,8 +1602,7 @@ unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate)
 	int ret;
 	struct clk_rate_request req;
 
-	clk_core_get_boundaries(hw->core, &req.min_rate, &req.max_rate);
-	req.rate = rate;
+	clk_core_init_rate_req(hw->core, &req, rate);
 
 	ret = clk_core_round_rate_nolock(hw->core, &req);
 	if (ret)
@@ -1468,8 +1634,7 @@ long clk_round_rate(struct clk *clk, unsigned long rate)
 	if (clk->exclusive_count)
 		clk_core_rate_unprotect(clk->core);
 
-	clk_core_get_boundaries(clk->core, &req.min_rate, &req.max_rate);
-	req.rate = rate;
+	clk_core_init_rate_req(clk->core, &req, rate);
 
 	ret = clk_core_round_rate_nolock(clk->core, &req);
 
@@ -1598,6 +1763,7 @@ static unsigned long clk_recalc(struct clk_core *core,
 /**
  * __clk_recalc_rates
  * @core: first clk in the subtree
+ * @update_req: Whether req_rate should be updated with the new rate
  * @msg: notification type (see include/linux/clk.h)
  *
  * Walks the subtree of clks starting with clk and recalculates rates as it
@@ -1607,7 +1773,8 @@ static unsigned long clk_recalc(struct clk_core *core,
  * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
  * if necessary.
  */
-static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
+static void __clk_recalc_rates(struct clk_core *core, bool update_req,
+			       unsigned long msg)
 {
 	unsigned long old_rate;
 	unsigned long parent_rate = 0;
@@ -1621,6 +1788,8 @@ static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
 		parent_rate = core->parent->rate;
 
 	core->rate = clk_recalc(core, parent_rate);
+	if (update_req)
+		core->req_rate = core->rate;
 
 	/*
 	 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
@@ -1630,13 +1799,13 @@ static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
 		__clk_notify(core, msg, old_rate, core->rate);
 
 	hlist_for_each_entry(child, &core->children, child_node)
-		__clk_recalc_rates(child, msg);
+		__clk_recalc_rates(child, update_req, msg);
 }
 
 static unsigned long clk_core_get_rate_recalc(struct clk_core *core)
 {
 	if (core && (core->flags & CLK_GET_RATE_NOCACHE))
-		__clk_recalc_rates(core, 0);
+		__clk_recalc_rates(core, false, 0);
 
 	return clk_core_get_rate_nolock(core);
 }
@@ -1646,8 +1815,9 @@ static unsigned long clk_core_get_rate_recalc(struct clk_core *core)
  * @clk: the clk whose rate is being returned
  *
  * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
- * is set, which means a recalc_rate will be issued.
- * If clk is NULL then returns 0.
+ * is set, which means a recalc_rate will be issued. Can be called regardless of
+ * the clock enabledness. If clk is NULL, or if an error occurred, then returns
+ * 0.
  */
 unsigned long clk_get_rate(struct clk *clk)
 {
@@ -1851,6 +2021,7 @@ static int __clk_set_parent(struct clk_core *core, struct clk_core *parent,
 		flags = clk_enable_lock();
 		clk_reparent(core, old_parent);
 		clk_enable_unlock(flags);
+
 		__clk_set_parent_after(core, old_parent, parent);
 
 		return ret;
@@ -1956,11 +2127,7 @@ static struct clk_core *clk_calc_new_rates(struct clk_core *core,
 	if (clk_core_can_round(core)) {
 		struct clk_rate_request req;
 
-		req.rate = rate;
-		req.min_rate = min_rate;
-		req.max_rate = max_rate;
-
-		clk_core_init_rate_req(core, &req);
+		clk_core_init_rate_req(core, &req, rate);
 
 		ret = clk_core_determine_round_nolock(core, &req);
 		if (ret < 0)
@@ -2159,8 +2326,7 @@ static unsigned long clk_core_req_round_rate_nolock(struct clk_core *core,
 	if (cnt < 0)
 		return cnt;
 
