diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/rtc/class.c | 545 |
1 files changed, 545 insertions, 0 deletions
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c new file mode 100644 index 000000000..0fca4d74c --- /dev/null +++ b/drivers/rtc/class.c @@ -0,0 +1,545 @@ +/* + * RTC subsystem, base class + * + * Copyright (C) 2005 Tower Technologies + * Author: Alessandro Zummo <a.zummo@towertech.it> + * + * class skeleton from drivers/hwmon/hwmon.c + * + * 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. +*/ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/of.h> +#include <linux/rtc.h> +#include <linux/kdev_t.h> +#include <linux/idr.h> +#include <linux/slab.h> +#include <linux/workqueue.h> + +#include "rtc-core.h" + + +static DEFINE_IDA(rtc_ida); +struct class *rtc_class; + +static void rtc_device_release(struct device *dev) +{ + struct rtc_device *rtc = to_rtc_device(dev); + ida_simple_remove(&rtc_ida, rtc->id); + kfree(rtc); +} + +#ifdef CONFIG_RTC_HCTOSYS_DEVICE +/* Result of the last RTC to system clock attempt. */ +int rtc_hctosys_ret = -ENODEV; +#endif + +#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) +/* + * On suspend(), measure the delta between one RTC and the + * system's wall clock; restore it on resume(). + */ + +static struct timespec64 old_rtc, old_system, old_delta; + + +static int rtc_suspend(struct device *dev) +{ + struct rtc_device *rtc = to_rtc_device(dev); + struct rtc_time tm; + struct timespec64 delta, delta_delta; + int err; + + if (timekeeping_rtc_skipsuspend()) + return 0; + + if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) + return 0; + + /* snapshot the current RTC and system time at suspend*/ + err = rtc_read_time(rtc, &tm); + if (err < 0) { + pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); + return 0; + } + + ktime_get_real_ts64(&old_system); + old_rtc.tv_sec = rtc_tm_to_time64(&tm); + + + /* + * To avoid drift caused by repeated suspend/resumes, + * which each can add ~1 second drift error, + * try to compensate so the difference in system time + * and rtc time stays close to constant. + */ + delta = timespec64_sub(old_system, old_rtc); + delta_delta = timespec64_sub(delta, old_delta); + if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { + /* + * if delta_delta is too large, assume time correction + * has occured and set old_delta to the current delta. + */ + old_delta = delta; + } else { + /* Otherwise try to adjust old_system to compensate */ + old_system = timespec64_sub(old_system, delta_delta); + } + + return 0; +} + +static int rtc_resume(struct device *dev) +{ + struct rtc_device *rtc = to_rtc_device(dev); + struct rtc_time tm; + struct timespec64 new_system, new_rtc; + struct timespec64 sleep_time; + int err; + + if (timekeeping_rtc_skipresume()) + return 0; + + rtc_hctosys_ret = -ENODEV; + if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) + return 0; + + /* snapshot the current rtc and system time at resume */ + ktime_get_real_ts64(&new_system); + err = rtc_read_time(rtc, &tm); + if (err < 0) { + pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); + return 0; + } + + new_rtc.tv_sec = rtc_tm_to_time64(&tm); + new_rtc.tv_nsec = 0; + + if (new_rtc.tv_sec < old_rtc.tv_sec) { + pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); + return 0; + } + + /* calculate the RTC time delta (sleep time)*/ + sleep_time = timespec64_sub(new_rtc, old_rtc); + + /* + * Since these RTC suspend/resume handlers are not called + * at the very end of suspend or the start of resume, + * some run-time may pass on either sides of the sleep time + * so subtract kernel run-time between rtc_suspend to rtc_resume + * to keep things accurate. + */ + sleep_time = timespec64_sub(sleep_time, + timespec64_sub(new_system, old_system)); + + if (sleep_time.tv_sec >= 0) + timekeeping_inject_sleeptime64(&sleep_time); + rtc_hctosys_ret = 0; + return 0; +} + +static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume); +#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops) +#else +#define RTC_CLASS_DEV_PM_OPS NULL +#endif + +/* Ensure the caller will set the id before releasing the device */ +static struct rtc_device *rtc_allocate_device(void) +{ + struct rtc_device *rtc; + + rtc = kzalloc(sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return NULL; + + device_initialize(&rtc->dev); + + /* Drivers can revise this default after allocating the device. */ + rtc->set_offset_nsec = NSEC_PER_SEC / 2; + + rtc->irq_freq = 1; + rtc->max_user_freq = 64; + rtc->dev.class = rtc_class; + rtc->dev.groups = rtc_get_dev_attribute_groups(); + rtc->dev.release = rtc_device_release; + + mutex_init(&rtc->ops_lock); + spin_lock_init(&rtc->irq_lock); + init_waitqueue_head(&rtc->irq_queue); + + /* Init