drivers/rtc/rtc-lp8788.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI LP8788 MFD - rtc driver
   4  *
   5  * Copyright 2012 Texas Instruments
   6  *
   7  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/irqdomain.h>
  12 #include <linux/mfd/lp8788.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/rtc.h>
  16 #include <linux/slab.h>
  17
  18 /* register address */
  19 #define LP8788_INTEN_3                  0x05
  20 #define LP8788_RTC_UNLOCK               0x64
  21 #define LP8788_RTC_SEC                  0x70
  22 #define LP8788_ALM1_SEC                 0x77
  23 #define LP8788_ALM1_EN                  0x7D
  24 #define LP8788_ALM2_SEC                 0x7E
  25 #define LP8788_ALM2_EN                  0x84
  26
  27 /* mask/shift bits */
  28 #define LP8788_INT_RTC_ALM1_M           BIT(1)  /* Addr 05h */
  29 #define LP8788_INT_RTC_ALM1_S           1
  30 #define LP8788_INT_RTC_ALM2_M           BIT(2)  /* Addr 05h */
  31 #define LP8788_INT_RTC_ALM2_S           2
  32 #define LP8788_ALM_EN_M                 BIT(7)  /* Addr 7Dh or 84h */
  33 #define LP8788_ALM_EN_S                 7
  34
  35 #define DEFAULT_ALARM_SEL               LP8788_ALARM_1
  36 #define LP8788_MONTH_OFFSET             1
  37 #define LP8788_BASE_YEAR                2000
  38 #define MAX_WDAY_BITS                   7
  39 #define LP8788_WDAY_SET                 1
  40 #define RTC_UNLOCK                      0x1
  41 #define RTC_LATCH                       0x2
  42 #define ALARM_IRQ_FLAG                  (RTC_IRQF | RTC_AF)
  43
  44 enum lp8788_time {
  45         LPTIME_SEC,
  46         LPTIME_MIN,
  47         LPTIME_HOUR,
  48         LPTIME_MDAY,
  49         LPTIME_MON,
  50         LPTIME_YEAR,
  51         LPTIME_WDAY,
  52         LPTIME_MAX,
  53 };
  54
  55 struct lp8788_rtc {
  56         struct lp8788 *lp;
  57         struct rtc_device *rdev;
  58         enum lp8788_alarm_sel alarm;
  59         int irq;
  60 };
  61
  62 static const u8 addr_alarm_sec[LP8788_ALARM_MAX] = {
  63         LP8788_ALM1_SEC,
  64         LP8788_ALM2_SEC,
  65 };
  66
  67 static const u8 addr_alarm_en[LP8788_ALARM_MAX] = {
  68         LP8788_ALM1_EN,
  69         LP8788_ALM2_EN,
  70 };
  71
  72 static const u8 mask_alarm_en[LP8788_ALARM_MAX] = {
  73         LP8788_INT_RTC_ALM1_M,
  74         LP8788_INT_RTC_ALM2_M,
  75 };
  76
  77 static const u8 shift_alarm_en[LP8788_ALARM_MAX] = {
  78         LP8788_INT_RTC_ALM1_S,
  79         LP8788_INT_RTC_ALM2_S,
  80 };
  81
  82 static int _to_tm_wday(u8 lp8788_wday)
  83 {
  84         int i;
  85
  86         if (lp8788_wday == 0)
  87                 return 0;
  88
  89         /* lookup defined weekday from read register value */
  90         for (i = 0; i < MAX_WDAY_BITS; i++) {
  91                 if ((lp8788_wday >> i) == LP8788_WDAY_SET)
  92                         break;
  93         }
  94
  95         return i + 1;
  96 }
  97
  98 static inline int _to_lp8788_wday(int tm_wday)
  99 {
 100         return LP8788_WDAY_SET << (tm_wday - 1);
 101 }
 102
 103 static void lp8788_rtc_unlock(struct lp8788 *lp)
 104 {
 105         lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_UNLOCK);
 106         lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_LATCH);
 107 }
 108
 109 static int lp8788_rtc_read_time(struct device *dev, struct rtc_time *tm)
 110 {
 111         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 112         struct lp8788 *lp = rtc->lp;
 113         u8 data[LPTIME_MAX];
 114         int ret;
 115
 116         lp8788_rtc_unlock(lp);
 117
 118         ret = lp8788_read_multi_bytes(lp, LP8788_RTC_SEC, data, LPTIME_MAX);
 119         if (ret)
 120                 return ret;
