drivers/rtc/rtc-lp8788.c

   1 /*
   2  * TI LP8788 MFD - rtc driver
   3  *
   4  * Copyright 2012 Texas Instruments
   5  *
   6  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/err.h>
  15 #include <linux/irqdomain.h>
  16 #include <linux/mfd/lp8788.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21
  22 /* register address */
  23 #define LP8788_INTEN_3                  0x05
  24 #define LP8788_RTC_UNLOCK               0x64
  25 #define LP8788_RTC_SEC                  0x70
  26 #define LP8788_ALM1_SEC                 0x77
  27 #define LP8788_ALM1_EN                  0x7D
  28 #define LP8788_ALM2_SEC                 0x7E
  29 #define LP8788_ALM2_EN                  0x84
  30
  31 /* mask/shift bits */
  32 #define LP8788_INT_RTC_ALM1_M           BIT(1)  /* Addr 05h */
  33 #define LP8788_INT_RTC_ALM1_S           1
  34 #define LP8788_INT_RTC_ALM2_M           BIT(2)  /* Addr 05h */
  35 #define LP8788_INT_RTC_ALM2_S           2
  36 #define LP8788_ALM_EN_M                 BIT(7)  /* Addr 7Dh or 84h */
  37 #define LP8788_ALM_EN_S                 7
  38
  39 #define DEFAULT_ALARM_SEL               LP8788_ALARM_1
  40 #define LP8788_MONTH_OFFSET             1
  41 #define LP8788_BASE_YEAR                2000
  42 #define MAX_WDAY_BITS                   7
  43 #define LP8788_WDAY_SET                 1
  44 #define RTC_UNLOCK                      0x1
  45 #define RTC_LATCH                       0x2
  46 #define ALARM_IRQ_FLAG                  (RTC_IRQF | RTC_AF)
  47
  48 enum lp8788_time {
  49         LPTIME_SEC,
  50         LPTIME_MIN,
  51         LPTIME_HOUR,
  52         LPTIME_MDAY,
  53         LPTIME_MON,
  54         LPTIME_YEAR,
  55         LPTIME_WDAY,
  56         LPTIME_MAX,
  57 };
  58
  59 struct lp8788_rtc {
  60         struct lp8788 *lp;
  61         struct rtc_device *rdev;
  62         enum lp8788_alarm_sel alarm;
  63         int irq;
  64 };
  65
  66 static const u8 addr_alarm_sec[LP8788_ALARM_MAX] = {
  67         LP8788_ALM1_SEC,
  68         LP8788_ALM2_SEC,
  69 };
  70
  71 static const u8 addr_alarm_en[LP8788_ALARM_MAX] = {
  72         LP8788_ALM1_EN,
  73         LP8788_ALM2_EN,
  74 };
  75
  76 static const u8 mask_alarm_en[LP8788_ALARM_MAX] = {
  77         LP8788_INT_RTC_ALM1_M,
  78         LP8788_INT_RTC_ALM2_M,
  79 };
  80
  81 static const u8 shift_alarm_en[LP8788_ALARM_MAX] = {
  82         LP8788_INT_RTC_ALM1_S,
  83         LP8788_INT_RTC_ALM2_S,
  84 };
  85
  86 static int _to_tm_wday(u8 lp8788_wday)
  87 {
  88         int i;
  89
  90         if (lp8788_wday == 0)
  91                 return 0;
  92
  93         /* lookup defined weekday from read register value */
  94         for (i = 0; i < MAX_WDAY_BITS; i++) {
  95                 if ((lp8788_wday >> i) == LP8788_WDAY_SET)
  96                         break;
  97         }
  98
  99         return i + 1;
 100 }
 101
 102 static inline int _to_lp8788_wday(int tm_wday)
 103 {
 104         return LP8788_WDAY_SET << (tm_wday - 1);
 105 }
 106
 107 static void lp8788_rtc_unlock(struct lp8788 *lp)
 108 {
 109         lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_UNLOCK);
 110         lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_LATCH);
 111 }
 112
 113 static int lp8788_rtc_read_time(struct device *dev, struct rtc_time *tm)
 114 {
 115         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 116         struct lp8788 *lp = rtc->lp;
 117         u8 data[LPTIME_MAX];
 118         int ret;
 119
 120         lp8788_rtc_unlock(lp);
 121
 122         ret = lp8788_read_multi_bytes(lp, LP8788_RTC_SEC, data, LPTIME_MAX);
 123         if (ret)
 124                 return ret;
 125
 126         tm->tm_sec  = data[LPTIME_SEC];
