1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2 /*
3 * Copyright (c) 2016 AmLogic, Inc.
4 * Author: Michael Turquette <mturquette@baylibre.com>
5 */
6
7 /*
8 * MultiPhase Locked Loops are outputs from a PLL with additional frequency
9 * scaling capabilities. MPLL rates are calculated as:
10 *
11 * f(N2_integer, SDM_IN ) = 2.0G/(N2_integer + SDM_IN/16384)
12 */
13
14 #include <linux/clk-provider.h>
15 #include <linux/module.h>
16 #include <linux/spinlock.h>
17
18 #include "clk-regmap.h"
19 #include "clk-mpll.h"
20
21 #define SDM_DEN 16384
22 #define N2_MIN 4
23 #define N2_MAX 511
24
25 static inline struct meson_clk_mpll_data *
meson_clk_mpll_data(struct clk_regmap * clk)26 meson_clk_mpll_data(struct clk_regmap *clk)
27 {
28 return (struct meson_clk_mpll_data *)clk->data;
29 }
30
rate_from_params(unsigned long parent_rate,unsigned int sdm,unsigned int n2)31 static long rate_from_params(unsigned long parent_rate,
32 unsigned int sdm,
33 unsigned int n2)
34 {
35 unsigned long divisor = (SDM_DEN * n2) + sdm;
36
37 if (n2 < N2_MIN)
38 return -EINVAL;
39
40 return DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, divisor);
41 }
42
params_from_rate(unsigned long requested_rate,unsigned long parent_rate,unsigned int * sdm,unsigned int * n2,u8 flags)43 static void params_from_rate(unsigned long requested_rate,
44 unsigned long parent_rate,
45 unsigned int *sdm,
46 unsigned int *n2,
47 u8 flags)
48 {
49 uint64_t div = parent_rate;
50 uint64_t frac = do_div(div, requested_rate);
51
52 frac *= SDM_DEN;
53
54 if (flags & CLK_MESON_MPLL_ROUND_CLOSEST)
55 *sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate);
56 else
57 *sdm = DIV_ROUND_UP_ULL(frac, requested_rate);
58
59 if (*sdm == SDM_DEN) {
60 *sdm = 0;
61 div += 1;
62 }
63
64 if (div < N2_MIN) {
65 *n2 = N2_MIN;
66 *sdm = 0;
67 } else if (div > N2_MAX) {
68 *n2 = N2_MAX;
69 *sdm = SDM_DEN - 1;
70 } else {
71 *n2 = div;
72 }
73 }
74
mpll_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)75 static unsigned long mpll_recalc_rate(struct clk_hw *hw,
76 unsigned long parent_rate)
77 {
78 struct clk_regmap *clk = to_clk_regmap(hw);
79 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
80 unsigned int sdm, n2;
81 long rate;
82
83 sdm = meson_parm_read(clk->map, &mpll->sdm);
84 n2 = meson_parm_read(clk->map, &mpll->n2);
85
86 rate = rate_from_params(parent_rate, sdm, n2);
87 return rate < 0 ? 0 : rate;
88 }
89
mpll_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)90 static long mpll_round_rate(struct clk_hw *hw,
91 unsigned long rate,
92 unsigned long *parent_rate)
93 {
94 struct clk_regmap *clk = to_clk_regmap(hw);
95 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
96 unsigned int sdm, n2;
97
98 params_from_rate(rate, *parent_rate, &sdm, &n2, mpll->flags);
99 return rate_from_params(*parent_rate, sdm, n2);
100 }
101
mpll_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)102 static int mpll_set_rate(struct clk_hw *hw,
103 unsigned long rate,
104 unsigned long parent_rate)
105 {
106 struct clk_regmap *clk = to_clk_regmap(hw);
107 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
108 unsigned int sdm, n2;
109 unsigned long flags = 0;
110
111 params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
112
113 if (mpll->lock)
114 spin_lock_irqsave(mpll->lock, flags);
115 else
116 __acquire(mpll->lock);
117
118 /* Set the fractional part */
119 meson_parm_write(clk->map, &mpll->sdm, sdm);
120
121 /* Set the integer divider part */
122 meson_parm_write(clk->map, &mpll->n2, n2);
123
124 if (mpll->lock)
125 spin_unlock_irqrestore(mpll->lock, flags);
126 else
127 __release(mpll->lock);
128
129 return 0;
130 }
131
mpll_init(struct clk_hw * hw)132 static int mpll_init(struct clk_hw *hw)
133 {
134 struct clk_regmap *clk = to_clk_regmap(hw);
135 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
136
137 if (mpll->init_count)
138 regmap_multi_reg_write(clk->map, mpll->init_regs,
139 mpll->init_count);
140
141 /* Enable the fractional part */
142 meson_parm_write(clk->map, &mpll->sdm_en, 1);
143
144 /* Set spread spectrum if possible */
145 if (MESON_PARM_APPLICABLE(&mpll->ssen)) {
146 unsigned int ss =
147 mpll->flags & CLK_MESON_MPLL_SPREAD_SPECTRUM ? 1 : 0;
148 meson_parm_write(clk->map, &mpll->ssen, ss);
149 }
150
151 /* Set the magic misc bit if required */
152 if (MESON_PARM_APPLICABLE(&mpll->misc))
153 meson_parm_write(clk->map, &mpll->misc, 1);
154
155 return 0;
156 }
157
158 const struct clk_ops meson_clk_mpll_ro_ops = {
159 .recalc_rate = mpll_recalc_rate,
160 .round_rate = mpll_round_rate,
161 };
162 EXPORT_SYMBOL_GPL(meson_clk_mpll_ro_ops);
163
164 const struct clk_ops meson_clk_mpll_ops = {
165 .recalc_rate = mpll_recalc_rate,
166 .round_rate = mpll_round_rate,
167 .set_rate = mpll_set_rate,
168 .init = mpll_init,
169 };
170 EXPORT_SYMBOL_GPL(meson_clk_mpll_ops);
171
172 MODULE_DESCRIPTION("Amlogic MPLL driver");
173 MODULE_AUTHOR("Michael Turquette <mturquette@baylibre.com>");
174 MODULE_LICENSE("GPL v2");
175