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
  24 #define OSIRIS_GPIO_DVS S3C2410_GPB(5)
  25
  26 static bool dvs_en;
  27
  28 static 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
  45 static 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 */
  52 static bool cur_dvs = false;
  53
  54 static 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
  92 static struct notifier_block osiris_dvs_nb = {
  93         .notifier_call  = osiris_dvs_notify,
  94 };
  95
  96 static int 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
 122 err_nofreq:
 123         gpio_free(OSIRIS_GPIO_DVS);
 124
 125 err_nogpio:
 126         return ret;
 127 }
 128
 129 static int 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
 148 static 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
 157 static int osiris_dvs_resume(struct device *dev)
 158 {
 159         osiris_dvs_tps_setdvs(true);
 160         return 0;
 161 }
 162
 163 static const struct dev_pm_ops osiris_dvs_pm = {
 164         .suspend        = osiris_dvs_suspend,
 165         .resume         = osiris_dvs_resume,
 166 };
 167
 168 static struct platform_driver osiris_dvs_driver = {
 169         .probe          = osiris_dvs_probe,
 170         .remove         = osiris_dvs_remove,
 171         .driver         = {
 172                 .name   = "osiris-dvs",
 173                 .owner  = THIS_MODULE,
 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");