timerqueue */ + timerqueue_init_head(&rtc->timerqueue); + INIT_WORK(&rtc->irqwork, rtc_timer_do_work); + /* Init aie timer */ + rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc); + /* Init uie timer */ + rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc); + /* Init pie timer */ + hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + rtc->pie_timer.function = rtc_pie_update_irq; + rtc->pie_enabled = 0; + + return rtc; +} + +static int rtc_device_get_id(struct device *dev) +{ + int of_id = -1, id = -1; + + if (dev->of_node) + of_id = of_alias_get_id(dev->of_node, "rtc"); + else if (dev->parent && dev->parent->of_node) + of_id = of_alias_get_id(dev->parent->of_node, "rtc"); + + if (of_id >= 0) { + id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL); + if (id < 0) + dev_warn(dev, "/aliases ID %d not available\n", of_id); + } + + if (id < 0) + id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL); + + return id; +} + +static void rtc_device_get_offset(struct rtc_device *rtc) +{ + time64_t range_secs; + u32 start_year; + int ret; + + /* + * If RTC driver did not implement the range of RTC hardware device, + * then we can not expand the RTC range by adding or subtracting one + * offset. + */ + if (rtc->range_min == rtc->range_max) + return; + + ret = device_property_read_u32(rtc->dev.parent, "start-year", + &start_year); + if (!ret) { + rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0); + rtc->set_start_time = true; + } + + /* + * If user did not implement the start time for RTC driver, then no + * need to expand the RTC range. + */ + if (!rtc->set_start_time) + return; + + range_secs = rtc->range_max - rtc->range_min + 1; + + /* + * If the start_secs is larger than the maximum seconds (rtc->range_max) + * supported by RTC hardware or the maximum seconds of new expanded + * range (start_secs + rtc->range_max - rtc->range_min) is less than + * rtc->range_min, which means the minimum seconds (rtc->range_min) of + * RTC hardware will be mapped to start_secs by adding one offset, so + * the offset seconds calculation formula should be: + * rtc->offset_secs = rtc->start_secs - rtc->range_min; + * + * If the start_secs is larger than the minimum seconds (rtc->range_min) + * supported by RTC hardware, then there is one region is overlapped + * between the original RTC hardware range and the new expanded range, + * and this overlapped region do not need to be mapped into the new + * expanded range due to it is valid for RTC device. So the minimum + * seconds of RTC hardware (rtc->range_min) should be mapped to + * rtc->range_max + 1, then the offset seconds formula should be: + * rtc->offset_secs = rtc->range_max - rtc->range_min + 1; + * + * If the start_secs is less than the minimum seconds (rtc->range_min), + * which is similar to case 2. So the start_secs should be mapped to + * start_secs + rtc->range_max - rtc->range_min + 1, then the + * offset seconds formula should be: + * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1); + * + * Otherwise the offset seconds should be 0. + */ + if (rtc->start_secs > rtc->range_max || + rtc->start_secs + range_secs - 1 < rtc->range_min) + rtc->offset_secs = rtc->start_secs - rtc->range_min; + else if (rtc->start_secs > rtc->range_min) + rtc->offset_secs = range_secs; + else if (rtc->start_secs < rtc->range_min) + rtc->offset_secs = -range_secs; + else + rtc->offset_secs = 0; +} + +/** + * rtc_device_register - register w/ RTC class + * @dev: the device to register + * + * rtc_device_unregister() must be called when the class device is no + * longer needed. + * + * Returns the pointer to the new struct class device. + */ +struct rtc_device *rtc_device_register(const char *name, struct device *dev, + const struct rtc_class_ops *ops, + struct module *owner) +{ + struct rtc_device *rtc; + struct rtc_wkalrm alrm; + int id, err; + + id = rtc_device_get_id(dev); + if (id < 0) { + err = id; + goto exit; + } + + rtc = rtc_allocate_device(); + if (!rtc) { + err = -ENOMEM; + goto exit_ida; + } + + rtc->id = id; + rtc->ops = ops; + rtc->owner = owner; + rtc->dev.parent = dev; + + dev_set_name(&rtc->dev, "rtc%d", id); + + rtc_device_get_offset(rtc); + + /* Check to see if there is an ALARM already set in hw */ + err = __rtc_read_alarm(rtc, &alrm); + + if (!err && !rtc_valid_tm(&alrm.time)) + rtc_initialize_alarm(rtc, &alrm); + + rtc_dev_prepare(rtc); + + err = cdev_device_add(&rtc->char_dev, &rtc->dev); + if (err) { + dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n", + name, MAJOR(rtc->dev.devt), rtc->id); + + /* This will free both memory and the ID */ + put_device(&rtc->dev); + goto exit; + } else { + dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", name, + MAJOR(rtc->dev.devt), rtc->id); + } + + rtc_proc_add_device(rtc); + + dev_info(dev, "rtc