clk: qcom: Add simple regmap based muxes

Add support for muxes that use regmap instead of readl/writel
directly. We don't support as many features as clk-mux.c, but
this is good enough to support getting and setting parents.
Adding a table based lookup can be added in the future if needed.

Signed-off-by: Stephen Boyd <[e-mail]>
Tested-by: Kenneth Westfield <[e-mail]>
Signed-off-by: Michael Turquette <[e-mail]>

drivers/clk/qcom/Makefile

···
 clk-qcom-y += clk-rcg2.o
 clk-qcom-y += clk-branch.o
 clk-qcom-y += clk-regmap-divider.o
+clk-qcom-y += clk-regmap-mux.o
 clk-qcom-y += reset.o
 
 obj-$(CONFIG_APQ_GCC_8084) += gcc-apq8084.o

drivers/clk/qcom/clk-regmap-mux.c

···
+/*
+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/regmap.h>
+#include <linux/export.h>
+
+#include "clk-regmap-mux.h"
+
+static inline struct clk_regmap_mux *to_clk_regmap_mux(struct clk_hw *hw)
+{
+	return container_of(to_clk_regmap(hw), struct clk_regmap_mux, clkr);
+}
+
+static u8 mux_get_parent(struct clk_hw *hw)
+{
+	struct clk_regmap_mux *mux = to_clk_regmap_mux(hw);
+	struct clk_regmap *clkr = to_clk_regmap(hw);
+	unsigned int mask = GENMASK(mux->width - 1, 0);
+	unsigned int val;
+
+	regmap_read(clkr->regmap, mux->reg, &val);
+
+	val >>= mux->shift;
+	val &= mask;
+
+	return val;
+}
+
+static int mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_regmap_mux *mux = to_clk_regmap_mux(hw);
+	struct clk_regmap *clkr = to_clk_regmap(hw);
+	unsigned int mask = GENMASK(mux->width + mux->shift - 1, mux->shift);
+	unsigned int val;
+
+	val = index;
+	val <<= mux->shift;
+
+	return regmap_update_bits(clkr->regmap, mux->reg, mask, val);
+}
+
+const struct clk_ops clk_regmap_mux_closest_ops = {
+	.get_parent = mux_get_parent,
+	.set_parent = mux_set_parent,
+	.determine_rate = __clk_mux_determine_rate_closest,
+};
+EXPORT_SYMBOL_GPL(clk_regmap_mux_closest_ops);

drivers/clk/qcom/clk-regmap-mux.h

···
+/*
+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __QCOM_CLK_REGMAP_MUX_H__
+#define __QCOM_CLK_REGMAP_MUX_H__
+
+#include <linux/clk-provider.h>
+#include "clk-regmap.h"
+
+struct clk_regmap_mux {
+	u32			reg;
+	u32			shift;
+	u32			width;
+	struct clk_regmap	clkr;
+};
+
+extern const struct clk_ops clk_regmap_mux_closest_ops;
+
+#endif