diff options
Diffstat (limited to 'drivers/rtc/rtc-loongson.c')
| -rw-r--r-- | drivers/rtc/rtc-loongson.c | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c new file mode 100644 index 0000000000..e8ffc1ab90 --- /dev/null +++ b/drivers/rtc/rtc-loongson.c @@ -0,0 +1,397 @@ +// 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"); |