drivers/rtc/rtc-asm9260.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Oleksij Rempel <linux@rempel-privat.de>
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/io.h>
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/rtc.h>
  13
  14 /* Miscellaneous registers */
  15 /* Interrupt Location Register */
  16 #define HW_ILR                  0x00
  17 #define BM_RTCALF               BIT(1)
  18 #define BM_RTCCIF               BIT(0)
  19
  20 /* Clock Control Register */
  21 #define HW_CCR                  0x08
  22 /* Calibration counter disable */
  23 #define BM_CCALOFF              BIT(4)
  24 /* Reset internal oscillator divider */
  25 #define BM_CTCRST               BIT(1)
  26 /* Clock Enable */
  27 #define BM_CLKEN                BIT(0)
  28
  29 /* Counter Increment Interrupt Register */
  30 #define HW_CIIR                 0x0C
  31 #define BM_CIIR_IMYEAR          BIT(7)
  32 #define BM_CIIR_IMMON           BIT(6)
  33 #define BM_CIIR_IMDOY           BIT(5)
  34 #define BM_CIIR_IMDOW           BIT(4)
  35 #define BM_CIIR_IMDOM           BIT(3)
  36 #define BM_CIIR_IMHOUR          BIT(2)
  37 #define BM_CIIR_IMMIN           BIT(1)
  38 #define BM_CIIR_IMSEC           BIT(0)
  39
  40 /* Alarm Mask Register */
  41 #define HW_AMR                  0x10
  42 #define BM_AMR_IMYEAR           BIT(7)
  43 #define BM_AMR_IMMON            BIT(6)
  44 #define BM_AMR_IMDOY            BIT(5)
  45 #define BM_AMR_IMDOW            BIT(4)
  46 #define BM_AMR_IMDOM            BIT(3)
  47 #define BM_AMR_IMHOUR           BIT(2)
  48 #define BM_AMR_IMMIN            BIT(1)
  49 #define BM_AMR_IMSEC            BIT(0)
  50 #define BM_AMR_OFF              0xff
  51
  52 /* Consolidated time registers */
  53 #define HW_CTIME0               0x14
  54 #define BM_CTIME0_DOW_S         24
  55 #define BM_CTIME0_DOW_M         0x7
  56 #define BM_CTIME0_HOUR_S        16
  57 #define BM_CTIME0_HOUR_M        0x1f
  58 #define BM_CTIME0_MIN_S         8
  59 #define BM_CTIME0_MIN_M         0x3f
  60 #define BM_CTIME0_SEC_S         0
  61 #define BM_CTIME0_SEC_M         0x3f
  62
  63 #define HW_CTIME1               0x18
  64 #define BM_CTIME1_YEAR_S        16
  65 #define BM_CTIME1_YEAR_M        0xfff
  66 #define BM_CTIME1_MON_S         8
  67 #define BM_CTIME1_MON_M         0xf
  68 #define BM_CTIME1_DOM_S         0
  69 #define BM_CTIME1_DOM_M         0x1f
  70
  71 #define HW_CTIME2               0x1C
  72 #define BM_CTIME2_DOY_S         0
  73 #define BM_CTIME2_DOY_M         0xfff
  74
  75 /* Time counter registers */
  76 #define HW_SEC                  0x20
  77 #define HW_MIN                  0x24
  78 #define HW_HOUR                 0x28
  79 #define HW_DOM                  0x2C
  80 #define HW_DOW                  0x30
  81 #define HW_DOY                  0x34
  82 #define HW_MONTH                0x38
  83 #define HW_YEAR                 0x3C
  84
  85 #define HW_CALIBRATION          0x40
  86 #define BM_CALDIR_BACK          BIT(17)
  87 #define BM_CALVAL_M             0x1ffff
  88
  89 /* General purpose registers */
  90 #define HW_GPREG0               0x44
  91 #define HW_GPREG1               0x48
  92 #define HW_GPREG2               0x4C
  93 #define HW_GPREG3               0x50
  94 #define HW_GPREG4               0x54
  95
  96 /* Alarm register group */
  97 #define HW_ALSEC                0x60
  98 #define HW_ALMIN                0x64
  99 #define HW_ALHOUR               0x68
 100 #define HW_ALDOM                0x6C
 101 #define HW_ALDOW                0x70
 102 #define HW_ALDOY                0x74
 103 #define HW_ALMON                0x78
 104 #define HW_ALYEAR               0x7C
 105
 106 struct asm9260_rtc_priv {
 107         struct device           *dev;
 108         void __iomem            *iobase;
 109         struct rtc_device       *rtc;
 110         struct clk              *clk;
 111 };
 112
 113 static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
 114 {
 115         struct asm9260_rtc_priv *priv = dev_id;
 116         u32 isr;
 117         unsigned long events = 0;
 118
 119         rtc_lock(priv->rtc);
 120         isr = ioread32(priv->iobase + HW_CIIR);
 121         if (!isr) {
 122                 rtc_unlock(priv->rtc);
 123                 return IRQ_NONE;
 124         }
 125
 126         iowrite32(0, priv->iobase + HW_CIIR);
 127         rtc_unlock(priv->rtc);
 128
 129         events |= RTC_AF | RTC_IRQF;
 130
 131         rtc_update_irq(priv->rtc, 1, events);
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
 137 {
 138         struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 139         u32 ctime0, ctime1, ctime2;
 140
 141         ctime0 = ioread32(priv->iobase + HW_CTIME0);
 142         ctime1 = ioread32(priv->iobase + HW_CTIME1);
 143         ctime2 = ioread32(priv->iobase + HW_CTIME2);
 144
 145         if (ctime1 != ioread32(priv->iobase + HW_CTIME1)) {
 146                 /*
 147                  * woops, counter flipped right now. Now we are safe
 148                  * to reread.