-	clk_core_get_boundaries(core, &req.min_rate, &req.max_rate);
-	req.rate = req_rate;
+	clk_core_init_rate_req(core, &req, req_rate);
 
 	ret = clk_core_round_rate_nolock(core, &req);
 
@@ -2175,7 +2341,7 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
 {
 	struct clk_core *top, *fail_clk;
 	unsigned long rate;
-	int ret = 0;
+	int ret;
 
 	if (!core)
 		return 0;
@@ -2311,19 +2477,15 @@ int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
 }
 EXPORT_SYMBOL_GPL(clk_set_rate_exclusive);
 
-/**
- * clk_set_rate_range - set a rate range for a clock source
- * @clk: clock source
- * @min: desired minimum clock rate in Hz, inclusive
- * @max: desired maximum clock rate in Hz, inclusive
- *
- * Returns success (0) or negative errno.
- */
-int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
+static int clk_set_rate_range_nolock(struct clk *clk,
+				     unsigned long min,
+				     unsigned long max)
 {
 	int ret = 0;
 	unsigned long old_min, old_max, rate;
 
+	lockdep_assert_held(&prepare_lock);
+
 	if (!clk)
 		return 0;
 
@@ -2336,8 +2498,6 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
 		return -EINVAL;
 	}
 
-	clk_prepare_lock();
-
 	if (clk->exclusive_count)
 		clk_core_rate_unprotect(clk->core);
 
@@ -2347,37 +2507,66 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
 	clk->min_rate = min;
 	clk->max_rate = max;
 
-	rate = clk_core_get_rate_nolock(clk->core);
-	if (rate < min || rate > max) {
-		/*
-		 * FIXME:
-		 * We are in bit of trouble here, current rate is outside the
-		 * the requested range. We are going try to request appropriate
-		 * range boundary but there is a catch. It may fail for the
-		 * usual reason (clock broken, clock protected, etc) but also
-		 * because:
-		 * - round_rate() was not favorable and fell on the wrong
-		 *   side of the boundary
-		 * - the determine_rate() callback does not really check for
-		 *   this corner case when determining the rate
-		 */
+	if (!clk_core_check_boundaries(clk->core, min, max)) {
+		ret = -EINVAL;
+		goto out;
+	}
 
-		if (rate < min)
-			rate = min;
-		else
-			rate = max;
+	rate = clk->core->req_rate;
+	if (clk->core->flags & CLK_GET_RATE_NOCACHE)
+		rate = clk_core_get_rate_recalc(clk->core);
 
-		ret = clk_core_set_rate_nolock(clk->core, rate);
-		if (ret) {
-			/* rollback the changes */
-			clk->min_rate = old_min;
-			clk->max_rate = old_max;
-		}
+	/*
+	 * Since the boundaries have been changed, let's give the
+	 * opportunity to the provider to adjust the clock rate based on
+	 * the new boundaries.
+	 *
+	 * We also need to handle the case where the clock is currently
+	 * outside of the boundaries. Clamping the last requested rate
+	 * to the current minimum and maximum will also handle this.
+	 *
+	 * FIXME:
+	 * There is a catch. It may fail for the usual reason (clock
+	 * broken, clock protected, etc) but also because:
+	 * - round_rate() was not favorable and fell on the wrong
+	 *   side of the boundary
+	 * - the determine_rate() callback does not really check for
+	 *   this corner case when determining the rate
+	 */
+	rate = clamp(rate, min, max);
+	ret = clk_core_set_rate_nolock(clk->core, rate);
+	if (ret) {
+		/* rollback the changes */
+		clk->min_rate = old_min;
+		clk->max_rate = old_max;
 	}
 
+out:
 	if (clk->exclusive_count)
 		clk_core_rate_protect(clk->core);
 
