clk: qcom: Add API to query corner voltage on given clk frequency

Add new API for clients to query corner voltage required by a
given frequency.

Change-Id: Ic469c36e016899d882ca084f74e0d2cb2020476c
Signed-off-by: Vivek Aknurwar <viveka@codeaurora.org>

drivers/clk/qcom/common.c

@@ -11,12 +11,14 @@
 #include <linux/clk-provider.h>
 #include <linux/reset-controller.h>
 #include <linux/of.h>
+#include <linux/clk/qcom.h>
 
 #include "common.h"
 #include "clk-rcg.h"
 #include "clk-regmap.h"
 #include "reset.h"
 #include "gdsc.h"
+#include "vdd-level.h"
 
 struct qcom_cc {
 	struct qcom_reset_controller reset;
@@ -357,4 +359,22 @@ void qcom_cc_sync_state(struct device *dev, const struct qcom_cc_desc *desc)
 }
 EXPORT_SYMBOL(qcom_cc_sync_state);
 
+int qcom_clk_get_voltage(struct clk *clk, unsigned long rate)
+{
+	struct clk_regmap *rclk;
+	struct clk_hw *hw = __clk_get_hw(clk);
+	int vdd_level;
+
+	if (!clk_is_regmap_clk(hw))
+		return -EINVAL;
+
+	rclk = to_clk_regmap(hw);
+	vdd_level = clk_find_vdd_level(hw, &rclk->vdd_data, rate);
+	if (vdd_level < 0)
+		return vdd_level;
+
+	return rclk->vdd_data.vdd_class->vdd_uv[vdd_level];
+}
+EXPORT_SYMBOL(qcom_clk_get_voltage);
+
 MODULE_LICENSE("GPL v2");

drivers/clk/qcom/vdd-class.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2019, The Linux Foundation. All rights reserved. */
+/* Copyright (c) 2019-2020, The Linux Foundation. All rights reserved. */
 
 #include <linux/clk-provider.h>
 #include <linux/kernel.h>
@@ -147,6 +147,9 @@ int clk_find_vdd_level(struct clk_hw *hw,
 {
 	int level;
 
+	if (!vdd_data->num_rate_max)
+		return -ENODATA;
+
 	/*
 	 * For certain PLLs, due to the limitation in the bits allocated for
 	 * programming the fractional divider, the actual rate of the PLL will

include/linux/clk/qcom.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2020 The Linux Foundation. All rights reserved.
+ */
+
+#ifndef __LINUX_CLK_QCOM_H_
+#define __LINUX_CLK_QCOM_H_
+
+#include <linux/clk-provider.h>
+
+int qcom_clk_get_voltage(struct clk *clk, unsigned long rate);
+
+#endif  /* __LINUX_CLK_QCOM_H_ */