drivers/rtc/rtc-meson-vrtc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2019 BayLibre, SAS
   4  * Author: Neil Armstrong <narmstrong@baylibre.com>
   5  * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
   6  */
   7 #include <linux/module.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/rtc.h>
  10 #include <linux/io.h>
  11 #include <linux/of.h>
  12 #include <linux/time64.h>
  13
  14 struct meson_vrtc_data {
  15         void __iomem *io_alarm;
  16         struct rtc_device *rtc;
  17         unsigned long alarm_time;
  18         bool enabled;
  19 };
  20
  21 static int meson_vrtc_read_time(struct device *dev, struct rtc_time *tm)
  22 {
  23         struct timespec64 time;
  24
  25         dev_dbg(dev, "%s\n", __func__);
  26         ktime_get_real_ts64(&time);
  27         rtc_time64_to_tm(time.tv_sec, tm);
  28
  29         return 0;
  30 }
  31
  32 static void meson_vrtc_set_wakeup_time(struct meson_vrtc_data *vrtc,
  33                                        unsigned long time)
  34 {
  35         writel_relaxed(time, vrtc->io_alarm);
  36 }
  37
  38 static int meson_vrtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
  39 {
  40         struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
  41
  42         dev_dbg(dev, "%s: alarm->enabled=%d\n", __func__, alarm->enabled);
  43         if (alarm->enabled)
  44                 vrtc->alarm_time = rtc_tm_to_time64(&alarm->time);
  45         else
  46                 vrtc->alarm_time = 0;
  47
  48         return 0;
  49 }
  50
  51 static int meson_vrtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  52 {
  53         struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
  54
  55         vrtc->enabled = enabled;
  56         return 0;
  57 }
  58
  59 static const struct rtc_class_ops meson_vrtc_ops = {
  60         .read_time = meson_vrtc_read_time,
  61         .set_alarm = meson_vrtc_set_alarm,
  62         .alarm_irq_enable = meson_vrtc_alarm_irq_enable,
  63 };
  64
  65 static int meson_vrtc_probe(struct platform_device *pdev)
  66 {
  67         struct meson_vrtc_data *vrtc;
  68
  69         vrtc = devm_kzalloc(&pdev->dev, sizeof(*vrtc), GFP_KERNEL);
  70         if (!vrtc)
  71                 return -ENOMEM;
  72
  73         vrtc->io_alarm = devm_platform_ioremap_resource(pdev, 0);
  74         if (IS_ERR(vrtc->io_alarm))
  75                 return PTR_ERR(vrtc->io_alarm);
  76
  77         device_init_wakeup(&pdev->dev, 1);
  78
  79         platform_set_drvdata(pdev, vrtc);
  80
  81         vrtc->rtc = devm_rtc_allocate_device(&pdev->dev);
  82         if (IS_ERR(vrtc->rtc))
  83                 return PTR_ERR(vrtc->rtc);
  84
  85         vrtc->rtc->ops = &meson_vrtc_ops;
  86         return devm_rtc_register_device(vrtc->rtc);
  87 }
  88
  89 static int __maybe_unused meson_vrtc_suspend(struct device *dev)
  90 {
  91         struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
  92
  93         dev_dbg(dev, "%s\n", __func__);
  94         if (vrtc->alarm_time) {
  95                 unsigned long local_time;
  96                 long alarm_secs;
  97                 struct timespec64 time;
  98
  99                 ktime_get_real_ts64(&time);
 100                 local_time = time.tv_sec;
 101
 102                 dev_dbg(dev, "alarm_time = %lus, local_time=%lus\n",
 103                         vrtc->alarm_time, local_time);
 104                 alarm_secs = vrtc->alarm_time - local_time;
 105                 if (alarm_secs > 0) {
 106                         meson_vrtc_set_wakeup_time(vrtc, alarm_secs);
 107                         dev_dbg(dev, "system will wakeup in %lds.\n",
 108                                 alarm_secs);
 109                 } else {
 110                         dev_err(dev, "alarm time already passed: %lds.\n",
 111                                 alarm_secs);
 112                 }
 113         }
 114
 115         return 0;
 116 }
 117
 118 static int __maybe_unused meson_vrtc_resume(struct device *dev)
 119 {
 120         struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
 121
 122         dev_dbg(dev, "%s\n", __func__);
 123
 124         vrtc->alarm_time = 0;
 125         meson_vrtc_set_wakeup_time(vrtc, 0);
 126         return 0;
 127 }
 128
 129 static SIMPLE_DEV_PM_OPS(meson_vrtc_pm_ops,
 130                          meson_vrtc_suspend, meson_vrtc_resume);
 131
 132 static const struct of_device_id meson_vrtc_dt_match[] = {
 133         { .compatible = "amlogic,meson-vrtc"},
 134         {},
 135 };
 136 MODULE_DEVICE_TABLE(of, meson_vrtc_dt_match);
 137
 138 static struct platform_driver meson_vrtc_driver = {
 139         .probe = meson_vrtc_probe,
 140         .driver = {
 141                 .name = "meson-vrtc",
 142                 .of_match_table = meson_vrtc_dt_match,
 143                 .pm = &meson_vrtc_pm_ops,
 144         },
 145 };
 146
 147 module_platform_driver(meson_vrtc_driver);
 148
 149 MODULE_DESCRIPTION("Amlogic Virtual Wakeup RTC Timer driver");
 150 MODULE_LICENSE("GPL");