LXR linux/arch/arm/mach-s3c24xx/mach-osiris-dvs.c

   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 actually 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