1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
4 */
5
6#include <linux/clk-provider.h>
7#include <linux/clkdev.h>
8#include <linux/clk/at91_pmc.h>
9#include <linux/of.h>
10#include <linux/mfd/syscon.h>
11#include <linux/regmap.h>
12
13#include "pmc.h"
14
15#define SYSTEM_MAX_ID		31
16
17#define SYSTEM_MAX_NAME_SZ	32
18
19#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
20struct clk_system {
21	struct clk_hw hw;
22	struct regmap *regmap;
23	struct at91_clk_pms pms;
24	u8 id;
25};
26
27static inline int is_pck(int id)
28{
29	return (id >= 8) && (id <= 15);
30}
31
32static inline bool clk_system_ready(struct regmap *regmap, int id)
33{
34	unsigned int status;
35
36	regmap_read(regmap, AT91_PMC_SR, &status);
37
38	return !!(status & (1 << id));
39}
40
41static int clk_system_prepare(struct clk_hw *hw)
42{
43	struct clk_system *sys = to_clk_system(hw);
44
45	regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
46
47	if (!is_pck(sys->id))
48		return 0;
49
50	while (!clk_system_ready(sys->regmap, sys->id))
51		cpu_relax();
52
53	return 0;
54}
55
56static void clk_system_unprepare(struct clk_hw *hw)
57{
58	struct clk_system *sys = to_clk_system(hw);
59
60	regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
61}
62
63static int clk_system_is_prepared(struct clk_hw *hw)
64{
65	struct clk_system *sys = to_clk_system(hw);
66	unsigned int status;
67
68	regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
69
70	if (!(status & (1 << sys->id)))
71		return 0;
72
73	if (!is_pck(sys->id))
74		return 1;
75
76	regmap_read(sys->regmap, AT91_PMC_SR, &status);
77
78	return !!(status & (1 << sys->id));
79}
80
81static int clk_system_save_context(struct clk_hw *hw)
82{
83	struct clk_system *sys = to_clk_system(hw);
84
85	sys->pms.status = clk_system_is_prepared(hw);
86
87	return 0;
88}
89
90static void clk_system_restore_context(struct clk_hw *hw)
91{
92	struct clk_system *sys = to_clk_system(hw);
93
94	if (sys->pms.status)
95		clk_system_prepare(&sys->hw);
96}
97
98static const struct clk_ops system_ops = {
99	.prepare = clk_system_prepare,
100	.unprepare = clk_system_unprepare,
101	.is_prepared = clk_system_is_prepared,
102	.save_context = clk_system_save_context,
103	.restore_context = clk_system_restore_context,
104};
105
106struct clk_hw * __init
107at91_clk_register_system(struct regmap *regmap, const char *name,
108			 const char *parent_name, struct clk_hw *parent_hw, u8 id,
109			 unsigned long flags)
110{
111	struct clk_system *sys;
112	struct clk_hw *hw;
113	struct clk_init_data init = {};
114	int ret;
115
116	if (!(parent_name || parent_hw) || id > SYSTEM_MAX_ID)
117		return ERR_PTR(-EINVAL);
118
119	sys = kzalloc(sizeof(*sys), GFP_KERNEL);
120	if (!sys)
121		return ERR_PTR(-ENOMEM);
122
123	init.name = name;
124	init.ops = &system_ops;
125	if (parent_hw)
126		init.parent_hws = (const struct clk_hw **)&parent_hw;
127	else
128		init.parent_names = &parent_name;
129	init.num_parents = 1;
130	init.flags = CLK_SET_RATE_PARENT | flags;
131
132	sys->id = id;
133	sys->hw.init = &init;
134	sys->regmap = regmap;
135
136	hw = &sys->hw;
137	ret = clk_hw_register(NULL, &sys->hw);
138	if (ret) {
139		kfree(sys);
140		hw = ERR_PTR(ret);
141	}
142
143	return hw;
144}
145