drivers/rtc/rtc-max8907.c

   1 /*
   2  * RTC driver for Maxim MAX8907
   3  *
   4  * Copyright (c) 2011-2012, NVIDIA Corporation.
   5  *
   6  * Based on drivers/rtc/rtc-max8925.c,
   7  * Copyright (C) 2009-2010 Marvell International Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/bcd.h>
  15 #include <linux/i2c.h>
  16 #include <linux/mfd/max8907.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/regmap.h>
  20 #include <linux/rtc.h>
  21 #include <linux/slab.h>
  22
  23 enum {
  24         RTC_SEC = 0,
  25         RTC_MIN,
  26         RTC_HOUR,
  27         RTC_WEEKDAY,
  28         RTC_DATE,
  29         RTC_MONTH,
  30         RTC_YEAR1,
  31         RTC_YEAR2,
  32 };
  33
  34 #define TIME_NUM                        8
  35 #define ALARM_1SEC                      (1 << 7)
  36 #define HOUR_12                         (1 << 7)
  37 #define HOUR_AM_PM                      (1 << 5)
  38 #define ALARM0_IRQ                      (1 << 3)
  39 #define ALARM1_IRQ                      (1 << 2)
  40 #define ALARM0_STATUS                   (1 << 2)
  41 #define ALARM1_STATUS                   (1 << 1)
  42
  43 struct max8907_rtc {
  44         struct max8907          *max8907;
  45         struct regmap           *regmap;
  46         struct rtc_device       *rtc_dev;
  47         int                     irq;
  48 };
  49
  50 static irqreturn_t max8907_irq_handler(int irq, void *data)
  51 {
  52         struct max8907_rtc *rtc = data;
  53
  54         regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
  55
  56         rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
  57
  58         return IRQ_HANDLED;
  59 }
  60
  61 static void regs_to_tm(u8 *regs, struct rtc_time *tm)
  62 {
  63         tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
  64                 bcd2bin(regs[RTC_YEAR1]) - 1900;
  65         tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
  66         tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
  67         tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07);
  68         if (regs[RTC_HOUR] & HOUR_12) {
  69                 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
  70                 if (tm->tm_hour == 12)
  71                         tm->tm_hour = 0;
  72                 if (regs[RTC_HOUR] & HOUR_AM_PM)
  73                         tm->tm_hour += 12;
  74         } else {
  75                 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x03f);
  76         }
  77         tm->tm_min = bcd2bin(regs[RTC_MIN] & 0x7f);
  78         tm->tm_sec = bcd2bin(regs[RTC_SEC] & 0x7f);
  79 }
  80
  81 static void tm_to_regs(struct rtc_time *tm, u8 *regs)
  82 {
  83         u8 high, low;
  84
  85         high = (tm->tm_year + 1900) / 100;
  86         low = tm->tm_year % 100;
  87         regs[RTC_YEAR2] = bin2bcd(high);
  88         regs[RTC_YEAR1] = bin2bcd(low);
  89         regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
  90         regs[RTC_DATE] = bin2bcd(tm->tm_mday);
  91         regs[RTC_WEEKDAY] = tm->tm_wday;
  92         regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
  93         regs[RTC_MIN] = bin2bcd(tm->tm_min);
  94         regs[RTC_SEC] = bin2bcd(tm->tm_sec);
  95 }
  96
  97 static int max8907_rtc_read_time(struct device *dev, struct rtc_time *tm)
  98 {
  99         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 100         u8 regs[TIME_NUM];
 101         int ret;
 102
 103         ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
 104                                TIME_NUM);
 105         if (ret < 0)
 106                 return ret;
 107
 108         regs_to_tm(regs, tm);
 109
 110         return 0;
 111 }
 112
 113 static int max8907_rtc_set_time(struct device *dev, struct rtc_time *tm)
 114 {
 115         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 116         u8 regs[TIME_NUM];
 117
 118         tm_to_regs(tm, regs);
 119
 120         return regmap_bulk_write(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
 121                                  TIME_NUM);
 122 }
 123
 124 static int max8907_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 125 {
 126         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 127         u8 regs[TIME_NUM];
 128         unsigned int val;
 129         int ret;
 130
 131         ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
 132                                TIME_NUM);
 133         if (ret < 0)
 134                 return ret;
 135
 136         regs_to_tm(regs, &alrm->time);
 137
 138         ret = regmap_read(rtc->regmap, MAX8907_REG_ALARM0_CNTL, &val);
 139         if (ret < 0)
 140                 return ret;
 141
 142         alrm->enabled = !!(val & 0x7f);
 143
 144         return 0;
 145 }
 146
 147 static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 148 {
 149         struct max8907_rtc *rtc = dev_get_drvdata(dev);
 150         u8 regs[TIME_NUM];
 151         int ret;
 152
 153         tm_to_regs(&alrm->time, regs);
 154
 155         /* Disable alarm while we update the target time */
 156         ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
 157         if (ret < 0)
 158                 return ret;
 159
 160         ret = regmap_bulk_write(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
 161                                 TIME_NUM);
 162         if (ret < 0)
 163                 return ret;
 164
 165         if (alrm->enabled)
 166                 ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x77);
 167
 168         return ret;
 169 }
 170
 171 static const struct rtc_class_ops max8907_rtc_ops = {
 172         .read_time      = max8907_rtc_read_time,
 173         .set_time       = max8907_rtc_set_time,
 174         .read_alarm     = max8907_rtc_read_alarm,
 175         .set_alarm      = max8907_rtc_set_alarm,
 176 };
 177
 178 static int max8907_rtc_probe(struct platform_device *pdev)
 179 {
 180         struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
 181         struct max8907_rtc *rtc;
 182         int ret;
 183
 184         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 185         if (!rtc)
 186                 return -ENOMEM;
 187         platform_set_drvdata(pdev, rtc);
 188
 189         rtc->max8907 = max8907;
 190         rtc->regmap = max8907->regmap_rtc;
 191
 192         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8907-rtc",
 193                                         &max8907_rtc_ops, THIS_MODULE);
 194         if (IS_ERR(rtc->rtc_dev)) {
 195                 ret = PTR_ERR(rtc->rtc_dev);
 196                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 197                 return ret;
 198         }
 199
 200         rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
 201                                        MAX8907_IRQ_RTC_ALARM0);
 202         if (rtc->irq < 0)
 203                 return rtc->irq;
 204
 205         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 206                                 max8907_irq_handler,
 207                                 IRQF_ONESHOT, "max8907-alarm0", rtc);
 208         if (ret < 0)
 209                 dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
 210                         rtc->irq, ret);
 211
 212         return ret;
 213 }
 214
 215 static struct platform_driver max8907_rtc_driver = {
 216         .driver = {
 217                 .name = "max8907-rtc",
 218                 .owner = THIS_MODULE,
 219         },
 220         .probe = max8907_rtc_probe,
 221 };
 222 module_platform_driver(max8907_rtc_driver);
 223
 224 MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
 225 MODULE_LICENSE("GPL v2");