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_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)90 static int mpll_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
91 {
92 struct clk_regmap *clk = to_clk_regmap(hw);
93 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
94 unsigned int sdm, n2;
95 long rate;
96
97 params_from_rate(req->rate, req->best_parent_rate, &sdm, &n2,
98 mpll->flags);
99
100 rate = rate_from_params(req->best_parent_rate, sdm, n2);
101 if (rate < 0)
102 return rate;
103
104 req->rate = rate;
105 return 0;
106 }
107
mpll_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)108 static int mpll_set_rate(struct clk_hw *hw,
109 unsigned long rate,
110 unsigned long parent_rate)
111 {
112 struct clk_regmap *clk = to_clk_regmap(hw);
113 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
114 unsigned int sdm, n2;
115 unsigned long flags = 0;
116
117 params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
118
119 if (mpll->lock)
120 spin_lock_irqsave(mpll->lock, flags);
121 else
122 __acquire(mpll->lock);
123
124 /* Set the fractional part */
125 meson_parm_write(clk->map, &mpll->sdm, sdm);
126
127 /* Set the integer divider part */
128 meson_parm_write(clk->map, &mpll->n2, n2);
129
130 if (mpll->lock)
131 spin_unlock_irqrestore(mpll->lock, flags);
132 else
133 __release(mpll->lock);
134
135 return 0;
136 }
137
mpll_init(struct clk_hw * hw)138 static int mpll_init(struct clk_hw *hw)
139 {
140 struct clk_regmap *clk = to_clk_regmap(hw);
141 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
142
143 if (mpll->init_count)
144 regmap_multi_reg_write(clk->map, mpll->init_regs,
145 mpll->init_count);
146
147 /* Enable the fractional part */
148 meson_parm_write(clk->map, &mpll->sdm_en, 1);
149
150 /* Set spread spectrum if possible */
151 if (MESON_PARM_APPLICABLE(&mpll->ssen)) {
152 unsigned int ss =
153 mpll->flags & CLK_MESON_MPLL_SPREAD_SPECTRUM ? 1 : 0;
154 meson_parm_write(clk->map, &mpll->ssen, ss);
155 }
156
157 /* Set the magic misc bit if required */
158 if (MESON_PARM_APPLICABLE(&mpll->misc))
159 meson_parm_write(clk->map, &mpll->misc, 1);
160
161 return 0;
162 }
163
164 const struct clk_ops meson_clk_mpll_ro_ops = {
165 .recalc_rate = mpll_recalc_rate,
166 .determine_rate = mpll_determine_rate,
167 };
168 EXPORT_SYMBOL_GPL(meson_clk_mpll_ro_ops);
169
170 const struct clk_ops meson_clk_mpll_ops = {
171 .recalc_rate = mpll_recalc_rate,
172 .determine_rate = mpll_determine_rate,
173 .set_rate = mpll_set_rate,
174 .init = mpll_init,
175 };
176 EXPORT_SYMBOL_GPL(meson_clk_mpll_ops);
177
178 MODULE_DESCRIPTION("Amlogic MPLL driver");
179 MODULE_AUTHOR("Michael Turquette <mturquette@baylibre.com>");
180 MODULE_LICENSE("GPL v2");
181