1 // SPDX-License-Identifier: GPL-2.0
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 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/cpufreq.h>
13 #include <linux/gpio.h>
14
15 #include <linux/mfd/tps65010.h>
16
17 #include <linux/soc/samsung/s3c-cpu-freq.h>
18 #include "gpio-samsung.h"
19
20 #define OSIRIS_GPIO_DVS S3C2410_GPB(5)
21
22 static bool dvs_en;
23
osiris_dvs_tps_setdvs(bool on)24 static void osiris_dvs_tps_setdvs(bool on)
25 {
26 unsigned vregs1 = 0, vdcdc2 = 0;
27
28 if (!on) {
29 vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
30 vregs1 = TPS_LDO1_OFF; /* turn off in low-power mode */
31 }
32
33 dvs_en = on;
34 vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
35 vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
36
37 tps65010_config_vregs1(vregs1);
38 tps65010_config_vdcdc2(vdcdc2);
39 }
40
is_dvs(struct s3c_freq * f)41 static bool is_dvs(struct s3c_freq *f)
42 {
43 /* at the moment, we assume ARMCLK = HCLK => DVS */
44 return f->armclk == f->hclk;
45 }
46
47 /* keep track of current state */
48 static bool cur_dvs = false;
49
osiris_dvs_notify(struct notifier_block * nb,unsigned long val,void * data)50 static int osiris_dvs_notify(struct notifier_block *nb,
51 unsigned long val, void *data)
52 {
53 struct cpufreq_freqs *cf = data;
54 struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
55 bool old_dvs = is_dvs(&freqs->old);
56 bool new_dvs = is_dvs(&freqs->new);
57 int ret = 0;
58
59 if (!dvs_en)
60 return 0;
61
62 printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
63 freqs->old.armclk, freqs->old.hclk,
64 freqs->new.armclk, freqs->new.hclk);
65
66 switch (val) {
67 case CPUFREQ_PRECHANGE:
68 if ((old_dvs && !new_dvs) ||
69 (cur_dvs && !new_dvs)) {
70 pr_debug("%s: exiting dvs\n", __func__);
71 cur_dvs = false;
72 gpio_set_value(OSIRIS_GPIO_DVS, 1);
73 }
74 break;
75 case CPUFREQ_POSTCHANGE:
76 if ((!old_dvs && new_dvs) ||
77 (!cur_dvs && new_dvs)) {
78 pr_debug("entering dvs\n");
79 cur_dvs = true;
80 gpio_set_value(OSIRIS_GPIO_DVS, 0);
81 }
82 break;
83 }
84
85 return ret;
86 }
87
88 static struct notifier_block osiris_dvs_nb = {
89 .notifier_call = osiris_dvs_notify,
90 };
91
osiris_dvs_probe(struct platform_device * pdev)92 static int osiris_dvs_probe(struct platform_device *pdev)
93 {
94 int ret;
95
96 dev_info(&pdev->dev, "initialising\n");
97
98 ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
99 if (ret) {
100 dev_err(&pdev->dev, "cannot claim gpio\n");
101 goto err_nogpio;
102 }
103
104 /* start with dvs disabled */
105 gpio_direction_output(OSIRIS_GPIO_DVS, 1);
106
107 ret = cpufreq_register_notifier(&osiris_dvs_nb,
108 CPUFREQ_TRANSITION_NOTIFIER);
109 if (ret) {
110 dev_err(&pdev->dev, "failed to register with cpufreq\n");
111 goto err_nofreq;
112 }
113
114 osiris_dvs_tps_setdvs(true);
115
116 return 0;
117
118 err_nofreq:
119 gpio_free(OSIRIS_GPIO_DVS);
120
121 err_nogpio:
122 return ret;
123 }
124
osiris_dvs_remove(struct platform_device * pdev)125 static int osiris_dvs_remove(struct platform_device *pdev)
126 {
127 dev_info(&pdev->dev, "exiting\n");
128
129 /* disable any current dvs */
130 gpio_set_value(OSIRIS_GPIO_DVS, 1);
131 osiris_dvs_tps_setdvs(false);
132
133 cpufreq_unregister_notifier(&osiris_dvs_nb,
134 CPUFREQ_TRANSITION_NOTIFIER);
135
136 gpio_free(OSIRIS_GPIO_DVS);
137
138 return 0;
139 }
140
141 /* the CONFIG_PM block is so small, it isn't worth actually compiling it
142 * out if the configuration isn't set. */
143
osiris_dvs_suspend(struct device * dev)144 static int osiris_dvs_suspend(struct device *dev)
145 {
146 gpio_set_value(OSIRIS_GPIO_DVS, 1);
147 osiris_dvs_tps_setdvs(false);
148 cur_dvs = false;
149
150 return 0;
151 }
152
osiris_dvs_resume(struct device * dev)153 static int osiris_dvs_resume(struct device *dev)
154 {
155 osiris_dvs_tps_setdvs(true);
156 return 0;
157 }
158
159 static const struct dev_pm_ops osiris_dvs_pm = {
160 .suspend = osiris_dvs_suspend,
161 .resume = osiris_dvs_resume,
162 };
163
164 static struct platform_driver osiris_dvs_driver = {
165 .probe = osiris_dvs_probe,
166 .remove = osiris_dvs_remove,
167 .driver = {
168 .name = "osiris-dvs",
169 .pm = &osiris_dvs_pm,
170 },
171 };
172
173 module_platform_driver(osiris_dvs_driver);
174
175 MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
176 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
177 MODULE_LICENSE("GPL");
178 MODULE_ALIAS("platform:osiris-dvs");
179