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Linux/arch/arm/mach-s3c24xx/mach-osiris-dvs.c

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  1 // SPDX-License-Identifier: GPL-2.0
  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 #include <linux/kernel.h>
 10 #include <linux/module.h>
 11 #include <linux/platform_device.h>
 12 #include <linux/cpufreq.h>
 13 #include <linux/gpio.h>
 14 
 15 #include <linux/mfd/tps65010.h>
 16 
 17 #include <plat/cpu-freq.h>
 18 #include <mach/gpio-samsung.h>
 19 
 20 #define OSIRIS_GPIO_DVS S3C2410_GPB(5)
 21 
 22 static bool dvs_en;
 23 
 24 static void osiris_dvs_tps_setdvs(bool on)
 25 {
 26         unsigned vregs1 = 0, vdcdc2 = 0;
 27 
 28         if (!on) {
 29                 vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
 30                 vregs1 = TPS_LDO1_OFF;  /* turn off in low-power mode */
 31         }
 32 
 33         dvs_en = on;
 34         vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
 35         vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
 36 
 37         tps65010_config_vregs1(vregs1);
 38         tps65010_config_vdcdc2(vdcdc2);
 39 }
 40 
 41 static bool is_dvs(struct s3c_freq *f)
 42 {
 43         /* at the moment, we assume ARMCLK = HCLK => DVS */
 44         return f->armclk == f->hclk;
 45 }
 46 
 47 /* keep track of current state */
 48 static bool cur_dvs = false;
 49 
 50 static int osiris_dvs_notify(struct notifier_block *nb,
 51                               unsigned long val, void *data)
 52 {
 53         struct cpufreq_freqs *cf = data;
 54         struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
 55         bool old_dvs = is_dvs(&freqs->old);
 56         bool new_dvs = is_dvs(&freqs->new);
 57         int ret = 0;
 58 
 59         if (!dvs_en)
 60                 return 0;
 61 
 62         printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
 63                freqs->old.armclk, freqs->old.hclk,
 64                freqs->new.armclk, freqs->new.hclk);
 65 
 66         switch (val) {
 67         case CPUFREQ_PRECHANGE:
 68                 if ((old_dvs && !new_dvs) ||
 69                     (cur_dvs && !new_dvs)) {
 70                         pr_debug("%s: exiting dvs\n", __func__);
 71                         cur_dvs = false;
 72                         gpio_set_value(OSIRIS_GPIO_DVS, 1);
 73                 }
 74                 break;
 75         case CPUFREQ_POSTCHANGE:
 76                 if ((!old_dvs && new_dvs) ||
 77                     (!cur_dvs && new_dvs)) {
 78                         pr_debug("entering dvs\n");
 79                         cur_dvs = true;
 80                         gpio_set_value(OSIRIS_GPIO_DVS, 0);
 81                 }
 82                 break;
 83         }
 84 
 85         return ret;
 86 }
 87 
 88 static struct notifier_block osiris_dvs_nb = {
 89         .notifier_call  = osiris_dvs_notify,
 90 };
 91 
 92 static int osiris_dvs_probe(struct platform_device *pdev)
 93 {
 94         int ret;
 95 
 96         dev_info(&pdev->dev, "initialising\n");
 97 
 98         ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
 99         if (ret) {
100                 dev_err(&pdev->dev, "cannot claim gpio\n");
101                 goto err_nogpio;
102         }
103 
104         /* start with dvs disabled */
105         gpio_direction_output(OSIRIS_GPIO_DVS, 1);
106 
107         ret = cpufreq_register_notifier(&osiris_dvs_nb,
108                                         CPUFREQ_TRANSITION_NOTIFIER);
109         if (ret) {
110                 dev_err(&pdev->dev, "failed to register with cpufreq\n");
111                 goto err_nofreq;
112         }
113 
114         osiris_dvs_tps_setdvs(true);
115 
116         return 0;
117 
118 err_nofreq:
119         gpio_free(OSIRIS_GPIO_DVS);
120 
121 err_nogpio:
122         return ret;
123 }
124 
125 static int osiris_dvs_remove(struct platform_device *pdev)
126 {
127         dev_info(&pdev->dev, "exiting\n");
128 
129         /* disable any current dvs */
130         gpio_set_value(OSIRIS_GPIO_DVS, 1);
131         osiris_dvs_tps_setdvs(false);
132 
133         cpufreq_unregister_notifier(&osiris_dvs_nb,
134                                     CPUFREQ_TRANSITION_NOTIFIER);
135 
136         gpio_free(OSIRIS_GPIO_DVS);
137 
138         return 0;
139 }
140 
141 /* the CONFIG_PM block is so small, it isn't worth actually compiling it
142  * out if the configuration isn't set. */
143 
144 static int osiris_dvs_suspend(struct device *dev)
145 {
146         gpio_set_value(OSIRIS_GPIO_DVS, 1);
147         osiris_dvs_tps_setdvs(false);
148         cur_dvs = false;
149 
150         return 0;
151 }
152 
153 static int osiris_dvs_resume(struct device *dev)
154 {
155         osiris_dvs_tps_setdvs(true);
156         return 0;
157 }
158 
159 static const struct dev_pm_ops osiris_dvs_pm = {
160         .suspend        = osiris_dvs_suspend,
161         .resume         = osiris_dvs_resume,
162 };
163 
164 static struct platform_driver osiris_dvs_driver = {
165         .probe          = osiris_dvs_probe,
166         .remove         = osiris_dvs_remove,
167         .driver         = {
168                 .name   = "osiris-dvs",
169                 .pm     = &osiris_dvs_pm,
170         },
171 };
172 
173 module_platform_driver(osiris_dvs_driver);
174 
175 MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
176 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
177 MODULE_LICENSE("GPL");
178 MODULE_ALIAS("platform:osiris-dvs");
179 

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