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1// SPDX-License-Identifier: GPL-2.0+2//3// RTC driver for Maxim MAX89984//5// Copyright (C) 2010 Samsung Electronics Co.Ltd6// Author: Minkyu Kang <mk7.kang@samsung.com>7// Author: Joonyoung Shim <jy0922.shim@samsung.com>8 9#include <linux/module.h>10#include <linux/i2c.h>11#include <linux/slab.h>12#include <linux/bcd.h>13#include <linux/irqdomain.h>14#include <linux/rtc.h>15#include <linux/platform_device.h>16#include <linux/mfd/max8998.h>17#include <linux/mfd/max8998-private.h>18#include <linux/delay.h>19 20#define MAX8998_RTC_SEC 0x0021#define MAX8998_RTC_MIN 0x0122#define MAX8998_RTC_HOUR 0x0223#define MAX8998_RTC_WEEKDAY 0x0324#define MAX8998_RTC_DATE 0x0425#define MAX8998_RTC_MONTH 0x0526#define MAX8998_RTC_YEAR1 0x0627#define MAX8998_RTC_YEAR2 0x0728#define MAX8998_ALARM0_SEC 0x0829#define MAX8998_ALARM0_MIN 0x0930#define MAX8998_ALARM0_HOUR 0x0a31#define MAX8998_ALARM0_WEEKDAY 0x0b32#define MAX8998_ALARM0_DATE 0x0c33#define MAX8998_ALARM0_MONTH 0x0d34#define MAX8998_ALARM0_YEAR1 0x0e35#define MAX8998_ALARM0_YEAR2 0x0f36#define MAX8998_ALARM1_SEC 0x1037#define MAX8998_ALARM1_MIN 0x1138#define MAX8998_ALARM1_HOUR 0x1239#define MAX8998_ALARM1_WEEKDAY 0x1340#define MAX8998_ALARM1_DATE 0x1441#define MAX8998_ALARM1_MONTH 0x1542#define MAX8998_ALARM1_YEAR1 0x1643#define MAX8998_ALARM1_YEAR2 0x1744#define MAX8998_ALARM0_CONF 0x1845#define MAX8998_ALARM1_CONF 0x1946#define MAX8998_RTC_STATUS 0x1a47#define MAX8998_WTSR_SMPL_CNTL 0x1b48#define MAX8998_TEST 0x1f49 50#define HOUR_12 (1 << 7)51#define HOUR_PM (1 << 5)52#define ALARM0_STATUS (1 << 1)53#define ALARM1_STATUS (1 << 2)54 55enum {56 RTC_SEC = 0,57 RTC_MIN,58 RTC_HOUR,59 RTC_WEEKDAY,60 RTC_DATE,61 RTC_MONTH,62 RTC_YEAR1,63 RTC_YEAR2,64};65 66struct max8998_rtc_info {67 struct device *dev;68 struct max8998_dev *max8998;69 struct i2c_client *rtc;70 struct rtc_device *rtc_dev;71 int irq;72 bool lp3974_bug_workaround;73};74 75static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)76{77 tm->tm_sec = bcd2bin(data[RTC_SEC]);78 tm->tm_min = bcd2bin(data[RTC_MIN]);79 if (data[RTC_HOUR] & HOUR_12) {80 tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);81 if (data[RTC_HOUR] & HOUR_PM)82 tm->tm_hour += 12;83 } else84 tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);85 86 tm->tm_wday = data[RTC_WEEKDAY] & 0x07;87 tm->tm_mday = bcd2bin(data[RTC_DATE]);88 tm->tm_mon = bcd2bin(data[RTC_MONTH]);89 tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;90 tm->tm_year -= 1900;91}92 93static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)94{95 data[RTC_SEC] = bin2bcd(tm->tm_sec);96 data[RTC_MIN] = bin2bcd(tm->tm_min);97 data[RTC_HOUR] = bin2bcd(tm->tm_hour);98 data[RTC_WEEKDAY] = tm->tm_wday;99 data[RTC_DATE] = bin2bcd(tm->tm_mday);100 data[RTC_MONTH] = bin2bcd(tm->tm_mon);101 data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);102 data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);103}104 105static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)106{107 struct max8998_rtc_info *info = dev_get_drvdata(dev);108 u8 data[8];109 int ret;110 111 ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);112 if (ret < 0)113 return ret;114 115 max8998_data_to_tm(data, tm);116 117 return 0;118}119 120static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)121{122 struct max8998_rtc_info *info = dev_get_drvdata(dev);123 u8 data[8];124 int ret;125 126 max8998_tm_to_data(tm, data);127 128 ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);129 130 if (info->lp3974_bug_workaround)131 msleep(2000);132 133 return ret;134}135 136static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)137{138 struct max8998_rtc_info *info = dev_get_drvdata(dev);139 u8 data[8];140 u8 val;141 int ret;142 143 ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);144 if (ret < 0)145 return ret;146 147 max8998_data_to_tm(data, &alrm->time);148 149 ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);150 if (ret < 0)151 return ret;152 153 alrm->enabled = !!val;154 155 ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);156 