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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 "clkc.h"
16
17#define SDM_DEN 16384
18#define N2_MIN 4
19#define N2_MAX 511
20
21static inline struct meson_clk_mpll_data *
22meson_clk_mpll_data(struct clk_regmap *clk)
23{
24 return (struct meson_clk_mpll_data *)clk->data;
25}
26
27static long rate_from_params(unsigned long parent_rate,
28 unsigned int sdm,
29 unsigned int n2)
30{
31 unsigned long divisor = (SDM_DEN * n2) + sdm;
32
33 if (n2 < N2_MIN)
34 return -EINVAL;
35
36 return DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, divisor);
37}
38
39static void params_from_rate(unsigned long requested_rate,
40 unsigned long parent_rate,
41 unsigned int *sdm,
42 unsigned int *n2,
43 u8 flags)
44{
45 uint64_t div = parent_rate;
46 uint64_t frac = do_div(div, requested_rate);
47
48 frac *= SDM_DEN;
49
50 if (flags & CLK_MESON_MPLL_ROUND_CLOSEST)
51 *sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate);
52 else
53 *sdm = DIV_ROUND_UP_ULL(frac, requested_rate);
54
55 if (*sdm == SDM_DEN) {
56 *sdm = 0;
57 div += 1;
58 }
59
60 if (div < N2_MIN) {
61 *n2 = N2_MIN;
62 *sdm = 0;
63 } else if (div > N2_MAX) {
64 *n2 = N2_MAX;
65 *sdm = SDM_DEN - 1;
66 } else {
67 *n2 = div;
68 }
69}
70
71static unsigned long mpll_recalc_rate(struct clk_hw *hw,
72 unsigned long parent_rate)
73{
74 struct clk_regmap *clk = to_clk_regmap(hw);
75 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
76 unsigned int sdm, n2;
77 long rate;
78
79 sdm = meson_parm_read(clk->map, &mpll->sdm);
80 n2 = meson_parm_read(clk->map, &mpll->n2);
81
82 rate = rate_from_params(parent_rate, sdm, n2);
83 return rate < 0 ? 0 : rate;
84}
85
86static long mpll_round_rate(struct clk_hw *hw,
87 unsigned long rate,
88 unsigned long *parent_rate)
89{
90 struct clk_regmap *clk = to_clk_regmap(hw);
91 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
92 unsigned int sdm, n2;
93
94 params_from_rate(rate, *parent_rate, &sdm, &n2, mpll->flags);
95 return rate_from_params(*parent_rate, sdm, n2);
96}
97
98static int mpll_set_rate(struct clk_hw *hw,
99 unsigned long rate,
100 unsigned long parent_rate)
101{
102 struct clk_regmap *clk = to_clk_regmap(hw);
103 struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
104 unsigned int sdm, n2;
105 unsigned long flags = 0;
106
107 params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
108
109 if (mpll->lock)
110 spin_lock_irqsave(mpll->lock, flags);
111 else
112 __acquire(mpll->lock);
113
114 /* Enable and set the fractional part */
115 meson_parm_write(clk->map, &mpll->sdm, sdm);
116 meson_parm_write(clk->map, &mpll->sdm_en, 1);
117
118 /* Set additional fractional part enable if required */
119 if (MESON_PARM_APPLICABLE(&mpll->ssen))
120 meson_parm_write(clk->map, &mpll->ssen, 1);
121
122 /* Set the integer divider part */
123 meson_parm_write(clk->map, &mpll->n2, n2);
124
125 /* Set the magic misc bit if required */
126 if (MESON_PARM_APPLICABLE(&mpll->misc))
127 meson_parm_write(clk->map, &mpll->misc, 1);
128
129 if (mpll->lock)
130 spin_unlock_irqrestore(mpll->lock, flags);
131 else
132 __release(mpll->lock);
133
134 return 0;
135}
136
137const struct clk_ops meson_clk_mpll_ro_ops = {
138 .recalc_rate = mpll_recalc_rate,
139 .round_rate = mpll_round_rate,
140};
141
142const struct clk_ops meson_clk_mpll_ops = {
143 .recalc_rate = mpll_recalc_rate,
144 .round_rate = mpll_round_rate,
145 .set_rate = mpll_set_rate,
146};