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
 22static bool dvs_en;
 23
 24static 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
 41static 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 */
 48static bool cur_dvs = false;
 49
 50static 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
 88static struct notifier_block osiris_dvs_nb = {
 89	.notifier_call	= osiris_dvs_notify,
 90};
 91
 92static 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
118err_nofreq:
119	gpio_free(OSIRIS_GPIO_DVS);
120
121err_nogpio:
122	return ret;
123}
124
125static 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
144static 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
153static int osiris_dvs_resume(struct device *dev)
154{
155	osiris_dvs_tps_setdvs(true);
156	return 0;
157}
158
159static const struct dev_pm_ops osiris_dvs_pm = {
160	.suspend	= osiris_dvs_suspend,
161	.resume		= osiris_dvs_resume,
162};
163
164static 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
173module_platform_driver(osiris_dvs_driver);
174
175MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
176MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
177MODULE_LICENSE("GPL");
178MODULE_ALIAS("platform:osiris-dvs");