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/of.h>
15#include <linux/of_address.h>
16#include <linux/io.h>
17#include <linux/irq.h>
18#include <linux/of_irq.h>
19#include <linux/interrupt.h>
20#include <linux/wait.h>
21#include <linux/sched.h>
22
23#include "pmc.h"
24
25#define SYSTEM_MAX_ID		31
26
27#define SYSTEM_MAX_NAME_SZ	32
28
29#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
30struct clk_system {
31	struct clk_hw hw;
32	struct at91_pmc *pmc;
33	unsigned int irq;
34	wait_queue_head_t wait;
35	u8 id;
36};
37
38static inline int is_pck(int id)
39{
40	return (id >= 8) && (id <= 15);
41}
42static irqreturn_t clk_system_irq_handler(int irq, void *dev_id)
43{
44	struct clk_system *sys = (struct clk_system *)dev_id;
45
46	wake_up(&sys->wait);
47	disable_irq_nosync(sys->irq);
48
49	return IRQ_HANDLED;
50}
51
52static int clk_system_prepare(struct clk_hw *hw)
53{
54	struct clk_system *sys = to_clk_system(hw);
55	struct at91_pmc *pmc = sys->pmc;
56	u32 mask = 1 << sys->id;
57
58	pmc_write(pmc, AT91_PMC_SCER, mask);
59
60	if (!is_pck(sys->id))
61		return 0;
62
63	while (!(pmc_read(pmc, AT91_PMC_SR) & mask)) {
64		if (sys->irq) {
65			enable_irq(sys->irq);
66			wait_event(sys->wait,
67				   pmc_read(pmc, AT91_PMC_SR) & mask);
68		} else
69			cpu_relax();
70	}
71	return 0;
72}
73
74static void clk_system_unprepare(struct clk_hw *hw)
75{
76	struct clk_system *sys = to_clk_system(hw);
77	struct at91_pmc *pmc = sys->pmc;
78
79	pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id);
80}
81
82static int clk_system_is_prepared(struct clk_hw *hw)
83{
84	struct clk_system *sys = to_clk_system(hw);
85	struct at91_pmc *pmc = sys->pmc;
86
87	if (!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id)))
88		return 0;
89
90	if (!is_pck(sys->id))
91		return 1;
92
93	return !!(pmc_read(pmc, AT91_PMC_SR) & (1 << sys->id));
94}
95
96static const struct clk_ops system_ops = {
97	.prepare = clk_system_prepare,
98	.unprepare = clk_system_unprepare,
99	.is_prepared = clk_system_is_prepared,
100};
101
102static struct clk * __init
103at91_clk_register_system(struct at91_pmc *pmc, const char *name,
104			 const char *parent_name, u8 id, int irq)
105{
106	struct clk_system *sys;
107	struct clk *clk = NULL;
108	struct clk_init_data init;
109	int ret;
110
111	if (!parent_name || id > SYSTEM_MAX_ID)
112		return ERR_PTR(-EINVAL);
113
114	sys = kzalloc(sizeof(*sys), GFP_KERNEL);
115	if (!sys)
116		return ERR_PTR(-ENOMEM);
117
118	init.name = name;
119	init.ops = &system_ops;
120	init.parent_names = &parent_name;
121	init.num_parents = 1;
122	init.flags = CLK_SET_RATE_PARENT;
123
124	sys->id = id;
125	sys->hw.init = &init;
126	sys->pmc = pmc;
127	sys->irq = irq;
128	if (irq) {
129		init_waitqueue_head(&sys->wait);
130		irq_set_status_flags(sys->irq, IRQ_NOAUTOEN);
131		ret = request_irq(sys->irq, clk_system_irq_handler,
132				IRQF_TRIGGER_HIGH, name, sys);
133		if (ret) {
134			kfree(sys);
135			return ERR_PTR(ret);
136		}
137	}
138
139	clk = clk_register(NULL, &sys->hw);
140	if (IS_ERR(clk)) {
141		if (irq)
142			free_irq(sys->irq, sys);
143		kfree(sys);
144	}
145
146	return clk;
147}
148
149static void __init
150of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc)
151{
152	int num;
153	int irq = 0;
154	u32 id;
155	struct clk *clk;
156	const char *name;
157	struct device_node *sysclknp;
158	const char *parent_name;
159
160	num = of_get_child_count(np);
161	if (num > (SYSTEM_MAX_ID + 1))
162		return;
163
164	for_each_child_of_node(np, sysclknp) {
165		if (of_property_read_u32(sysclknp, "reg", &id))
166			continue;
167
168		if (of_property_read_string(np, "clock-output-names", &name))
169			name = sysclknp->name;
170
171		if (is_pck(id))
172			irq = irq_of_parse_and_map(sysclknp, 0);
173
174		parent_name = of_clk_get_parent_name(sysclknp, 0);
175
176		clk = at91_clk_register_system(pmc, name, parent_name, id, irq);
177		if (IS_ERR(clk))
178			continue;
179
180		of_clk_add_provider(sysclknp, of_clk_src_simple_get, clk);
181	}
182}
183
184void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
185					struct at91_pmc *pmc)
186{
187	of_at91_clk_sys_setup(np, pmc);
188}
189