1/*
2 * Copyright 2014 Chen-Yu Tsai
3 *
4 * Chen-Yu Tsai <wens@csie.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/clk.h>
18#include <linux/clk-provider.h>
19#include <linux/of_address.h>
20
21#include "clk-factors.h"
22
23/**
24 * sun8i_a23_get_mbus_factors() - calculates m factor for MBUS clocks
25 * MBUS rate is calculated as follows
26 * rate = parent_rate / (m + 1);
27 */
28
29static void sun8i_a23_get_mbus_factors(u32 *freq, u32 parent_rate,
30				       u8 *n, u8 *k, u8 *m, u8 *p)
31{
32	u8 div;
33
34	/*
35	 * These clocks can only divide, so we will never be able to
36	 * achieve frequencies higher than the parent frequency
37	 */
38	if (*freq > parent_rate)
39		*freq = parent_rate;
40
41	div = DIV_ROUND_UP(parent_rate, *freq);
42
43	if (div > 8)
44		div = 8;
45
46	*freq = parent_rate / div;
47
48	/* we were called to round the frequency, we can now return */
49	if (m == NULL)
50		return;
51
52	*m = div - 1;
53}
54
55static struct clk_factors_config sun8i_a23_mbus_config = {
56	.mshift = 0,
57	.mwidth = 3,
58};
59
60static const struct factors_data sun8i_a23_mbus_data __initconst = {
61	.enable = 31,
62	.mux = 24,
63	.muxmask = BIT(1) | BIT(0),
64	.table = &sun8i_a23_mbus_config,
65	.getter = sun8i_a23_get_mbus_factors,
66};
67
68static DEFINE_SPINLOCK(sun8i_a23_mbus_lock);
69
70static void __init sun8i_a23_mbus_setup(struct device_node *node)
71{
72	struct clk *mbus;
73	void __iomem *reg;
74
75	reg = of_iomap(node, 0);
76	if (!reg) {
77		pr_err("Could not get registers for a23-mbus-clk\n");
78		return;
79	}
80
81	mbus = sunxi_factors_register(node, &sun8i_a23_mbus_data,
82				      &sun8i_a23_mbus_lock, reg);
83
84	/* The MBUS clocks needs to be always enabled */
85	__clk_get(mbus);
86	clk_prepare_enable(mbus);
87}
88CLK_OF_DECLARE(sun8i_a23_mbus, "allwinner,sun8i-a23-mbus-clk", sun8i_a23_mbus_setup);
89