diff options
Diffstat (limited to 'drivers/rtc/rtc-rzn1.c')
| -rw-r--r-- | drivers/rtc/rtc-rzn1.c | 518 |
1 files changed, 518 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c new file mode 100644 index 000000000000..c4ed43735457 --- /dev/null +++ b/drivers/rtc/rtc-rzn1.c @@ -0,0 +1,518 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Renesas RZ/N1 Real Time Clock interface for Linux + * + * Copyright: + * - 2014 Renesas Electronics Europe Limited + * - 2022 Schneider Electric + * + * Authors: + * - Michel Pollet <buserror@gmail.com> + * - Miquel Raynal <miquel.raynal@bootlin.com> + */ + +#include <linux/bcd.h> +#include <linux/clk.h> +#include <linux/init.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/rtc.h> +#include <linux/spinlock.h> + +#define RZN1_RTC_CTL0 0x00 +#define RZN1_RTC_CTL0_SLSB_SCMP BIT(4) +#define RZN1_RTC_CTL0_AMPM BIT(5) +#define RZN1_RTC_CTL0_CEST BIT(6) +#define RZN1_RTC_CTL0_CE BIT(7) + +#define RZN1_RTC_CTL1 0x04 +#define RZN1_RTC_CTL1_1SE BIT(3) +#define RZN1_RTC_CTL1_ALME BIT(4) + +#define RZN1_RTC_CTL2 0x08 +#define RZN1_RTC_CTL2_WAIT BIT(0) +#define RZN1_RTC_CTL2_WST BIT(1) +#define RZN1_RTC_CTL2_WUST BIT(5) +#define RZN1_RTC_CTL2_STOPPED (RZN1_RTC_CTL2_WAIT | RZN1_RTC_CTL2_WST) + +#define RZN1_RTC_TIME 0x30 +#define RZN1_RTC_TIME_MIN_SHIFT 8 +#define RZN1_RTC_TIME_HOUR_SHIFT 16 +#define RZN1_RTC_CAL 0x34 +#define RZN1_RTC_CAL_DAY_SHIFT 8 +#define RZN1_RTC_CAL_MON_SHIFT 16 +#define RZN1_RTC_CAL_YEAR_SHIFT 24 + +#define RZN1_RTC_SUBU 0x38 +#define RZN1_RTC_SUBU_DEV BIT(7) +#define RZN1_RTC_SUBU_DECR BIT(6) + +#define RZN1_RTC_SCMP 0x3c + +#define RZN1_RTC_ALM 0x40 +#define RZN1_RTC_ALH 0x44 +#define RZN1_RTC_ALW 0x48 + +#define RZN1_RTC_SECC 0x4c +#define RZN1_RTC_TIMEC 0x68 +#define RZN1_RTC_CALC 0x6c + +struct rzn1_rtc { + struct rtc_device *rtcdev; + void __iomem *base; + /* + * Protects access to RZN1_RTC_CTL1 reg. rtc_lock with threaded_irqs + * would introduce race conditions when switching interrupts because + * of potential sleeps + */ + spinlock_t ctl1_access_lock; + struct rtc_time tm_alarm; +}; + +static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm) +{ + u32 val; + + val = readl(rtc->base + RZN1_RTC_TIMEC); + tm->tm_sec = bcd2bin(val); + tm->tm_min = bcd2bin(val >> RZN1_RTC_TIME_MIN_SHIFT); + tm->tm_hour = bcd2bin(val >> RZN1_RTC_TIME_HOUR_SHIFT); + + val = readl(rtc->base + RZN1_RTC_CALC); + tm->tm_wday = val & 0x0f; + tm->tm_mday = bcd2bin(val >> RZN1_RTC_CAL_DAY_SHIFT); + tm->tm_mon = bcd2bin(val >> RZN1_RTC_CAL_MON_SHIFT) - 1; + tm->tm_year = bcd2bin(val >> RZN1_RTC_CAL_YEAR_SHIFT) + 100; +} + +static int rzn1_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + u32 val, secs; + + /* + * The RTC was not started or is stopped and thus does not carry the + * proper time/date. + */ + val = readl(rtc->base + RZN1_RTC_CTL2); + if (val & RZN1_RTC_CTL2_STOPPED) + return -EINVAL; + + rzn1_rtc_get_time_snapshot(rtc, tm); + secs = readl(rtc->base + RZN1_RTC_SECC); + if (tm->tm_sec != bcd2bin(secs)) + rzn1_rtc_get_time_snapshot(rtc, tm); + + return 0; +} + +static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + u32 val; + int ret; + + val = readl(rtc->base + RZN1_RTC_CTL2); + if (!