drivers/rtc/rtc-loongson.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Loongson RTC driver
   4  *
   5  * Maintained out-of-tree by Huacai Chen <chenhuacai@kernel.org>.
   6  * Rewritten for mainline by WANG Xuerui <git@xen0n.name>.
   7  *                           Binbin Zhou <zhoubinbin@loongson.cn>
   8  */
   9
  10 #include <linux/bitfield.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/regmap.h>
  15 #include <linux/rtc.h>
  16 #include <linux/acpi.h>
  17
  18 /* Time Of Year(TOY) counters registers */
  19 #define TOY_TRIM_REG            0x20 /* Must be initialized to 0 */
  20 #define TOY_WRITE0_REG          0x24 /* TOY low 32-bits value (write-only) */
  21 #define TOY_WRITE1_REG          0x28 /* TOY high 32-bits value (write-only) */
  22 #define TOY_READ0_REG           0x2c /* TOY low 32-bits value (read-only) */
  23 #define TOY_READ1_REG           0x30 /* TOY high 32-bits value (read-only) */
  24 #define TOY_MATCH0_REG          0x34 /* TOY timing interrupt 0 */
  25 #define TOY_MATCH1_REG          0x38 /* TOY timing interrupt 1 */
  26 #define TOY_MATCH2_REG          0x3c /* TOY timing interrupt 2 */
  27
  28 /* RTC counters registers */
  29 #define RTC_CTRL_REG            0x40 /* TOY and RTC control register */
  30 #define RTC_TRIM_REG            0x60 /* Must be initialized to 0 */
  31 #define RTC_WRITE0_REG          0x64 /* RTC counters value (write-only) */
  32 #define RTC_READ0_REG           0x68 /* RTC counters value (read-only) */
  33 #define RTC_MATCH0_REG          0x6c /* RTC timing interrupt 0 */
  34 #define RTC_MATCH1_REG          0x70 /* RTC timing interrupt 1 */
  35 #define RTC_MATCH2_REG          0x74 /* RTC timing interrupt 2 */
  36
  37 /* bitmask of TOY_WRITE0_REG */
  38 #define TOY_MON                 GENMASK(31, 26)
  39 #define TOY_DAY                 GENMASK(25, 21)
  40 #define TOY_HOUR                GENMASK(20, 16)
  41 #define TOY_MIN                 GENMASK(15, 10)
  42 #define TOY_SEC                 GENMASK(9, 4)
  43 #define TOY_MSEC                GENMASK(3, 0)
  44
  45 /* bitmask of TOY_MATCH0/1/2_REG */
  46 #define TOY_MATCH_YEAR          GENMASK(31, 26)
  47 #define TOY_MATCH_MON           GENMASK(25, 22)
  48 #define TOY_MATCH_DAY           GENMASK(21, 17)
  49 #define TOY_MATCH_HOUR          GENMASK(16, 12)
  50 #define TOY_MATCH_MIN           GENMASK(11, 6)
  51 #define TOY_MATCH_SEC           GENMASK(5, 0)
  52
  53 /* bitmask of RTC_CTRL_REG */
  54 #define RTC_ENABLE              BIT(13) /* 1: RTC counters enable */
  55 #define TOY_ENABLE              BIT(11) /* 1: TOY counters enable */
  56 #define OSC_ENABLE              BIT(8) /* 1: 32.768k crystal enable */
  57 #define TOY_ENABLE_MASK         (TOY_ENABLE | OSC_ENABLE)
  58
  59 /* PM domain registers */
  60 #define PM1_STS_REG             0x0c    /* Power management 1 status register */
  61 #define RTC_STS                 BIT(10) /* RTC status */
  62 #define PM1_EN_REG              0x10    /* Power management 1 enable register */
  63 #define RTC_EN                  BIT(10) /* RTC event enable */
  64
  65 /*
  66  * According to the LS1C manual, RTC_CTRL and alarm-related registers are not defined.
  67  * Accessing the relevant registers will cause the system to hang.
