4 files changed, 472 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
new file mode 100644
index 000000000000..f007e428a1ab
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
@@ -0,0 +1,17 @@
+* sun6i Real Time Clock
+
+RTC controller for the Allwinner A31
+
+Required properties:
+- compatible    : Should be "allwinner,sun6i-a31-rtc"
+- reg           : physical base address of the controller and length of
+                  memory mapped region.
+- interrupts    : IRQ lines for the RTC alarm 0 and alarm 1, in that order.
+
+Example:
+
+rtc: rtc@01f00000 {
+        compatible = "allwinner,sun6i-a31-rtc";
+        reg = <0x01f00000 0x54>;
+        interrupts = <0 40 4>, <0 41 4>;
+};
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index a168e96142b9..f2300b4e9b17 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1175,6 +1175,13 @@ config RTC_DRV_SUN4V
           If you say Y here you will get support for the Hypervisor
           based RTC on SUN4V systems.
 
+config RTC_DRV_SUN6I
+        tristate "Allwinner A31 RTC"
+        depends on MACH_SUN6I || MACH_SUN8I
+        help
+          If you say Y here you will get support for the RTC found on
+          Allwinner A31.
+
 config RTC_DRV_SUNXI
         tristate "Allwinner sun4i/sun7i RTC"
         depends on ARCH_SUNXI
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 56f061c7c815..9055b7dd3dc5 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -128,6 +128,7 @@ obj-$(CONFIG_RTC_DRV_STARFIRE)	+= rtc-starfire.o
 obj-$(CONFIG_RTC_DRV_STK17TA8)  += rtc-stk17ta8.o
 obj-$(CONFIG_RTC_DRV_STMP)      += rtc-stmp3xxx.o
 obj-$(CONFIG_RTC_DRV_SUN4V)     += rtc-sun4v.o
+obj-$(CONFIG_RTC_DRV_SUN6I)     += rtc-sun6i.o
 obj-$(CONFIG_RTC_DRV_SUNXI)     += rtc-sunxi.o
 obj-$(CONFIG_RTC_DRV_TEGRA)     += rtc-tegra.o
 obj-$(CONFIG_RTC_DRV_TEST)      += rtc-test.o
diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
new file mode 100644
index 000000000000..c169a2cd4727
--- /dev/null
+++ b/drivers/rtc/rtc-sun6i.c
@@ -0,0 +1,447 @@
+/*
+ * An RTC driver for Allwinner A31/A23
+ *
+ * Copyright (c) 2014, Chen-Yu Tsai <wens@csie.org>
+ *
+ * based on rtc-sunxi.c
+ *
+ * An RTC driver for Allwinner A10/A20
+ *
+ * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+
+/* Control register */
+#define SUN6I_LOSC_CTRL                         0x0000
+#define SUN6I_LOSC_CTRL_ALM_DHMS_ACC            BIT(9)
+#define SUN6I_LOSC_CTRL_RTC_HMS_ACC             BIT(8)
+#define SUN6I_LOSC_CTRL_RTC_YMD_ACC             BIT(7)
+#define SUN6I_LOSC_CTRL_ACC_MASK                GENMASK(9, 7)
+
+/* RTC */
+#define SUN6I_RTC_YMD                           0x0010
+#define SUN6I_RTC_HMS                           0x0014
+
+/* Alarm 0 (counter) */
+#define SUN6I_ALRM_COUNTER                      0x0020
+#define SUN6I_ALRM_CUR_VAL                      0x0024
+#define SUN6I_ALRM_EN                           0x0028
+#define SUN6I_ALRM_EN_CNT_EN                    BIT(0)
+#define SUN6I_ALRM_IRQ_EN                       0x002c
+#define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN            BIT(0)
+#define SUN6I_ALRM_IRQ_STA                      0x0030
+#define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND         BIT(0)
+
+/* Alarm 1 (wall clock) */
+#define SUN6I_ALRM1_EN                          0x0044
+#define SUN6I_ALRM1_IRQ_EN                      0x0048
+#define SUN6I_ALRM1_IRQ_STA                     0x004c
+#define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND       BIT(0)
+
+/* Alarm config */
+#define SUN6I_ALARM_CONFIG                      0x0050
+#define SUN6I_ALARM_CONFIG_WAKEUP               BIT(0)
+
+/*
+ * Get date values
+ */
+#define SUN6I_DATE_GET_DAY_VALUE(x)             ((x)  & 0x0000001f)
+#define SUN6I_DATE_GET_MON_VALUE(x)             (((x) & 0x00000f00) >> 8)
+#define SUN6I_DATE_GET_YEAR_VALUE(x)            (((x) & 0x003f0000) >> 16)
+#define SUN6I_LEAP_GET_VALUE(x)                 (((x) & 0x00400000) >> 22)
+
+/*
+ * Get time values
+ */
+#define SUN6I_TIME_GET_SEC_VALUE(x)             ((x)  & 0x0000003f)
+#define SUN6I_TIME_GET_MIN_VALUE(x)             (((x) & 0x00003f00) >> 8)
+#define SUN6I_TIME_GET_HOUR_VALUE(x)            (((x) & 0x001f0000) >> 16)
+
+/*
+ * Set date values
+ */
+#define SUN6I_DATE_SET_DAY_VALUE(x)             ((x)       & 0x0000001f)
+#define SUN6I_DATE_SET_MON_VALUE(x)             ((x) <<  8 & 0x00000f00)
+#define SUN6I_DATE_SET_YEAR_VALUE(x)            ((x) << 16 & 0x003f0000)
+#define SUN6I_LEAP_SET_VALUE(x)                 ((x) << 22 & 0x00400000)
+
+/*
+ * Set time values
+ */
+#define SUN6I_TIME_SET_SEC_VALUE(x)             ((x)       & 0x0000003f)
+#define SUN6I_TIME_SET_MIN_VALUE(x)             ((x) <<  8 & 0x00003f00)
+#define SUN6I_TIME_SET_HOUR_VALUE(x)            ((x) << 16 & 0x001f0000)
+
+/*
+ * The year parameter passed to the driver is usually an offset relative to
+ * the year 1900. This macro is used to convert this offset to another one
+ * relative to the minimum year allowed by the hardware.
