Re: [PATCH v5 2/9] clk: mediatek: Add new clkmux register API

[James Liao <jamesjj.liao@mediatek.com>]

On Tue, 2019-03-05 at 13:05 +0800, Weiyi Lu wrote:
> From: Owen Chen <owen.chen@mediatek.com>
> 
> On both MT8183 & MT6765, there add "set/clr" register for
> each clkmux setting, and one update register to trigger value change.
> It is designed to prevent read-modify-write racing issue.
> The sw design need to add a new API to handle this hw change with
> a new mtk_clk_mux/mtk_mux struct in new file "clk-mux.c", "clk-mux.h".
> 
> Signed-off-by: Owen Chen <owen.chen@mediatek.com>
> Signed-off-by: Weiyi Lu <weiyi.lu@mediatek.com>

Reviewed-by: James Liao <jamesjj.liao@mediatek.com>

> ---
>  drivers/clk/mediatek/Makefile  |   3 +-
>  drivers/clk/mediatek/clk-mux.c | 223 +++++++++++++++++++++++++++++++++
>  drivers/clk/mediatek/clk-mux.h |  89 +++++++++++++
>  3 files changed, 314 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/clk/mediatek/clk-mux.c
>  create mode 100644 drivers/clk/mediatek/clk-mux.h
> 
> diff --git a/drivers/clk/mediatek/Makefile b/drivers/clk/mediatek/Makefile
> index ee4410ff43ab..20cf9eea4171 100644
> --- a/drivers/clk/mediatek/Makefile
> +++ b/drivers/clk/mediatek/Makefile
> @@ -1,5 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
> -obj-$(CONFIG_COMMON_CLK_MEDIATEK) += clk-mtk.o clk-pll.o clk-gate.o clk-apmixed.o clk-cpumux.o reset.o
> +obj-$(CONFIG_COMMON_CLK_MEDIATEK) += clk-mtk.o clk-pll.o clk-gate.o clk-apmixed.o clk-cpumux.o reset.o clk-mux.o
> +
>  obj-$(CONFIG_COMMON_CLK_MT6797) += clk-mt6797.o
>  obj-$(CONFIG_COMMON_CLK_MT6797_IMGSYS) += clk-mt6797-img.o
>  obj-$(CONFIG_COMMON_CLK_MT6797_MMSYS) += clk-mt6797-mm.o
> diff --git a/drivers/clk/mediatek/clk-mux.c b/drivers/clk/mediatek/clk-mux.c
> new file mode 100644
> index 000000000000..877a883fa616
> --- /dev/null
> +++ b/drivers/clk/mediatek/clk-mux.c
> @@ -0,0 +1,223 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + * Author: Owen Chen <owen.chen@mediatek.com>
> + */
> +
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +
> +#include "clk-mtk.h"
> +#include "clk-mux.h"
> +
> +static inline struct mtk_clk_mux *to_mtk_clk_mux(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct mtk_clk_mux, hw);
> +}
> +
> +static int mtk_clk_mux_enable(struct clk_hw *hw)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +	u32 mask = BIT(mux->data->gate_shift);
> +
> +	return regmap_update_bits(mux->regmap, mux->data->mux_ofs,
> +			mask, ~mask);
> +}
> +
> +static void mtk_clk_mux_disable(struct clk_hw *hw)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +	u32 mask = BIT(mux->data->gate_shift);
> +
> +	regmap_update_bits(mux->regmap, mux->data->mux_ofs, mask, mask);
> +}
> +
> +static int mtk_clk_mux_enable_setclr(struct clk_hw *hw)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +
> +	return regmap_write(mux->regmap, mux->data->clr_ofs,
> +			BIT(mux->data->gate_shift));
> +}
> +
> +static void mtk_clk_mux_disable_setclr(struct clk_hw *hw)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +
> +	regmap_write(mux->regmap, mux->data->set_ofs,
> +			BIT(mux->data->gate_shift));
> +}
> +
> +static int mtk_clk_mux_is_enabled(struct clk_hw *hw)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +	u32 val;
> +
> +	regmap_read(mux->regmap, mux->data->mux_ofs, &val);
> +
> +	return (val & BIT(mux->data->gate_shift)) == 0;
> +}
> +
> +static u8 mtk_clk_mux_get_parent(struct clk_hw *hw)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +	u32 mask = GENMASK(mux->data->mux_width - 1, 0);
