clk: sprd: add mux clock support

This patch adds clock multiplexor support for Spreadtrum platforms,
the mux clocks also can be found in sprd composite clocks, so
provides two helpers that can be reused later on.

Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/drivers/clk/sprd/mux.c b/drivers/clk/sprd/mux.c
new file mode 100644
index 000000000000..624041b60358
--- /dev/null
+++ b/drivers/clk/sprd/mux.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Spreadtrum multiplexer clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+
+#include "mux.h"
+
+u8 sprd_mux_helper_get_parent(const struct sprd_clk_common *common,
+			      const struct sprd_mux_ssel *mux)
+{
+	unsigned int reg;
+	u8 parent;
+	int num_parents;
+	int i;
+
+	regmap_read(common->regmap, common->reg, &reg);
+	parent = reg >> mux->shift;
+	parent &= (1 << mux->width) - 1;
+
+	if (!mux->table)
+		return parent;
+
+	num_parents = clk_hw_get_num_parents(&common->hw);
+
+	for (i = 0; i < num_parents - 1; i++)
+		if (parent >= mux->table[i] && parent < mux->table[i + 1])
+			return i;
+
+	return num_parents - 1;
+}
+EXPORT_SYMBOL_GPL(sprd_mux_helper_get_parent);
+
+static u8 sprd_mux_get_parent(struct clk_hw *hw)
+{
+	struct sprd_mux *cm = hw_to_sprd_mux(hw);
+
+	return sprd_mux_helper_get_parent(&cm->common, &cm->mux);
+}
+
+int sprd_mux_helper_set_parent(const struct sprd_clk_common *common,
+			       const struct sprd_mux_ssel *mux,
+			       u8 index)
+{
+	unsigned int reg;
+
+	if (mux->table)
+		index = mux->table[index];
+
+	regmap_read(common->regmap, common->reg, &reg);
+	reg &= ~GENMASK(mux->width + mux->shift - 1, mux->shift);
+	regmap_write(common->regmap, common->reg,
+			  reg | (index << mux->shift));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sprd_mux_helper_set_parent);
+
+static int sprd_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct sprd_mux *cm = hw_to_sprd_mux(hw);
+
+	return sprd_mux_helper_set_parent(&cm->common, &cm->mux, index);
+}
+
+const struct clk_ops sprd_mux_ops = {
+	.get_parent = sprd_mux_get_parent,
+	.set_parent = sprd_mux_set_parent,
+	.determine_rate = __clk_mux_determine_rate,
+};
+EXPORT_SYMBOL_GPL(sprd_mux_ops);