184 lines
3.9 KiB
C
184 lines
3.9 KiB
C
/* linux/arch/arm/mach-s3c2440/mach-osiris-dvs.c
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*
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* Copyright (c) 2009 Simtec Electronics
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* http://armlinux.simtec.co.uk/
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* Ben Dooks <ben@simtec.co.uk>
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*
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* Simtec Osiris Dynamic Voltage Scaling support.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/cpufreq.h>
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#include <linux/gpio.h>
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#include <linux/mfd/tps65010.h>
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#include <plat/cpu-freq.h>
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#include <mach/gpio-samsung.h>
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#define OSIRIS_GPIO_DVS S3C2410_GPB(5)
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static bool dvs_en;
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static void osiris_dvs_tps_setdvs(bool on)
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{
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unsigned vregs1 = 0, vdcdc2 = 0;
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if (!on) {
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vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
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vregs1 = TPS_LDO1_OFF; /* turn off in low-power mode */
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}
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dvs_en = on;
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vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
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vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
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tps65010_config_vregs1(vregs1);
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tps65010_config_vdcdc2(vdcdc2);
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}
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static bool is_dvs(struct s3c_freq *f)
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{
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/* at the moment, we assume ARMCLK = HCLK => DVS */
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return f->armclk == f->hclk;
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}
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/* keep track of current state */
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static bool cur_dvs = false;
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static int osiris_dvs_notify(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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struct cpufreq_freqs *cf = data;
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struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
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bool old_dvs = is_dvs(&freqs->old);
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bool new_dvs = is_dvs(&freqs->new);
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int ret = 0;
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if (!dvs_en)
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return 0;
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printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
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freqs->old.armclk, freqs->old.hclk,
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freqs->new.armclk, freqs->new.hclk);
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switch (val) {
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case CPUFREQ_PRECHANGE:
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if (old_dvs & !new_dvs ||
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cur_dvs & !new_dvs) {
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pr_debug("%s: exiting dvs\n", __func__);
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cur_dvs = false;
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gpio_set_value(OSIRIS_GPIO_DVS, 1);
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}
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break;
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case CPUFREQ_POSTCHANGE:
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if (!old_dvs & new_dvs ||
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!cur_dvs & new_dvs) {
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pr_debug("entering dvs\n");
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cur_dvs = true;
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gpio_set_value(OSIRIS_GPIO_DVS, 0);
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}
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break;
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}
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return ret;
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}
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static struct notifier_block osiris_dvs_nb = {
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.notifier_call = osiris_dvs_notify,
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};
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static int osiris_dvs_probe(struct platform_device *pdev)
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{
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int ret;
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dev_info(&pdev->dev, "initialising\n");
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ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
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if (ret) {
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dev_err(&pdev->dev, "cannot claim gpio\n");
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goto err_nogpio;
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}
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/* start with dvs disabled */
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gpio_direction_output(OSIRIS_GPIO_DVS, 1);
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ret = cpufreq_register_notifier(&osiris_dvs_nb,
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CPUFREQ_TRANSITION_NOTIFIER);
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if (ret) {
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dev_err(&pdev->dev, "failed to register with cpufreq\n");
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goto err_nofreq;
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}
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osiris_dvs_tps_setdvs(true);
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return 0;
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err_nofreq:
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gpio_free(OSIRIS_GPIO_DVS);
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err_nogpio:
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return ret;
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}
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static int osiris_dvs_remove(struct platform_device *pdev)
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{
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dev_info(&pdev->dev, "exiting\n");
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/* disable any current dvs */
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gpio_set_value(OSIRIS_GPIO_DVS, 1);
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osiris_dvs_tps_setdvs(false);
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cpufreq_unregister_notifier(&osiris_dvs_nb,
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CPUFREQ_TRANSITION_NOTIFIER);
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gpio_free(OSIRIS_GPIO_DVS);
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return 0;
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}
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/* the CONFIG_PM block is so small, it isn't worth actually compiling it
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* out if the configuration isn't set. */
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static int osiris_dvs_suspend(struct device *dev)
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{
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gpio_set_value(OSIRIS_GPIO_DVS, 1);
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osiris_dvs_tps_setdvs(false);
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cur_dvs = false;
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return 0;
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}
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static int osiris_dvs_resume(struct device *dev)
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{
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osiris_dvs_tps_setdvs(true);
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return 0;
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}
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static const struct dev_pm_ops osiris_dvs_pm = {
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.suspend = osiris_dvs_suspend,
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.resume = osiris_dvs_resume,
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};
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static struct platform_driver osiris_dvs_driver = {
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.probe = osiris_dvs_probe,
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.remove = osiris_dvs_remove,
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.driver = {
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.name = "osiris-dvs",
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.pm = &osiris_dvs_pm,
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},
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};
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module_platform_driver(osiris_dvs_driver);
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MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
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MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:osiris-dvs");
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