--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Loongson RTC driver
+ *
+ * Maintained out-of-tree by Huacai Chen <chenhuacai@kernel.org>.
+ * Rewritten for mainline by WANG Xuerui <git@xen0n.name>.
+ * Binbin Zhou <zhoubinbin@loongson.cn>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/acpi.h>
+
+/* Time Of Year(TOY) counters registers */
+#define TOY_TRIM_REG 0x20 /* Must be initialized to 0 */
+#define TOY_WRITE0_REG 0x24 /* TOY low 32-bits value (write-only) */
+#define TOY_WRITE1_REG 0x28 /* TOY high 32-bits value (write-only) */
+#define TOY_READ0_REG 0x2c /* TOY low 32-bits value (read-only) */
+#define TOY_READ1_REG 0x30 /* TOY high 32-bits value (read-only) */
+#define TOY_MATCH0_REG 0x34 /* TOY timing interrupt 0 */
+#define TOY_MATCH1_REG 0x38 /* TOY timing interrupt 1 */
+#define TOY_MATCH2_REG 0x3c /* TOY timing interrupt 2 */
+
+/* RTC counters registers */
+#define RTC_CTRL_REG 0x40 /* TOY and RTC control register */
+#define RTC_TRIM_REG 0x60 /* Must be initialized to 0 */
+#define RTC_WRITE0_REG 0x64 /* RTC counters value (write-only) */
+#define RTC_READ0_REG 0x68 /* RTC counters value (read-only) */
+#define RTC_MATCH0_REG 0x6c /* RTC timing interrupt 0 */
+#define RTC_MATCH1_REG 0x70 /* RTC timing interrupt 1 */
+#define RTC_MATCH2_REG 0x74 /* RTC timing interrupt 2 */
+
+/* bitmask of TOY_WRITE0_REG */
+#define TOY_MON GENMASK(31, 26)
+#define TOY_DAY GENMASK(25, 21)
+#define TOY_HOUR GENMASK(20, 16)
+#define TOY_MIN GENMASK(15, 10)
+#define TOY_SEC GENMASK(9, 4)
+#define TOY_MSEC GENMASK(3, 0)
+
+/* bitmask of TOY_MATCH0/1/2_REG */
+#define TOY_MATCH_YEAR GENMASK(31, 26)
+#define TOY_MATCH_MON GENMASK(25, 22)
+#define TOY_MATCH_DAY GENMASK(21, 17)
+#define TOY_MATCH_HOUR GENMASK(16, 12)
+#define TOY_MATCH_MIN GENMASK(11, 6)
+#define TOY_MATCH_SEC GENMASK(5, 0)
+
+/* bitmask of RTC_CTRL_REG */
+#define RTC_ENABLE BIT(13) /* 1: RTC counters enable */
+#define TOY_ENABLE BIT(11) /* 1: TOY counters enable */
+#define OSC_ENABLE BIT(8) /* 1: 32.768k crystal enable */
+#define TOY_ENABLE_MASK (TOY_ENABLE | OSC_ENABLE)
+
+/* PM domain registers */
+#define PM1_STS_REG 0x0c /* Power management 1 status register */
+#define RTC_STS BIT(10) /* RTC status */
+#define PM1_EN_REG 0x10 /* Power management 1 enable register */
+#define RTC_EN BIT(10) /* RTC event enable */
+
+/*
+ * According to the LS1C manual, RTC_CTRL and alarm-related registers are not defined.
+ * Accessing the relevant registers will cause the system to hang.
+ */
+#define LS1C_RTC_CTRL_WORKAROUND BIT(0)
+
+struct loongson_rtc_config {
+ u32 pm_offset; /* Offset of PM domain, for RTC alarm wakeup */
+ u32 flags; /* Workaround bits */
+};
+
+struct loongson_rtc_priv {
+ spinlock_t lock; /* protects PM registers access */
+ u32 fix_year; /* RTC alarm year compensation value */
+ struct rtc_device *rtcdev;
+ struct regmap *regmap;
+ void __iomem *pm_base; /* PM domain base, for RTC alarm wakeup */
+ const struct loongson_rtc_config *config;
+};
+
+static const struct loongson_rtc_config ls1b_rtc_config = {
+ .pm_offset = 0,
+ .flags = 0,
+};
+
+static const struct loongson_rtc_config ls1c_rtc_config = {
+ .pm_offset = 0,
+ .flags = LS1C_RTC_CTRL_WORKAROUND,
+};
+
+static const struct loongson_rtc_config generic_rtc_config = {
+ .pm_offset = 0x100,
+ .flags = 0,
+};
+
+static const struct loongson_rtc_config ls2k1000_rtc_config = {
+ .pm_offset = 0x800,
+ .flags = 0,
+};
+
+static const struct regmap_config loongson_rtc_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+/* RTC alarm irq handler */
+static irqreturn_t loongson_rtc_isr(int irq, void *id)
+{
+ struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
+
+ rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
+ return IRQ_HANDLED;
+}
+
+/* For ACPI fixed event handler */
+static u32 loongson_rtc_handler(void *id)
+{
+ struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
+
+ spin_lock(&priv->lock);
+ /* Disable RTC alarm wakeup and interrupt */
+ writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
+ priv->pm_base + PM1_EN_REG);
+
+ /* Clear RTC interrupt status */
+ writel(RTC_STS, priv->pm_base + PM1_STS_REG);
+ spin_unlock(&priv->lock);
+
+ /*
+ * The TOY_MATCH0_REG should be cleared 0 here,
+ * otherwise the interrupt cannot be cleared.