 149                  */
 150                 ctime0 = ioread32(priv->iobase + HW_CTIME0);
 151                 ctime1 = ioread32(priv->iobase + HW_CTIME1);
 152                 ctime2 = ioread32(priv->iobase + HW_CTIME2);
 153         }
 154
 155         tm->tm_sec  = (ctime0 >> BM_CTIME0_SEC_S)  & BM_CTIME0_SEC_M;
 156         tm->tm_min  = (ctime0 >> BM_CTIME0_MIN_S)  & BM_CTIME0_MIN_M;
 157         tm->tm_hour = (ctime0 >> BM_CTIME0_HOUR_S) & BM_CTIME0_HOUR_M;
 158         tm->tm_wday = (ctime0 >> BM_CTIME0_DOW_S)  & BM_CTIME0_DOW_M;
 159
 160         tm->tm_mday = (ctime1 >> BM_CTIME1_DOM_S)  & BM_CTIME1_DOM_M;
 161         tm->tm_mon  = (ctime1 >> BM_CTIME1_MON_S)  & BM_CTIME1_MON_M;
 162         tm->tm_year = (ctime1 >> BM_CTIME1_YEAR_S) & BM_CTIME1_YEAR_M;
 163
 164         tm->tm_yday = (ctime2 >> BM_CTIME2_DOY_S)  & BM_CTIME2_DOY_M;
 165
 166         return 0;
 167 }
 168
 169 static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
 170 {
 171         struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 172
 173         /*
 174          * make sure SEC counter will not flip other counter on write time,
 175          * real value will be written at the enf of sequence.
 176          */
 177         iowrite32(0, priv->iobase + HW_SEC);
 178
 179         iowrite32(tm->tm_year, priv->iobase + HW_YEAR);
 180         iowrite32(tm->tm_mon,  priv->iobase + HW_MONTH);
 181         iowrite32(tm->tm_mday, priv->iobase + HW_DOM);
 182         iowrite32(tm->tm_wday, priv->iobase + HW_DOW);
 183         iowrite32(tm->tm_yday, priv->iobase + HW_DOY);
 184         iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
 185         iowrite32(tm->tm_min,  priv->iobase + HW_MIN);
 186         iowrite32(tm->tm_sec,  priv->iobase + HW_SEC);
 187
 188         return 0;
 189 }
 190
 191 static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 192 {
 193         struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 194
 195         alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
 196         alrm->time.tm_mon  = ioread32(priv->iobase + HW_ALMON);
 197         alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
 198         alrm->time.tm_wday = ioread32(priv->iobase + HW_ALDOW);
 199         alrm->time.tm_yday = ioread32(priv->iobase + HW_ALDOY);
 200         alrm->time.tm_hour = ioread32(priv->iobase + HW_ALHOUR);
 201         alrm->time.tm_min  = ioread32(priv->iobase + HW_ALMIN);
 202         alrm->time.tm_sec  = ioread32(priv->iobase + HW_ALSEC);
 203
 204         alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
 205         alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;
 206
 207         return rtc_valid_tm(&alrm->time);
 208 }
 209
 210 static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 211 {
 212         struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 213
 214         iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
 215         iowrite32(alrm->time.tm_mon,  priv->iobase + HW_ALMON);
 216         iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
 217         iowrite32(alrm->time.tm_wday, priv->iobase + HW_ALDOW);
 218         iowrite32(alrm->time.tm_yday, priv->iobase + HW_ALDOY);
 219         iowrite32(alrm->time.tm_hour, priv->iobase + HW_ALHOUR);
 220         iowrite32(alrm->time.tm_min,  priv->iobase + HW_ALMIN);
 221         iowrite32(alrm->time.tm_sec,  priv->iobase + HW_ALSEC);
 222
 223         iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
 224
 225         return 0;
 226 }
 227
 228 static int asm9260_alarm_irq_enable(struct device *dev, unsigned int enabled)
 229 {
 230         struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 231
 232         iowrite32(enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
 233         return 0;
 234 }
 235
 236 static const struct rtc_class_ops asm9260_rtc_ops = {
