This is a feature that can also be found in sprd composite clocks,
provide two helpers that can be reused later on.

Original-by: Xiaolong Zhang <xiaolong.zh...@spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zh...@spreadtrum.com>
---
 drivers/clk/sprd/Makefile  |  2 +-
 drivers/clk/sprd/ccu_mux.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/sprd/ccu_mux.h | 63 +++++++++++++++++++++++++++++++++++
 3 files changed, 146 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/sprd/ccu_mux.c
 create mode 100644 drivers/clk/sprd/ccu_mux.h

diff --git a/drivers/clk/sprd/Makefile b/drivers/clk/sprd/Makefile
index 333e2b2..dc89790 100644
--- a/drivers/clk/sprd/Makefile
+++ b/drivers/clk/sprd/Makefile
@@ -1,3 +1,3 @@
 ifneq ($(CONFIG_OF),)
-obj-y  += ccu_common.o ccu_gate.o
+obj-y  += ccu_common.o ccu_gate.o ccu_mux.o
 endif
diff --git a/drivers/clk/sprd/ccu_mux.c b/drivers/clk/sprd/ccu_mux.c
new file mode 100644
index 0000000..51c744e
--- /dev/null
+++ b/drivers/clk/sprd/ccu_mux.c
@@ -0,0 +1,82 @@
+/*
+ * Spreadtrum multiplexer clock driver
+ *
+ * Copyright (C) 2017 Spreadtrum, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+
+#include "ccu_mux.h"
+
+DEFINE_SPINLOCK(mux_lock);
+
+u8 ccu_mux_helper_get_parent(struct ccu_common *common,
+                            struct ccu_mux_internal *mux)
+{
+       u32 reg;
+       u8 parent;
+       int num_parents;
+       int i;
+
+       reg = ccu_readl(common);
+       parent = reg >> mux->shift;
+       parent &= (1 << mux->width) - 1;
+
+       if (mux->table) {
+               num_parents = clk_hw_get_num_parents(&common->hw);
+
+               for (i = 0; i < num_parents; i++)
+                       if (parent == mux->table[i] ||
+                           (i < (num_parents - 1) && parent > mux->table[i] &&
+                            parent < mux->table[i + 1]))
+                               return i;
+               if (i == num_parents)
+                       return i - 1;
+       }
+
+       return parent;
+}
+
+static u8 ccu_mux_get_parent(struct clk_hw *hw)
+{
+       struct ccu_mux *cm = hw_to_ccu_mux(hw);
+
+       return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
+}
+
+int ccu_mux_helper_set_parent(struct ccu_common *common,
+                             struct ccu_mux_internal *mux,
+                             u8 index)
+{
+       unsigned long flags = 0;
+       u32 reg;
+
+       if (mux->table)
+               index = mux->table[index];
+
+       spin_lock_irqsave(common->lock, flags);
+
+       reg = ccu_readl(common);
+       reg &= ~GENMASK(mux->width + mux->shift - 1, mux->shift);
+       ccu_writel(reg | (index << mux->shift), common);
+
+       spin_unlock_irqrestore(common->lock, flags);
+
+       return 0;
+}
+
+static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+       struct ccu_mux *cm = hw_to_ccu_mux(hw);
+
+       return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
+}
+
+const struct clk_ops ccu_mux_ops = {
+       .get_parent = ccu_mux_get_parent,
+       .set_parent = ccu_mux_set_parent,
+       .determine_rate = __clk_mux_determine_rate,
+};
diff --git a/drivers/clk/sprd/ccu_mux.h b/drivers/clk/sprd/ccu_mux.h
new file mode 100644
index 0000000..f3e3fb4
--- /dev/null
+++ b/drivers/clk/sprd/ccu_mux.h
@@ -0,0 +1,63 @@
+/*
+ * Spreadtrum multiplexer clock driver
+ *
+ * Copyright (C) 2017 Spreadtrum, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef _CCU_MUX_H_
+#define _CCU_MUX_H_
+
+#include "ccu_common.h"
+
+struct ccu_mux_internal {
+       u8              shift;
+       u8              width;
+       const u8        *table;
+};
+
+struct ccu_mux {
+       struct ccu_mux_internal mux;
+       struct ccu_common       common;
+};
+
+#define _SPRD_CCU_MUX(_shift, _width, _table)          \
+       {                                               \
+               .shift  = _shift,                       \
+               .width  = _width,                       \
+               .table  = _table,                       \
+       }
+
+#define SPRD_CCU_MUX(_struct, _name, _parents, _table,                 \
+                                    _reg, _shift, _width,              \
+                                    _flags)                            \
+       struct ccu_mux _struct = {                                      \
+               .mux    = _SPRD_CCU_MUX(_shift, _width, _table),        \
+               .common = {                                             \
+                       .reg            = _reg,                         \
+                       .lock           = &mux_lock,                    \
+                       .hw.init        = CLK_HW_INIT_PARENTS(_name,    \
+                                                             _parents, \
+                                                             &ccu_mux_ops,\
+                                                             _flags),  \
+               }                                                       \
+       }
+
+static inline struct ccu_mux *hw_to_ccu_mux(struct clk_hw *hw)
+{
+       struct ccu_common *common = hw_to_ccu_common(hw);
+
+       return container_of(common, struct ccu_mux, common);
+}
+
+extern const struct clk_ops ccu_mux_ops;
+extern spinlock_t mux_lock;
+
+u8 ccu_mux_helper_get_parent(struct ccu_common *common,
+                            struct ccu_mux_internal *mux);
+int ccu_mux_helper_set_parent(struct ccu_common *common,
+                             struct ccu_mux_internal *mux,
+                             u8 index);
+
+#endif /* _CCU_MUX_H_ */
-- 
2.7.4

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