+ */
+ return regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
+}
+
+static int loongson_rtc_set_enabled(struct device *dev)
+{
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
+ return 0;
+
+ /* Enable RTC TOY counters and crystal */
+ return regmap_update_bits(priv->regmap, RTC_CTRL_REG, TOY_ENABLE_MASK,
+ TOY_ENABLE_MASK);
+}
+
+static bool loongson_rtc_get_enabled(struct device *dev)
+{
+ int ret;
+ u32 ctrl_data;
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
+ return true;
+
+ ret = regmap_read(priv->regmap, RTC_CTRL_REG, &ctrl_data);
+ if (ret < 0)
+ return false;
+
+ return ctrl_data & TOY_ENABLE_MASK;
+}
+
+static int loongson_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ int ret;
+ u32 rtc_data[2];
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ if (!loongson_rtc_get_enabled(dev))
+ return -EINVAL;
+
+ ret = regmap_bulk_read(priv->regmap, TOY_READ0_REG, rtc_data,
+ ARRAY_SIZE(rtc_data));
+ if (ret < 0)
+ return ret;
+
+ tm->tm_sec = FIELD_GET(TOY_SEC, rtc_data[0]);
+ tm->tm_min = FIELD_GET(TOY_MIN, rtc_data[0]);
+ tm->tm_hour = FIELD_GET(TOY_HOUR, rtc_data[0]);
+ tm->tm_mday = FIELD_GET(TOY_DAY, rtc_data[0]);
+ tm->tm_mon = FIELD_GET(TOY_MON, rtc_data[0]) - 1;
+ tm->tm_year = rtc_data[1];
+
+ /* Prepare for RTC alarm year compensation value. */
+ priv->fix_year = tm->tm_year / 64 * 64;
+ return 0;
+}
+
+static int loongson_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ int ret;
+ u32 rtc_data[2];
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ rtc_data[0] = FIELD_PREP(TOY_SEC, tm->tm_sec)
+ | FIELD_PREP(TOY_MIN, tm->tm_min)
+ | FIELD_PREP(TOY_HOUR, tm->tm_hour)
+ | FIELD_PREP(TOY_DAY, tm->tm_mday)
+ | FIELD_PREP(TOY_MON, tm->tm_mon + 1);
+ rtc_data[1] = tm->tm_year;
+
+ ret = regmap_bulk_write(priv->regmap, TOY_WRITE0_REG, rtc_data,
+ ARRAY_SIZE(rtc_data));
+ if (ret < 0)
+ return ret;
+
+ return loongson_rtc_set_enabled(dev);
+}
+
+static int loongson_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ int ret;
+ u32 alarm_data;
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ ret = regmap_read(priv->regmap, TOY_MATCH0_REG, &alarm_data);
+ if (ret < 0)
+ return ret;
+
+ alrm->time.tm_sec = FIELD_GET(TOY_MATCH_SEC, alarm_data);
+ alrm->time.tm_min = FIELD_GET(TOY_MATCH_MIN, alarm_data);
+ alrm->time.tm_hour = FIELD_GET(TOY_MATCH_HOUR, alarm_data);
+ alrm->time.tm_mday = FIELD_GET(TOY_MATCH_DAY, alarm_data);
+ alrm->time.tm_mon = FIELD_GET(TOY_MATCH_MON, alarm_data) - 1;
+ /*
+ * This is a hardware bug: the year field of SYS_TOYMATCH is only 6 bits,
+ * making it impossible to save year values larger than 64.
+ *
+ * SYS_TOYMATCH is used to match the alarm time value and determine if
+ * an alarm is triggered, so we must keep the lower 6 bits of the year
+ * value constant during the value conversion.
+ *
+ * In summary, we need to manually add 64(or a multiple of 64) to the
+ * year value to avoid the invalid alarm prompt at startup.