  68  */
  69 #define LS1C_RTC_CTRL_WORKAROUND        BIT(0)
  70
  71 struct loongson_rtc_config {
  72         u32 pm_offset;  /* Offset of PM domain, for RTC alarm wakeup */
  73         u32 flags;      /* Workaround bits */
  74 };
  75
  76 struct loongson_rtc_priv {
  77         spinlock_t lock;        /* protects PM registers access */
  78         u32 fix_year;           /* RTC alarm year compensation value */
  79         struct rtc_device *rtcdev;
  80         struct regmap *regmap;
  81         void __iomem *pm_base;  /* PM domain base, for RTC alarm wakeup */
  82         const struct loongson_rtc_config *config;
  83 };
  84
  85 static const struct loongson_rtc_config ls1b_rtc_config = {
  86         .pm_offset = 0,
  87         .flags = 0,
  88 };
  89
  90 static const struct loongson_rtc_config ls1c_rtc_config = {
  91         .pm_offset = 0,
  92         .flags = LS1C_RTC_CTRL_WORKAROUND,
  93 };
  94
  95 static const struct loongson_rtc_config generic_rtc_config = {
  96         .pm_offset = 0x100,
  97         .flags = 0,
  98 };
  99
 100 static const struct loongson_rtc_config ls2k1000_rtc_config = {
 101         .pm_offset = 0x800,
 102         .flags = 0,
 103 };
 104
 105 static const struct regmap_config loongson_rtc_regmap_config = {
 106         .reg_bits = 32,
 107         .val_bits = 32,
 108         .reg_stride = 4,
 109 };
 110
 111 /* RTC alarm irq handler */
 112 static irqreturn_t loongson_rtc_isr(int irq, void *id)
 113 {
 114         struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
 115
 116         rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
 117         return IRQ_HANDLED;
 118 }
 119
 120 /* For ACPI fixed event handler */
 121 static u32 loongson_rtc_handler(void *id)
 122 {
 123         struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
 124
 125         spin_lock(&priv->lock);
 126         /* Disable RTC alarm wakeup and interrupt */
 127         writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
 128                priv->pm_base + PM1_EN_REG);
 129
 130         /* Clear RTC interrupt status */
 131         writel(RTC_STS, priv->pm_base + PM1_STS_REG);
 132         spin_unlock(&priv->lock);
 133
 134         /*
 135          * The TOY_MATCH0_REG should be cleared 0 here,
 136          * otherwise the interrupt cannot be cleared.
 137          */
 138         return regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
 139 }
 140
 141 static int loongson_rtc_set_enabled(struct device *dev)
 142 {
 143         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 144
 145         if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
 146                 return 0;
 147
 148         /* Enable RTC TOY counters and crystal */
 149         return regmap_update_bits(priv->regmap, RTC_CTRL_REG, TOY_ENABLE_MASK,
 150                                   TOY_ENABLE_MASK);
 151 }
 152
 153 static bool loongson_rtc_get_enabled(struct device *dev)
 154 {
 155         int ret;
 156         u32 ctrl_data;
 157         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 158
 159         if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
 160                 return true;
 161
 162         ret = regmap_read(priv->regmap, RTC_CTRL_REG, &ctrl_data);
 163         if (ret < 0)
 164                 return false;
 165
 166         return ctrl_data & TOY_ENABLE_MASK;
 167 }
 168
 169 static int loongson_rtc_read_time(struct device *dev, struct rtc_time *tm)
 170 {
 171         int ret;
 172         u32 rtc_data[2];
 173         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 174
 175         if (!loongson_rtc_get_enabled(dev))
 176                 return -EINVAL;
 177
 178         ret = regmap_bulk_read(priv->regmap, TOY_READ0_REG, rtc_data,
 179                                ARRAY_SIZE(rtc_data));
 180         if (ret < 0)
 181                 return ret;
 182
 183         tm->tm_sec = FIELD_GET(TOY_SEC, rtc_data[0]);
 184         tm->tm_min = FIELD_GET(TOY_MIN, rtc_data[0]);
 185         tm->tm_hour = FIELD_GET(TOY_HOUR, rtc_data[0]);
 186         tm->tm_mday = FIELD_GET(TOY_DAY, rtc_data[0]);
 187         tm->tm_mon = FIELD_GET(TOY_MON, rtc_data[0]) - 1;
 188         tm->tm_year = rtc_data[1];
 189
 190         /* Prepare for RTC alarm year compensation value. */
 191         priv->fix_year = tm->tm_year / 64 * 64;
 192         return 0;
 193 }
 194
