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/export.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/io.h>
14 #include <linux/err.h>
15 #include <linux/string.h>
16 #include "clk.h"
17
18 /**
19 * DOC: basic gateable clock which can gate and ungate its output
20 *
21 * Traits of this clock:
22 * prepare - clk_(un)prepare only ensures parent is (un)prepared
23 * enable - clk_enable and clk_disable are functional & control gating
24 * rate - inherits rate from parent. No clk_set_rate support
25 * parent - fixed parent. No clk_set_parent support
26 */
27
28 struct clk_gate2 {
29 struct clk_hw hw;
30 void __iomem *reg;
31 u8 bit_idx;
32 u8 cgr_val;
33 u8 cgr_mask;
34 u8 flags;
35 spinlock_t *lock;
36 unsigned int *share_count;
37 };
38
39 #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
40
clk_gate2_do_shared_clks(struct clk_hw * hw,bool enable)41 static void clk_gate2_do_shared_clks(struct clk_hw *hw, bool enable)
42 {
43 struct clk_gate2 *gate = to_clk_gate2(hw);
44 u32 reg;
45
46 reg = readl(gate->reg);
47 reg &= ~(gate->cgr_mask << gate->bit_idx);
48 if (enable)
49 reg |= (gate->cgr_val & gate->cgr_mask) << gate->bit_idx;
50 writel(reg, gate->reg);
51 }
52
clk_gate2_enable(struct clk_hw * hw)53 static int clk_gate2_enable(struct clk_hw *hw)
54 {
55 struct clk_gate2 *gate = to_clk_gate2(hw);
56 unsigned long flags;
57
58 spin_lock_irqsave(gate->lock, flags);
59
60 if (gate->share_count && (*gate->share_count)++ > 0)
61 goto out;
62
63 clk_gate2_do_shared_clks(hw, true);
64 out:
65 spin_unlock_irqrestore(gate->lock, flags);
66
67 return 0;
68 }
69
clk_gate2_disable(struct clk_hw * hw)70 static void clk_gate2_disable(struct clk_hw *hw)
71 {
72 struct clk_gate2 *gate = to_clk_gate2(hw);
73 unsigned long flags;
74
75 spin_lock_irqsave(gate->lock, flags);
76
77 if (gate->share_count) {
78 if (WARN_ON(*gate->share_count == 0))
79 goto out;
80 else if (--(*gate->share_count) > 0)
81 goto out;
82 }
83
84 clk_gate2_do_shared_clks(hw, false);
85 out:
86 spin_unlock_irqrestore(gate->lock, flags);
87 }
88
clk_gate2_reg_is_enabled(void __iomem * reg,u8 bit_idx,u8 cgr_val,u8 cgr_mask)89 static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx,
90 u8 cgr_val, u8 cgr_mask)
91 {
92 u32 val = readl(reg);
93
94 if (((val >> bit_idx) & cgr_mask) == cgr_val)
95 return 1;
96
97 return 0;
98 }
99
clk_gate2_is_enabled(struct clk_hw * hw)100 static int clk_gate2_is_enabled(struct clk_hw *hw)
101 {
102 struct clk_gate2 *gate = to_clk_gate2(hw);
103 unsigned long flags;
104 int ret = 0;
105
106 spin_lock_irqsave(gate->lock, flags);
107
108 ret = clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx,
109 gate->cgr_val, gate->cgr_mask);
110
111 spin_unlock_irqrestore(gate->lock, flags);
112
113 return ret;
114 }
115
clk_gate2_disable_unused(struct clk_hw * hw)116 static void clk_gate2_disable_unused(struct clk_hw *hw)
117 {
118 struct clk_gate2 *gate = to_clk_gate2(hw);
119 unsigned long flags;
120
121 spin_lock_irqsave(gate->lock, flags);
122
123 if (!gate->share_count || *gate->share_count == 0)
124 clk_gate2_do_shared_clks(hw, false);
125
126 spin_unlock_irqrestore(gate->lock, flags);
127 }
128
129 static const struct clk_ops clk_gate2_ops = {
130 .enable = clk_gate2_enable,
131 .disable = clk_gate2_disable,
132 .disable_unused = clk_gate2_disable_unused,
133 .is_enabled = clk_gate2_is_enabled,
134 };
135
clk_hw_register_gate2(struct device * dev,const char * name,const char * parent_name,unsigned long flags,void __iomem * reg,u8 bit_idx,u8 cgr_val,u8 cgr_mask,u8 clk_gate2_flags,spinlock_t * lock,unsigned int * share_count)136 struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
137 const char *parent_name, unsigned long flags,
138 void __iomem *reg, u8 bit_idx, u8 cgr_val, u8 cgr_mask,
139 u8 clk_gate2_flags, spinlock_t *lock,
140 unsigned int *share_count)
141 {
142 struct clk_gate2 *gate;
143 struct clk_hw *hw;
144 struct clk_init_data init;
145 int ret;
146
147 gate = kzalloc(sizeof(struct clk_gate2), GFP_KERNEL);
148 if (!gate)
149 return ERR_PTR(-ENOMEM);
150
151 /* struct clk_gate2 assignments */
152 gate->reg = reg;
153 gate->bit_idx = bit_idx;
154 gate->cgr_val = cgr_val;
155 gate->cgr_mask = cgr_mask;
156 gate->flags = clk_gate2_flags;
157 gate->lock = lock;
158 gate->share_count = share_count;
159
160 init.name = name;
161 init.ops = &clk_gate2_ops;
162 init.flags = flags;
163 init.parent_names = parent_name ? &parent_name : NULL;
164 init.num_parents = parent_name ? 1 : 0;
165
166 gate->hw.init = &init;
167 hw = &gate->hw;
168
169 ret = clk_hw_register(dev, hw);
170 if (ret) {
171 kfree(gate);
172 return ERR_PTR(ret);
173 }
174
175 return hw;
176 }
177 EXPORT_SYMBOL_GPL(clk_hw_register_gate2);
178