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192.168.1.100 / T800 / ae7cf9c1566c697c2ba616a120c7ff3e90d20dfd / . / src / kernel / linux / v4.19 / drivers / clk / bcm / clk-bcm53573-ilp.c
blob: 36eb3716ffb005795d39638ba4c6ea385087bf93 [file] [log] [blame]
xjb04a4022021-11-25 15:01:52 +0800[diff] [blame]1/*
2 * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/clk-provider.h>
10#include <linux/err.h>
11#include <linux/io.h>
12#include <linux/mfd/syscon.h>
13#include <linux/of.h>
14#include <linux/of_address.h>
15#include <linux/regmap.h>
16#include <linux/slab.h>
17
18#define PMU_XTAL_FREQ_RATIO 0x66c
19#define XTAL_ALP_PER_4ILP 0x00001fff
20#define XTAL_CTL_EN 0x80000000
21#define PMU_SLOW_CLK_PERIOD 0x6dc
22
23struct bcm53573_ilp {
24 struct clk_hw hw;
25 struct regmap *regmap;
26};
27
28static int bcm53573_ilp_enable(struct clk_hw *hw)
29{
30 struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
31
32 regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0x10199);
33 regmap_write(ilp->regmap, 0x674, 0x10000);
34
35 return 0;
36}
37
38static void bcm53573_ilp_disable(struct clk_hw *hw)
39{
40 struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
41
42 regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0);
43 regmap_write(ilp->regmap, 0x674, 0);
44}
45
46static unsigned long bcm53573_ilp_recalc_rate(struct clk_hw *hw,
47 unsigned long parent_rate)
48{
49 struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
50 struct regmap *regmap = ilp->regmap;
51 u32 last_val, cur_val;
52 int sum = 0, num = 0, loop_num = 0;
53 int avg;
54
55 /* Enable measurement */
56 regmap_write(regmap, PMU_XTAL_FREQ_RATIO, XTAL_CTL_EN);
57
58 /* Read initial value */
59 regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &last_val);
60 last_val &= XTAL_ALP_PER_4ILP;
61
62 /*
63 * At minimum we should loop for a bit to let hardware do the
64 * measurement. This isn't very accurate however, so for a better
65 * precision lets try getting 20 different values for and use average.
66 */
67 while (num < 20) {
68 regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &cur_val);
69 cur_val &= XTAL_ALP_PER_4ILP;
70
71 if (cur_val != last_val) {
72 /* Got different value, use it */
73 sum += cur_val;
74 num++;
75 loop_num = 0;
76 last_val = cur_val;
77 } else if (++loop_num > 5000) {
78 /* Same value over and over, give up */
79 sum += cur_val;
80 num++;
81 break;
82 }
83
84 cpu_relax();
85 }
86
87 /* Disable measurement to save power */
88 regmap_write(regmap, PMU_XTAL_FREQ_RATIO, 0x0);
89
90 avg = sum / num;
91
92 return parent_rate * 4 / avg;
93}
94
95static const struct clk_ops bcm53573_ilp_clk_ops = {
96 .enable = bcm53573_ilp_enable,
97 .disable = bcm53573_ilp_disable,
98 .recalc_rate = bcm53573_ilp_recalc_rate,
99};
100
101static void bcm53573_ilp_init(struct device_node *np)
102{
103 struct bcm53573_ilp *ilp;
104 struct clk_init_data init = { };
105 const char *parent_name;
106 int err;
107
108 ilp = kzalloc(sizeof(*ilp), GFP_KERNEL);
109 if (!ilp)
110 return;
111
112 parent_name = of_clk_get_parent_name(np, 0);
113 if (!parent_name) {
114 err = -ENOENT;
115 goto err_free_ilp;
116 }
117
118 ilp->regmap = syscon_node_to_regmap(of_get_parent(np));
119 if (IS_ERR(ilp->regmap)) {
120 err = PTR_ERR(ilp->regmap);
121 goto err_free_ilp;
122 }
123
124 init.name = np->name;
125 init.ops = &bcm53573_ilp_clk_ops;
126 init.parent_names = &parent_name;
127 init.num_parents = 1;
128
129 ilp->hw.init = &init;
130 err = clk_hw_register(NULL, &ilp->hw);
131 if (err)
132 goto err_free_ilp;
133
134 err = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &ilp->hw);
135 if (err)
136 goto err_clk_hw_unregister;
137
138 return;
139
140err_clk_hw_unregister:
141 clk_hw_unregister(&ilp->hw);
142err_free_ilp:
143 kfree(ilp);
144 pr_err("Failed to init ILP clock: %d\n", err);
145}
146
147/* We need it very early for arch code, before device model gets ready */
148CLK_OF_DECLARE(bcm53573_ilp_clk, "brcm,bcm53573-ilp", bcm53573_ilp_init);