+ */
+ alrm->time.tm_year = FIELD_GET(TOY_MATCH_YEAR, alarm_data) + priv->fix_year;
+
+ alrm->enabled = !!(readl(priv->pm_base + PM1_EN_REG) & RTC_EN);
+ return 0;
+}
+
+static int loongson_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ u32 val;
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ spin_lock(&priv->lock);
+ val = readl(priv->pm_base + PM1_EN_REG);
+ /* Enable RTC alarm wakeup */
+ writel(enabled ? val | RTC_EN : val & ~RTC_EN,
+ priv->pm_base + PM1_EN_REG);
+ spin_unlock(&priv->lock);
+
+ return 0;
+}
+
+static int loongson_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ int ret;
+ u32 alarm_data;
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ alarm_data = FIELD_PREP(TOY_MATCH_SEC, alrm->time.tm_sec)
+ | FIELD_PREP(TOY_MATCH_MIN, alrm->time.tm_min)
+ | FIELD_PREP(TOY_MATCH_HOUR, alrm->time.tm_hour)
+ | FIELD_PREP(TOY_MATCH_DAY, alrm->time.tm_mday)
+ | FIELD_PREP(TOY_MATCH_MON, alrm->time.tm_mon + 1)
+ | FIELD_PREP(TOY_MATCH_YEAR, alrm->time.tm_year - priv->fix_year);
+
+ ret = regmap_write(priv->regmap, TOY_MATCH0_REG, alarm_data);
+ if (ret < 0)
+ return ret;
+
+ return loongson_rtc_alarm_irq_enable(dev, alrm->enabled);
+}
+
+static const struct rtc_class_ops loongson_rtc_ops = {
+ .read_time = loongson_rtc_read_time,
+ .set_time = loongson_rtc_set_time,
+ .read_alarm = loongson_rtc_read_alarm,
+ .set_alarm = loongson_rtc_set_alarm,
+ .alarm_irq_enable = loongson_rtc_alarm_irq_enable,
+};
+
+static int loongson_rtc_probe(struct platform_device *pdev)
+{
+ int ret, alarm_irq;
+ void __iomem *regs;
+ struct loongson_rtc_priv *priv;
+ struct device *dev = &pdev->dev;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(regs))
+ return dev_err_probe(dev, PTR_ERR(regs),
+ "devm_platform_ioremap_resource failed\n");
+
+ priv->regmap = devm_regmap_init_mmio(dev, regs,
+ &loongson_rtc_regmap_config);
+ if (IS_ERR(priv->regmap))
+ return dev_err_probe(dev, PTR_ERR(priv->regmap),
+ "devm_regmap_init_mmio failed\n");
+
+ priv->config = device_get_match_data(dev);
+ spin_lock_init(&priv->lock);
+ platform_set_drvdata(pdev, priv);
+
+ priv->rtcdev = devm_rtc_allocate_device(dev);
+ if (IS_ERR(priv->rtcdev))
+ return dev_err_probe(dev, PTR_ERR(priv->rtcdev),
+ "devm_rtc_allocate_device failed\n");
+
+ /* Get RTC alarm irq */
+ alarm_irq = platform_get_irq(pdev, 0);
+ if (alarm_irq > 0) {
+ ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr,
+ 0, "loongson-alarm", priv);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Unable to request irq %d\n",
+ alarm_irq);
+
+ priv->pm_base = regs - priv->config->pm_offset;
+ device_init_wakeup(dev, 1);
+
+ if (has_acpi_companion(dev))
+ acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
+ loongson_rtc_handler, priv);
+ } else {
+ /* Loongson-1C RTC does not support alarm */
+ clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
+ }
+
+ /* Loongson RTC does not support UIE */
+ clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, priv->rtcdev->features);
+ priv->rtcdev->ops = &loongson_rtc_ops;
+ priv->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ priv->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
+
+ return devm_rtc_register_device(priv->rtcdev);
+}
+
+static void loongson_rtc_remove(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
+
+ if (!test_bit(RTC_FEATURE_ALARM, priv->rtcdev->features))
+ return;
+
+ if (has_acpi_companion(dev))
+ acpi_remove_fixed_event_handler(ACPI_EVENT_RTC,
+ loongson_rtc_handler);
+
+ device_init_wakeup(dev, 0);
+ loongson_rtc_alarm_irq_enable(dev, 0);
+}
+
+static const struct of_device_id loongson_rtc_of_match[] = {
+ { .compatible = "loongson,ls1b-rtc", .data = &ls1b_rtc_config },
+ { .compatible = "loongson,ls1c-rtc", .data = &ls1c_rtc_config },
+ { .compatible = "loongson,ls7a-rtc", .data = &generic_rtc_config },
+ { .compatible = "loongson,ls2k1000-rtc", .data = &ls2k1000_rtc_config },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, loongson_rtc_of_match);
+
+static const struct acpi_device_id loongson_rtc_acpi_match[] = {
+ { "LOON0001", .driver_data = (kernel_ulong_t)&generic_rtc_config },
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, loongson_rtc_acpi_match);
+
+static struct platform_driver loongson_rtc_driver = {
+ .probe = loongson_rtc_probe,
+ .remove_new = loongson_rtc_remove,
+ .driver = {
+ .name = "loongson-rtc",
+ .of_match_table = loongson_rtc_of_match,
+ .acpi_match_table = loongson_rtc_acpi_match,
+ },
+};
+module_platform_driver(loongson_rtc_driver);
+
+MODULE_DESCRIPTION("Loongson RTC driver");
+MODULE_AUTHOR("Binbin Zhou <zhoubinbin@loongson.cn>");
+MODULE_AUTHOR("WANG Xuerui <git@xen0n.name>");
+MODULE_AUTHOR("Huacai Chen <chenhuacai@kernel.org>");
+MODULE_LICENSE("GPL");
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