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	u8 id;
24};
25
26static inline int is_pck(int id)
27{
28	return (id >= 8) && (id <= 15);
29}
30
31static inline bool clk_system_ready(struct regmap *regmap, int id)
32{
33	unsigned int status;
34
35	regmap_read(regmap, AT91_PMC_SR, &status);
36
37	return !!(status & (1 << id));
38}
39
40static int clk_system_prepare(struct clk_hw *hw)
41{
42	struct clk_system *sys = to_clk_system(hw);
43
44	regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
45
46	if (!is_pck(sys->id))
47		return 0;
48
49	while (!clk_system_ready(sys->regmap, sys->id))
50		cpu_relax();
51
52	return 0;
53}
54
55static void clk_system_unprepare(struct clk_hw *hw)
56{
57	struct clk_system *sys = to_clk_system(hw);
58
59	regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
60}
61
62static int clk_system_is_prepared(struct clk_hw *hw)
63{
64	struct clk_system *sys = to_clk_system(hw);
65	unsigned int status;
66
67	regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
68
69	if (!(status & (1 << sys->id)))
70		return 0;
71
72	if (!is_pck(sys->id))
73		return 1;
74
75	regmap_read(sys->regmap, AT91_PMC_SR, &status);
76
77	return !!(status & (1 << sys->id));
78}
79
80static const struct clk_ops system_ops = {
81	.prepare = clk_system_prepare,
82	.unprepare = clk_system_unprepare,
83	.is_prepared = clk_system_is_prepared,
84};
85
86struct clk_hw * __init
87at91_clk_register_system(struct regmap *regmap, const char *name,
88			 const char *parent_name, u8 id)
89{
90	struct clk_system *sys;
91	struct clk_hw *hw;
92	struct clk_init_data init;
93	int ret;
94
95	if (!parent_name || id > SYSTEM_MAX_ID)
96		return ERR_PTR(-EINVAL);
97
98	sys = kzalloc(sizeof(*sys), GFP_KERNEL);
99	if (!sys)
100		return ERR_PTR(-ENOMEM);
101
102	init.name = name;
103	init.ops = &system_ops;
104	init.parent_names = &parent_name;
105	init.num_parents = 1;
106	init.flags = CLK_SET_RATE_PARENT;
107
108	sys->id = id;
109	sys->hw.init = &init;
110	sys->regmap = regmap;
111
112	hw = &sys->hw;
113	ret = clk_hw_register(NULL, &sys->hw);
114	if (ret) {
115		kfree(sys);
116		hw = ERR_PTR(ret);
117	}
118
119	return hw;
120}
121