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14b03204 MH |
1 | /* |
2 | * Copyright 2008 Analog Devices Inc. | |
3 | * | |
4 | * Licensed under the GPL-2 or later. | |
5 | */ | |
6 | ||
7 | #include <linux/cdev.h> | |
8 | #include <linux/device.h> | |
9 | #include <linux/errno.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/cpufreq.h> | |
16 | ||
17 | #include <asm/delay.h> | |
18 | #include <asm/dpmc.h> | |
19 | ||
20 | #define DRIVER_NAME "bfin dpmc" | |
21 | ||
22 | #define dprintk(msg...) \ | |
23 | cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, DRIVER_NAME, msg) | |
24 | ||
25 | struct bfin_dpmc_platform_data *pdata; | |
26 | ||
27 | /** | |
28 | * bfin_set_vlev - Update VLEV field in VR_CTL Reg. | |
29 | * Avoid BYPASS sequence | |
30 | */ | |
31 | static void bfin_set_vlev(unsigned int vlev) | |
32 | { | |
33 | unsigned pll_lcnt; | |
34 | ||
35 | pll_lcnt = bfin_read_PLL_LOCKCNT(); | |
36 | ||
37 | bfin_write_PLL_LOCKCNT(1); | |
38 | bfin_write_VR_CTL((bfin_read_VR_CTL() & ~VLEV) | vlev); | |
39 | bfin_write_PLL_LOCKCNT(pll_lcnt); | |
40 | } | |
41 | ||
42 | /** | |
43 | * bfin_get_vlev - Get CPU specific VLEV from platform device data | |
44 | */ | |
45 | static unsigned int bfin_get_vlev(unsigned int freq) | |
46 | { | |
47 | int i; | |
48 | ||
49 | if (!pdata) | |
50 | goto err_out; | |
51 | ||
52 | freq >>= 16; | |
53 | ||
54 | for (i = 0; i < pdata->tabsize; i++) | |
55 | if (freq <= (pdata->tuple_tab[i] & 0xFFFF)) | |
56 | return pdata->tuple_tab[i] >> 16; | |
57 | ||
58 | err_out: | |
59 | printk(KERN_WARNING "DPMC: No suitable CCLK VDDINT voltage pair found\n"); | |
60 | return VLEV_120; | |
61 | } | |
62 | ||
63 | #ifdef CONFIG_CPU_FREQ | |
64 | static int | |
65 | vreg_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data) | |
66 | { | |
67 | struct cpufreq_freqs *freq = data; | |
68 | ||
69 | if (val == CPUFREQ_PRECHANGE && freq->old < freq->new) { | |
70 | bfin_set_vlev(bfin_get_vlev(freq->new)); | |
71 | udelay(pdata->vr_settling_time); /* Wait until Volatge settled */ | |
72 | ||
73 | } else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) | |
74 | bfin_set_vlev(bfin_get_vlev(freq->new)); | |
75 | ||
76 | return 0; | |
77 | } | |
78 | ||
79 | static struct notifier_block vreg_cpufreq_notifier_block = { | |
80 | .notifier_call = vreg_cpufreq_notifier | |
81 | }; | |
82 | #endif /* CONFIG_CPU_FREQ */ | |
83 | ||
84 | /** | |
85 | * bfin_dpmc_probe - | |
86 | * | |
87 | */ | |
88 | static int __devinit bfin_dpmc_probe(struct platform_device *pdev) | |
89 | { | |
90 | if (pdev->dev.platform_data) | |
91 | pdata = pdev->dev.platform_data; | |
92 | else | |
93 | return -EINVAL; | |
94 | ||
95 | return cpufreq_register_notifier(&vreg_cpufreq_notifier_block, | |
96 | CPUFREQ_TRANSITION_NOTIFIER); | |
97 | } | |
98 | ||
99 | /** | |
100 | * bfin_dpmc_remove - | |
101 | */ | |
102 | static int __devexit bfin_dpmc_remove(struct platform_device *pdev) | |
103 | { | |
104 | pdata = NULL; | |
105 | return cpufreq_unregister_notifier(&vreg_cpufreq_notifier_block, | |
106 | CPUFREQ_TRANSITION_NOTIFIER); | |
107 | } | |
108 | ||
109 | struct platform_driver bfin_dpmc_device_driver = { | |
110 | .probe = bfin_dpmc_probe, | |
111 | .remove = __devexit_p(bfin_dpmc_remove), | |
112 | .driver = { | |
113 | .name = DRIVER_NAME, | |
114 | } | |
115 | }; | |
116 | ||
117 | /** | |
118 | * bfin_dpmc_init - Init driver | |
119 | */ | |
120 | static int __init bfin_dpmc_init(void) | |
121 | { | |
122 | return platform_driver_register(&bfin_dpmc_device_driver); | |
123 | } | |
124 | module_init(bfin_dpmc_init); | |
125 | ||
126 | /** | |
127 | * bfin_dpmc_exit - break down driver | |
128 | */ | |
129 | static void __exit bfin_dpmc_exit(void) | |
130 | { | |
131 | platform_driver_unregister(&bfin_dpmc_device_driver); | |
132 | } | |
133 | module_exit(bfin_dpmc_exit); | |
134 | ||
135 | MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); | |
136 | MODULE_DESCRIPTION("cpu power management driver for Blackfin"); | |
137 | MODULE_LICENSE("GPL"); |