 237         .read_time              = asm9260_rtc_read_time,
 238         .set_time               = asm9260_rtc_set_time,
 239         .read_alarm             = asm9260_rtc_read_alarm,
 240         .set_alarm              = asm9260_rtc_set_alarm,
 241         .alarm_irq_enable       = asm9260_alarm_irq_enable,
 242 };
 243
 244 static int asm9260_rtc_probe(struct platform_device *pdev)
 245 {
 246         struct asm9260_rtc_priv *priv;
 247         struct device *dev = &pdev->dev;
 248         int irq_alarm, ret;
 249         u32 ccr;
 250
 251         priv = devm_kzalloc(dev, sizeof(struct asm9260_rtc_priv), GFP_KERNEL);
 252         if (!priv)
 253                 return -ENOMEM;
 254
 255         priv->dev = &pdev->dev;
 256         platform_set_drvdata(pdev, priv);
 257
 258         irq_alarm = platform_get_irq(pdev, 0);
 259         if (irq_alarm < 0)
 260                 return irq_alarm;
 261
 262         priv->iobase = devm_platform_ioremap_resource(pdev, 0);
 263         if (IS_ERR(priv->iobase))
 264                 return PTR_ERR(priv->iobase);
 265
 266         priv->clk = devm_clk_get(dev, "ahb");
 267         if (IS_ERR(priv->clk))
 268                 return PTR_ERR(priv->clk);
 269
 270         ret = clk_prepare_enable(priv->clk);
 271         if (ret) {
 272                 dev_err(dev, "Failed to enable clk!\n");
 273                 return ret;
 274         }
 275
 276         ccr = ioread32(priv->iobase + HW_CCR);
 277         /* if dev is not enabled, reset it */
 278         if ((ccr & (BM_CLKEN | BM_CTCRST)) != BM_CLKEN) {
 279                 iowrite32(BM_CTCRST, priv->iobase + HW_CCR);
 280                 ccr = 0;
 281         }
 282
 283         iowrite32(BM_CLKEN | ccr, priv->iobase + HW_CCR);
 284         iowrite32(0, priv->iobase + HW_CIIR);
 285         iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
 286
 287         priv->rtc = devm_rtc_device_register(dev, dev_name(dev),
 288                                              &asm9260_rtc_ops, THIS_MODULE);
 289         if (IS_ERR(priv->rtc)) {
 290                 ret = PTR_ERR(priv->rtc);
 291                 dev_err(dev, "Failed to register RTC device: %d\n", ret);
 292                 goto err_return;
 293         }
 294
 295         ret = devm_request_threaded_irq(dev, irq_alarm, NULL,
 296                                         asm9260_rtc_irq, IRQF_ONESHOT,
 297                                         dev_name(dev), priv);
 298         if (ret < 0) {
 299                 dev_err(dev, "can't get irq %i, err %d\n",
 300                         irq_alarm, ret);
 301                 goto err_return;
 302         }
 303
 304         return 0;
 305
 306 err_return:
 307         clk_disable_unprepare(priv->clk);
 308         return ret;
 309 }
 310
 311 static int asm9260_rtc_remove(struct platform_device *pdev)
 312 {
 313         struct asm9260_rtc_priv *priv = platform_get_drvdata(pdev);
 314
 315         /* Disable alarm matching */
 316         iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
 317         clk_disable_unprepare(priv->clk);
 318         return 0;
 319 }
 320
 321 static const struct of_device_id asm9260_dt_ids[] = {
 322         { .compatible = "alphascale,asm9260-rtc", },
 323         {}
 324 };
 325 MODULE_DEVICE_TABLE(of, asm9260_dt_ids);
 326
 327 static struct platform_driver asm9260_rtc_driver = {
 328         .probe          = asm9260_rtc_probe,
 329         .remove         = asm9260_rtc_remove,
 330         .driver         = {
 331                 .name   = "asm9260-rtc",
 332                 .of_match_table = asm9260_dt_ids,
 333         },
 334 };
 335
 336 module_platform_driver(asm9260_rtc_driver);
 337
 338 MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
 339 MODULE_DESCRIPTION("Alphascale asm9260 SoC Realtime Clock Driver (RTC)");
 340 MODULE_LICENSE("GPL");