1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
  4 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
  5 *
  6 * Gated clock implementation
  7 */
  8
  9#include <linux/clk-provider.h>
 10#include <linux/module.h>
 11#include <linux/slab.h>
 12#include <linux/io.h>
 13#include <linux/err.h>
 14#include <linux/string.h>
 15#include "clk.h"
 16
 17/**
 18 * DOC: basic gatable clock which can gate and ungate it's ouput
 19 *
 20 * Traits of this clock:
 21 * prepare - clk_(un)prepare only ensures parent is (un)prepared
 22 * enable - clk_enable and clk_disable are functional & control gating
 23 * rate - inherits rate from parent.  No clk_set_rate support
 24 * parent - fixed parent.  No clk_set_parent support
 25 */
 26
 27struct clk_gate2 {
 28	struct clk_hw hw;
 29	void __iomem	*reg;
 30	u8		bit_idx;
 31	u8		cgr_val;
 32	u8		flags;
 33	spinlock_t	*lock;
 34	unsigned int	*share_count;
 35};
 36
 37#define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
 38
 39static int clk_gate2_enable(struct clk_hw *hw)
 40{
 41	struct clk_gate2 *gate = to_clk_gate2(hw);
 42	u32 reg;
 43	unsigned long flags = 0;
 44
 45	spin_lock_irqsave(gate->lock, flags);
 46
 47	if (gate->share_count && (*gate->share_count)++ > 0)
 48		goto out;
 49
 50	reg = readl(gate->reg);
 51	reg &= ~(3 << gate->bit_idx);
 52	reg |= gate->cgr_val << gate->bit_idx;
 53	writel(reg, gate->reg);
 54
 55out:
 56	spin_unlock_irqrestore(gate->lock, flags);
 57
 58	return 0;
 59}
 60
 61static void clk_gate2_disable(struct clk_hw *hw)
 62{
 63	struct clk_gate2 *gate = to_clk_gate2(hw);
 64	u32 reg;
 65	unsigned long flags = 0;
 66
 67	spin_lock_irqsave(gate->lock, flags);
 68
 69	if (gate->share_count) {
 70		if (WARN_ON(*gate->share_count == 0))
 71			goto out;
 72		else if (--(*gate->share_count) > 0)
 73			goto out;
 74	}
 75
 76	reg = readl(gate->reg);
 77	reg &= ~(3 << gate->bit_idx);
 78	writel(reg, gate->reg);
 79
 80out:
 81	spin_unlock_irqrestore(gate->lock, flags);
 82}
 83
 84static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx)
 85{
 86	u32 val = readl(reg);
 87
 88	if (((val >> bit_idx) & 1) == 1)
 89		return 1;
 90
 91	return 0;
 92}
 93
 94static int clk_gate2_is_enabled(struct clk_hw *hw)
 95{
 96	struct clk_gate2 *gate = to_clk_gate2(hw);
 97
 98	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx);
 99}
100
101static void clk_gate2_disable_unused(struct clk_hw *hw)
102{
103	struct clk_gate2 *gate = to_clk_gate2(hw);
104	unsigned long flags = 0;
105	u32 reg;
106
107	spin_lock_irqsave(gate->lock, flags);
108
109	if (!gate->share_count || *gate->share_count == 0) {
110		reg = readl(gate->reg);
111		reg &= ~(3 << gate->bit_idx);
112		writel(reg, gate->reg);
113	}
114
115	spin_unlock_irqrestore(gate->lock, flags);
116}
117
118static const struct clk_ops clk_gate2_ops = {
119	.enable = clk_gate2_enable,
120	.disable = clk_gate2_disable,
121	.disable_unused = clk_gate2_disable_unused,
122	.is_enabled = clk_gate2_is_enabled,
123};
124
125struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
126		const char *parent_name, unsigned long flags,
127		void __iomem *reg, u8 bit_idx, u8 cgr_val,
128		u8 clk_gate2_flags, spinlock_t *lock,
129		unsigned int *share_count)
130{
131	struct clk_gate2 *gate;
132	struct clk_hw *hw;
133	struct clk_init_data init;
134	int ret;
135
136	gate = kzalloc(sizeof(struct clk_gate2), GFP_KERNEL);
137	if (!gate)
138		return ERR_PTR(-ENOMEM);
139
140	/* struct clk_gate2 assignments */
141	gate->reg = reg;
142	gate->bit_idx = bit_idx;
143	gate->cgr_val = cgr_val;
144	gate->flags = clk_gate2_flags;
145	gate->lock = lock;
146	gate->share_count = share_count;
147
148	init.name = name;
149	init.ops = &clk_gate2_ops;
150	init.flags = flags;
151	init.parent_names = parent_name ? &parent_name : NULL;
152	init.num_parents = parent_name ? 1 : 0;
153
154	gate->hw.init = &init;
155	hw = &gate->hw;
156
157	ret = clk_hw_register(NULL, hw);
158	if (ret) {
159		kfree(gate);
160		return ERR_PTR(ret);
161	}
162
163	return hw;
164}