 121
 122         tm->tm_sec  = data[LPTIME_SEC];
 123         tm->tm_min  = data[LPTIME_MIN];
 124         tm->tm_hour = data[LPTIME_HOUR];
 125         tm->tm_mday = data[LPTIME_MDAY];
 126         tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
 127         tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
 128         tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
 129
 130         return 0;
 131 }
 132
 133 static int lp8788_rtc_set_time(struct device *dev, struct rtc_time *tm)
 134 {
 135         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 136         struct lp8788 *lp = rtc->lp;
 137         u8 data[LPTIME_MAX - 1];
 138         int ret, i, year;
 139
 140         year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
 141         if (year < 0) {
 142                 dev_err(lp->dev, "invalid year: %d\n", year);
 143                 return -EINVAL;
 144         }
 145
 146         /* because rtc weekday is a readonly register, do not update */
 147         data[LPTIME_SEC]  = tm->tm_sec;
 148         data[LPTIME_MIN]  = tm->tm_min;
 149         data[LPTIME_HOUR] = tm->tm_hour;
 150         data[LPTIME_MDAY] = tm->tm_mday;
 151         data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
 152         data[LPTIME_YEAR] = year;
 153
 154         for (i = 0; i < ARRAY_SIZE(data); i++) {
 155                 ret = lp8788_write_byte(lp, LP8788_RTC_SEC + i, data[i]);
 156                 if (ret)
 157                         return ret;
 158         }
 159
 160         return 0;
 161 }
 162
 163 static int lp8788_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 164 {
 165         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 166         struct lp8788 *lp = rtc->lp;
 167         struct rtc_time *tm = &alarm->time;
 168         u8 addr, data[LPTIME_MAX];
 169         int ret;
 170
 171         addr = addr_alarm_sec[rtc->alarm];
 172         ret = lp8788_read_multi_bytes(lp, addr, data, LPTIME_MAX);
 173         if (ret)
 174                 return ret;
 175
 176         tm->tm_sec  = data[LPTIME_SEC];
 177         tm->tm_min  = data[LPTIME_MIN];
 178         tm->tm_hour = data[LPTIME_HOUR];
 179         tm->tm_mday = data[LPTIME_MDAY];
 180         tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
 181         tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
 182         tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
 183         alarm->enabled = data[LPTIME_WDAY] & LP8788_ALM_EN_M;
 184
 185         return 0;
 186 }
 187
 188 static int lp8788_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 189 {
 190         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 191         struct lp8788 *lp = rtc->lp;
 192         struct rtc_time *tm = &alarm->time;
 193         u8 addr, data[LPTIME_MAX];
 194         int ret, i, year;
 195
 196         year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
 197         if (year < 0) {
 198                 dev_err(lp->dev, "invalid year: %d\n", year);
 199                 return -EINVAL;
 200         }
 201
 202         data[LPTIME_SEC]  = tm->tm_sec;
 203         data[LPTIME_MIN]  = tm->tm_min;
 204         data[LPTIME_HOUR] = tm->tm_hour;
 205         data[LPTIME_MDAY] = tm->tm_mday;
 206         data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
 207         data[LPTIME_YEAR] = year;
 208         data[LPTIME_WDAY] = _to_lp8788_wday(tm->tm_wday);
 209
 210         for (i = 0; i < ARRAY_SIZE(data); i++) {
 211                 addr = addr_alarm_sec[rtc->alarm] + i;
 212                 ret = lp8788_write_byte(lp, addr, data[i]);
 213                 if (ret)
 214                         return ret;
 215         }
