clk: sprd: add divider clock support

This is a feature that can also be found in sprd composite clocks,
provide a bunch of 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, 75 insertions, 0 deletions

diff --git a/drivers/clk/sprd/div.h b/drivers/clk/sprd/div.h
new file mode 100644
index 000000000000..b3033d24d431
--- /dev/null
+++ b/drivers/clk/sprd/div.h
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Spreadtrum divider clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#ifndef _SPRD_DIV_H_
+#define _SPRD_DIV_H_
+
+#include "common.h"
+
+/**
+ * struct sprd_div_internal - Internal divider description
+ * @shift: Bit offset of the divider in its register
+ * @width: Width of the divider field in its register
+ *
+ * That structure represents a single divider, and is meant to be
+ * embedded in other structures representing the various clock
+ * classes.
+ */
+struct sprd_div_internal {
+	u8	shift;
+	u8	width;
+};
+
+#define _SPRD_DIV_CLK(_shift, _width)	\
+	{				\
+		.shift	= _shift,	\
+		.width	= _width,	\
+	}
+
+struct sprd_div {
+	struct sprd_div_internal	div;
+	struct sprd_clk_common	common;
+};
+
+#define SPRD_DIV_CLK(_struct, _name, _parent, _reg,			\
+			_shift, _width, _flags)				\
+	struct sprd_div _struct = {					\
+		.div	= _SPRD_DIV_CLK(_shift, _width),		\
+		.common	= {						\
+			.regmap		= NULL,				\
+			.reg		= _reg,				\
+			.hw.init	= CLK_HW_INIT(_name,		\
+						      _parent,		\
+						      &sprd_div_ops,	\
+						      _flags),		\
+		}							\
+	}
+
+static inline struct sprd_div *hw_to_sprd_div(const struct clk_hw *hw)
+{
+	struct sprd_clk_common *common = hw_to_sprd_clk_common(hw);
+
+	return container_of(common, struct sprd_div, common);
+}
+
+long sprd_div_helper_round_rate(struct sprd_clk_common *common,
+				const struct sprd_div_internal *div,
+				unsigned long rate,
+				unsigned long *parent_rate);
+
+unsigned long sprd_div_helper_recalc_rate(struct sprd_clk_common *common,
+					  const struct sprd_div_internal *div,
+					  unsigned long parent_rate);
+
+int sprd_div_helper_set_rate(const struct sprd_clk_common *common,
+			     const struct sprd_div_internal *div,
+			     unsigned long rate,
+			     unsigned long parent_rate);
+
+extern const struct clk_ops sprd_div_ops;
+
+#endif /* _SPRD_DIV_H_ */