(val & RZN1_RTC_CTL2_STOPPED)) { + /* Hold the counter if it was counting up */ + writel(RZN1_RTC_CTL2_WAIT, rtc->base + RZN1_RTC_CTL2); + + /* Wait for the counter to stop: two 32k clock cycles */ + usleep_range(61, 100); + ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val, + val & RZN1_RTC_CTL2_WST, 0, 100); + if (ret) + return ret; + } + + val = bin2bcd(tm->tm_sec); + val |= bin2bcd(tm->tm_min) << RZN1_RTC_TIME_MIN_SHIFT; + val |= bin2bcd(tm->tm_hour) << RZN1_RTC_TIME_HOUR_SHIFT; + writel(val, rtc->base + RZN1_RTC_TIME); + + val = tm->tm_wday; + val |= bin2bcd(tm->tm_mday) << RZN1_RTC_CAL_DAY_SHIFT; + val |= bin2bcd(tm->tm_mon + 1) << RZN1_RTC_CAL_MON_SHIFT; + val |= bin2bcd(tm->tm_year - 100) << RZN1_RTC_CAL_YEAR_SHIFT; + writel(val, rtc->base + RZN1_RTC_CAL); + + writel(0, rtc->base + RZN1_RTC_CTL2); + + return 0; +} + +static irqreturn_t rzn1_rtc_alarm_irq(int irq, void *dev_id) +{ + struct rzn1_rtc *rtc = dev_id; + u32 ctl1, set_irq_bits = 0; + + if (rtc->tm_alarm.tm_sec == 0) + rtc_update_irq(rtc->rtcdev, 1, RTC_AF | RTC_IRQF); + else + /* Switch to 1s interrupts */ + set_irq_bits = RZN1_RTC_CTL1_1SE; + + guard(spinlock)(&rtc->ctl1_access_lock); + + ctl1 = readl(rtc->base + RZN1_RTC_CTL1); + ctl1 &= ~RZN1_RTC_CTL1_ALME; + ctl1 |= set_irq_bits; + writel(ctl1, rtc->base + RZN1_RTC_CTL1); + + return IRQ_HANDLED; +} + +static irqreturn_t rzn1_rtc_1s_irq(int irq, void *dev_id) +{ + struct rzn1_rtc *rtc = dev_id; + u32 ctl1; + + if (readl(rtc->base + RZN1_RTC_SECC) == bin2bcd(rtc->tm_alarm.tm_sec)) { + guard(spinlock)(&rtc->ctl1_access_lock); + + ctl1 = readl(rtc->base + RZN1_RTC_CTL1); + ctl1 &= ~RZN1_RTC_CTL1_1SE; + writel(ctl1, rtc->base + RZN1_RTC_CTL1); + + rtc_update_irq(rtc->rtcdev, 1, RTC_AF | RTC_IRQF); + } + + return IRQ_HANDLED; +} + +static int rzn1_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &rtc->tm_alarm, tm_now; + u32 ctl1; + int ret; + + guard(spinlock_irqsave)(&rtc->ctl1_access_lock); + + ctl1 = readl(rtc->base + RZN1_RTC_CTL1); + + if (enable) { + /* + * Use alarm interrupt if alarm time is at least a minute away + * or less than a minute but in the next minute. Otherwise use + * 1 second interrupt to wait for the proper second + */ + do { + ctl1 &= ~(RZN1_RTC_CTL1_ALME | RZN1_RTC_CTL1_1SE); + + ret = rzn1_rtc_read_time(dev, &tm_now); + if (ret) + return ret; + + if (rtc_tm_sub(tm, &tm_now) > 59 || tm->tm_min != tm_now.tm_min) + ctl1 |= RZN1_RTC_CTL1_ALME; + else + ctl1 |= RZN1_RTC_CTL1_1SE; + + writel(ctl1, rtc->base + RZN1_RTC_CTL1); + } while (readl(rtc->base + RZN1_RTC_SECC) != bin2bcd(tm_now.tm_sec)); + } else { + ctl1 &= ~(RZN1_RTC_CTL1_ALME | RZN1_RTC_CTL1_1SE); + writel(ctl1, rtc->base + RZN1_RTC_CTL1); + } + + return 0; +} + +static int rzn1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time; + unsigned int min, hour, wday, delta_days; + time64_t alarm; + u32 ctl1; + int ret; + + ret = rzn1_rtc_read_time(dev, tm); + if (ret) + return ret; + + min = readl(rtc->base + RZN1_RTC_ALM); + hour = readl(rtc->base + RZN1_RTC_ALH); + wday = readl(rtc->base + RZN1_RTC_ALW); + + tm->tm_sec = 0; + tm->tm_min = bcd2bin(min); + tm->tm_hour = bcd2bin(hour); + delta_days = ((fls(wday) - 1) - tm->tm_wday + 7) % 7; + tm->tm_wday = fls(wday) - 1; + + if (delta_days) { + alarm = rtc_tm_to_time64(tm) + (delta_days * 86400); + rtc_time64_to_tm(alarm, tm); + } + + ctl1 = readl(rtc->base + RZN1_RTC_CTL1); + alrm->enabled = !!