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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/rtc/class.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/rtc/class.c')
-rw-r--r--drivers/rtc/class.c487
1 files changed, 487 insertions, 0 deletions
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
new file mode 100644
index 000000000..e5b7b48cf
--- /dev/null
+++ b/drivers/rtc/class.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC subsystem, base class
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * class skeleton from drivers/hwmon/hwmon.c
+ */
+
+#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);
+ struct timerqueue_head *head = &rtc->timerqueue;
+ struct timerqueue_node *node;
+
+ mutex_lock(&rtc->ops_lock);
+ while ((node = timerqueue_getnext(head)))
+ timerqueue_del(head, node);
+ mutex_unlock(&rtc->ops_lock);
+
+ cancel_work_sync(&rtc->irqwork);
+
+ ida_free(&rtc_ida, rtc->id);
+ mutex_destroy(&rtc->ops_lock);
+ kfree(rtc);
+}
+
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+/* Result of the last RTC to system clock attempt. */
+int rtc_hctosys_ret = -ENODEV;
+
+/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
+ * whether it stores the most close value or the value with partial
+ * seconds truncated. However, it is important that we use it to store
+ * the truncated value. This is because otherwise it is necessary,
+ * in an rtc sync function, to read both xtime.tv_sec and
+ * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
+ * of >32bits is not possible. So storing the most close value would
+ * slow down the sync API. So here we have the truncated value and
+ * the best guess is to add 0.5s.
+ */
+
+static void rtc_hctosys(struct rtc_device *rtc)
+{
+ int err;
+ struct rtc_time tm;
+ struct timespec64 tv64 = {
+ .tv_nsec = NSEC_PER_SEC >> 1,
+ };
+
+ err = rtc_read_time(rtc, &tm);
+ if (err) {
+ dev_err(rtc->dev.parent,
+ "hctosys: unable to read the hardware clock\n");
+ goto err_read;
+ }
+
+ tv64.tv_sec = rtc_tm_to_time64(&tm);
+
+#if BITS_PER_LONG == 32
+ if (tv64.tv_sec > INT_MAX) {
+ err = -ERANGE;
+ goto err_read;
+ }
+#endif
+
+ err = do_settimeofday64(&tv64);
+
+ dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
+ &tm, (long long)tv64.tv_sec);
+
+err_read:
+ rtc_hctosys_ret = err;
+}
+#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 occurred 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.
+ * The default is what most RTCs do: Increment seconds exactly one
+ * second after the write happened. This adds a default transport
+ * time of 5ms which is at least halfways close to reality.
+ */
+ rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC;
+
+ 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, rtc);
+ /* Init uie timer */
+ rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, 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;
+
+ set_bit(RTC_FEATURE_ALARM, rtc->features);
+ set_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
+
+ 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_alloc(&rtc_ida, 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;
+}
+
+static void devm_rtc_unregister_device(void *data)
+{
+ struct rtc_device *rtc = data;
+
+ 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);
+ if (!test_bit(RTC_NO_CDEV, &rtc->flags))
+ cdev_device_del(&rtc->char_dev, &rtc->dev);
+ rtc->ops = NULL;
+ mutex_unlock(&rtc->ops_lock);
+}
+
+static void devm_rtc_release_device(void *res)
+{
+ struct rtc_device *rtc = res;
+
+ put_device(&rtc->dev);
+}
+
+struct rtc_device *devm_rtc_allocate_device(struct device *dev)
+{
+ struct rtc_device *rtc;
+ int id, err;
+
+ id = rtc_device_get_id(dev);
+ if (id < 0)
+ return ERR_PTR(id);
+
+ rtc = rtc_allocate_device();
+ if (!rtc) {
+ ida_free(&rtc_ida, id);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ rtc->id = id;
+ rtc->dev.parent = dev;
+ err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc);
+ if (err)
+ return ERR_PTR(err);
+
+ err = dev_set_name(&rtc->dev, "rtc%d", id);
+ if (err)
+ return ERR_PTR(err);
+
+ return rtc;
+}
+EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
+
+int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
+{
+ struct rtc_wkalrm alrm;
+ int err;
+
+ if (!rtc->ops) {
+ dev_dbg(&rtc->dev, "no ops set\n");
+ return -EINVAL;
+ }
+
+ if (!rtc->ops->set_alarm)
+ clear_bit(RTC_FEATURE_ALARM, rtc->features);
+
+ if (rtc->ops->set_offset)
+ set_bit(RTC_FEATURE_CORRECTION, rtc->features);
+
+ 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) {
+ set_bit(RTC_NO_CDEV, &rtc->flags);
+ 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);
+
+ dev_info(rtc->dev.parent, "registered as %s\n",
+ dev_name(&rtc->dev));
+
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+ if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE))
+ rtc_hctosys(rtc);
+#endif
+
+ return devm_add_action_or_reset(rtc->dev.parent,
+ devm_rtc_unregister_device, rtc);
+}
+EXPORT_SYMBOL_GPL(__devm_rtc_register_device);
+
+/**
+ * devm_rtc_device_register - resource managed rtc_device_register()
+ * @dev: the device to register
+ * @name: the name of the device (unused)
+ * @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.
+ * This function is deprecated, use devm_rtc_allocate_device and
+ * rtc_register_device instead
+ */
+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 *rtc;
+ int err;
+
+ rtc = devm_rtc_allocate_device(dev);
+ if (IS_ERR(rtc))
+ return rtc;
+
+ rtc->ops = ops;
+
+ err = __devm_rtc_register_device(owner, rtc);
+ if (err)
+ return ERR_PTR(err);
+
+ return rtc;
+}
+EXPORT_SYMBOL_GPL(devm_rtc_device_register);
+
+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);