drivers/rtc/rtc-max8907.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * RTC driver for Maxim MAX8907
   4  *
   5  * Copyright (c) 2011-2012, NVIDIA Corporation.
   6  *
   7  * Based on drivers/rtc/rtc-max8925.c,
   8  * Copyright (C) 2009-2010 Marvell International Ltd.
   9  */
  10
  11 #include <linux/bcd.h>
  12 #include <linux/mfd/max8907.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/regmap.h>
  16 #include <linux/rtc.h>
  17 #include <linux/slab.h>
  18
  19 enum {
  20         RTC_SEC = 0,
  21         RTC_MIN,
  22         RTC_HOUR,
  23         RTC_WEEKDAY,
  24         RTC_DATE,
  25         RTC_MONTH,
  26         RTC_YEAR1,
  27         RTC_YEAR2,
  28 };
  29
  30 #define TIME_NUM                        8
  31 #define ALARM_1SEC                      (1 << 7)
  32 #define HOUR_12                         (1 << 7)
  33 #define HOUR_AM_PM                      (1 << 5)
  34 #define ALARM0_IRQ                      (1 << 3)
  35 #define ALARM1_IRQ                      (1 << 2)
  36 #define ALARM0_STATUS                   (1 << 2)
  37 #define ALARM1_STATUS                   (1 << 1)
  38
  39 struct max8907_rtc {
  40         struct max8907          *max8907;
  41         struct regmap           *regmap;
  42         struct rtc_device       *rtc_dev;
  43         int                     irq;
  44 };
  45
  46 static irqreturn_t max8907_irq_handler(int irq, void *data)
  47 {
  48         struct max8907_rtc *rtc = data;
  49
  50         regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
  51
  52         rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
  53
  54         return IRQ_HANDLED;
  55 }
  56
  57 static void regs_to_tm(u8 *regs, struct rtc_time *tm)
  58 {
  59         tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
  60                 bcd2bin(regs[RTC_YEAR1]) - 1900;
  61         tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
  62         tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
  63         tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07);
  64         if (regs[RTC_HOUR] & HOUR_12) {
  65                 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
  66                 if (tm->tm_hour == 12)
  67                         tm->tm_hour = 0;
  68                 if (regs[RTC_HOUR] & HOUR_AM_PM)
  69                         tm->tm_hour += 12;
  70         } else {
  71                 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x03f);
  72         }
  73         tm->tm_min = bcd2bin(regs[RTC_MIN] & 0x7f);
  74         tm->tm_sec = bcd2bin(regs[RTC_SEC] & 0x7f);
  75 }
  76
  77 static void tm_to_regs(struct rtc_time *tm, u8 *regs)
  78 {
  79         u8 high, low;
  80
  81         high = (tm->tm_year + 1900) / 100;
  82         low = tm->tm_year % 100;
  83         regs[RTC_YEAR2] = bin2bcd(high);
  84         regs[RTC_YEAR1] = bin2bcd(low);
  85         regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
  86         regs[RTC_DATE] = bin2bcd(tm->tm_mday);
  87         regs[RTC_WEEKDAY] = tm->tm_wday;
  88         regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
  89         regs[RTC_MIN] = bin2bcd(tm->tm_min);
  90         regs[RTC_SEC] = bin2bcd(tm->tm_sec);
  91 }
  92
  93 static int max8907_rtc_read_time(struct device *dev, struct rtc_time *tm)
  94 {
  95         struct max8907_rtc *rtc = dev_get_drvdata(dev);
  96         u8 regs[TIME_NUM];
  97         int ret;
  98
  99         ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
 100                                TIME_NUM);
 101         if (ret < 0)
 102                 return ret;
 103
 104         regs_to_tm(regs, tm);
 105
 106         return 0;
 107 }
 108
 109 static int max8907_rtc_set_time(struct device *dev, struct rtc_time *tm)
 110 {
 111         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 112         u8 regs[TIME_NUM];
 113
 114         tm_to_regs(tm, regs);
 115
 116         return regmap_bulk_write(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
 117                                  TIME_NUM);
 118 }
 119
 120 static int max8907_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 121 {
 122         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 123         u8 regs[TIME_NUM];
 124         unsigned int val;
 125         int ret;
 126
 127         ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
 128                                TIME_NUM);
 129         if (ret < 0)
 130                 return ret;
 131
 132         regs_to_tm(regs, &alrm->time);
 133
 134         ret = regmap_read(rtc->regmap, MAX8907_REG_ALARM0_CNTL, &val);
 135         if (ret < 0)
 136                 return ret;
 137
 138         alrm->enabled = !!(val & 0x7f);
 139
 140         return 0;
 141 }
 142
 143 static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 144 {
 145         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 146         u8 regs[TIME_NUM];
 147         int ret;
 148
 149         tm_to_regs(&alrm->time, regs);
 150
 151         /* Disable alarm while we update the target time */
 152         ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
 153         if (ret < 0)
 154                 return ret;
 155
 156         ret = regmap_bulk_write(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
 157                                 TIME_NUM);
 158         if (ret < 0)
 159                 return ret;
 160
 161         if (alrm->enabled)
 162                 ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x77);
 163
 164         return ret;
 165 }
 166
 167 static const struct rtc_class_ops max8907_rtc_ops = {
 168         .read_time      = max8907_rtc_read_time,
 169         .set_time       = max8907_rtc_set_time,
 170         .read_alarm     = max8907_rtc_read_alarm,
 171         .set_alarm      = max8907_rtc_set_alarm,
 172 };
 173
 174 static int max8907_rtc_probe(struct platform_device *pdev)
 175 {
 176         struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
 177         struct max8907_rtc *rtc;
 178         int ret;
 179
 180         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 181         if (!rtc)
 182                 return -ENOMEM;
 183         platform_set_drvdata(pdev, rtc);
 184
 185         rtc->max8907 = max8907;
 186         rtc->regmap = max8907->regmap_rtc;
 187
 188         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8907-rtc",
 189                                         &max8907_rtc_ops, THIS_MODULE);
 190         if (IS_ERR(rtc->rtc_dev)) {
 191                 ret = PTR_ERR(rtc->rtc_dev);
 192                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 193                 return ret;
 194         }
 195
 196         rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
 197                                        MAX8907_IRQ_RTC_ALARM0);
 198         if (rtc->irq < 0)
 199                 return rtc->irq;
 200
 201         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 202                                 max8907_irq_handler,
 203                                 IRQF_ONESHOT, "max8907-alarm0", rtc);
 204         if (ret < 0)
 205                 dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
 206                         rtc->irq, ret);
 207
 208         return ret;
 209 }
 210
 211 static struct platform_driver max8907_rtc_driver = {
 212         .driver = {
 213                 .name = "max8907-rtc",
 214         },
 215         .probe = max8907_rtc_probe,
 216 };
 217 module_platform_driver(max8907_rtc_driver);
 218
 219 MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
 220 MODULE_LICENSE("GPL v2");