 127         tm->tm_min  = data[LPTIME_MIN];
 128         tm->tm_hour = data[LPTIME_HOUR];
 129         tm->tm_mday = data[LPTIME_MDAY];
 130         tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
 131         tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
 132         tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
 133
 134         return 0;
 135 }
 136
 137 static int lp8788_rtc_set_time(struct device *dev, struct rtc_time *tm)
 138 {
 139         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 140         struct lp8788 *lp = rtc->lp;
 141         u8 data[LPTIME_MAX - 1];
 142         int ret, i, year;
 143
 144         year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
 145         if (year < 0) {
 146                 dev_err(lp->dev, "invalid year: %d\n", year);
 147                 return -EINVAL;
 148         }
 149
 150         /* because rtc weekday is a readonly register, do not update */
 151         data[LPTIME_SEC]  = tm->tm_sec;
 152         data[LPTIME_MIN]  = tm->tm_min;
 153         data[LPTIME_HOUR] = tm->tm_hour;
 154         data[LPTIME_MDAY] = tm->tm_mday;
 155         data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
 156         data[LPTIME_YEAR] = year;
 157
 158         for (i = 0; i < ARRAY_SIZE(data); i++) {
 159                 ret = lp8788_write_byte(lp, LP8788_RTC_SEC + i, data[i]);
 160                 if (ret)
 161                         return ret;
 162         }
 163
 164         return 0;
 165 }
 166
 167 static int lp8788_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 168 {
 169         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 170         struct lp8788 *lp = rtc->lp;
 171         struct rtc_time *tm = &alarm->time;
 172         u8 addr, data[LPTIME_MAX];
 173         int ret;
 174
 175         addr = addr_alarm_sec[rtc->alarm];
 176         ret = lp8788_read_multi_bytes(lp, addr, data, LPTIME_MAX);
 177         if (ret)
 178                 return ret;
 179
 180         tm->tm_sec  = data[LPTIME_SEC];
 181         tm->tm_min  = data[LPTIME_MIN];
 182         tm->tm_hour = data[LPTIME_HOUR];
 183         tm->tm_mday = data[LPTIME_MDAY];
 184         tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
 185         tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
 186         tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
 187         alarm->enabled = data[LPTIME_WDAY] & LP8788_ALM_EN_M;
 188
 189         return 0;
 190 }
 191
 192 static int lp8788_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 193 {
 194         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 195         struct lp8788 *lp = rtc->lp;
 196         struct rtc_time *tm = &alarm->time;
 197         u8 addr, data[LPTIME_MAX];
 198         int ret, i, year;
 199
 200         year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
 201         if (year < 0) {
 202                 dev_err(lp->dev, "invalid year: %d\n", year);
 203                 return -EINVAL;
 204         }
 205
 206         data[LPTIME_SEC]  = tm->tm_sec;
 207         data[LPTIME_MIN]  = tm->tm_min;
 208         data[LPTIME_HOUR] = tm->tm_hour;
 209         data[LPTIME_MDAY] = tm->tm_mday;
 210         data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
 211         data[LPTIME_YEAR] = year;
 212         data[LPTIME_WDAY] = _to_lp8788_wday(tm->tm_wday);
 213
 214         for (i = 0; i < ARRAY_SIZE(data); i++) {
 215                 addr = addr_alarm_sec[rtc->alarm] + i;
 216                 ret = lp8788_write_byte(lp, addr, data[i]);
 217                 if (ret)
 218                         return ret;
 219         }
 220
 221         alarm->enabled = 1;
