xref: /openbmc/linux/drivers/clk/x86/clk-cgu-pll.c (revision 0c6dfa75)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2020-2022 MaxLinear, Inc.
4  * Copyright (C) 2020 Intel Corporation.
5  * Zhu Yixin <yzhu@maxlinear.com>
6  * Rahul Tanwar <rtanwar@maxlinear.com>
7  */
8 
9 #include <linux/clk-provider.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/iopoll.h>
13 #include <linux/of.h>
14 
15 #include "clk-cgu.h"
16 
17 #define to_lgm_clk_pll(_hw)	container_of(_hw, struct lgm_clk_pll, hw)
18 #define PLL_REF_DIV(x)		((x) + 0x08)
19 
20 /*
21  * Calculate formula:
22  * rate = (prate * mult + (prate * frac) / frac_div) / div
23  */
24 static unsigned long
25 lgm_pll_calc_rate(unsigned long prate, unsigned int mult,
26 		  unsigned int div, unsigned int frac, unsigned int frac_div)
27 {
28 	u64 crate, frate, rate64;
29 
30 	rate64 = prate;
31 	crate = rate64 * mult;
32 	frate = rate64 * frac;
33 	do_div(frate, frac_div);
34 	crate += frate;
35 	do_div(crate, div);
36 
37 	return crate;
38 }
39 
40 static unsigned long lgm_pll_recalc_rate(struct clk_hw *hw, unsigned long prate)
41 {
42 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
43 	unsigned int div, mult, frac;
44 
45 	mult = lgm_get_clk_val(pll->membase, PLL_REF_DIV(pll->reg), 0, 12);
46 	div = lgm_get_clk_val(pll->membase, PLL_REF_DIV(pll->reg), 18, 6);
47 	frac = lgm_get_clk_val(pll->membase, pll->reg, 2, 24);
48 
49 	if (pll->type == TYPE_LJPLL)
50 		div *= 4;
51 
52 	return lgm_pll_calc_rate(prate, mult, div, frac, BIT(24));
53 }
54 
55 static int lgm_pll_is_enabled(struct clk_hw *hw)
56 {
57 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
58 	unsigned int ret;
59 
60 	ret = lgm_get_clk_val(pll->membase, pll->reg, 0, 1);
61 
62 	return ret;
63 }
64 
65 static int lgm_pll_enable(struct clk_hw *hw)
66 {
67 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
68 	u32 val;
69 	int ret;
70 
71 	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 1);
72 	ret = regmap_read_poll_timeout_atomic(pll->membase, pll->reg,
73 					      val, (val & 0x1), 1, 100);
74 
75 
76 	return ret;
77 }
78 
79 static void lgm_pll_disable(struct clk_hw *hw)
80 {
81 	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
82 
83 	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 0);
84 }
85 
86 static const struct clk_ops lgm_pll_ops = {
87 	.recalc_rate = lgm_pll_recalc_rate,
88 	.is_enabled = lgm_pll_is_enabled,
89 	.enable = lgm_pll_enable,
90 	.disable = lgm_pll_disable,
91 };
92 
93 static struct clk_hw *
94 lgm_clk_register_pll(struct lgm_clk_provider *ctx,
95 		     const struct lgm_pll_clk_data *list)
96 {
97 	struct clk_init_data init = {};
98 	struct lgm_clk_pll *pll;
99 	struct device *dev = ctx->dev;
100 	struct clk_hw *hw;
101 	int ret;
102 
103 	init.ops = &lgm_pll_ops;
104 	init.name = list->name;
105 	init.flags = list->flags;
106 	init.parent_data = list->parent_data;
107 	init.num_parents = list->num_parents;
108 
109 	pll = devm_kzalloc(dev, sizeof(*pll), GFP_KERNEL);
110 	if (!pll)
111 		return ERR_PTR(-ENOMEM);
112 
113 	pll->membase = ctx->membase;
114 	pll->reg = list->reg;
115 	pll->flags = list->flags;
116 	pll->type = list->type;
117 	pll->hw.init = &init;
118 
119 	hw = &pll->hw;
120 	ret = devm_clk_hw_register(dev, hw);
121 	if (ret)
122 		return ERR_PTR(ret);
123 
124 	return hw;
125 }
126 
127 int lgm_clk_register_plls(struct lgm_clk_provider *ctx,
128 			  const struct lgm_pll_clk_data *list,
129 			  unsigned int nr_clk)
130 {
131 	struct clk_hw *hw;
132 	int i;
133 
134 	for (i = 0; i < nr_clk; i++, list++) {
135 		hw = lgm_clk_register_pll(ctx, list);
136 		if (IS_ERR(hw)) {
137 			dev_err(ctx->dev, "failed to register pll: %s\n",
138 				list->name);
139 			return PTR_ERR(hw);
140 		}
141 		ctx->clk_data.hws[list->id] = hw;
142 	}
143 
144 	return 0;
145 }
146