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