core: registered %s as %s\n", + name, dev_name(&rtc->dev)); + + return rtc; + +exit_ida: + ida_simple_remove(&rtc_ida, id); + +exit: + dev_err(dev, "rtc core: unable to register %s, err = %d\n", + name, err); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(rtc_device_register); + + +/** + * rtc_device_unregister - removes the previously registered RTC class device + * + * @rtc: the RTC class device to destroy + */ +void rtc_device_unregister(struct rtc_device *rtc) +{ + mutex_lock(&rtc->ops_lock); + /* + * Remove innards of this RTC, then disable it, before + * letting any rtc_class_open() users access it again + */ + rtc_proc_del_device(rtc); + cdev_device_del(&rtc->char_dev, &rtc->dev); + rtc->ops = NULL; + mutex_unlock(&rtc->ops_lock); + put_device(&rtc->dev); +} +EXPORT_SYMBOL_GPL(rtc_device_unregister); + +static void devm_rtc_device_release(struct device *dev, void *res) +{ + struct rtc_device *rtc = *(struct rtc_device **)res; + + rtc_nvmem_unregister(rtc); + rtc_device_unregister(rtc); +} + +static int devm_rtc_device_match(struct device *dev, void *res, void *data) +{ + struct rtc **r = res; + + return *r == data; +} + +/** + * devm_rtc_device_register - resource managed rtc_device_register() + * @dev: the device to register + * @name: the name of the device + * @ops: the rtc operations structure + * @owner: the module owner + * + * @return a struct rtc on success, or an ERR_PTR on error + * + * Managed rtc_device_register(). The rtc_device returned from this function + * are automatically freed on driver detach. See rtc_device_register() + * for more information. + */ + +struct rtc_device *devm_rtc_device_register(struct device *dev, + const char *name, + const struct rtc_class_ops *ops, + struct module *owner) +{ + struct rtc_device **ptr, *rtc; + + ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + rtc = rtc_device_register(name, dev, ops, owner); + if (!IS_ERR(rtc)) { + *ptr = rtc; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return rtc; +} +EXPORT_SYMBOL_GPL(devm_rtc_device_register); + +/** + * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister() + * @dev: the device to unregister + * @rtc: the RTC class device to unregister + * + * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this + * function will not need to be called and the resource management code will + * ensure that the resource is freed. + */ +void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc) +{ + int rc; + + rc = devres_release(dev, devm_rtc_device_release, + devm_rtc_device_match, rtc); + WARN_ON(rc); +} +EXPORT_SYMBOL_GPL(devm_rtc_device_unregister); + +static void devm_rtc_release_device(struct device *dev, void *res) +{ + struct rtc_device *rtc = *(struct rtc_device **)res; + + rtc_nvmem_unregister(rtc); + + if (rtc->registered) + rtc_device_unregister(rtc); + else + put_device(&rtc->dev); +} + +struct rtc_device *devm_rtc_allocate_device(struct device *dev) +{ + struct rtc_device **ptr, *rtc; + int id, err; + + id = rtc_device_get_id(dev); + if (id < 0) + return ERR_PTR(id); + + ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL); + if (!ptr) { + err = -ENOMEM; + goto exit_ida; + } + + rtc = rtc_allocate_device(); + if (!rtc) { + err = -ENOMEM; + goto exit_devres; + } + + *ptr = rtc; + devres_add(dev, ptr); + + rtc->id = id; + rtc->dev.parent = dev; + dev_set_name(&rtc->dev, "rtc%d", id); + + return rtc; + +exit_devres: + devres_free(ptr); +exit_ida: + ida_simple_remove(&rtc_ida, id); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(devm_rtc_allocate_device); + +int __rtc_register_device(struct module *owner, struct rtc_device *rtc) +{ + struct rtc_wkalrm alrm; + int err; + + if (!rtc->ops) + return -EINVAL; + + rtc->owner = owner; + rtc_device_get_offset(rtc); + + /* Check to see if there is an ALARM already set in hw */ + err = __rtc_read_alarm(rtc, &alrm); + if (!err && !rtc_valid_tm(&alrm.time)) + rtc_initialize_alarm(rtc, &alrm); + + rtc_dev_prepare(rtc); + + err = cdev_device_add(&rtc->char_dev, &rtc->dev); + if (err) + dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n", + MAJOR(rtc->dev.devt), rtc->id); + else + dev_dbg(rtc->dev.parent, "char device (%d:%d)\n", + MAJOR(rtc->dev.devt), rtc->id); + + rtc_proc_add_device(rtc); + + rtc->registered = true; + dev_info(rtc->dev.parent, "registered as %s\n", + dev_name(&rtc->dev)); + + return 0; +} +EXPORT_SYMBOL_GPL(__rtc_register_device); + +static int __init rtc_init(void) +{ + rtc_class = class_create(THIS_MODULE, "rtc"); + if (IS_ERR(rtc_class)) { + pr_err("couldn't create class\n"); + return PTR_ERR(rtc_class); + } + rtc_class->pm = RTC_CLASS_DEV_PM_OPS; + rtc_dev_init(); + return 0; +} +subsys_initcall(rtc_init); |