+	return ret;
+}
+
+/**
+ * clk_set_rate_range - set a rate range for a clock source
+ * @clk: clock source
+ * @min: desired minimum clock rate in Hz, inclusive
+ * @max: desired maximum clock rate in Hz, inclusive
+ *
+ * Return: 0 for success or negative errno on failure.
+ */
+int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
+{
+	int ret;
+
+	if (!clk)
+		return 0;
+
+	clk_prepare_lock();
+
+	ret = clk_set_rate_range_nolock(clk, min, max);
+
 	clk_prepare_unlock();
 
 	return ret;
@@ -2457,7 +2646,7 @@ static void clk_core_reparent(struct clk_core *core,
 {
 	clk_reparent(core, new_parent);
 	__clk_recalc_accuracies(core);
-	__clk_recalc_rates(core, POST_RATE_CHANGE);
+	__clk_recalc_rates(core, true, POST_RATE_CHANGE);
 }
 
 void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
@@ -2478,27 +2667,13 @@ void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
  *
  * Returns true if @parent is a possible parent for @clk, false otherwise.
  */
-bool clk_has_parent(struct clk *clk, struct clk *parent)
+bool clk_has_parent(const struct clk *clk, const struct clk *parent)
 {
-	struct clk_core *core, *parent_core;
-	int i;
-
 	/* NULL clocks should be nops, so return success if either is NULL. */
 	if (!clk || !parent)
 		return true;
 
-	core = clk->core;
-	parent_core = parent->core;
-
-	/* Optimize for the case where the parent is already the parent. */
-	if (core->parent == parent_core)
-		return true;
-
-	for (i = 0; i < core->num_parents; i++)
-		if (!strcmp(core->parents[i].name, parent_core->name))
-			return true;
-
-	return false;
+	return clk_core_has_parent(clk->core, parent->core);
 }
 EXPORT_SYMBOL_GPL(clk_has_parent);
 
@@ -2555,9 +2730,9 @@ static int clk_core_set_parent_nolock(struct clk_core *core,
 
 	/* propagate rate an accuracy recalculation accordingly */
 	if (ret) {
-		__clk_recalc_rates(core, ABORT_RATE_CHANGE);
+		__clk_recalc_rates(core, true, ABORT_RATE_CHANGE);
 	} else {
-		__clk_recalc_rates(core, POST_RATE_CHANGE);
+		__clk_recalc_rates(core, true, POST_RATE_CHANGE);
 		__clk_recalc_accuracies(core);
 	}
 
@@ -2965,7 +3140,9 @@ static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
 {
 	struct clk_core *child;
 
+	clk_pm_runtime_get(c);
 	clk_summary_show_one(s, c, level);
+	clk_pm_runtime_put(c);
 
 	hlist_for_each_entry(child, &c->children, child_node)
 		clk_summary_show_subtree(s, child, level + 1);
@@ -3217,6 +3394,42 @@ static int current_parent_show(struct seq_file *s, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(current_parent);
 
+#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
+static ssize_t current_parent_write(struct file *file, const char __user *ubuf,
+				    size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct clk_core *core = s->private;
+	struct clk_core *parent;
+	u8 idx;
+	int err;
+
+	err = kstrtou8_from_user(ubuf, count, 0, &idx);
+	if (err < 0)
+		return err;
+
+	parent = clk_core_get_parent_by_index(core, idx);
+	if (!parent)
+		return -ENOENT;
+
+	clk_prepare_lock();
+	err = clk_core_set_parent_nolock(core, parent);
+	clk_prepare_unlock();
+	if (err)
+		return err;
+
+	return count;
+}
+
+static const struct file_operations current_parent_rw_fops = {
+	.open		= current_parent_open,
+	.write		= current_parent_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+#endif
+
 static int clk_duty_cycle_show(struct seq_file *s, void *data)
 {
 	struct clk_core *core = s->private;
@@ -3282,8 +3495,12 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
 #ifdef CLOCK_ALLOW_WRITE_DEBUGFS
 	debugfs_create_file("clk_prepare_enable", 0644, root, core,
 			    &clk_prepare_enable_fops);
-#endif
 