if (ret < 0)157 return ret;158 159 if (val & ALARM0_STATUS)160 alrm->pending = 1;161 else162 alrm->pending = 0;163 164 return 0;165}166 167static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)168{169 int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);170 171 if (info->lp3974_bug_workaround)172 msleep(2000);173 174 return ret;175}176 177static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)178{179 int ret;180 u8 alarm0_conf = 0x77;181 182 /* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */183 if (info->lp3974_bug_workaround)184 alarm0_conf = 0x57;185 186 ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);187 188 if (info->lp3974_bug_workaround)189 msleep(2000);190 191 return ret;192}193 194static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)195{196 struct max8998_rtc_info *info = dev_get_drvdata(dev);197 u8 data[8];198 int ret;199 200 max8998_tm_to_data(&alrm->time, data);201 202 ret = max8998_rtc_stop_alarm(info);203 if (ret < 0)204 return ret;205 206 ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);207 if (ret < 0)208 return ret;209 210 if (info->lp3974_bug_workaround)211 msleep(2000);212 213 if (alrm->enabled)214 ret = max8998_rtc_start_alarm(info);215 216 return ret;217}218 219static int max8998_rtc_alarm_irq_enable(struct device *dev,220 unsigned int enabled)221{222 struct max8998_rtc_info *info = dev_get_drvdata(dev);223 224 if (enabled)225 return max8998_rtc_start_alarm(info);226 else227 return max8998_rtc_stop_alarm(info);228}229 230static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)231{232 struct max8998_rtc_info *info = data;233 234 rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);235 236 return IRQ_HANDLED;237}238 239static const struct rtc_class_ops max8998_rtc_ops = {240 .read_time = max8998_rtc_read_time,241 .set_time = max8998_rtc_set_time,242 .read_alarm = max8998_rtc_read_alarm,243 .set_alarm = max8998_rtc_set_alarm,244 .alarm_irq_enable = max8998_rtc_alarm_irq_enable,245};246 247static int max8998_rtc_probe(struct platform_device *pdev)248{249 struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);250 struct max8998_platform_data *pdata = max8998->pdata;251 struct max8998_rtc_info *info;252 int ret;253 254 info = devm_kzalloc(&pdev->dev, sizeof(struct max8998_rtc_info),255 GFP_KERNEL);256 if (!info)257 return -ENOMEM;258 259 info->dev = &pdev->dev;260 info->max8998 = max8998;261 info->rtc = max8998->rtc;262 263 platform_set_drvdata(pdev, info);264 265 info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8998-rtc",266 &max8998_rtc_ops, THIS_MODULE);267 268 if (IS_ERR(info->rtc_dev)) {269 ret = PTR_ERR(info->rtc_dev);270 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);271 return ret;272 }273 274 if (!max8998->irq_domain)275 goto no_irq;276 277 info->irq = irq_create_mapping(max8998->irq_domain, MAX8998_IRQ_ALARM0);278 if (!info->irq) {279 dev_warn(&pdev->dev, "Failed to map alarm IRQ\n");280 goto no_irq;281 }282 283 ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,284 max8998_rtc_alarm_irq, 0, "rtc-alarm0", info);285 286 if (ret < 0)287 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",288 info->irq, ret);289 290no_irq:291 dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);292 if (pdata && pdata->rtc_delay) {293 info->lp3974_bug_workaround = true;294 dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."295 " RTC updates will be extremely slow.\n");296 }297 298 return 0;299}300 301static const struct platform_device_id max8998_rtc_id[] = {302 { "max8998-rtc", TYPE_MAX8998 },303 { "lp3974-rtc", TYPE_LP3974 },304 { }305};306MODULE_DEVICE_TABLE(platform, max8998_rtc_id);307 308static struct platform_driver max8998_rtc_driver = {309 .driver = {310 .name = "max8998-rtc",311 },312 .probe = max8998_rtc_probe,313 .id_table = max8998_rtc_id,314};315 316module_platform_driver(max8998_rtc_driver);317 318MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");319MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");320MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");321MODULE_LICENSE("GPL");322