1/*
2 * Driver for the ICST307 VCO clock found in the ARM Reference designs.
3 * We wrap the custom interface from <asm/hardware/icst.h> into the generic
4 * clock framework.
5 *
6 * Copyright (C) 2012 Linus Walleij
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 version 2 as
10 * published by the Free Software Foundation.
11 *
12 * TODO: when all ARM reference designs are migrated to generic clocks, the
13 * ICST clock code from the ARM tree should probably be merged into this
14 * file.
15 */
16#include <linux/clk.h>
17#include <linux/clkdev.h>
18#include <linux/err.h>
19#include <linux/clk-provider.h>
20#include <linux/io.h>
21
22#include "clk-icst.h"
23
24/**
25 * struct clk_icst - ICST VCO clock wrapper
26 * @hw: corresponding clock hardware entry
27 * @vcoreg: VCO register address
28 * @lockreg: VCO lock register address
29 * @params: parameters for this ICST instance
30 * @rate: current rate
31 */
32struct clk_icst {
33	struct clk_hw hw;
34	void __iomem *vcoreg;
35	void __iomem *lockreg;
36	struct icst_params *params;
37	unsigned long rate;
38};
39
40#define to_icst(_hw) container_of(_hw, struct clk_icst, hw)
41
42/**
43 * vco_get() - get ICST VCO settings from a certain register
44 * @vcoreg: register containing the VCO settings
45 */
46static struct icst_vco vco_get(void __iomem *vcoreg)
47{
48	u32 val;
49	struct icst_vco vco;
50
51	val = readl(vcoreg);
52	vco.v = val & 0x1ff;
53	vco.r = (val >> 9) & 0x7f;
54	vco.s = (val >> 16) & 03;
55	return vco;
56}
57
58/**
59 * vco_set() - commit changes to an ICST VCO
60 * @locreg: register to poke to unlock the VCO for writing
61 * @vcoreg: register containing the VCO settings
62 * @vco: ICST VCO parameters to commit
63 */
64static void vco_set(void __iomem *lockreg,
65			void __iomem *vcoreg,
66			struct icst_vco vco)
67{
68	u32 val;
69
70	val = readl(vcoreg) & ~0x7ffff;
71	val |= vco.v | (vco.r << 9) | (vco.s << 16);
72
73	/* This magic unlocks the VCO so it can be controlled */
74	writel(0xa05f, lockreg);
75	writel(val, vcoreg);
76	/* This locks the VCO again */
77	writel(0, lockreg);
78}
79
80
81static unsigned long icst_recalc_rate(struct clk_hw *hw,
82				      unsigned long parent_rate)
83{
84	struct clk_icst *icst = to_icst(hw);
85	struct icst_vco vco;
86
87	if (parent_rate)
88		icst->params->ref = parent_rate;
89	vco = vco_get(icst->vcoreg);
90	icst->rate = icst_hz(icst->params, vco);
91	return icst->rate;
92}
93
94static long icst_round_rate(struct clk_hw *hw, unsigned long rate,
95			    unsigned long *prate)
96{
97	struct clk_icst *icst = to_icst(hw);
98	struct icst_vco vco;
99
100	vco = icst_hz_to_vco(icst->params, rate);
101	return icst_hz(icst->params, vco);
102}
103
104static int icst_set_rate(struct clk_hw *hw, unsigned long rate,
105			 unsigned long parent_rate)
106{
107	struct clk_icst *icst = to_icst(hw);
108	struct icst_vco vco;
109
110	if (parent_rate)
111		icst->params->ref = parent_rate;
112	vco = icst_hz_to_vco(icst->params, rate);
113	icst->rate = icst_hz(icst->params, vco);
114	vco_set(icst->lockreg, icst->vcoreg, vco);
115	return 0;
116}
117
118static const struct clk_ops icst_ops = {
119	.recalc_rate = icst_recalc_rate,
120	.round_rate = icst_round_rate,
121	.set_rate = icst_set_rate,
122};
123
124struct clk *icst_clk_register(struct device *dev,
125			const struct clk_icst_desc *desc,
126			const char *name,
127			const char *parent_name,
128			void __iomem *base)
129{
130	struct clk *clk;
131	struct clk_icst *icst;
132	struct clk_init_data init;
133	struct icst_params *pclone;
134
135	icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL);
136	if (!icst) {
137		pr_err("could not allocate ICST clock!\n");
138		return ERR_PTR(-ENOMEM);
139	}
140
141	pclone = kmemdup(desc->params, sizeof(*pclone), GFP_KERNEL);
142	if (!pclone) {
143		kfree(icst);
144		pr_err("could not clone ICST params\n");
145		return ERR_PTR(-ENOMEM);
146	}
147
148	init.name = name;
149	init.ops = &icst_ops;
150	init.flags = CLK_IS_ROOT;
151	init.parent_names = (parent_name ? &parent_name : NULL);
152	init.num_parents = (parent_name ? 1 : 0);
153	icst->hw.init = &init;
154	icst->params = pclone;
155	icst->vcoreg = base + desc->vco_offset;
156	icst->lockreg = base + desc->lock_offset;
157
158	clk = clk_register(dev, &icst->hw);
159	if (IS_ERR(clk)) {
160		kfree(pclone);
161		kfree(icst);
162	}
163
164	return clk;
165}
166EXPORT_SYMBOL_GPL(icst_clk_register);
167