[PATCH v1 01/11] clk: mediatek: add new clkmux register API
From: Nicolas Boichat <hidden>
Date: 2018-11-13 16:00:52
Also in:
linux-clk, linux-mediatek, lkml
On Mon, Nov 5, 2018 at 10:42 PM Weiyi Lu [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Owen Chen <redacted> 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 <redacted> Signed-off-by: Weiyi Lu <redacted> --- drivers/clk/mediatek/Makefile | 2 +- drivers/clk/mediatek/clk-mux.c | 252 +++++++++++++++++++++++++++++++++ drivers/clk/mediatek/clk-mux.h | 101 +++++++++++++ 3 files changed, 354 insertions(+), 1 deletion(-) create mode 100644 drivers/clk/mediatek/clk-mux.c create mode 100644 drivers/clk/mediatek/clk-mux.hdiff --git a/drivers/clk/mediatek/Makefile b/drivers/clk/mediatek/Makefile index 844b55d2770d..b97980dbb738 100644 --- a/drivers/clk/mediatek/Makefile +++ b/drivers/clk/mediatek/Makefile@@ -1,5 +1,5 @@ # 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.odiff --git a/drivers/clk/mediatek/clk-mux.c b/drivers/clk/mediatek/clk-mux.c new file mode 100644 index 000000000000..18bc9a146be0 --- /dev/null +++ b/drivers/clk/mediatek/clk-mux.c@@ -0,0 +1,252 @@ +// 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->gate_shift); + + regmap_update_bits(mux->regmap, mux->mux_ofs, mask, 0); + + return 0;
Might as well return regmap_update_bits(...).
+}
+
+static void mtk_clk_mux_disable(struct clk_hw *hw)
+{
+ struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+ u32 mask = BIT(mux->gate_shift);
+
+ regmap_update_bits(mux->regmap, mux->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);
+ u32 val;
+
+ val = BIT(mux->gate_shift);
+ regmap_write(mux->regmap, mux->mux_clr_ofs, val);
+
+ return 0;ditto: return regmap_write(...) .
+}
+
+static void mtk_clk_mux_disable_setclr(struct clk_hw *hw)
+{
+ struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+ u32 val;
+
+ val = BIT(mux->gate_shift);
+ regmap_write(mux->regmap, mux->mux_set_ofs, val);
+}
+
+static int mtk_clk_mux_is_enabled(struct clk_hw *hw)
+{
+ struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+ u32 val = 0;No need to init to 0.
+ + regmap_read(mux->regmap, mux->mux_ofs, &val); + + return ((val & BIT(mux->gate_shift)) == 0) ? 1 : 0;
Just (val & BIT(mux->gate_shift)) != 0. Or more simply val & BIT(mux->gate_shift).
+}
+
+static u8 mtk_clk_mux_get_parent(struct clk_hw *hw)
+{
+ struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+ int num_parents = clk_hw_get_num_parents(hw);
+ u32 mask = GENMASK(mux->mux_width - 1, 0);
+ u32 val;
+
+ regmap_read(mux->regmap, mux->mux_ofs, &val);
+ val = (val >> mux->mux_shift) & mask;
+
+ if (val >= num_parents || val >= U8_MAX)val > U8_MAX, technically.
+ return -ERANGE;
This looks wrong, -34 will be cast to an u8 and appear to be valid...
+
+ 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->mux_width - 1, 0);
+ u32 val;
+ unsigned long flags = 0;No need to init to 0.
+
+ if (mux->lock)
+ spin_lock_irqsave(mux->lock, flags);
+ else
+ __acquire(mux->lock);
+
+ regmap_read(mux->regmap, mux->mux_ofs, &val);
+ val = (val & mask) >> mux->mux_shift;
+
+ if (val != index) {
+ val = index << mux->mux_shift;
+ regmap_update_bits(mux->regmap, mux->mux_ofs, mask, val);
+ }What's the point of doing read/compare/update? Are there side effects if you just write the value unconditionally?
+
+ 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->mux_width - 1, 0);
+ u32 val, orig;
+ unsigned long flags = 0;
+
+ if (mux->lock)
+ spin_lock_irqsave(mux->lock, flags);
+ else
+ __acquire(mux->lock);
+
+ regmap_read(mux->regmap, mux->mux_ofs, &val);
+ orig = val;Just read into &orig above.
+ val &= ~(mask << mux->mux_shift); + val |= index << mux->mux_shift;
Maybe this is more readable? val = orig & ~(mask << mux->mux_shift) | (index << mux->mux_shift)
+
+ if (val != orig) {
+ val = (mask << mux->mux_shift);
+ regmap_write(mux->regmap, mux->mux_clr_ofs, val);I'd just regmap_write(..., mask << mux->mux_shift), instead if overriding val.
+ val = (index << mux->mux_shift);
+ regmap_write(mux->regmap, mux->mux_set_ofs, val);
+
+ if (mux->upd_shift >= 0)
+ regmap_write(mux->regmap, mux->upd_ofs,
+ BIT(mux->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 *mtk_mux = NULL;Not necessary to init to NULL.
+ struct clk_init_data init; + struct clk *clk; + + mtk_mux = kzalloc(sizeof(*mtk_mux), GFP_KERNEL); + if (!mtk_mux) + return ERR_PTR(-ENOMEM); + + init.name = mux->name; + init.flags = (mux->flags) | CLK_SET_RATE_PARENT;
mux->flags | CLK_SET_RATE_PARENT
+ init.parent_names = mux->parent_names;
+ init.num_parents = mux->num_parents;
+ init.ops = mux->ops;
+
+ mtk_mux->regmap = regmap;
+ mtk_mux->name = mux->name;
+ mtk_mux->mux_ofs = mux->mux_ofs;
+ mtk_mux->mux_set_ofs = mux->set_ofs;
+ mtk_mux->mux_clr_ofs = mux->clr_ofs;
+ mtk_mux->upd_ofs = mux->upd_ofs;
+ mtk_mux->mux_shift = mux->mux_shift;
+ mtk_mux->mux_width = mux->mux_width;
+ mtk_mux->gate_shift = mux->gate_shift;
+ mtk_mux->upd_shift = mux->upd_shift;
+
+ mtk_mux->lock = lock;
+ mtk_mux->hw.init = &init;
+
+ clk = clk_register(NULL, &mtk_mux->hw);
+ if (IS_ERR(clk)) {
+ kfree(mtk_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;
+
+ if (!clk_data)
+ return -ENOMEM;Is this check necessary? After all you know who the callers are and maybe you need to be careful not to call this with NULL clk_data?
+
+ 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])) {A NULL check seems enough, as you'll never assign a PTR_ERR(..) value into 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;Are we ok with returning 0 even though some of these calls failed?
quoted hunk ↗ jump to hunk
+ } + + 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..ff0276bb771c --- /dev/null +++ b/drivers/clk/mediatek/clk-mux.h@@ -0,0 +1,101 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2018 MediaTek Inc. + * Author: Owen Chen <owen.chen@mediatek.com> + */ + +#ifndef __DRV_CLK_MUX_H +#define __DRV_CLK_MUX_H + +#include <linux/clk-provider.h> + +struct mtk_clk_mux { + struct clk_hw hw; + struct regmap *regmap; + + const char *name; + + u32 mux_set_ofs; + u32 mux_clr_ofs; + u32 mux_ofs; + u32 upd_ofs; + + u8 mux_shift; + u8 mux_width; + u8 gate_shift; + u8 upd_shift; + + 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; + u8 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_MUX_H */ --2.18.0