linux_dsm_epyc7002/drivers/clk/sprd/gate.c
Chunyan Zhang 8b4f6b8d59 clk: sprd: check its parent status before reading gate clock
Some clocks only can be accessed if their parent is enabled. mipi_csi_xx
clocks on SC9863A are an examples. We have to ensure the parent clock is
enabled when reading those clocks.

Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lkml.kernel.org/r/20200527053638.31439-2-zhang.lyra@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-26 23:41:14 -07:00

136 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
//
// Spreadtrum gate clock driver
//
// Copyright (C) 2017 Spreadtrum, Inc.
// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include "gate.h"
static void clk_gate_toggle(const struct sprd_gate *sg, bool en)
{
const struct sprd_clk_common *common = &sg->common;
unsigned int reg;
bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? true : false;
set ^= en;
regmap_read(common->regmap, common->reg, &reg);
if (set)
reg |= sg->enable_mask;
else
reg &= ~sg->enable_mask;
regmap_write(common->regmap, common->reg, reg);
}
static void clk_sc_gate_toggle(const struct sprd_gate *sg, bool en)
{
const struct sprd_clk_common *common = &sg->common;
bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
unsigned int offset;
set ^= en;
/*
* Each set/clear gate clock has three registers:
* common->reg - base register
* common->reg + offset - set register
* common->reg + 2 * offset - clear register
*/
offset = set ? sg->sc_offset : sg->sc_offset * 2;
regmap_write(common->regmap, common->reg + offset,
sg->enable_mask);
}
static void sprd_gate_disable(struct clk_hw *hw)
{
struct sprd_gate *sg = hw_to_sprd_gate(hw);
clk_gate_toggle(sg, false);
}
static int sprd_gate_enable(struct clk_hw *hw)
{
struct sprd_gate *sg = hw_to_sprd_gate(hw);
clk_gate_toggle(sg, true);
return 0;
}
static void sprd_sc_gate_disable(struct clk_hw *hw)
{
struct sprd_gate *sg = hw_to_sprd_gate(hw);
clk_sc_gate_toggle(sg, false);
}
static int sprd_sc_gate_enable(struct clk_hw *hw)
{
struct sprd_gate *sg = hw_to_sprd_gate(hw);
clk_sc_gate_toggle(sg, true);
return 0;
}
static int sprd_pll_sc_gate_prepare(struct clk_hw *hw)
{
struct sprd_gate *sg = hw_to_sprd_gate(hw);
clk_sc_gate_toggle(sg, true);
udelay(sg->udelay);
return 0;
}
static int sprd_gate_is_enabled(struct clk_hw *hw)
{
struct sprd_gate *sg = hw_to_sprd_gate(hw);
struct sprd_clk_common *common = &sg->common;
struct clk_hw *parent;
unsigned int reg;
if (sg->flags & SPRD_GATE_NON_AON) {
parent = clk_hw_get_parent(hw);
if (!parent || !clk_hw_is_enabled(parent))
return 0;
}
regmap_read(common->regmap, common->reg, &reg);
if (sg->flags & CLK_GATE_SET_TO_DISABLE)
reg ^= sg->enable_mask;
reg &= sg->enable_mask;
return reg ? 1 : 0;
}
const struct clk_ops sprd_gate_ops = {
.disable = sprd_gate_disable,
.enable = sprd_gate_enable,
.is_enabled = sprd_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(sprd_gate_ops);
const struct clk_ops sprd_sc_gate_ops = {
.disable = sprd_sc_gate_disable,
.enable = sprd_sc_gate_enable,
.is_enabled = sprd_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(sprd_sc_gate_ops);
const struct clk_ops sprd_pll_sc_gate_ops = {
.unprepare = sprd_sc_gate_disable,
.prepare = sprd_pll_sc_gate_prepare,
.is_enabled = sprd_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(sprd_pll_sc_gate_ops);