drivers/rtc/rtc-max8998.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // RTC driver for Maxim MAX8998
   4 //
   5 // Copyright (C) 2010 Samsung Electronics Co.Ltd
   6 // 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                 0x00
  21 #define MAX8998_RTC_MIN                 0x01
  22 #define MAX8998_RTC_HOUR                0x02
  23 #define MAX8998_RTC_WEEKDAY             0x03
  24 #define MAX8998_RTC_DATE                0x04
  25 #define MAX8998_RTC_MONTH               0x05
  26 #define MAX8998_RTC_YEAR1               0x06
  27 #define MAX8998_RTC_YEAR2               0x07
  28 #define MAX8998_ALARM0_SEC              0x08
  29 #define MAX8998_ALARM0_MIN              0x09
  30 #define MAX8998_ALARM0_HOUR             0x0a
  31 #define MAX8998_ALARM0_WEEKDAY          0x0b
  32 #define MAX8998_ALARM0_DATE             0x0c
  33 #define MAX8998_ALARM0_MONTH            0x0d
  34 #define MAX8998_ALARM0_YEAR1            0x0e
  35 #define MAX8998_ALARM0_YEAR2            0x0f
  36 #define MAX8998_ALARM1_SEC              0x10
  37 #define MAX8998_ALARM1_MIN              0x11
  38 #define MAX8998_ALARM1_HOUR             0x12
  39 #define MAX8998_ALARM1_WEEKDAY          0x13
  40 #define MAX8998_ALARM1_DATE             0x14
  41 #define MAX8998_ALARM1_MONTH            0x15
  42 #define MAX8998_ALARM1_YEAR1            0x16
  43 #define MAX8998_ALARM1_YEAR2            0x17
  44 #define MAX8998_ALARM0_CONF             0x18
  45 #define MAX8998_ALARM1_CONF             0x19
  46 #define MAX8998_RTC_STATUS              0x1a
  47 #define MAX8998_WTSR_SMPL_CNTL          0x1b
  48 #define MAX8998_TEST                    0x1f
  49
  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
  55 enum {
  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
  66 struct 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
  75 static 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         } else
  84                 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
  93 static 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
 105 static 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
 120 static 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
 136 static 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         else
 162                 alrm->pending = 0;
 163
 164         return 0;
 165 }
 166
 167 static 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
 177 static 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
 194 static 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
 219 static 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         else
 227                 return max8998_rtc_stop_alarm(info);
 228 }
 229
 230 static 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
 239 static 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
 247 static 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
 290 no_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
 301 static const struct platform_device_id max8998_rtc_id[] = {
 302         { "max8998-rtc", TYPE_MAX8998 },
 303         { "lp3974-rtc", TYPE_LP3974 },
 304         { }
 305 };
 306 MODULE_DEVICE_TABLE(platform, max8998_rtc_id);
 307
 308 static 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
 316 module_platform_driver(max8998_rtc_driver);
 317
 318 MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
 319 MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
 320 MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
 321 MODULE_LICENSE("GPL");