xref: /openbmc/linux/drivers/clk/at91/clk-smd.c (revision 6c33a6f4) 
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 
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 
39 static long at91sam9x5_clk_smd_round_rate(struct clk_hw *hw, unsigned long rate,
40 					  unsigned long *parent_rate)
41 {
42 	unsigned long div;
43 	unsigned long bestrate;
44 	unsigned long tmp;
45 
46 	if (rate >= *parent_rate)
47 		return *parent_rate;
48 
49 	div = *parent_rate / rate;
50 	if (div > SMD_MAX_DIV)
51 		return *parent_rate / (SMD_MAX_DIV + 1);
52 
53 	bestrate = *parent_rate / div;
54 	tmp = *parent_rate / (div + 1);
55 	if (bestrate - rate > rate - tmp)
56 		bestrate = tmp;
57 
58 	return bestrate;
59 }
60 
61 static int at91sam9x5_clk_smd_set_parent(struct clk_hw *hw, u8 index)
62 {
63 	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
64 
65 	if (index > 1)
66 		return -EINVAL;
67 
68 	regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMDS,
69 			   index ? AT91_PMC_SMDS : 0);
70 
71 	return 0;
72 }
73 
74 static u8 at91sam9x5_clk_smd_get_parent(struct clk_hw *hw)
75 {
76 	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
77 	unsigned int smdr;
78 
79 	regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
80 
81 	return smdr & AT91_PMC_SMDS;
82 }
83 
84 static int at91sam9x5_clk_smd_set_rate(struct clk_hw *hw, unsigned long rate,
85 				       unsigned long parent_rate)
86 {
87 	struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
88 	unsigned long div = parent_rate / rate;
89 
90 	if (parent_rate % rate || div < 1 || div > (SMD_MAX_DIV + 1))
91 		return -EINVAL;
92 
93 	regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMD_DIV,
94 			   (div - 1) << SMD_DIV_SHIFT);
95 
96 	return 0;
97 }
98 
99 static const struct clk_ops at91sam9x5_smd_ops = {
100 	.recalc_rate = at91sam9x5_clk_smd_recalc_rate,
101 	.round_rate = at91sam9x5_clk_smd_round_rate,
102 	.get_parent = at91sam9x5_clk_smd_get_parent,
103 	.set_parent = at91sam9x5_clk_smd_set_parent,
104 	.set_rate = at91sam9x5_clk_smd_set_rate,
105 };
106 
107 struct clk_hw * __init
108 at91sam9x5_clk_register_smd(struct regmap *regmap, const char *name,
109 			    const char **parent_names, u8 num_parents)
110 {
111 	struct at91sam9x5_clk_smd *smd;
112 	struct clk_hw *hw;
113 	struct clk_init_data init;
114 	int ret;
115 
116 	smd = kzalloc(sizeof(*smd), GFP_KERNEL);
117 	if (!smd)
118 		return ERR_PTR(-ENOMEM);
119 
120 	init.name = name;
121 	init.ops = &at91sam9x5_smd_ops;
122 	init.parent_names = parent_names;
123 	init.num_parents = num_parents;
124 	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
125 
126 	smd->hw.init = &init;
127 	smd->regmap = regmap;
128 
129 	hw = &smd->hw;
130 	ret = clk_hw_register(NULL, &smd->hw);
131 	if (ret) {
132 		kfree(smd);
133 		hw = ERR_PTR(ret);
134 	}
135 
136 	return hw;
137 }
138