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 SMD_DIV_SHIFT 8
16 #define SMD_MAX_DIV 0xf
17
18 struct at91sam9x5_clk_smd {
19 struct clk_hw hw;
20 struct regmap *regmap;
21 };
22
23 #define to_at91sam9x5_clk_smd(hw) \
24 container_of(hw, struct at91sam9x5_clk_smd, hw)
25
at91sam9x5_clk_smd_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)26 static unsigned long at91sam9x5_clk_smd_recalc_rate(struct clk_hw *hw,
27 unsigned long parent_rate)
28 {
29 struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
30 unsigned int smdr;
31 u8 smddiv;
32
33 regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
34 smddiv = (smdr & AT91_PMC_SMD_DIV) >> SMD_DIV_SHIFT;
35
36 return parent_rate / (smddiv + 1);
37 }
38
at91sam9x5_clk_smd_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)39 static int at91sam9x5_clk_smd_determine_rate(struct clk_hw *hw,
40 struct clk_rate_request *req)
41 {
42 unsigned long div;
43 unsigned long bestrate;
44 unsigned long tmp;
45
46 if (req->rate >= req->best_parent_rate) {
47 req->rate = req->best_parent_rate;
48 return 0;
49 }
50
51 div = req->best_parent_rate / req->rate;
52 if (div > SMD_MAX_DIV) {
53 req->rate = req->best_parent_rate / (SMD_MAX_DIV + 1);
54 return 0;
55 }
56
57 bestrate = req->best_parent_rate / div;
58 tmp = req->best_parent_rate / (div + 1);
59 if (bestrate - req->rate > req->rate - tmp)
60 bestrate = tmp;
61
62 req->rate = bestrate;
63 return 0;
64 }
65
at91sam9x5_clk_smd_set_parent(struct clk_hw * hw,u8 index)66 static int at91sam9x5_clk_smd_set_parent(struct clk_hw *hw, u8 index)
67 {
68 struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
69
70 if (index > 1)
71 return -EINVAL;
72
73 regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMDS,
74 index ? AT91_PMC_SMDS : 0);
75
76 return 0;
77 }
78
at91sam9x5_clk_smd_get_parent(struct clk_hw * hw)79 static u8 at91sam9x5_clk_smd_get_parent(struct clk_hw *hw)
80 {
81 struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
82 unsigned int smdr;
83
84 regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
85
86 return smdr & AT91_PMC_SMDS;
87 }
88
at91sam9x5_clk_smd_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)89 static int at91sam9x5_clk_smd_set_rate(struct clk_hw *hw, unsigned long rate,
90 unsigned long parent_rate)
91 {
92 struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
93 unsigned long div = parent_rate / rate;
94
95 if (parent_rate % rate || div < 1 || div > (SMD_MAX_DIV + 1))
96 return -EINVAL;
97
98 regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMD_DIV,
99 (div - 1) << SMD_DIV_SHIFT);
100
101 return 0;
102 }
103
104 static const struct clk_ops at91sam9x5_smd_ops = {
105 .recalc_rate = at91sam9x5_clk_smd_recalc_rate,
106 .determine_rate = at91sam9x5_clk_smd_determine_rate,
107 .get_parent = at91sam9x5_clk_smd_get_parent,
108 .set_parent = at91sam9x5_clk_smd_set_parent,
109 .set_rate = at91sam9x5_clk_smd_set_rate,
110 };
111
112 struct clk_hw * __init
at91sam9x5_clk_register_smd(struct regmap * regmap,const char * name,const char ** parent_names,u8 num_parents)113 at91sam9x5_clk_register_smd(struct regmap *regmap, const char *name,
114 const char **parent_names, u8 num_parents)
115 {
116 struct at91sam9x5_clk_smd *smd;
117 struct clk_hw *hw;
118 struct clk_init_data init;
119 int ret;
120
121 smd = kzalloc(sizeof(*smd), GFP_KERNEL);
122 if (!smd)
123 return ERR_PTR(-ENOMEM);
124
125 init.name = name;
126 init.ops = &at91sam9x5_smd_ops;
127 init.parent_names = parent_names;
128 init.num_parents = num_parents;
129 init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
130
131 smd->hw.init = &init;
132 smd->regmap = regmap;
133
134 hw = &smd->hw;
135 ret = clk_hw_register(NULL, &smd->hw);
136 if (ret) {
137 kfree(smd);
138 hw = ERR_PTR(ret);
139 }
140
141 return hw;
142 }
143