> +	u32 val;
> +
> +	regmap_read(mux->regmap, mux->data->mux_ofs, &val);
> +	val = (val >> mux->data->mux_shift) & mask;
> +
> +	return val;
> +}
> +
> +static int mtk_clk_mux_set_parent_lock(struct clk_hw *hw, u8 index)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +	u32 mask = GENMASK(mux->data->mux_width - 1, 0);
> +	unsigned long flags;
> +
> +	if (mux->lock)
> +		spin_lock_irqsave(mux->lock, flags);
> +	else
> +		__acquire(mux->lock);
> +
> +	regmap_update_bits(mux->regmap, mux->data->mux_ofs, mask,
> +		index << mux->data->mux_shift);
> +
> +	if (mux->lock)
> +		spin_unlock_irqrestore(mux->lock, flags);
> +	else
> +		__release(mux->lock);
> +
> +	return 0;
> +}
> +
> +static int mtk_clk_mux_set_parent_setclr_lock(struct clk_hw *hw, u8 index)
> +{
> +	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
> +	u32 mask = GENMASK(mux->data->mux_width - 1, 0);
> +	u32 val, orig;
> +	unsigned long flags;
> +
> +	if (mux->lock)
> +		spin_lock_irqsave(mux->lock, flags);
> +	else
> +		__acquire(mux->lock);
> +
> +	regmap_read(mux->regmap, mux->data->mux_ofs, &orig);
> +	val = (orig & ~(mask << mux->data->mux_shift))
> +			| (index << mux->data->mux_shift);
> +
> +	if (val != orig) {
> +		regmap_write(mux->regmap, mux->data->clr_ofs,
> +				mask << mux->data->mux_shift);
> +		regmap_write(mux->regmap, mux->data->set_ofs,
> +				index << mux->data->mux_shift);
> +
> +		if (mux->data->upd_shift >= 0)
> +			regmap_write(mux->regmap, mux->data->upd_ofs,
> +					BIT(mux->data->upd_shift));
> +	}
> +
> +	if (mux->lock)
> +		spin_unlock_irqrestore(mux->lock, flags);
> +	else
> +		__release(mux->lock);
> +
> +	return 0;
> +}
> +
> +const struct clk_ops mtk_mux_ops = {
> +	.get_parent = mtk_clk_mux_get_parent,
> +	.set_parent = mtk_clk_mux_set_parent_lock,
> +};
> +
> +const struct clk_ops mtk_mux_clr_set_upd_ops = {
> +	.get_parent = mtk_clk_mux_get_parent,
> +	.set_parent = mtk_clk_mux_set_parent_setclr_lock,
> +};
> +
> +const struct clk_ops mtk_mux_gate_ops = {
> +	.enable = mtk_clk_mux_enable,
> +	.disable = mtk_clk_mux_disable,
> +	.is_enabled = mtk_clk_mux_is_enabled,
> +	.get_parent = mtk_clk_mux_get_parent,
> +	.set_parent = mtk_clk_mux_set_parent_lock,
> +};
> +
> +const struct clk_ops mtk_mux_gate_clr_set_upd_ops = {
> +	.enable = mtk_clk_mux_enable_setclr,
> +	.disable = mtk_clk_mux_disable_setclr,
> +	.is_enabled = mtk_clk_mux_is_enabled,
> +	.get_parent = mtk_clk_mux_get_parent,
> +	.set_parent = mtk_clk_mux_set_parent_setclr_lock,
> +};
> +
> +struct clk *mtk_clk_register_mux(const struct mtk_mux *mux,
> +				 struct regmap *regmap,
> +				 spinlock_t *lock)
> +{
> +	struct mtk_clk_mux *clk_mux;
> +	struct clk_init_data init;
> +	struct clk *clk;
> +
> +	clk_mux = kzalloc(sizeof(*clk_mux), GFP_KERNEL);
> +	if (!clk_mux)
> +		return ERR_PTR(-ENOMEM);
> +
> +	init.name = mux->name;
> +	init.flags = mux->flags | CLK_SET_RATE_PARENT;
> +	init.parent_names = mux->parent_names;
> +	init.num_parents = mux->num_parents;
> +	init.ops = mux->ops;
> +
> +	clk_mux->regmap = regmap;
> +	clk_mux->data = mux;
> +	clk_mux->lock = lock;
> +	clk_mux->hw.init = &init;
> +
> +	clk = clk_register(NULL, &clk_mux->hw);
> +	if (IS_ERR(clk)) {
> +		kfree(clk_mux);
> +		return clk;
> +	}
> +
> +	return clk;
> +}
> +
> +int mtk_clk_register_muxes(const struct mtk_mux *muxes,
> +			   int num, struct device_node *node,
> +			   spinlock_t *lock,
> +			   struct clk_onecell_data *clk_data)
> +{