 222         addr = addr_alarm_en[rtc->alarm];
 223
 224         return lp8788_update_bits(lp, addr, LP8788_ALM_EN_M,
 225                                 alarm->enabled << LP8788_ALM_EN_S);
 226 }
 227
 228 static int lp8788_alarm_irq_enable(struct device *dev, unsigned int enable)
 229 {
 230         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 231         struct lp8788 *lp = rtc->lp;
 232         u8 mask, shift;
 233
 234         if (!rtc->irq)
 235                 return -EIO;
 236
 237         mask = mask_alarm_en[rtc->alarm];
 238         shift = shift_alarm_en[rtc->alarm];
 239
 240         return lp8788_update_bits(lp, LP8788_INTEN_3, mask, enable << shift);
 241 }
 242
 243 static const struct rtc_class_ops lp8788_rtc_ops = {
 244         .read_time = lp8788_rtc_read_time,
 245         .set_time = lp8788_rtc_set_time,
 246         .read_alarm = lp8788_read_alarm,
 247         .set_alarm = lp8788_set_alarm,
 248         .alarm_irq_enable = lp8788_alarm_irq_enable,
 249 };
 250
 251 static irqreturn_t lp8788_alarm_irq_handler(int irq, void *ptr)
 252 {
 253         struct lp8788_rtc *rtc = ptr;
 254
 255         rtc_update_irq(rtc->rdev, 1, ALARM_IRQ_FLAG);
 256         return IRQ_HANDLED;
 257 }
 258
 259 static int lp8788_alarm_irq_register(struct platform_device *pdev,
 260                                 struct lp8788_rtc *rtc)
 261 {
 262         struct resource *r;
 263         struct lp8788 *lp = rtc->lp;
 264         struct irq_domain *irqdm = lp->irqdm;
 265         int irq;
 266
 267         rtc->irq = 0;
 268
 269         /* even the alarm IRQ number is not specified, rtc time should work */
 270         r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, LP8788_ALM_IRQ);
 271         if (!r)
 272                 return 0;
 273
 274         if (rtc->alarm == LP8788_ALARM_1)
 275                 irq = r->start;
 276         else
 277                 irq = r->end;
 278
 279         rtc->irq = irq_create_mapping(irqdm, irq);
 280
 281         return devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 282                                 lp8788_alarm_irq_handler,
 283                                 0, LP8788_ALM_IRQ, rtc);
 284 }
 285
 286 static int lp8788_rtc_probe(struct platform_device *pdev)
 287 {
 288         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
 289         struct lp8788_rtc *rtc;
 290         struct device *dev = &pdev->dev;
 291
 292         rtc = devm_kzalloc(dev, sizeof(struct lp8788_rtc), GFP_KERNEL);
 293         if (!rtc)
 294                 return -ENOMEM;
 295
 296         rtc->lp = lp;
 297         rtc->alarm = lp->pdata ? lp->pdata->alarm_sel : DEFAULT_ALARM_SEL;
 298         platform_set_drvdata(pdev, rtc);
 299
 300         device_init_wakeup(dev, 1);
 301
 302         rtc->rdev = devm_rtc_device_register(dev, "lp8788_rtc",
 303                                         &lp8788_rtc_ops, THIS_MODULE);
 304         if (IS_ERR(rtc->rdev)) {
 305                 dev_err(dev, "can not register rtc device\n");
 306                 return PTR_ERR(rtc->rdev);
 307         }
 308
 309         if (lp8788_alarm_irq_register(pdev, rtc))
 310                 dev_warn(lp->dev, "no rtc irq handler\n");
 311
 312         return 0;
 313 }
 314
 315 static struct platform_driver lp8788_rtc_driver = {
 316         .probe = lp8788_rtc_probe,
 317         .driver = {
 318                 .name = LP8788_DEV_RTC,
 319                 .owner = THIS_MODULE,
 320         },
 321 };
 322 module_platform_driver(lp8788_rtc_driver);
 323
 324 MODULE_DESCRIPTION("Texas Instruments LP8788 RTC Driver");
 325 MODULE_AUTHOR("Milo Kim");
 326 MODULE_LICENSE("GPL");
 327 MODULE_ALIAS("platform:lp8788-rtc");