xref: /openbmc/linux/drivers/clk/at91/clk-utmi.c (revision 4f3db074)
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 
27 struct 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 
36 static 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 
46 static 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 
64 static 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 
72 static 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 
81 static 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 
88 static 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 
95 static struct clk * __init
96 at91_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 
131 static void __init
132 of_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 
155 void __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