xref: /openbmc/linux/drivers/clk/imx/clk-lpcg-scu.c (revision 054ef44e)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright 2018 NXP
4  *	Dong Aisheng <aisheng.dong@nxp.com>
5  */
6 
7 #include <linux/bits.h>
8 #include <linux/clk-provider.h>
9 #include <linux/err.h>
10 #include <linux/io.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 
14 #include "clk-scu.h"
15 
16 static DEFINE_SPINLOCK(imx_lpcg_scu_lock);
17 
18 #define CLK_GATE_SCU_LPCG_MASK		0x3
19 #define CLK_GATE_SCU_LPCG_HW_SEL	BIT(0)
20 #define CLK_GATE_SCU_LPCG_SW_SEL	BIT(1)
21 
22 /*
23  * struct clk_lpcg_scu - Description of LPCG clock
24  *
25  * @hw: clk_hw of this LPCG
26  * @reg: register of this LPCG clock
27  * @bit_idx: bit index of this LPCG clock
28  * @hw_gate: HW auto gate enable
29  *
30  * This structure describes one LPCG clock
31  */
32 struct clk_lpcg_scu {
33 	struct clk_hw hw;
34 	void __iomem *reg;
35 	u8 bit_idx;
36 	bool hw_gate;
37 
38 	/* for state save&restore */
39 	u32 state;
40 };
41 
42 #define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
43 
clk_lpcg_scu_enable(struct clk_hw * hw)44 static int clk_lpcg_scu_enable(struct clk_hw *hw)
45 {
46 	struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
47 	unsigned long flags;
48 	u32 reg, val;
49 
50 	spin_lock_irqsave(&imx_lpcg_scu_lock, flags);
51 
52 	reg = readl_relaxed(clk->reg);
53 	reg &= ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx);
54 
55 	val = CLK_GATE_SCU_LPCG_SW_SEL;
56 	if (clk->hw_gate)
57 		val |= CLK_GATE_SCU_LPCG_HW_SEL;
58 
59 	reg |= val << clk->bit_idx;
60 	writel(reg, clk->reg);
61 
62 	spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags);
63 
64 	return 0;
65 }
66 
clk_lpcg_scu_disable(struct clk_hw * hw)67 static void clk_lpcg_scu_disable(struct clk_hw *hw)
68 {
69 	struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
70 	unsigned long flags;
71 	u32 reg;
72 
73 	spin_lock_irqsave(&imx_lpcg_scu_lock, flags);
74 
75 	reg = readl_relaxed(clk->reg);
76 	reg &= ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx);
77 	writel(reg, clk->reg);
78 
79 	spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags);
80 }
81 
82 static const struct clk_ops clk_lpcg_scu_ops = {
83 	.enable = clk_lpcg_scu_enable,
84 	.disable = clk_lpcg_scu_disable,
85 };
86 
__imx_clk_lpcg_scu(struct device * dev,const char * name,const char * parent_name,unsigned long flags,void __iomem * reg,u8 bit_idx,bool hw_gate)87 struct clk_hw *__imx_clk_lpcg_scu(struct device *dev, const char *name,
88 				  const char *parent_name, unsigned long flags,
89 				  void __iomem *reg, u8 bit_idx, bool hw_gate)
90 {
91 	struct clk_lpcg_scu *clk;
92 	struct clk_init_data init;
93 	struct clk_hw *hw;
94 	int ret;
95 
96 	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
97 	if (!clk)
98 		return ERR_PTR(-ENOMEM);
99 
100 	clk->reg = reg;
101 	clk->bit_idx = bit_idx;
102 	clk->hw_gate = hw_gate;
103 
104 	init.name = name;
105 	init.ops = &clk_lpcg_scu_ops;
106 	init.flags = CLK_SET_RATE_PARENT | flags;
107 	init.parent_names = parent_name ? &parent_name : NULL;
108 	init.num_parents = parent_name ? 1 : 0;
109 
110 	clk->hw.init = &init;
111 
112 	hw = &clk->hw;
113 	ret = clk_hw_register(dev, hw);
114 	if (ret) {
115 		kfree(clk);
116 		hw = ERR_PTR(ret);
117 		return hw;
118 	}
119 
120 	if (dev)
121 		dev_set_drvdata(dev, clk);
122 
123 	return hw;
124 }
125 
imx_clk_lpcg_scu_unregister(struct clk_hw * hw)126 void imx_clk_lpcg_scu_unregister(struct clk_hw *hw)
127 {
128 	struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
129 
130 	clk_hw_unregister(&clk->hw);
131 	kfree(clk);
132 }
133 
imx_clk_lpcg_scu_suspend(struct device * dev)134 static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
135 {
136 	struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
137 
138 	clk->state = readl_relaxed(clk->reg);
139 	dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
140 
141 	return 0;
142 }
143 
imx_clk_lpcg_scu_resume(struct device * dev)144 static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
145 {
146 	struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
147 
148 	/*
149 	 * FIXME: Sometimes writes don't work unless the CPU issues
150 	 * them twice
151 	 */
152 
153 	writel(clk->state, clk->reg);
154 	writel(clk->state, clk->reg);
155 	dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);
156 
157 	return 0;
158 }
159 
160 const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops = {
161 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_lpcg_scu_suspend,
162 				      imx_clk_lpcg_scu_resume)
163 };
164