b66add7a74
With device frequency scaling, the mux clock that (indirectly) feeds the
device selects between a dedicated PLL, and some other stable clocks.
When a clk rate change is requested, the (normally) upstream PLL is
reconfigured. It's possible for the clock output of the PLL to become
unstable during this process.
To avoid causing the device to glitch, the mux should temporarily be
switched over to another "stable" clock during the PLL rate change.
This is done with clk notifiers.
This patch adds common functions for notifiers to temporarily and
transparently reparent mux clocks.
This was loosely based on commit 8adfb08605a9 ("clk: sunxi-ng: mux: Add
clk notifier functions").
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
[Angelo: Changed mtk_mux_nb to hold a pointer to clk_ops instead of mtk_mux]
Co-developed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Miles Chen <miles.chen@mediatek.com>
Link: https://lore.kernel.org/r/20220927101128.44758-4-angelogioacchino.delregno@collabora.com
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
108 lines
2.9 KiB
C
108 lines
2.9 KiB
C
/* 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/notifier.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/types.h>
|
|
|
|
struct clk;
|
|
struct clk_hw_onecell_data;
|
|
struct clk_ops;
|
|
struct device;
|
|
struct device_node;
|
|
|
|
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;
|
|
};
|
|
|
|
#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, \
|
|
}
|
|
|
|
extern const struct clk_ops mtk_mux_clr_set_upd_ops;
|
|
extern const struct clk_ops mtk_mux_gate_clr_set_upd_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)
|
|
|
|
#define MUX_CLR_SET_UPD(_id, _name, _parents, _mux_ofs, \
|
|
_mux_set_ofs, _mux_clr_ofs, _shift, _width, \
|
|
_upd_ofs, _upd) \
|
|
GATE_CLR_SET_UPD_FLAGS(_id, _name, _parents, _mux_ofs, \
|
|
_mux_set_ofs, _mux_clr_ofs, _shift, _width, \
|
|
0, _upd_ofs, _upd, CLK_SET_RATE_PARENT, \
|
|
mtk_mux_clr_set_upd_ops)
|
|
|
|
int mtk_clk_register_muxes(const struct mtk_mux *muxes,
|
|
int num, struct device_node *node,
|
|
spinlock_t *lock,
|
|
struct clk_hw_onecell_data *clk_data);
|
|
|
|
void mtk_clk_unregister_muxes(const struct mtk_mux *muxes, int num,
|
|
struct clk_hw_onecell_data *clk_data);
|
|
|
|
struct mtk_mux_nb {
|
|
struct notifier_block nb;
|
|
const struct clk_ops *ops;
|
|
|
|
u8 bypass_index; /* Which parent to temporarily use */
|
|
u8 original_index; /* Set by notifier callback */
|
|
};
|
|
|
|
#define to_mtk_mux_nb(_nb) container_of(_nb, struct mtk_mux_nb, nb)
|
|
|
|
int devm_mtk_clk_mux_notifier_register(struct device *dev, struct clk *clk,
|
|
struct mtk_mux_nb *mux_nb);
|
|
|
|
#endif /* __DRV_CLK_MTK_MUX_H */
|