Linux Kernel iMX6
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/* linux/arch/arm/mach-s3c2440/mach-osiris-dvs.c
*
* Copyright (c) 2009 Simtec Electronics
* http://armlinux.simtec.co.uk/
* Ben Dooks <ben@simtec.co.uk>
*
* Simtec Osiris Dynamic Voltage Scaling support.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/cpufreq.h>
#include <linux/gpio.h>
#include <linux/i2c/tps65010.h>
#include <plat/cpu-freq.h>
#include <mach/gpio-samsung.h>
#define OSIRIS_GPIO_DVS S3C2410_GPB(5)
static bool dvs_en;
static void osiris_dvs_tps_setdvs(bool on)
{
unsigned vregs1 = 0, vdcdc2 = 0;
if (!on) {
vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
vregs1 = TPS_LDO1_OFF; /* turn off in low-power mode */
}
dvs_en = on;
vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
tps65010_config_vregs1(vregs1);
tps65010_config_vdcdc2(vdcdc2);
}
static bool is_dvs(struct s3c_freq *f)
{
/* at the moment, we assume ARMCLK = HCLK => DVS */
return f->armclk == f->hclk;
}
/* keep track of current state */
static bool cur_dvs = false;
static int osiris_dvs_notify(struct notifier_block *nb,
unsigned long val, void *data)
{
struct cpufreq_freqs *cf = data;
struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
bool old_dvs = is_dvs(&freqs->old);
bool new_dvs = is_dvs(&freqs->new);
int ret = 0;
if (!dvs_en)
return 0;
printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
freqs->old.armclk, freqs->old.hclk,
freqs->new.armclk, freqs->new.hclk);
switch (val) {
case CPUFREQ_PRECHANGE:
if (old_dvs & !new_dvs ||
cur_dvs & !new_dvs) {
pr_debug("%s: exiting dvs\n", __func__);
cur_dvs = false;
gpio_set_value(OSIRIS_GPIO_DVS, 1);
}
break;
case CPUFREQ_POSTCHANGE:
if (!old_dvs & new_dvs ||
!cur_dvs & new_dvs) {
pr_debug("entering dvs\n");
cur_dvs = true;
gpio_set_value(OSIRIS_GPIO_DVS, 0);
}
break;
}
return ret;
}
static struct notifier_block osiris_dvs_nb = {
.notifier_call = osiris_dvs_notify,
};
static int osiris_dvs_probe(struct platform_device *pdev)
{
int ret;
dev_info(&pdev->dev, "initialising\n");
ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
if (ret) {
dev_err(&pdev->dev, "cannot claim gpio\n");
goto err_nogpio;
}
/* start with dvs disabled */
gpio_direction_output(OSIRIS_GPIO_DVS, 1);
ret = cpufreq_register_notifier(&osiris_dvs_nb,
CPUFREQ_TRANSITION_NOTIFIER);
if (ret) {
dev_err(&pdev->dev, "failed to register with cpufreq\n");
goto err_nofreq;
}
osiris_dvs_tps_setdvs(true);
return 0;
err_nofreq:
gpio_free(OSIRIS_GPIO_DVS);
err_nogpio:
return ret;
}
static int osiris_dvs_remove(struct platform_device *pdev)
{
dev_info(&pdev->dev, "exiting\n");
/* disable any current dvs */
gpio_set_value(OSIRIS_GPIO_DVS, 1);
osiris_dvs_tps_setdvs(false);
cpufreq_unregister_notifier(&osiris_dvs_nb,
CPUFREQ_TRANSITION_NOTIFIER);
gpio_free(OSIRIS_GPIO_DVS);
return 0;
}
/* the CONFIG_PM block is so small, it isn't worth actaully compiling it
* out if the configuration isn't set. */
static int osiris_dvs_suspend(struct device *dev)
{
gpio_set_value(OSIRIS_GPIO_DVS, 1);
osiris_dvs_tps_setdvs(false);
cur_dvs = false;
return 0;
}
static int osiris_dvs_resume(struct device *dev)
{
osiris_dvs_tps_setdvs(true);
return 0;
}
static const struct dev_pm_ops osiris_dvs_pm = {
.suspend = osiris_dvs_suspend,
.resume = osiris_dvs_resume,
};
static struct platform_driver osiris_dvs_driver = {
.probe = osiris_dvs_probe,
.remove = osiris_dvs_remove,
.driver = {
.name = "osiris-dvs",
.owner = THIS_MODULE,
.pm = &osiris_dvs_pm,
},
};
module_platform_driver(osiris_dvs_driver);
MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:osiris-dvs");