linux/drivers/rtc/rtc-max8907.c
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   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
  23enum {
  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
  43struct max8907_rtc {
  44        struct max8907          *max8907;
  45        struct regmap           *regmap;
  46        struct rtc_device       *rtc_dev;
  47        int                     irq;
  48};
  49
  50static irqreturn_t max8907_irq_handler(int irq, void *data)
  51{
  52        struct max8907_rtc *rtc = data;
  53
  54        regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);
  55
  56        rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
  57
  58        return IRQ_HANDLED;
  59}
  60
  61static 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) - 1;
  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
  81static 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 + 1;
  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
  97static 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
 113static 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
 124static 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
 147static 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_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 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_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL,
 167                                         0x7f, 0x7f);
 168
 169        return ret;
 170}
 171
 172static const struct rtc_class_ops max8907_rtc_ops = {
 173        .read_time      = max8907_rtc_read_time,
 174        .set_time       = max8907_rtc_set_time,
 175        .read_alarm     = max8907_rtc_read_alarm,
 176        .set_alarm      = max8907_rtc_set_alarm,
 177};
 178
 179static int max8907_rtc_probe(struct platform_device *pdev)
 180{
 181        struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
 182        struct max8907_rtc *rtc;
 183        int ret;
 184
 185        rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 186        if (!rtc)
 187                return -ENOMEM;
 188        platform_set_drvdata(pdev, rtc);
 189
 190        rtc->max8907 = max8907;
 191        rtc->regmap = max8907->regmap_rtc;
 192
 193        rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8907-rtc",
 194                                        &max8907_rtc_ops, THIS_MODULE);
 195        if (IS_ERR(rtc->rtc_dev)) {
 196                ret = PTR_ERR(rtc->rtc_dev);
 197                dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 198                return ret;
 199        }
 200
 201        rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
 202                                       MAX8907_IRQ_RTC_ALARM0);
 203        if (rtc->irq < 0)
 204                return rtc->irq;
 205
 206        ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 207                                max8907_irq_handler,
 208                                IRQF_ONESHOT, "max8907-alarm0", rtc);
 209        if (ret < 0)
 210                dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
 211                        rtc->irq, ret);
 212
 213        return ret;
 214}
 215
 216static int max8907_rtc_remove(struct platform_device *pdev)
 217{
 218        return 0;
 219}
 220
 221static struct platform_driver max8907_rtc_driver = {
 222        .driver = {
 223                .name = "max8907-rtc",
 224                .owner = THIS_MODULE,
 225        },
 226        .probe = max8907_rtc_probe,
 227        .remove = max8907_rtc_remove,
 228};
 229module_platform_driver(max8907_rtc_driver);
 230
 231MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
 232MODULE_LICENSE("GPL v2");
 233
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