tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2016 Free Electrons
3 * Copyright (C) 2016 NextThing Co
4 *
5 * Maxime Ripard <maxime.ripard@free-electrons.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
11 */
12
13#include <linux/clk-provider.h>
14
15#include "sun4i_tcon.h"
16#include "sun4i_hdmi.h"
17
18struct sun4i_ddc {
19 struct clk_hw hw;
20 struct sun4i_hdmi *hdmi;
21};
22
23static inline struct sun4i_ddc *hw_to_ddc(struct clk_hw *hw)
24{
25 return container_of(hw, struct sun4i_ddc, hw);
26}
27
28static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
29 unsigned long parent_rate,
30 u8 *m, u8 *n)
31{
32 unsigned long best_rate = 0;
33 u8 best_m = 0, best_n = 0, _m, _n;
34
35 for (_m = 0; _m < 8; _m++) {
36 for (_n = 0; _n < 8; _n++) {
37 unsigned long tmp_rate;
38
39 tmp_rate = (((parent_rate / 2) / 10) >> _n) / (_m + 1);
40
41 if (tmp_rate > rate)
42 continue;
43
44 if (abs(rate - tmp_rate) < abs(rate - best_rate)) {
45 best_rate = tmp_rate;
46 best_m = _m;
47 best_n = _n;
48 }
49 }
50 }
51
52 if (m && n) {
53 *m = best_m;
54 *n = best_n;
55 }
56
57 return best_rate;
58}
59
60static long sun4i_ddc_round_rate(struct clk_hw *hw, unsigned long rate,
61 unsigned long *prate)
62{
63 return sun4i_ddc_calc_divider(rate, *prate, NULL, NULL);
64}
65
66static unsigned long sun4i_ddc_recalc_rate(struct clk_hw *hw,
67 unsigned long parent_rate)
68{
69 struct sun4i_ddc *ddc = hw_to_ddc(hw);
70 u32 reg;
71 u8 m, n;
72
73 reg = readl(ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
74 m = (reg >> 3) & 0x7;
75 n = reg & 0x7;
76
77 return (((parent_rate / 2) / 10) >> n) / (m + 1);
78}
79
80static int sun4i_ddc_set_rate(struct clk_hw *hw, unsigned long rate,
81 unsigned long parent_rate)
82{
83 struct sun4i_ddc *ddc = hw_to_ddc(hw);
84 u8 div_m, div_n;
85
86 sun4i_ddc_calc_divider(rate, parent_rate, &div_m, &div_n);
87
88 writel(SUN4I_HDMI_DDC_CLK_M(div_m) | SUN4I_HDMI_DDC_CLK_N(div_n),
89 ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
90
91 return 0;
92}
93
94static const struct clk_ops sun4i_ddc_ops = {
95 .recalc_rate = sun4i_ddc_recalc_rate,
96 .round_rate = sun4i_ddc_round_rate,
97 .set_rate = sun4i_ddc_set_rate,
98};
99
100int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *parent)
101{
102 struct clk_init_data init;
103 struct sun4i_ddc *ddc;
104 const char *parent_name;
105
106 parent_name = __clk_get_name(parent);
107 if (!parent_name)
108 return -ENODEV;
109
110 ddc = devm_kzalloc(hdmi->dev, sizeof(*ddc), GFP_KERNEL);
111 if (!ddc)
112 return -ENOMEM;
113
114 init.name = "hdmi-ddc";
115 init.ops = &sun4i_ddc_ops;
116 init.parent_names = &parent_name;
117 init.num_parents = 1;
118
119 ddc->hdmi = hdmi;
120 ddc->hw.init = &init;
121
122 hdmi->ddc_clk = devm_clk_register(hdmi->dev, &ddc->hw);
123 if (IS_ERR(hdmi->ddc_clk))
124 return PTR_ERR(hdmi->ddc_clk);
125
126 return 0;
127}