+	if (core->num_parents > 1)
+		debugfs_create_file("clk_parent", 0644, root, core,
+				    &current_parent_rw_fops);
+	else
+#endif
 	if (core->num_parents > 0)
 		debugfs_create_file("clk_parent", 0444, root, core,
 				    &current_parent_fops);
@@ -3343,6 +3560,24 @@ static int __init clk_debug_init(void)
 {
 	struct clk_core *core;
 
+#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
+	pr_warn("\n");
+	pr_warn("********************************************************************\n");
+	pr_warn("**     NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE           **\n");
+	pr_warn("**                                                                **\n");
+	pr_warn("**  WRITEABLE clk DebugFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL **\n");
+	pr_warn("**                                                                **\n");
+	pr_warn("** This means that this kernel is built to expose clk operations  **\n");
+	pr_warn("** such as parent or rate setting, enabling, disabling, etc.      **\n");
+	pr_warn("** to userspace, which may compromise security on your system.    **\n");
+	pr_warn("**                                                                **\n");
+	pr_warn("** If you see this message and you are not debugging the          **\n");
+	pr_warn("** kernel, report this immediately to your vendor!                **\n");
+	pr_warn("**                                                                **\n");
+	pr_warn("**     NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE           **\n");
+	pr_warn("********************************************************************\n");
+#endif
+
 	rootdir = debugfs_create_dir("clk", NULL);
 
 	debugfs_create_file("clk_summary", 0444, rootdir, &all_lists,
@@ -3385,7 +3620,7 @@ static void clk_core_reparent_orphans_nolock(void)
 
 		/*
 		 * We need to use __clk_set_parent_before() and _after() to
-		 * to properly migrate any prepare/enable count of the orphan
+		 * properly migrate any prepare/enable count of the orphan
 		 * clock. This is important for CLK_IS_CRITICAL clocks, which
 		 * are enabled during init but might not have a parent yet.
 		 */
@@ -3394,7 +3629,20 @@ static void clk_core_reparent_orphans_nolock(void)
 			__clk_set_parent_before(orphan, parent);
 			__clk_set_parent_after(orphan, parent, NULL);
 			__clk_recalc_accuracies(orphan);
-			__clk_recalc_rates(orphan, 0);
+			__clk_recalc_rates(orphan, true, 0);
+
+			/*
+			 * __clk_init_parent() will set the initial req_rate to
+			 * 0 if the clock doesn't have clk_ops::recalc_rate and
+			 * is an orphan when it's registered.
+			 *
+			 * 'req_rate' is used by clk_set_rate_range() and
+			 * clk_put() to trigger a clk_set_rate() call whenever
+			 * the boundaries are modified. Let's make sure
+			 * 'req_rate' is set to something non-zero so that
+			 * clk_set_rate_range() doesn't drop the frequency.
+			 */
+			orphan->req_rate = orphan->rate;
 		}
 	}
 }
@@ -3413,9 +3661,6 @@ static int __clk_core_init(struct clk_core *core)
 	unsigned long rate;
 	int phase;
 
-	if (!core)
-		return -EINVAL;
-
 	clk_prepare_lock();
 
 	/*
@@ -3585,7 +3830,6 @@ static int __clk_core_init(struct clk_core *core)
 
 	clk_core_reparent_orphans_nolock();
 
-
 	kref_init(&core->ref);
 out:
 	clk_pm_runtime_put(core);
@@ -3715,8 +3959,9 @@ struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw,
 struct clk *clk_hw_get_clk(struct clk_hw *hw, const char *con_id)
 {
 	struct device *dev = hw->core->dev;
+	const char *name = dev ? dev_name(dev) : NULL;
 
-	return clk_hw_create_clk(dev, hw, dev_name(dev), con_id);
+	return clk_hw_create_clk(dev, hw, name, con_id);
 }
 EXPORT_SYMBOL(clk_hw_get_clk);
 
