1/*
2 *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 */
10
11#include <linux/clk-provider.h>
12#include <linux/clkdev.h>
13#include <linux/clk/at91_pmc.h>
14#include <linux/interrupt.h>
15#include <linux/irq.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/of_irq.h>
19#include <linux/io.h>
20#include <linux/sched.h>
21#include <linux/wait.h>
22
23#include "pmc.h"
24
25#define UTMI_FIXED_MUL		40
26
27struct clk_utmi {
28	struct clk_hw hw;
29	struct at91_pmc *pmc;
30	unsigned int irq;
31	wait_queue_head_t wait;
32};
33
34#define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
35
36static irqreturn_t clk_utmi_irq_handler(int irq, void *dev_id)
37{
38	struct clk_utmi *utmi = (struct clk_utmi *)dev_id;
39
40	wake_up(&utmi->wait);
41	disable_irq_nosync(utmi->irq);
42
43	return IRQ_HANDLED;
44}
45
46static int clk_utmi_prepare(struct clk_hw *hw)
47{
48	struct clk_utmi *utmi = to_clk_utmi(hw);
49	struct at91_pmc *pmc = utmi->pmc;
50	u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) | AT91_PMC_UPLLEN |
51		  AT91_PMC_UPLLCOUNT | AT91_PMC_BIASEN;
52
53	pmc_write(pmc, AT91_CKGR_UCKR, tmp);
54
55	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU)) {
56		enable_irq(utmi->irq);
57		wait_event(utmi->wait,
58			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU);
59	}
60
61	return 0;
62}
63
64static int clk_utmi_is_prepared(struct clk_hw *hw)
65{
66	struct clk_utmi *utmi = to_clk_utmi(hw);
67	struct at91_pmc *pmc = utmi->pmc;
68
69	return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU);
70}
71
72static void clk_utmi_unprepare(struct clk_hw *hw)
73{
74	struct clk_utmi *utmi = to_clk_utmi(hw);
75	struct at91_pmc *pmc = utmi->pmc;
76	u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) & ~AT91_PMC_UPLLEN;
77
78	pmc_write(pmc, AT91_CKGR_UCKR, tmp);
79}
80
81static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
82					  unsigned long parent_rate)
83{
84	/* UTMI clk is a fixed clk multiplier */
85	return parent_rate * UTMI_FIXED_MUL;
86}
87
88static const struct clk_ops utmi_ops = {
89	.prepare = clk_utmi_prepare,
90	.unprepare = clk_utmi_unprepare,
91	.is_prepared = clk_utmi_is_prepared,
92	.recalc_rate = clk_utmi_recalc_rate,
93};
94
95static struct clk * __init
96at91_clk_register_utmi(struct at91_pmc *pmc, unsigned int irq,
97		       const char *name, const char *parent_name)
98{
99	int ret;
100	struct clk_utmi *utmi;
101	struct clk *clk = NULL;
102	struct clk_init_data init;
103
104	utmi = kzalloc(sizeof(*utmi), GFP_KERNEL);
105	if (!utmi)
106		return ERR_PTR(-ENOMEM);
107
108	init.name = name;
109	init.ops = &utmi_ops;
110	init.parent_names = parent_name ? &parent_name : NULL;
111	init.num_parents = parent_name ? 1 : 0;
112	init.flags = CLK_SET_RATE_GATE;
113
114	utmi->hw.init = &init;
115	utmi->pmc = pmc;
116	utmi->irq = irq;
117	init_waitqueue_head(&utmi->wait);
118	irq_set_status_flags(utmi->irq, IRQ_NOAUTOEN);
119	ret = request_irq(utmi->irq, clk_utmi_irq_handler,
120			  IRQF_TRIGGER_HIGH, "clk-utmi", utmi);
121	if (ret)
122		return ERR_PTR(ret);
123
124	clk = clk_register(NULL, &utmi->hw);
125	if (IS_ERR(clk))
126		kfree(utmi);
127
128	return clk;
129}
130
131static void __init
132of_at91_clk_utmi_setup(struct device_node *np, struct at91_pmc *pmc)
133{
134	unsigned int irq;
135	struct clk *clk;
136	const char *parent_name;
137	const char *name = np->name;
138
139	parent_name = of_clk_get_parent_name(np, 0);
140
141	of_property_read_string(np, "clock-output-names", &name);
142
143	irq = irq_of_parse_and_map(np, 0);
144	if (!irq)
145		return;
146
147	clk = at91_clk_register_utmi(pmc, irq, name, parent_name);
148	if (IS_ERR(clk))
149		return;
150
151	of_clk_add_provider(np, of_clk_src_simple_get, clk);
152	return;
153}
154
155void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np,
156					 struct at91_pmc *pmc)
157{
158	of_at91_clk_utmi_setup(np, pmc);
159}
160