 195 static int loongson_rtc_set_time(struct device *dev, struct rtc_time *tm)
 196 {
 197         int ret;
 198         u32 rtc_data[2];
 199         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 200
 201         rtc_data[0] = FIELD_PREP(TOY_SEC, tm->tm_sec)
 202                     | FIELD_PREP(TOY_MIN, tm->tm_min)
 203                     | FIELD_PREP(TOY_HOUR, tm->tm_hour)
 204                     | FIELD_PREP(TOY_DAY, tm->tm_mday)
 205                     | FIELD_PREP(TOY_MON, tm->tm_mon + 1);
 206         rtc_data[1] = tm->tm_year;
 207
 208         ret = regmap_bulk_write(priv->regmap, TOY_WRITE0_REG, rtc_data,
 209                                 ARRAY_SIZE(rtc_data));
 210         if (ret < 0)
 211                 return ret;
 212
 213         return loongson_rtc_set_enabled(dev);
 214 }
 215
 216 static int loongson_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 217 {
 218         int ret;
 219         u32 alarm_data;
 220         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 221
 222         ret = regmap_read(priv->regmap, TOY_MATCH0_REG, &alarm_data);
 223         if (ret < 0)
 224                 return ret;
 225
 226         alrm->time.tm_sec = FIELD_GET(TOY_MATCH_SEC, alarm_data);
 227         alrm->time.tm_min = FIELD_GET(TOY_MATCH_MIN, alarm_data);
 228         alrm->time.tm_hour = FIELD_GET(TOY_MATCH_HOUR, alarm_data);
 229         alrm->time.tm_mday = FIELD_GET(TOY_MATCH_DAY, alarm_data);
 230         alrm->time.tm_mon = FIELD_GET(TOY_MATCH_MON, alarm_data) - 1;
 231         /*
 232          * This is a hardware bug: the year field of SYS_TOYMATCH is only 6 bits,
 233          * making it impossible to save year values larger than 64.
 234          *
 235          * SYS_TOYMATCH is used to match the alarm time value and determine if
 236          * an alarm is triggered, so we must keep the lower 6 bits of the year
 237          * value constant during the value conversion.
 238          *
 239          * In summary, we need to manually add 64(or a multiple of 64) to the
 240          * year value to avoid the invalid alarm prompt at startup.
 241          */
 242         alrm->time.tm_year = FIELD_GET(TOY_MATCH_YEAR, alarm_data) + priv->fix_year;
 243
 244         alrm->enabled = !!(readl(priv->pm_base + PM1_EN_REG) & RTC_EN);
 245         return 0;
 246 }
 247
 248 static int loongson_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 249 {
 250         u32 val;
 251         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 252
 253         spin_lock(&priv->lock);
 254         val = readl(priv->pm_base + PM1_EN_REG);
 255         /* Enable RTC alarm wakeup */
 256         writel(enabled ? val | RTC_EN : val & ~RTC_EN,
 257                priv->pm_base + PM1_EN_REG);
 258         spin_unlock(&priv->lock);
 259
 260         return 0;
 261 }
 262
 263 static int loongson_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 264 {
 265         int ret;
 266         u32 alarm_data;
 267         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 268
 269         alarm_data = FIELD_PREP(TOY_MATCH_SEC, alrm->time.tm_sec)
 270                    | FIELD_PREP(TOY_MATCH_MIN, alrm->time.tm_min)
 271                    | FIELD_PREP(TOY_MATCH_HOUR, alrm->time.tm_hour)
 272                    | FIELD_PREP(TOY_MATCH_DAY, alrm->time.tm_mday)
 273                    | FIELD_PREP(TOY_MATCH_MON, alrm->time.tm_mon + 1)
 274                    | FIELD_PREP(TOY_MATCH_YEAR, alrm->time.tm_year - priv->fix_year);
 275
 276         ret = regmap_write(priv->regmap, TOY_MATCH0_REG, alarm_data);
 277         if (ret < 0)
 278                 return ret;
 279
 280         return loongson_rtc_alarm_irq_enable(dev, alrm->enabled);
 281 }
 282
 283 static const struct rtc_class_ops loongson_rtc_ops = {
 284         .read_time = loongson_rtc_read_time,
 285         .set_time = loongson_rtc_set_time,
 286         .read_alarm = loongson_rtc_read_alarm,
 287         .set_alarm = loongson_rtc_set_alarm,
 288         .alarm_irq_enable = loongson_rtc_alarm_irq_enable,
 289 };
 290
 291 static int loongson_rtc_probe(struct platform_device *pdev)
 292 {
 293         int ret, alarm_irq;
 294         void __iomem *regs;
 295         struct loongson_rtc_priv *priv;
 296         struct device *dev = &pdev->dev;
 297
 298         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 299         if (!priv)
 300                 return -ENOMEM;
 301
