--- /dev/null
+// 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 <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
+ * - Miquel Raynal <miquel.raynal@bootlin.com>
+ */
+
+#include <linux/bcd.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/rtc.h>
+
+#define RZN1_RTC_CTL0 0x00
+#define RZN1_RTC_CTL0_SLSB_SUBU 0
+#define RZN1_RTC_CTL0_SLSB_SCMP BIT(4)
+#define RZN1_RTC_CTL0_AMPM BIT(5)
+#define RZN1_RTC_CTL0_CE BIT(7)
+
+#define RZN1_RTC_CTL1 0x04
+#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_SEC 0x14
+#define RZN1_RTC_MIN 0x18
+#define RZN1_RTC_HOUR 0x1c
+#define RZN1_RTC_WEEK 0x20
+#define RZN1_RTC_DAY 0x24
+#define RZN1_RTC_MONTH 0x28
+#define RZN1_RTC_YEAR 0x2c
+
+#define RZN1_RTC_SUBU 0x38
+#define RZN1_RTC_SUBU_DEV BIT(7)
+#define RZN1_RTC_SUBU_DECR BIT(6)
+
+#define RZN1_RTC_ALM 0x40
+#define RZN1_RTC_ALH 0x44
+#define RZN1_RTC_ALW 0x48
+
+#define RZN1_RTC_SECC 0x4c
+#define RZN1_RTC_MINC 0x50
+#define RZN1_RTC_HOURC 0x54
+#define RZN1_RTC_WEEKC 0x58
+#define RZN1_RTC_DAYC 0x5c
+#define RZN1_RTC_MONTHC 0x60
+#define RZN1_RTC_YEARC 0x64
+
+struct rzn1_rtc {
+ struct rtc_device *rtcdev;
+ void __iomem *base;
+};
+
+static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm)
+{
+ tm->tm_sec = readl(rtc->base + RZN1_RTC_SECC);
+ tm->tm_min = readl(rtc->base + RZN1_RTC_MINC);
+ tm->tm_hour = readl(rtc->base + RZN1_RTC_HOURC);
+ tm->tm_wday = readl(rtc->base + RZN1_RTC_WEEKC);
+ tm->tm_mday = readl(rtc->base + RZN1_RTC_DAYC);
+ tm->tm_mon = readl(rtc->base + RZN1_RTC_MONTHC);
+ tm->tm_year = readl(rtc->base + RZN1_RTC_YEARC);
+}
+
+static unsigned int rzn1_rtc_tm_to_wday(struct rtc_time *tm)
+{
+ time64_t time;
+ unsigned int days;
+ u32 secs;
+
+ time = rtc_tm_to_time64(tm);
+ days = div_s64_rem(time, 86400, &secs);
+
+ /* day of the week, 1970-01-01 was a Thursday */
+ return (days + 4) % 7;
+}
+
+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 != secs)
+ rzn1_rtc_get_time_snapshot(rtc, tm);
+
+ tm->tm_sec = bcd2bin(tm->tm_sec);
+ tm->tm_min = bcd2bin(tm->tm_min);
+ tm->tm_hour = bcd2bin(tm->tm_hour);
+ tm->tm_wday = bcd2bin(tm->tm_wday);
+ tm->tm_mday = bcd2bin(tm->tm_mday);
+ tm->tm_mon = bcd2bin(tm->tm_mon);
+ tm->tm_year = bcd2bin(tm->tm_year);
+
+ 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;
+
+ tm->tm_sec = bin2bcd(tm->tm_sec);
+ tm->tm_min = bin2bcd(tm->tm_min);
+ tm->tm_hour = bin2bcd(tm->tm_hour);
+ tm->tm_wday = bin2bcd(rzn1_rtc_tm_to_wday(tm));
+ tm->tm_mday = bin2bcd(tm->tm_mday);
+ tm->tm_mon = bin2bcd(tm->tm_mon);
+ tm->tm_year = bin2bcd(tm->tm_year);
+
+ 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;
+ }
+
+ writel(tm->tm_sec, rtc->base + RZN1_RTC_SEC);
+ writel(tm->tm_min, rtc->base + RZN1_RTC_MIN);
+ writel(tm->tm_hour, rtc->base + RZN1_RTC_HOUR);
+ writel(tm->tm_wday, rtc->base + RZN1_RTC_WEEK);
+ writel(tm->tm_mday, rtc->base + RZN1_RTC_DAY);
+ writel(tm->tm_mon, rtc->base + RZN1_RTC_MONTH);
+ writel(tm->tm_year, rtc->base + RZN1_RTC_YEAR);
+ 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;
+
+ 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);
+ u32 ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
+
+ if (enable)
+ ctl1 |= RZN1_RTC_CTL1_ALME;
+ else
+ ctl1 &= ~RZN1_RTC_CTL1_ALME;
+
+ 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);
+
+ 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) + (7 * 86400);
+ 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);
+
+ 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 = {
+ .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 int rzn1_rtc_probe(struct platform_device *pdev)
+{
+ struct rzn1_rtc *rtc;
+ int alarm_irq;
+ int 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");
+
+ alarm_irq = platform_get_irq(pdev, 0);
+ if (alarm_irq < 0)
+ return alarm_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->ops = &rzn1_rtc_ops;
+ set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtcdev->features);
+ clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
+
+ devm_pm_runtime_enable(&pdev->dev);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Ensure the clock counter is enabled.
+ * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
+ */
+ writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
+ rtc->base + RZN1_RTC_CTL0);
+
+ /* Disable all interrupts */
+ writel(0, rtc->base + RZN1_RTC_CTL1);
+
+ ret = devm_request_irq(&pdev->dev, alarm_irq, rzn1_rtc_alarm_irq, 0,
+ dev_name(&pdev->dev), rtc);
+ if (ret) {
+ dev_err(&pdev->dev, "RTC timer interrupt not available\n");
+ goto dis_runtime_pm;
+ }
+
+ 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 int rzn1_rtc_remove(struct platform_device *pdev)
+{
+ pm_runtime_put(&pdev->dev);
+
+ return 0;
+}
+
+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 <Michel.Pollet@bp.renesas.com");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
+MODULE_DESCRIPTION("RZ/N1 RTC driver");
+MODULE_LICENSE("GPL");
git.samba.org / sfrench / cifs-2.6.git / commitdiff