 216
 217         alarm->enabled = 1;
 218         addr = addr_alarm_en[rtc->alarm];
 219
 220         return lp8788_update_bits(lp, addr, LP8788_ALM_EN_M,
 221                                 alarm->enabled << LP8788_ALM_EN_S);
 222 }
 223
 224 static int lp8788_alarm_irq_enable(struct device *dev, unsigned int enable)
 225 {
 226         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
 227         struct lp8788 *lp = rtc->lp;
 228         u8 mask, shift;
 229
 230         if (!rtc->irq)
 231                 return -EIO;
 232
 233         mask = mask_alarm_en[rtc->alarm];
 234         shift = shift_alarm_en[rtc->alarm];
 235
 236         return lp8788_update_bits(lp, LP8788_INTEN_3, mask, enable << shift);
 237 }
 238
 239 static const struct rtc_class_ops lp8788_rtc_ops = {
 240         .read_time = lp8788_rtc_read_time,
 241         .set_time = lp8788_rtc_set_time,
 242         .read_alarm = lp8788_read_alarm,
 243         .set_alarm = lp8788_set_alarm,
 244         .alarm_irq_enable = lp8788_alarm_irq_enable,
 245 };
 246
 247 static irqreturn_t lp8788_alarm_irq_handler(int irq, void *ptr)
 248 {
 249         struct lp8788_rtc *rtc = ptr;
 250
 251         rtc_update_irq(rtc->rdev, 1, ALARM_IRQ_FLAG);
 252         return IRQ_HANDLED;
 253 }
 254
 255 static int lp8788_alarm_irq_register(struct platform_device *pdev,
 256                                 struct lp8788_rtc *rtc)
 257 {
 258         struct resource *r;
 259         struct lp8788 *lp = rtc->lp;
 260         struct irq_domain *irqdm = lp->irqdm;
 261         int irq;
 262
 263         rtc->irq = 0;
 264
 265         /* even the alarm IRQ number is not specified, rtc time should work */
 266         r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, LP8788_ALM_IRQ);
 267         if (!r)
 268                 return 0;
 269
 270         if (rtc->alarm == LP8788_ALARM_1)
 271                 irq = r->start;
 272         else
 273                 irq = r->end;
 274
 275         rtc->irq = irq_create_mapping(irqdm, irq);
 276
 277         return devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 278                                 lp8788_alarm_irq_handler,
 279                                 0, LP8788_ALM_IRQ, rtc);
 280 }
 281
 282 static int lp8788_rtc_probe(struct platform_device *pdev)
 283 {
 284         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
 285         struct lp8788_rtc *rtc;
 286         struct device *dev = &pdev->dev;
 287
 288         rtc = devm_kzalloc(dev, sizeof(struct lp8788_rtc), GFP_KERNEL);
 289         if (!rtc)
 290                 return -ENOMEM;
 291
 292         rtc->lp = lp;
 293         rtc->alarm = lp->pdata ? lp->pdata->alarm_sel : DEFAULT_ALARM_SEL;
 294         platform_set_drvdata(pdev, rtc);
 295
 296         device_init_wakeup(dev, 1);
 297
 298         rtc->rdev = devm_rtc_device_register(dev, "lp8788_rtc",
 299                                         &lp8788_rtc_ops, THIS_MODULE);
 300         if (IS_ERR(rtc->rdev)) {
 301                 dev_err(dev, "can not register rtc device\n");
 302                 return PTR_ERR(rtc->rdev);
 303         }
 304
 305         if (lp8788_alarm_irq_register(pdev, rtc))
 306                 dev_warn(lp->dev, "no rtc irq handler\n");
 307
 308         return 0;
 309 }
 310
 311 static struct platform_driver lp8788_rtc_driver = {
 312         .probe = lp8788_rtc_probe,
 313         .driver = {
 314                 .name = LP8788_DEV_RTC,
 315         },
 316 };
 317 module_platform_driver(lp8788_rtc_driver);
 318
 319 MODULE_DESCRIPTION("Texas Instruments LP8788 RTC Driver");
 320 MODULE_AUTHOR("Milo Kim");
 321 MODULE_LICENSE("GPL");
 322 MODULE_ALIAS("platform:lp8788-rtc");