1 /* linux/arch/arm/mach-s3c2440/mach-osiris-dvs.c
2 *
3 * Copyright (c) 2009 Simtec Electronics
4 * http://armlinux.simtec.co.uk/
5 * Ben Dooks <ben@simtec.co.uk>
6 *
7 * Simtec Osiris Dynamic Voltage Scaling support.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/cpufreq.h>
18 #include <linux/gpio.h>
19
20 #include <linux/i2c/tps65010.h>
21
22 #include <plat/cpu-freq.h>
23 #include <mach/gpio-samsung.h>
24
25 #define OSIRIS_GPIO_DVS S3C2410_GPB(5)
26
27 static bool dvs_en;
28
osiris_dvs_tps_setdvs(bool on)29 static void osiris_dvs_tps_setdvs(bool on)
30 {
31 unsigned vregs1 = 0, vdcdc2 = 0;
32
33 if (!on) {
34 vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
35 vregs1 = TPS_LDO1_OFF; /* turn off in low-power mode */
36 }
37
38 dvs_en = on;
39 vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
40 vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
41
42 tps65010_config_vregs1(vregs1);
43 tps65010_config_vdcdc2(vdcdc2);
44 }
45
is_dvs(struct s3c_freq * f)46 static bool is_dvs(struct s3c_freq *f)
47 {
48 /* at the moment, we assume ARMCLK = HCLK => DVS */
49 return f->armclk == f->hclk;
50 }
51
52 /* keep track of current state */
53 static bool cur_dvs = false;
54
osiris_dvs_notify(struct notifier_block * nb,unsigned long val,void * data)55 static int osiris_dvs_notify(struct notifier_block *nb,
56 unsigned long val, void *data)
57 {
58 struct cpufreq_freqs *cf = data;
59 struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
60 bool old_dvs = is_dvs(&freqs->old);
61 bool new_dvs = is_dvs(&freqs->new);
62 int ret = 0;
63
64 if (!dvs_en)
65 return 0;
66
67 printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
68 freqs->old.armclk, freqs->old.hclk,
69 freqs->new.armclk, freqs->new.hclk);
70
71 switch (val) {
72 case CPUFREQ_PRECHANGE:
73 if ((old_dvs && !new_dvs) ||
74 (cur_dvs && !new_dvs)) {
75 pr_debug("%s: exiting dvs\n", __func__);
76 cur_dvs = false;
77 gpio_set_value(OSIRIS_GPIO_DVS, 1);
78 }
79 break;
80 case CPUFREQ_POSTCHANGE:
81 if ((!old_dvs && new_dvs) ||
82 (!cur_dvs && new_dvs)) {
83 pr_debug("entering dvs\n");
84 cur_dvs = true;
85 gpio_set_value(OSIRIS_GPIO_DVS, 0);
86 }
87 break;
88 }
89
90 return ret;
91 }
92
93 static struct notifier_block osiris_dvs_nb = {
94 .notifier_call = osiris_dvs_notify,
95 };
96
osiris_dvs_probe(struct platform_device * pdev)97 static int osiris_dvs_probe(struct platform_device *pdev)
98 {
99 int ret;
100
101 dev_info(&pdev->dev, "initialising\n");
102
103 ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
104 if (ret) {
105 dev_err(&pdev->dev, "cannot claim gpio\n");
106 goto err_nogpio;
107 }
108
109 /* start with dvs disabled */
110 gpio_direction_output(OSIRIS_GPIO_DVS, 1);
111
112 ret = cpufreq_register_notifier(&osiris_dvs_nb,
113 CPUFREQ_TRANSITION_NOTIFIER);
114 if (ret) {
115 dev_err(&pdev->dev, "failed to register with cpufreq\n");
116 goto err_nofreq;
117 }
118
119 osiris_dvs_tps_setdvs(true);
120
121 return 0;
122
123 err_nofreq:
124 gpio_free(OSIRIS_GPIO_DVS);
125
126 err_nogpio:
127 return ret;
128 }
129
osiris_dvs_remove(struct platform_device * pdev)130 static int osiris_dvs_remove(struct platform_device *pdev)
131 {
132 dev_info(&pdev->dev, "exiting\n");
133
134 /* disable any current dvs */
135 gpio_set_value(OSIRIS_GPIO_DVS, 1);
136 osiris_dvs_tps_setdvs(false);
137
138 cpufreq_unregister_notifier(&osiris_dvs_nb,
139 CPUFREQ_TRANSITION_NOTIFIER);
140
141 gpio_free(OSIRIS_GPIO_DVS);
142
143 return 0;
144 }
145
146 /* the CONFIG_PM block is so small, it isn't worth actaully compiling it
147 * out if the configuration isn't set. */
148
osiris_dvs_suspend(struct device * dev)149 static int osiris_dvs_suspend(struct device *dev)
150 {
151 gpio_set_value(OSIRIS_GPIO_DVS, 1);
152 osiris_dvs_tps_setdvs(false);
153 cur_dvs = false;
154
155 return 0;
156 }
157
osiris_dvs_resume(struct device * dev)158 static int osiris_dvs_resume(struct device *dev)
159 {
160 osiris_dvs_tps_setdvs(true);
161 return 0;
162 }
163
164 static const struct dev_pm_ops osiris_dvs_pm = {
165 .suspend = osiris_dvs_suspend,
166 .resume = osiris_dvs_resume,
167 };
168
169 static struct platform_driver osiris_dvs_driver = {
170 .probe = osiris_dvs_probe,
171 .remove = osiris_dvs_remove,
172 .driver = {
173 .name = "osiris-dvs",
174 .pm = &osiris_dvs_pm,
175 },
176 };
177
178 module_platform_driver(osiris_dvs_driver);
179
180 MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
181 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
182 MODULE_LICENSE("GPL");
183 MODULE_ALIAS("platform:osiris-dvs");
184