clk: qcom: regmap: Add regmap support for voltage voting

Add support for prepare, unprepare, pre and post rate change regmap
clk_ops callback functions for regmap clocks to handle regulator
requirements.

Change-Id: If4657adcc047e1ca005d3d4f7ab88146dba85ee0
Signed-off-by: David Dai <daidavid1@codeaurora.org>

drivers/clk/qcom/clk-regmap.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2014, 2019 The Linux Foundation. All rights reserved.
  */
 
 #include <linux/device.h>
@@ -84,6 +84,152 @@ void clk_disable_regmap(struct clk_hw *hw)
 }
 EXPORT_SYMBOL_GPL(clk_disable_regmap);
 
+/**
+ * clk_pre_change_regmap() - standard pre_change call back for regmap clks
+ *
+ * @hw: clk to operate on
+ * @cur_rate: current rate of the clk
+ * @new_rate: new rate about to be set for the clk
+ *
+ * Finds the new vdd level corresponding to the new rate and swap out the
+ * existing vdd vote if the new_vdd_level is greater than the vdd_level and
+ * the clock is prepared.
+ *
+ * Returns 0 on success, -EERROR otherwise.
+ */
+int clk_pre_change_regmap(struct clk_hw *hw, unsigned long cur_rate,
+			unsigned long new_rate)
+{
+	struct clk_regmap *rclk = to_clk_regmap(hw);
+	int vdd_level = rclk->vdd_data.vdd_level;
+	int new_vdd_level;
+	int ret = 0;
+
+	if (!rclk->vdd_data.vdd_class)
+		return 0;
+
+	if (!clk_hw_is_prepared(hw))
+		return 0;
+
+	new_vdd_level = clk_find_vdd_level(hw, &rclk->vdd_data, new_rate);
+	if (new_vdd_level < 0)
+		return new_vdd_level;
+
+	if (new_vdd_level <= vdd_level)
+		return 0;
+
+	ret = clk_vote_vdd_level(&rclk->vdd_data, new_vdd_level);
+	if (ret)
+		return ret;
+
+	clk_unvote_vdd_level(&rclk->vdd_data, vdd_level);
+	rclk->vdd_data.vdd_level = new_vdd_level;
+
+	return 0;
+}
+EXPORT_SYMBOL(clk_pre_change_regmap);
+
+/**
+ * clk_post_change_regmap() - standard post_change call back for regmap clks
+ *
+ * @hw: clk to operate on
+ * @old_rate: previous rate of the clk
+ * @cur_rate: current rate of the recently changed clk
+ *
+ * Finds the vdd level corresponding to the cur rate and swap out the
+ * existing vdd vote if the cur_vdd_level is less than the vdd_level and the
+ * clock is prepared.
+ *
+ * Returns 0 on success, -EERROR otherwise.
+ */
+int clk_post_change_regmap(struct clk_hw *hw, unsigned long old_rate,
+			unsigned long cur_rate)
+{
+	struct clk_regmap *rclk = to_clk_regmap(hw);
+	int vdd_level = rclk->vdd_data.vdd_level;
+	int cur_vdd_level;
+	int ret = 0;
+
+	if (!rclk->vdd_data.vdd_class)
+		return 0;
+
+	if (!clk_hw_is_prepared(hw))
+		return 0;
+
+	cur_vdd_level = clk_find_vdd_level(hw, &rclk->vdd_data, cur_rate);
+	if (cur_vdd_level < 0)
+		return cur_vdd_level;
+
+	if (cur_vdd_level >= vdd_level)
+		return 0;
+
+	ret = clk_vote_vdd_level(&rclk->vdd_data, cur_vdd_level);
+	if (ret)
+		return ret;
+
+	clk_unvote_vdd_level(&rclk->vdd_data, vdd_level);
+	rclk->vdd_data.vdd_level = cur_vdd_level;
+
+	return 0;
+}
+EXPORT_SYMBOL(clk_post_change_regmap);
+
+/**
+ * clk_prepare_regmap() - standard prepare call back for regmap clks
+ *
+ * @hw: clk to operate on
+ *
+ * Prepare the clock by updating the vdd_level to level required by
+ * the current rate of the clock if it hasn't been initialized before.
+ * Vdd_level and level required by current clock rate mismatches can
+ * occur due to error cases and upon initial clock registration
+ * if the clock becomes an orphan and is later reparented.
+ *
+ * Returns 0 on success, -EERROR otherwise.
+ */
+int clk_prepare_regmap(struct clk_hw *hw)
+{
+	struct clk_regmap *rclk = to_clk_regmap(hw);
+	int rate = clk_hw_get_rate(hw);
+	int vdd_level;
+
+	if (!rclk->vdd_data.vdd_class)
+		return 0;
+
+	vdd_level = clk_find_vdd_level(hw, &rclk->vdd_data, rate);
+	if (vdd_level < 0)
+		return vdd_level;
+
+	if (rclk->vdd_data.vdd_level == 0)
+		rclk->vdd_data.vdd_level = vdd_level;
+
+	WARN(vdd_level > rclk->vdd_data.vdd_level,
+	     "%s level:%d > vdd_level:%d\n", clk_hw_get_name(hw),
+	     vdd_level, rclk->vdd_data.vdd_level);
+
+	return clk_vote_vdd_level(&rclk->vdd_data, rclk->vdd_data.vdd_level);
+}
+EXPORT_SYMBOL(clk_prepare_regmap);
+
+/**
+ * clk_prepare_regmap() - standard prepare call back for regmap clks
+ *
+ * @hw: clk to operate on
+ *
+ * Unprepare the clock by removing the outstanding vdd_level vote.
+ *
+ */
+void clk_unprepare_regmap(struct clk_hw *hw)
+{
+	struct clk_regmap *rclk = to_clk_regmap(hw);
+
+	if (!rclk->vdd_data.vdd_class)
+		return;
+
+	clk_unvote_vdd_level(&rclk->vdd_data, rclk->vdd_data.vdd_level);
+}
+EXPORT_SYMBOL(clk_unprepare_regmap);
+
 /**
  * devm_clk_register_regmap - register a clk_regmap clock
  *

