LXR linux/arch/arm/mach-s3c2440/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
  24#define OSIRIS_GPIO_DVS S3C2410_GPB(5)
  25
  26static bool dvs_en;
  27
  28static void osiris_dvs_tps_setdvs(bool on)
  29{
  30        unsigned vregs1 = 0, vdcdc2 = 0;
  31
  32        if (!on) {
  33                vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
  34                vregs1 = TPS_LDO1_OFF;  /* turn off in low-power mode */
  35        }
  36
  37        dvs_en = on;
  38        vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
  39        vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
  40
  41        tps65010_config_vregs1(vregs1);
  42        tps65010_config_vdcdc2(vdcdc2);
  43}
  44
  45static bool is_dvs(struct s3c_freq *f)
  46{
  47        /* at the moment, we assume ARMCLK = HCLK => DVS */
  48        return f->armclk == f->hclk;
  49}
  50
  51/* keep track of current state */
  52static bool cur_dvs = false;
  53
  54static int osiris_dvs_notify(struct notifier_block *nb,
  55                              unsigned long val, void *data)
  56{
  57        struct cpufreq_freqs *cf = data;
  58        struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
  59        bool old_dvs = is_dvs(&freqs->old);
  60        bool new_dvs = is_dvs(&freqs->new);
  61        int ret = 0;
  62
  63        if (!dvs_en)
  64                return 0;
  65
  66        printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
  67               freqs->old.armclk, freqs->old.hclk,
  68               freqs->new.armclk, freqs->new.hclk);
  69
  70        switch (val) {
  71        case CPUFREQ_PRECHANGE:
  72                if (old_dvs & !new_dvs ||
  73                    cur_dvs & !new_dvs) {
  74                        pr_debug("%s: exiting dvs\n", __func__);
  75                        cur_dvs = false;
  76                        gpio_set_value(OSIRIS_GPIO_DVS, 1);
  77                }
  78                break;
  79        case CPUFREQ_POSTCHANGE:
  80                if (!old_dvs & new_dvs ||
  81                    !cur_dvs & new_dvs) {
  82                        pr_debug("entering dvs\n");
  83                        cur_dvs = true;
  84                        gpio_set_value(OSIRIS_GPIO_DVS, 0);
  85                }
  86                break;
  87        }
  88
  89        return ret;
  90}
  91
  92static struct notifier_block osiris_dvs_nb = {
  93        .notifier_call  = osiris_dvs_notify,
  94};
  95
  96static int __devinit osiris_dvs_probe(struct platform_device *pdev)
  97{
  98        int ret;
  99
 100        dev_info(&pdev->dev, "initialising\n");
 101
 102        ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
 103        if (ret) {
 104                dev_err(&pdev->dev, "cannot claim gpio\n");
 105                goto err_nogpio;
 106        }
 107
 108        /* start with dvs disabled */
 109        gpio_direction_output(OSIRIS_GPIO_DVS, 1);
 110
 111        ret = cpufreq_register_notifier(&osiris_dvs_nb,
 112                                        CPUFREQ_TRANSITION_NOTIFIER);
 113        if (ret) {
 114                dev_err(&pdev->dev, "failed to register with cpufreq\n");
 115                goto err_nofreq;
 116        }
 117
 118        osiris_dvs_tps_setdvs(true);
 119
 120        return 0;
 121
 122err_nofreq:
 123        gpio_free(OSIRIS_GPIO_DVS);
 124
 125err_nogpio:
 126        return ret;
 127}
 128
 129static int __devexit osiris_dvs_remove(struct platform_device *pdev)
 130{
 131        dev_info(&pdev->dev, "exiting\n");
 132
 133        /* disable any current dvs */
 134        gpio_set_value(OSIRIS_GPIO_DVS, 1);
 135        osiris_dvs_tps_setdvs(false);
 136
 137        cpufreq_unregister_notifier(&osiris_dvs_nb,
 138                                    CPUFREQ_TRANSITION_NOTIFIER);
 139
 140        gpio_free(OSIRIS_GPIO_DVS);
 141
 142        return 0;
 143}
 144
 145/* the CONFIG_PM block is so small, it isn't worth actaully compiling it
 146 * out if the configuration isn't set. */
 147
 148static int osiris_dvs_suspend(struct device *dev)
 149{
 150        gpio_set_value(OSIRIS_GPIO_DVS, 1);
 151        osiris_dvs_tps_setdvs(false);
 152        cur_dvs = false;
 153
 154        return 0;
 155}
 156
 157static int osiris_dvs_resume(struct device *dev)
 158{
 159        osiris_dvs_tps_setdvs(true);
 160        return 0;
 161}
 162
 163static const struct dev_pm_ops osiris_dvs_pm = {
 164        .suspend        = osiris_dvs_suspend,
 165        .resume         = osiris_dvs_resume,
 166};
 167
 168static struct platform_driver osiris_dvs_driver = {
 169        .probe          = osiris_dvs_probe,
 170        .remove         = __devexit_p(osiris_dvs_remove),
 171        .driver         = {
 172                .name   = "osiris-dvs",
 173                .owner  = THIS_MODULE,
 174                .pm     = &osiris_dvs_pm,
 175        },
 176};
 177
 178static int __init osiris_dvs_init(void)
 179{
 180        return platform_driver_register(&osiris_dvs_driver);
 181}
 182
 183static void __exit osiris_dvs_exit(void)
 184{
 185        platform_driver_unregister(&osiris_dvs_driver);
 186}
 187
 188module_init(osiris_dvs_init);
 189module_exit(osiris_dvs_exit);
 190
 191MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
 192MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 193MODULE_LICENSE("GPL");
 194MODULE_ALIAS("platform:osiris-dvs");
 195