tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * clk-h32mx.c
3 *
4 * Copyright (C) 2014 Atmel
5 *
6 * Alexandre Belloni <alexandre.belloni@free-electrons.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 */
14
15#include <linux/clk-provider.h>
16#include <linux/clkdev.h>
17#include <linux/clk/at91_pmc.h>
18#include <linux/of.h>
19#include <linux/regmap.h>
20#include <linux/mfd/syscon.h>
21
22#include "pmc.h"
23
24#define H32MX_MAX_FREQ 90000000
25
26struct clk_sama5d4_h32mx {
27 struct clk_hw hw;
28 struct regmap *regmap;
29};
30
31#define to_clk_sama5d4_h32mx(hw) container_of(hw, struct clk_sama5d4_h32mx, hw)
32
33static unsigned long clk_sama5d4_h32mx_recalc_rate(struct clk_hw *hw,
34 unsigned long parent_rate)
35{
36 struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw);
37 unsigned int mckr;
38
39 regmap_read(h32mxclk->regmap, AT91_PMC_MCKR, &mckr);
40 if (mckr & AT91_PMC_H32MXDIV)
41 return parent_rate / 2;
42
43 if (parent_rate > H32MX_MAX_FREQ)
44 pr_warn("H32MX clock is too fast\n");
45 return parent_rate;
46}
47
48static long clk_sama5d4_h32mx_round_rate(struct clk_hw *hw, unsigned long rate,
49 unsigned long *parent_rate)
50{
51 unsigned long div;
52
53 if (rate > *parent_rate)
54 return *parent_rate;
55 div = *parent_rate / 2;
56 if (rate < div)
57 return div;
58
59 if (rate - div < *parent_rate - rate)
60 return div;
61
62 return *parent_rate;
63}
64
65static int clk_sama5d4_h32mx_set_rate(struct clk_hw *hw, unsigned long rate,
66 unsigned long parent_rate)
67{
68 struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw);
69 u32 mckr = 0;
70
71 if (parent_rate != rate && (parent_rate / 2) != rate)
72 return -EINVAL;
73
74 if ((parent_rate / 2) == rate)
75 mckr = AT91_PMC_H32MXDIV;
76
77 regmap_update_bits(h32mxclk->regmap, AT91_PMC_MCKR,
78 AT91_PMC_H32MXDIV, mckr);
79
80 return 0;
81}
82
83static const struct clk_ops h32mx_ops = {
84 .recalc_rate = clk_sama5d4_h32mx_recalc_rate,
85 .round_rate = clk_sama5d4_h32mx_round_rate,
86 .set_rate = clk_sama5d4_h32mx_set_rate,
87};
88
89struct clk_hw * __init
90at91_clk_register_h32mx(struct regmap *regmap, const char *name,
91 const char *parent_name)
92{
93 struct clk_sama5d4_h32mx *h32mxclk;
94 struct clk_init_data init;
95 int ret;
96
97 h32mxclk = kzalloc(sizeof(*h32mxclk), GFP_KERNEL);
98 if (!h32mxclk)
99 return ERR_PTR(-ENOMEM);
100
101 init.name = name;
102 init.ops = &h32mx_ops;
103 init.parent_names = parent_name ? &parent_name : NULL;
104 init.num_parents = parent_name ? 1 : 0;
105 init.flags = CLK_SET_RATE_GATE;
106
107 h32mxclk->hw.init = &init;
108 h32mxclk->regmap = regmap;
109
110 ret = clk_hw_register(NULL, &h32mxclk->hw);
111 if (ret) {
112 kfree(h32mxclk);
113 return ERR_PTR(ret);
114 }
115
116 return &h32mxclk->hw;
117}