(ctl1 & (RZN1_RTC_CTL1_ALME | RZN1_RTC_CTL1_1SE)); + + return 0; +} + +static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time, tm_now; + unsigned long alarm, farest; + unsigned int days_ahead, wday; + int ret; + + ret = rzn1_rtc_read_time(dev, &tm_now); + if (ret) + return ret; + + /* We cannot set alarms more than one week ahead */ + farest = rtc_tm_to_time64(&tm_now) + rtc->rtcdev->alarm_offset_max; + alarm = rtc_tm_to_time64(tm); + if (time_after(alarm, farest)) + return -ERANGE; + + /* Convert alarm day into week day */ + days_ahead = tm->tm_mday - tm_now.tm_mday; + wday = (tm_now.tm_wday + days_ahead) % 7; + + writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM); + writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH); + writel(BIT(wday), rtc->base + RZN1_RTC_ALW); + + rtc->tm_alarm = alrm->time; + + rzn1_rtc_alarm_irq_enable(dev, alrm->enabled); + + return 0; +} + +static int rzn1_rtc_read_offset(struct device *dev, long *offset) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + unsigned int ppb_per_step; + bool subtract; + u32 val; + + val = readl(rtc->base + RZN1_RTC_SUBU); + ppb_per_step = val & RZN1_RTC_SUBU_DEV ? 1017 : 3051; + subtract = val & RZN1_RTC_SUBU_DECR; + val &= 0x3F; + + if (!val) + *offset = 0; + else if (subtract) + *offset = -(((~val) & 0x3F) + 1) * ppb_per_step; + else + *offset = (val - 1) * ppb_per_step; + + return 0; +} + +static int rzn1_rtc_set_offset(struct device *dev, long offset) +{ + struct rzn1_rtc *rtc = dev_get_drvdata(dev); + int stepsh, stepsl, steps; + u32 subu = 0, ctl2; + int ret; + + /* + * Check which resolution mode (every 20 or 60s) can be used. + * Between 2 and 124 clock pulses can be added or substracted. + * + * In 20s mode, the minimum resolution is 2 / (32768 * 20) which is + * close to 3051 ppb. In 60s mode, the resolution is closer to 1017. + */ + stepsh = DIV_ROUND_CLOSEST(offset, 1017); + stepsl = DIV_ROUND_CLOSEST(offset, 3051); + + if (stepsh >= -0x3E && stepsh <= 0x3E) { + /* 1017 ppb per step */ + steps = stepsh; + subu |= RZN1_RTC_SUBU_DEV; + } else if (stepsl >= -0x3E && stepsl <= 0x3E) { + /* 3051 ppb per step */ + steps = stepsl; + } else { + return -ERANGE; + } + + if (!steps) + return 0; + + if (steps > 0) { + subu |= steps + 1; + } else { + subu |= RZN1_RTC_SUBU_DECR; + subu |= (~(-steps - 1)) & 0x3F; + } + + ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, ctl2, + !(ctl2 & RZN1_RTC_CTL2_WUST), 100, 2000000); + if (ret) + return ret; + + writel(subu, rtc->base + RZN1_RTC_SUBU); + + return 0; +} + +static const struct rtc_class_ops rzn1_rtc_ops_subu = { + .read_time = rzn1_rtc_read_time, + .set_time = rzn1_rtc_set_time, + .read_alarm = rzn1_rtc_read_alarm, + .set_alarm = rzn1_rtc_set_alarm, + .alarm_irq_enable = rzn1_rtc_alarm_irq_enable, + .read_offset = rzn1_rtc_read_offset, + .set_offset = rzn1_rtc_set_offset, +}; + +static const struct rtc_class_ops rzn1_rtc_ops_scmp = { + .read_time = rzn1_rtc_read_time, + .set_time = rzn1_rtc_set_time, + .read_alarm = rzn1_rtc_read_alarm, + .set_alarm = rzn1_rtc_set_alarm, + .alarm_irq_enable = rzn1_rtc_alarm_irq_enable, +}; + +static int rzn1_rtc_probe(struct platform_device *pdev) +{ + struct rzn1_rtc *rtc; + u32 val, scmp_val = 0; + struct clk *xtal; + unsigned long rate; + int irq, ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + platform_set_drvdata(pdev, rtc); + + rtc->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(rtc->base)) + return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n"); + + irq = platform_get_irq_byname(pdev, "alarm"); + if (irq < 0) + return irq; + + rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc->rtcdev)) + return PTR_ERR(rtc->rtcdev); + + rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000; + rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099; + rtc->rtcdev->alarm_offset_max = 7 * 86400; + + ret = devm_pm_runtime_enable(&pdev->dev); + if (ret < 0) + return ret; + ret = pm_runtime_resume_and_get(&pdev->dev); + if (ret < 0) + return ret; + + /* Only switch to scmp if we have an xtal clock with a valid rate and != 32768 */ + xtal = devm_clk_get_optional(&pdev->dev, "xtal"); + if (IS_ERR(xtal)) { + ret = PTR_ERR(xtal); + goto dis_runtime_pm; + } else if (xtal) { + rate = clk_get_rate(xtal); + + if (rate < 32000 || rate > BIT(22)) { + ret = -EOPNOTSUPP; + goto dis_runtime_pm; + } + + if (rate != 32768) + scmp_val = RZN1_RTC_CTL0_SLSB_SCMP; + } + + /* Disable controller during SUBU/SCMP setup */ + val = readl(rtc->base + RZN1_RTC_CTL0) & ~RZN1_RTC_CTL0_CE; + writel(val, rtc->base + RZN1_RTC_CTL0); + /* Wait 2-4 32k clock cycles for the disabled controller */ + ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL0, val, + !(val & RZN1_RTC_CTL0_CEST), 62, 123); + if (ret) + goto dis_runtime_pm; + + /* Set desired modes leaving the controller disabled */ + writel(RZN1_RTC_CTL0_AMPM | scmp_val, rtc->base + RZN1_RTC_CTL0); + + if (scmp_val) { + writel(rate - 1, rtc->base + RZN1_RTC_SCMP); + rtc->rtcdev->ops = &rzn1_rtc_ops_scmp; + } else { + rtc->rtcdev->ops = &rzn1_rtc_ops_subu; + } + + /* Enable controller finally */ + writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | scmp_val, rtc->base + RZN1_RTC_CTL0); + + /* Disable all interrupts */ + writel(0, rtc->base + RZN1_RTC_CTL1); + + spin_lock_init(&rtc->ctl1_access_lock); + + ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_alarm_irq, 0, "RZN1 RTC Alarm", rtc); + if (ret) { + dev_err(&pdev->dev, "RTC alarm interrupt not available\n"); + goto dis_runtime_pm; + } + + irq = platform_get_irq_byname_optional(pdev, "pps"); + if (irq >= 0) + ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_1s_irq, 0, "RZN1 RTC 1s", rtc); + + if (irq < 0 || ret) { + set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtcdev->features); + clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features); + dev_warn(&pdev->dev, "RTC pps interrupt not available. Alarm has only minute accuracy\n"); + } + + ret = devm_rtc_register_device(rtc->rtcdev); + if (ret) + goto dis_runtime_pm; + + return 0; + +dis_runtime_pm: + pm_runtime_put(&pdev->dev); + + return ret; +} + +static void rzn1_rtc_remove(struct platform_device *pdev) +{ + struct rzn1_rtc *rtc = platform_get_drvdata(pdev); + + /* Disable all interrupts */ + writel(0, rtc->base + RZN1_RTC_CTL1); + + pm_runtime_put(&pdev->dev); +} + +static const struct of_device_id rzn1_rtc_of_match[] = { + { .compatible = "renesas,rzn1-rtc" }, + {}, +}; +MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match); + +static struct platform_driver rzn1_rtc_driver = { + .probe = rzn1_rtc_probe, + .remove = rzn1_rtc_remove, + .driver = { + .name = "rzn1-rtc", + .of_match_table = rzn1_rtc_of_match, + }, +}; +module_platform_driver(rzn1_rtc_driver); + +MODULE_AUTHOR("Michel Pollet <buserror@gmail.com>"); +MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com"); +MODULE_DESCRIPTION("RZ/N1 RTC driver"); +MODULE_LICENSE("GPL"); |