@@ -4021,7 +4266,7 @@ static const struct clk_ops clk_nodrv_ops = {
 };
 
 static void clk_core_evict_parent_cache_subtree(struct clk_core *root,
-						struct clk_core *target)
+						const struct clk_core *target)
 {
 	int i;
 	struct clk_core *child;
@@ -4037,7 +4282,7 @@ static void clk_core_evict_parent_cache_subtree(struct clk_core *root,
 /* Remove this clk from all parent caches */
 static void clk_core_evict_parent_cache(struct clk_core *core)
 {
-	struct hlist_head **lists;
+	const struct hlist_head **lists;
 	struct clk_core *root;
 
 	lockdep_assert_held(&prepare_lock);
@@ -4191,54 +4436,6 @@ int devm_clk_hw_register(struct device *dev, struct clk_hw *hw)
 }
 EXPORT_SYMBOL_GPL(devm_clk_hw_register);
 
-static int devm_clk_match(struct device *dev, void *res, void *data)
-{
-	struct clk *c = res;
-	if (WARN_ON(!c))
-		return 0;
-	return c == data;
-}
-
-static int devm_clk_hw_match(struct device *dev, void *res, void *data)
-{
-	struct clk_hw *hw = res;
-
-	if (WARN_ON(!hw))
-		return 0;
-	return hw == data;
-}
-
-/**
- * devm_clk_unregister - resource managed clk_unregister()
- * @dev: device that is unregistering the clock data
- * @clk: clock to unregister
- *
- * Deallocate a clock allocated with devm_clk_register(). Normally
- * this function will not need to be called and the resource management
- * code will ensure that the resource is freed.
- */
-void devm_clk_unregister(struct device *dev, struct clk *clk)
-{
-	WARN_ON(devres_release(dev, devm_clk_unregister_cb, devm_clk_match, clk));
-}
-EXPORT_SYMBOL_GPL(devm_clk_unregister);
-
-/**
- * devm_clk_hw_unregister - resource managed clk_hw_unregister()
- * @dev: device that is unregistering the hardware-specific clock data
- * @hw: link to hardware-specific clock data
- *
- * Unregister a clk_hw registered with devm_clk_hw_register(). Normally
- * this function will not need to be called and the resource management
- * code will ensure that the resource is freed.
- */
-void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw)
-{
-	WARN_ON(devres_release(dev, devm_clk_hw_unregister_cb, devm_clk_hw_match,
-				hw));
-}
-EXPORT_SYMBOL_GPL(devm_clk_hw_unregister);
-
 static void devm_clk_release(struct device *dev, void *res)
 {
 	clk_put(*(struct clk **)res);
@@ -4308,9 +4505,10 @@ void __clk_put(struct clk *clk)
 	}
 
 	hlist_del(&clk->clks_node);
-	if (clk->min_rate > clk->core->req_rate ||
-	    clk->max_rate < clk->core->req_rate)
-		clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
+
+	/* If we had any boundaries on that clock, let's drop them. */
+	if (clk->min_rate > 0 || clk->max_rate < ULONG_MAX)
+		clk_set_rate_range_nolock(clk, 0, ULONG_MAX);
 
 	owner = clk->core->owner;
 	kref_put(&clk->core->ref, __clk_release);
@@ -4711,32 +4909,6 @@ void of_clk_del_provider(struct device_node *np)
 }
 EXPORT_SYMBOL_GPL(of_clk_del_provider);
 
-static int devm_clk_provider_match(struct device *dev, void *res, void *data)
-{
-	struct device_node **np = res;
-
-	if (WARN_ON(!np || !*np))
-		return 0;
-
-	return *np == data;
-}
-
-/**
- * devm_of_clk_del_provider() - Remove clock provider registered using devm
- * @dev: Device to whose lifetime the clock provider was bound
- */
-void devm_of_clk_del_provider(struct device *dev)
-{
-	int ret;
-	struct device_node *np = get_clk_provider_node(dev);
-
-	ret = devres_release(dev, devm_of_clk_release_provider,
-			     devm_clk_provider_match, np);
-
-	WARN_ON(ret);
-}
-EXPORT_SYMBOL(devm_of_clk_del_provider);
-
 /**
  * of_parse_clkspec() - Parse a DT clock specifier for a given device node
  * @np: device node to parse clock specifier from