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
27static bool dvs_en;
28
29static 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
46static 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 */
53static bool cur_dvs = false;
54
55static 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
93static struct notifier_block osiris_dvs_nb = {
94	.notifier_call	= osiris_dvs_notify,
95};
96
97static 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
123err_nofreq:
124	gpio_free(OSIRIS_GPIO_DVS);
125
126err_nogpio:
127	return ret;
128}
129
130static 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
149static 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
158static int osiris_dvs_resume(struct device *dev)
159{
160	osiris_dvs_tps_setdvs(true);
161	return 0;
162}
163
164static const struct dev_pm_ops osiris_dvs_pm = {
165	.suspend	= osiris_dvs_suspend,
166	.resume		= osiris_dvs_resume,
167};
168
169static 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
178module_platform_driver(osiris_dvs_driver);
179
180MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
181MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
182MODULE_LICENSE("GPL");
183MODULE_ALIAS("platform:osiris-dvs");
184