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authorLennert Buytenhek <buytenh@wantstofly.org>2006-06-24 05:33:02 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-06-24 05:33:02 -0400
commit1d81eedb8f6c13c262a70b8167530ec24b09c0ff (patch)
tree12b1231f90127b117cdd88c8240c002e57460c3e /arch/arm/mach-ep93xx/clock.c
parentd384ea691fe4ea8c2dd5b9b8d9042eb181776f18 (diff)
[ARM] 3634/1: ep93xx: initial implementation of the clk_* API
Patch from Lennert Buytenhek Add an initial implementation of the clk_* API for the cirrus ep93xx to the tree. The initial implementation is somewhat minimal, with the intention of extending it as we go along. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-ep93xx/clock.c')
-rw-r--r--arch/arm/mach-ep93xx/clock.c156
1 files changed, 156 insertions, 0 deletions
diff --git a/arch/arm/mach-ep93xx/clock.c b/arch/arm/mach-ep93xx/clock.c
new file mode 100644
index 000000000000..08ad782c1649
--- /dev/null
+++ b/arch/arm/mach-ep93xx/clock.c
@@ -0,0 +1,156 @@
1/*
2 * arch/arm/mach-ep93xx/clock.c
3 * Clock control for Cirrus EP93xx chips.
4 *
5 * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or (at
10 * your option) any later version.
11 */
12
13#include <linux/kernel.h>
14#include <linux/clk.h>
15#include <linux/err.h>
16#include <linux/string.h>
17#include <asm/div64.h>
18#include <asm/hardware.h>
19#include <asm/io.h>
20
21struct clk {
22 char *name;
23 unsigned long rate;
24 int users;
25 u32 enable_reg;
26 u32 enable_mask;
27};
28
29static struct clk clk_pll1 = {
30 .name = "pll1",
31};
32static struct clk clk_f = {
33 .name = "fclk",
34};
35static struct clk clk_h = {
36 .name = "hclk",
37};
38static struct clk clk_p = {
39 .name = "pclk",
40};
41static struct clk clk_pll2 = {
42 .name = "pll2",
43};
44static struct clk clk_usb_host = {
45 .name = "usb_host",
46 .enable_reg = EP93XX_SYSCON_CLOCK_CONTROL,
47 .enable_mask = EP93XX_SYSCON_CLOCK_USH_EN,
48};
49
50
51static struct clk *clocks[] = {
52 &clk_pll1,
53 &clk_f,
54 &clk_h,
55 &clk_p,
56 &clk_pll2,
57 &clk_usb_host,
58};
59
60struct clk *clk_get(struct device *dev, const char *id)
61{
62 int i;
63
64 for (i = 0; i < ARRAY_SIZE(clocks); i++) {
65 if (!strcmp(clocks[i]->name, id))
66 return clocks[i];
67 }
68
69 return ERR_PTR(-ENOENT);
70}
71
72int clk_enable(struct clk *clk)
73{
74 if (!clk->users++ && clk->enable_reg) {
75 u32 value;
76
77 value = __raw_readl(clk->enable_reg);
78 __raw_writel(value | clk->enable_mask, clk->enable_reg);
79 }
80
81 return 0;
82}
83
84void clk_disable(struct clk *clk)
85{
86 if (!--clk->users && clk->enable_reg) {
87 u32 value;
88
89 value = __raw_readl(clk->enable_reg);
90 __raw_writel(value & ~clk->enable_mask, clk->enable_reg);
91 }
92}
93
94unsigned long clk_get_rate(struct clk *clk)
95{
96 return clk->rate;
97}
98
99void clk_put(struct clk *clk)
100{
101}
102
103
104
105static char fclk_divisors[] = { 1, 2, 4, 8, 16, 1, 1, 1 };
106static char hclk_divisors[] = { 1, 2, 4, 5, 6, 8, 16, 32 };
107static char pclk_divisors[] = { 1, 2, 4, 8 };
108
109/*
110 * PLL rate = 14.7456 MHz * (X1FBD + 1) * (X2FBD + 1) / (X2IPD + 1) / 2^PS
111 */
112static unsigned long calc_pll_rate(u32 config_word)
113{
114 unsigned long long rate;
115 int i;
116
117 rate = 14745600;
118 rate *= ((config_word >> 11) & 0x1f) + 1; /* X1FBD */
119 rate *= ((config_word >> 5) & 0x3f) + 1; /* X2FBD */
120 do_div(rate, (config_word & 0x1f) + 1); /* X2IPD */
121 for (i = 0; i < ((config_word >> 16) & 3); i++) /* PS */
122 rate >>= 1;
123
124 return (unsigned long)rate;
125}
126
127void ep93xx_clock_init(void)
128{
129 u32 value;
130
131 value = __raw_readl(EP93XX_SYSCON_CLOCK_SET1);
132 if (!(value & 0x00800000)) { /* PLL1 bypassed? */
133 clk_pll1.rate = 14745600;
134 } else {
135 clk_pll1.rate = calc_pll_rate(value);
136 }
137 clk_f.rate = clk_pll1.rate / fclk_divisors[(value >> 25) & 0x7];
138 clk_h.rate = clk_pll1.rate / hclk_divisors[(value >> 20) & 0x7];
139 clk_p.rate = clk_h.rate / pclk_divisors[(value >> 18) & 0x3];
140
141 value = __raw_readl(EP93XX_SYSCON_CLOCK_SET2);
142 if (!(value & 0x00080000)) { /* PLL2 bypassed? */
143 clk_pll2.rate = 14745600;
144 } else if (value & 0x00040000) { /* PLL2 enabled? */
145 clk_pll2.rate = calc_pll_rate(value);
146 } else {
147 clk_pll2.rate = 0;
148 }
149 clk_usb_host.rate = clk_pll2.rate / (((value >> 28) & 0xf) + 1);
150
151 printk(KERN_INFO "ep93xx: PLL1 running at %ld MHz, PLL2 at %ld MHz\n",
152 clk_pll1.rate / 1000000, clk_pll2.rate / 1000000);
153 printk(KERN_INFO "ep93xx: FCLK %ld MHz, HCLK %ld MHz, PCLK %ld MHz\n",
154 clk_f.rate / 1000000, clk_h.rate / 1000000,
155 clk_p.rate / 1000000);
156}