drivers/clk/qcom/clk-regmap.h

@@ -1,10 +1,11 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/* Copyright (c) 2014, The Linux Foundation. All rights reserved. */
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2014, 2019, The Linux Foundation. All rights reserved. */
 
 #ifndef __QCOM_CLK_REGMAP_H__
 #define __QCOM_CLK_REGMAP_H__
 
 #include <linux/clk-provider.h>
+#include "vdd-class.h"
 
 struct regmap;
 
@@ -16,6 +17,7 @@ struct regmap;
  * @enable_mask: mask when using regmap enable/disable ops
  * @enable_is_inverted: flag to indicate set enable_mask bits to disable
  *                      when using clock_enable_regmap and friends APIs.
+ * @vdd_data:	struct containing vdd-class data for this clock
  */
 struct clk_regmap {
 	struct clk_hw hw;
@@ -23,6 +25,7 @@ struct clk_regmap {
 	unsigned int enable_reg;
 	unsigned int enable_mask;
 	bool enable_is_inverted;
+	struct clk_vdd_class_data vdd_data;
 };
 
 static inline struct clk_regmap *to_clk_regmap(struct clk_hw *hw)
@@ -33,6 +36,12 @@ static inline struct clk_regmap *to_clk_regmap(struct clk_hw *hw)
 int clk_is_enabled_regmap(struct clk_hw *hw);
 int clk_enable_regmap(struct clk_hw *hw);
 void clk_disable_regmap(struct clk_hw *hw);
+int clk_prepare_regmap(struct clk_hw *hw);
+void clk_unprepare_regmap(struct clk_hw *hw);
+int clk_pre_change_regmap(struct clk_hw *hw, unsigned long cur_rate,
+			unsigned long new_rate);
+int clk_post_change_regmap(struct clk_hw *hw, unsigned long old_rate,
+			unsigned long cur_rate);
 int devm_clk_register_regmap(struct device *dev, struct clk_regmap *rclk);
 
 #endif