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 */
bfin_set_vlev(unsigned int vlev)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 */
bfin_get_vlev(unsigned int freq)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
vreg_cpufreq_notifier(struct notifier_block * nb,unsigned long val,void * data)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 */
bfin_dpmc_probe(struct platform_device * pdev)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 */
bfin_dpmc_remove(struct platform_device * pdev)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 */
bfin_dpmc_init(void)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 */
bfin_dpmc_exit(void)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");
138