clk: rockchip: add a clock-type for muxes based in the grf

Rockchip socs often have some tiny number of muxes not controlled from
the core clock controller but through bits set in the general register
files. Add a clock-type that can control these as well, so that we
don't need to work around them being absent.

Signed-off-by: Heiko Stuebner <[e-mail]>

drivers/clk/rockchip/Makefile

···
 obj-y	+= clk-cpu.o
 obj-y	+= clk-inverter.o
 obj-y	+= clk-mmc-phase.o
+obj-y	+= clk-muxgrf.o
 obj-y	+= clk-ddr.o
 obj-$(CONFIG_RESET_CONTROLLER)	+= softrst.o
 

drivers/clk/rockchip/clk-muxgrf.c

···
+/*
+ *
+ * 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/slab.h>
+#include <linux/bitops.h>
+#include <linux/regmap.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include "clk.h"
+
+struct rockchip_muxgrf_clock {
+	struct clk_hw		hw;
+	struct regmap		*regmap;
+	u32			reg;
+	u32			shift;
+	u32			width;
+	int			flags;
+};
+
+#define to_muxgrf_clock(_hw) container_of(_hw, struct rockchip_muxgrf_clock, hw)
+
+static u8 rockchip_muxgrf_get_parent(struct clk_hw *hw)
+{
+	struct rockchip_muxgrf_clock *mux = to_muxgrf_clock(hw);
+	unsigned int mask = GENMASK(mux->width - 1, 0);
+	unsigned int val;
+
+	regmap_read(mux->regmap, mux->reg, &val);
+
+	val >>= mux->shift;
+	val &= mask;
+
+	return val;
+}
+
+static int rockchip_muxgrf_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct rockchip_muxgrf_clock *mux = to_muxgrf_clock(hw);
+	unsigned int mask = GENMASK(mux->width + mux->shift - 1, mux->shift);
+	unsigned int val;
+
+	val = index;
+	val <<= mux->shift;
+
+	if (mux->flags & CLK_MUX_HIWORD_MASK)
+		return regmap_write(mux->regmap, mux->reg, val | (mask << 16));
+	else
+		return regmap_update_bits(mux->regmap, mux->reg, mask, val);
+}
+
+static const struct clk_ops rockchip_muxgrf_clk_ops = {
+	.get_parent = rockchip_muxgrf_get_parent,
+	.set_parent = rockchip_muxgrf_set_parent,
+	.determine_rate = __clk_mux_determine_rate,
+};
+
+struct clk *rockchip_clk_register_muxgrf(const char *name,
+				const char *const *parent_names, u8 num_parents,
+				int flags, struct regmap *regmap, int reg,
+				int shift, int width, int mux_flags)
+{
+	struct rockchip_muxgrf_clock *muxgrf_clock;
+	struct clk_init_data init;
+	struct clk *clk;
+
+	if (IS_ERR(regmap)) {
+		pr_err("%s: regmap not available\n", __func__);
+		return ERR_PTR(-ENOTSUPP);
+	}
+
+	muxgrf_clock = kmalloc(sizeof(*muxgrf_clock), GFP_KERNEL);
+	if (!muxgrf_clock)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.flags = flags;
+	init.num_parents = num_parents;
+	init.parent_names = parent_names;
+	init.ops = &rockchip_muxgrf_clk_ops;
+
+	muxgrf_clock->hw.init = &init;
+	muxgrf_clock->regmap = regmap;
+	muxgrf_clock->reg = reg;
+	muxgrf_clock->shift = shift;
+	muxgrf_clock->width = width;
+	muxgrf_clock->flags = mux_flags;
+
+	clk = clk_register(NULL, &muxgrf_clock->hw);
+	if (IS_ERR(clk))
+		kfree(muxgrf_clock);
+
+	return clk;
+}

drivers/clk/rockchip/clk.c

···
 				list->mux_shift, list->mux_width,
 				list->mux_flags, &ctx->lock);
 			break;
+		case branch_muxgrf:
+			clk = rockchip_clk_register_muxgrf(list->name,
+				list->parent_names, list->num_parents,
+				flags, ctx->grf, list->muxdiv_offset,
+				list->mux_shift, list->mux_width,
+				list->mux_flags);
+			break;
 		case branch_divider:
 			if (list->div_table)
 				clk = clk_register_divider_table(NULL,

drivers/clk/rockchip/clk.h

···
 				void __iomem *reg, int shift, int flags,
 				spinlock_t *lock);
 
+struct clk *rockchip_clk_register_muxgrf(const char *name,
+				const char *const *parent_names, u8 num_parents,
+				int flags, struct regmap *grf, int reg,
+				int shift, int width, int mux_flags);
+
 #define PNAME(x) static const char *const x[] __initconst
 
 enum rockchip_clk_branch_type {
 	branch_composite,
 	branch_mux,
+	branch_muxgrf,
 	branch_divider,
 	branch_fraction_divider,
 	branch_gate,
···
 	{							\
 		.id		= _id,				\
 		.branch_type	= branch_mux,			\
+		.name		= cname,			\
+		.parent_names	= pnames,			\
+		.num_parents	= ARRAY_SIZE(pnames),		\
+		.flags		= f,				\
+		.muxdiv_offset	= o,				\
+		.mux_shift	= s,				\
+		.mux_width	= w,				\
+		.mux_flags	= mf,				\
+		.gate_offset	= -1,				\
+	}
+
+#define MUXGRF(_id, cname, pnames, f, o, s, w, mf)		\
+	{							\
+		.id		= _id,				\
+		.branch_type	= branch_muxgrf,		\
 		.name		= cname,			\
 		.parent_names	= pnames,			\
 		.num_parents	= ARRAY_SIZE(pnames),		\