> +	struct regmap *regmap;
> +	struct clk *clk;
> +	int i;
> +
> +	regmap = syscon_node_to_regmap(node);
> +	if (IS_ERR(regmap)) {
> +		pr_err("Cannot find regmap for %pOF: %ld\n", node,
> +		       PTR_ERR(regmap));
> +		return PTR_ERR(regmap);
> +	}
> +
> +	for (i = 0; i < num; i++) {
> +		const struct mtk_mux *mux = &muxes[i];
> +
> +		if (IS_ERR_OR_NULL(clk_data->clks[mux->id])) {
> +			clk = mtk_clk_register_mux(mux, regmap, lock);
> +
> +			if (IS_ERR(clk)) {
> +				pr_err("Failed to register clk %s: %ld\n",
> +				       mux->name, PTR_ERR(clk));
> +				continue;
> +			}
> +
> +			clk_data->clks[mux->id] = clk;
> +		}
> +	}
> +
> +	return 0;
> +}
> diff --git a/drivers/clk/mediatek/clk-mux.h b/drivers/clk/mediatek/clk-mux.h
> new file mode 100644
> index 000000000000..f5625f4d9e6c
> --- /dev/null
> +++ b/drivers/clk/mediatek/clk-mux.h
> @@ -0,0 +1,89 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + * Author: Owen Chen <owen.chen@mediatek.com>
> + */
> +
> +#ifndef __DRV_CLK_MTK_MUX_H
> +#define __DRV_CLK_MTK_MUX_H
> +
> +#include <linux/clk-provider.h>
> +
> +struct mtk_clk_mux {
> +	struct clk_hw hw;
> +	struct regmap *regmap;
> +	const struct mtk_mux *data;
> +	spinlock_t *lock;
> +};
> +
> +struct mtk_mux {
> +	int id;
> +	const char *name;
> +	const char * const *parent_names;
> +	unsigned int flags;
> +
> +	u32 mux_ofs;
> +	u32 set_ofs;
> +	u32 clr_ofs;
> +	u32 upd_ofs;
> +
> +	u8 mux_shift;
> +	u8 mux_width;
> +	u8 gate_shift;
> +	s8 upd_shift;
> +
> +	const struct clk_ops *ops;
> +
> +	signed char num_parents;
> +};
> +
> +extern const struct clk_ops mtk_mux_ops;
> +extern const struct clk_ops mtk_mux_clr_set_upd_ops;
> +extern const struct clk_ops mtk_mux_gate_ops;
> +extern const struct clk_ops mtk_mux_gate_clr_set_upd_ops;
> +
> +#define GATE_CLR_SET_UPD_FLAGS(_id, _name, _parents, _mux_ofs,		\
> +			_mux_set_ofs, _mux_clr_ofs, _shift, _width,	\
> +			_gate, _upd_ofs, _upd, _flags, _ops) {		\
> +		.id = _id,						\
> +		.name = _name,						\
> +		.mux_ofs = _mux_ofs,					\
> +		.set_ofs = _mux_set_ofs,				\
> +		.clr_ofs = _mux_clr_ofs,				\
> +		.upd_ofs = _upd_ofs,					\
> +		.mux_shift = _shift,					\
> +		.mux_width = _width,					\
> +		.gate_shift = _gate,					\
> +		.upd_shift = _upd,					\
> +		.parent_names = _parents,				\
> +		.num_parents = ARRAY_SIZE(_parents),			\
> +		.flags = _flags,					\
> +		.ops = &_ops,						\
> +	}
> +
> +#define MUX_GATE_CLR_SET_UPD_FLAGS(_id, _name, _parents, _mux_ofs,	\
> +			_mux_set_ofs, _mux_clr_ofs, _shift, _width,	\
> +			_gate, _upd_ofs, _upd, _flags)			\
> +		GATE_CLR_SET_UPD_FLAGS(_id, _name, _parents, _mux_ofs,	\
> +			_mux_set_ofs, _mux_clr_ofs, _shift, _width,	\
> +			_gate, _upd_ofs, _upd, _flags,			\
> +			mtk_mux_gate_clr_set_upd_ops)
> +
> +#define MUX_GATE_CLR_SET_UPD(_id, _name, _parents, _mux_ofs,		\
> +			_mux_set_ofs, _mux_clr_ofs, _shift, _width,	\
> +			_gate, _upd_ofs, _upd)				\
> +		MUX_GATE_CLR_SET_UPD_FLAGS(_id, _name, _parents,	\
> +			_mux_ofs, _mux_set_ofs, _mux_clr_ofs, _shift,	\
> +			_width, _gate, _upd_ofs, _upd,			\
> +			CLK_SET_RATE_PARENT)
> +
> +struct clk *mtk_clk_register_mux(const struct mtk_mux *mux,
> +				 struct regmap *regmap,
> +				 spinlock_t *lock);
> +
> +int mtk_clk_register_muxes(const struct mtk_mux *muxes,
> +			   int num, struct device_node *node,
> +			   spinlock_t *lock,
> +			   struct clk_onecell_data *clk_data);
> +
> +#endif /* __DRV_CLK_MTK_MUX_H */



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