 302         regs = devm_platform_ioremap_resource(pdev, 0);
 303         if (IS_ERR(regs))
 304                 return dev_err_probe(dev, PTR_ERR(regs),
 305                                      "devm_platform_ioremap_resource failed\n");
 306
 307         priv->regmap = devm_regmap_init_mmio(dev, regs,
 308                                              &loongson_rtc_regmap_config);
 309         if (IS_ERR(priv->regmap))
 310                 return dev_err_probe(dev, PTR_ERR(priv->regmap),
 311                                      "devm_regmap_init_mmio failed\n");
 312
 313         priv->config = device_get_match_data(dev);
 314         spin_lock_init(&priv->lock);
 315         platform_set_drvdata(pdev, priv);
 316
 317         priv->rtcdev = devm_rtc_allocate_device(dev);
 318         if (IS_ERR(priv->rtcdev))
 319                 return dev_err_probe(dev, PTR_ERR(priv->rtcdev),
 320                                      "devm_rtc_allocate_device failed\n");
 321
 322         /* Get RTC alarm irq */
 323         alarm_irq = platform_get_irq(pdev, 0);
 324         if (alarm_irq > 0) {
 325                 ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr,
 326                                        0, "loongson-alarm", priv);
 327                 if (ret < 0)
 328                         return dev_err_probe(dev, ret, "Unable to request irq %d\n",
 329                                              alarm_irq);
 330
 331                 priv->pm_base = regs - priv->config->pm_offset;
 332                 device_init_wakeup(dev, 1);
 333
 334                 if (has_acpi_companion(dev))
 335                         acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
 336                                                          loongson_rtc_handler, priv);
 337         } else {
 338                 /* Loongson-1C RTC does not support alarm */
 339                 clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
 340         }
 341
 342         /* Loongson RTC does not support UIE */
 343         clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, priv->rtcdev->features);
 344         priv->rtcdev->ops = &loongson_rtc_ops;
 345         priv->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
 346         priv->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
 347
 348         return devm_rtc_register_device(priv->rtcdev);
 349 }
 350
 351 static void loongson_rtc_remove(struct platform_device *pdev)
 352 {
 353         struct device *dev = &pdev->dev;
 354         struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
 355
 356         if (!test_bit(RTC_FEATURE_ALARM, priv->rtcdev->features))
 357                 return;
 358
 359         if (has_acpi_companion(dev))
 360                 acpi_remove_fixed_event_handler(ACPI_EVENT_RTC,
 361                                                 loongson_rtc_handler);
 362
 363         device_init_wakeup(dev, 0);
 364         loongson_rtc_alarm_irq_enable(dev, 0);
 365 }
 366
 367 static const struct of_device_id loongson_rtc_of_match[] = {
 368         { .compatible = "loongson,ls1b-rtc", .data = &ls1b_rtc_config },
 369         { .compatible = "loongson,ls1c-rtc", .data = &ls1c_rtc_config },
 370         { .compatible = "loongson,ls7a-rtc", .data = &generic_rtc_config },
 371         { .compatible = "loongson,ls2k1000-rtc", .data = &ls2k1000_rtc_config },
 372         { /* sentinel */ }
 373 };
 374 MODULE_DEVICE_TABLE(of, loongson_rtc_of_match);
 375
 376 static const struct acpi_device_id loongson_rtc_acpi_match[] = {
 377         { "LOON0001", .driver_data = (kernel_ulong_t)&generic_rtc_config },
 378         { }
 379 };
 380 MODULE_DEVICE_TABLE(acpi, loongson_rtc_acpi_match);
 381
 382 static struct platform_driver loongson_rtc_driver = {
 383         .probe          = loongson_rtc_probe,
 384         .remove_new     = loongson_rtc_remove,
 385         .driver         = {
 386                 .name   = "loongson-rtc",
 387                 .of_match_table = loongson_rtc_of_match,
 388                 .acpi_match_table = loongson_rtc_acpi_match,
 389         },
 390 };
 391 module_platform_driver(loongson_rtc_driver);
 392
 393 MODULE_DESCRIPTION("Loongson RTC driver");
 394 MODULE_AUTHOR("Binbin Zhou <zhoubinbin@loongson.cn>");
 395 MODULE_AUTHOR("WANG Xuerui <git@xen0n.name>");
 396 MODULE_AUTHOR("Huacai Chen <chenhuacai@kernel.org>");
 397 MODULE_LICENSE("GPL");