diff options
Diffstat (limited to 'arch/arm/mach-s3c2440/mach-osiris-dvs.c')
| -rw-r--r-- | arch/arm/mach-s3c2440/mach-osiris-dvs.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/arch/arm/mach-s3c2440/mach-osiris-dvs.c b/arch/arm/mach-s3c2440/mach-osiris-dvs.c new file mode 100644 index 000000000000..ad2792dfbee1 --- /dev/null +++ b/arch/arm/mach-s3c2440/mach-osiris-dvs.c @@ -0,0 +1,194 @@ +/* linux/arch/arm/mach-s3c2440/mach-osiris-dvs.c + * + * Copyright (c) 2009 Simtec Electronics + * http://armlinux.simtec.co.uk/ + * Ben Dooks <ben@simtec.co.uk> + * + * Simtec Osiris Dynamic Voltage Scaling support. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/cpufreq.h> +#include <linux/gpio.h> + +#include <linux/i2c/tps65010.h> + +#include <plat/cpu-freq.h> + +#define OSIRIS_GPIO_DVS S3C2410_GPB(5) + +static bool dvs_en; + +static void osiris_dvs_tps_setdvs(bool on) +{ + unsigned vregs1 = 0, vdcdc2 = 0; + + if (!on) { + vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF; + vregs1 = TPS_LDO1_OFF; /* turn off in low-power mode */ + } + + dvs_en = on; + vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V; + vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE; + + tps65010_config_vregs1(vregs1); + tps65010_config_vdcdc2(vdcdc2); +} + +static bool is_dvs(struct s3c_freq *f) +{ + /* at the moment, we assume ARMCLK = HCLK => DVS */ + return f->armclk == f->hclk; +} + +/* keep track of current state */ +static bool cur_dvs = false; + +static int osiris_dvs_notify(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct cpufreq_freqs *cf = data; + struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf); + bool old_dvs = is_dvs(&freqs->old); + bool new_dvs = is_dvs(&freqs->new); + int ret = 0; + + if (!dvs_en) + return 0; + + printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__, + freqs->old.armclk, freqs->old.hclk, + freqs->new.armclk, freqs->new.hclk); + + switch (val) { + case CPUFREQ_PRECHANGE: + if (old_dvs & !new_dvs || + cur_dvs & !new_dvs) { + pr_debug("%s: exiting dvs\n", __func__); + cur_dvs = false; + gpio_set_value(OSIRIS_GPIO_DVS, 1); + } + break; + case CPUFREQ_POSTCHANGE: + if (!old_dvs & new_dvs || + !cur_dvs & new_dvs) { + pr_debug("entering dvs\n"); + cur_dvs = true; + gpio_set_value(OSIRIS_GPIO_DVS, 0); + } + break; + } + + return ret; +} + +static struct notifier_block osiris_dvs_nb = { + .notifier_call = osiris_dvs_notify, +}; + +static int __devinit osiris_dvs_probe(struct platform_device *pdev) +{ + int ret; + + dev_info(&pdev->dev, "initialising\n"); + + ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs"); + if (ret) { + dev_err(&pdev->dev, "cannot claim gpio\n"); + goto err_nogpio; + } + + /* start with dvs disabled */ + gpio_direction_output(OSIRIS_GPIO_DVS, 1); + + ret = cpufreq_register_notifier(&osiris_dvs_nb, + CPUFREQ_TRANSITION_NOTIFIER); + if (ret) { + dev_err(&pdev->dev, "failed to register with cpufreq\n"); + goto err_nofreq; + } + + osiris_dvs_tps_setdvs(true); + + return 0; + +err_nofreq: + gpio_free(OSIRIS_GPIO_DVS); + +err_nogpio: + return ret; +} + +static int __devexit osiris_dvs_remove(struct platform_device *pdev) +{ + dev_info(&pdev->dev, "exiting\n"); + + /* disable any current dvs */ + gpio_set_value(OSIRIS_GPIO_DVS, 1); + osiris_dvs_tps_setdvs(false); + + cpufreq_unregister_notifier(&osiris_dvs_nb, + CPUFREQ_TRANSITION_NOTIFIER); + + gpio_free(OSIRIS_GPIO_DVS); + + return 0; +} + +/* the CONFIG_PM block is so small, it isn't worth actaully compiling it + * out if the configuration isn't set. */ + +static int osiris_dvs_suspend(struct device *dev) +{ + gpio_set_value(OSIRIS_GPIO_DVS, 1); + osiris_dvs_tps_setdvs(false); + cur_dvs = false; + + return 0; +} + +static int osiris_dvs_resume(struct device *dev) +{ + osiris_dvs_tps_setdvs(true); + return 0; +} + +static const struct dev_pm_ops osiris_dvs_pm = { + .suspend = osiris_dvs_suspend, + .resume = osiris_dvs_resume, +}; + +static struct platform_driver osiris_dvs_driver = { + .probe = osiris_dvs_probe, + .remove = __devexit_p(osiris_dvs_remove), + .driver = { + .name = "osiris-dvs", + .owner = THIS_MODULE, + .pm = &osiris_dvs_pm, + }, +}; + +static int __init osiris_dvs_init(void) +{ + return platform_driver_register(&osiris_dvs_driver); +} + +static void __exit osiris_dvs_exit(void) +{ + platform_driver_unregister(&osiris_dvs_driver); +} + +module_init(osiris_dvs_init); +module_exit(osiris_dvs_exit); + +MODULE_DESCRIPTION("Simtec OSIRIS DVS support"); +MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:osiris-dvs"); |