+ *
+ * The year range is 1970 - 2033. This range is selected to match Allwinner's
+ * driver, even though it is somewhat limited.
+ */
+#define SUN6I_YEAR_MIN                          1970
+#define SUN6I_YEAR_MAX                          2033
+#define SUN6I_YEAR_OFF                          (SUN6I_YEAR_MIN - 1900)
+
+struct sun6i_rtc_dev {
+        struct rtc_device *rtc;
+        struct device *dev;
+        void __iomem *base;
+        int irq;
+        unsigned long alarm;
+};
+
+static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
+{
+        struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
+        u32 val;
+
+        val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
+
+        if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
+                val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
+                writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
+
+                rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
+
+                return IRQ_HANDLED;
+        }
+
+        return IRQ_NONE;
+}
+
+static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
+{
+        u32 alrm_val = 0;
+        u32 alrm_irq_val = 0;
+        u32 alrm_wake_val = 0;
+
+        if (to) {
+                alrm_val = SUN6I_ALRM_EN_CNT_EN;
+                alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
+                alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
+        } else {
+                writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
+                       chip->base + SUN6I_ALRM_IRQ_STA);
+        }
+
+        writel(alrm_val, chip->base + SUN6I_ALRM_EN);
+        writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
+        writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
+}
+
+static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
+{
+        struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+        u32 date, time;
+
+        /*
+         * read again in case it changes
+         */
+        do {
+                date = readl(chip->base + SUN6I_RTC_YMD);
+                time = readl(chip->base + SUN6I_RTC_HMS);
+        } while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
+                 (time != readl(chip->base + SUN6I_RTC_HMS)));
+
+        rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
+        rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
+        rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
+
+        rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
+        rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
+        rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
+
+        rtc_tm->tm_mon  -= 1;
+
+        /*
+         * switch from (data_year->min)-relative offset to
+         * a (1900)-relative one
+         */
+        rtc_tm->tm_year += SUN6I_YEAR_OFF;
+
+        return rtc_valid_tm(rtc_tm);
+}
+
+static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+        struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+        u32 alrm_st;
+        u32 alrm_en;
+
+        alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
+        alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
+        wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
+        wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
+        rtc_time_to_tm(chip->alarm, &wkalrm->time);
+
+        return 0;
+}
+
+static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+        struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+        struct rtc_time *alrm_tm = &wkalrm->time;
+        struct rtc_time tm_now;
+        unsigned long time_now = 0;
+        unsigned long time_set = 0;
+        unsigned long time_gap = 0;
+        int ret = 0;
+
+        ret = sun6i_rtc_gettime(dev, &tm_now);
+        if (ret < 0) {
+                dev_err(dev, "Error in getting time\n");
+                return -EINVAL;
+        }
+
+        rtc_tm_to_time(alrm_tm, &time_set);
+        rtc_tm_to_time(&tm_now, &time_now);
+        if (time_set <= time_now) {
+                dev_err(dev, "Date to set in the past\n");
+                return -EINVAL;
+        }
+
+        time_gap = time_set - time_now;
+
+        if (time_gap > U32_MAX) {
+                dev_err(dev, "Date too far in the future\n");
+                return -EINVAL;
+        }
+
+        sun6i_rtc_setaie(0, chip);
+        writel(0, chip->base + SUN6I_ALRM_COUNTER);
+        usleep_range(100, 300);
+
+        writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
+        chip->alarm = time_set;
+
+        sun6i_rtc_setaie(wkalrm->enabled, chip);
+
+        return 0;
+}
+
+static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
+                          unsigned int mask, unsigned int ms_timeout)
+{
+        const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
+        u32 reg;
+
+        do {
+                reg = readl(chip->base + offset);
+                reg &= mask;
+
+                if (!reg)
+                        return 0;
+
+        } while (time_before(jiffies, timeout));
+
+        return -ETIMEDOUT;
+}
+
+static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
+{
+        struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+        u32 date = 0;
+        u32 time = 0;
+        int year;
+
+        year = rtc_tm->tm_year + 1900;
+        if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
+                dev_err(dev, "rtc only supports year in range %d - %d\n",
+                        SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
+                return -EINVAL;
+        }
+
+        rtc_tm->tm_year -= SUN6I_YEAR_OFF;
+        rtc_tm->tm_mon += 1;
+
+        date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
+                SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
+                SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
+
+        if (is_leap_year(year))
+                date |= SUN6I_LEAP_SET_VALUE(1);
+
+        time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
+                SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
+                SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
+
+        /* Check whether registers are writable */
+        if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
+                           SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
+                dev_err(dev, "rtc is still busy.\n");
+                return -EBUSY;
+        }
+
+        writel(time, chip->base + SUN6I_RTC_HMS);
+
+        /*
+         * After writing the RTC HH-MM-SS register, the
+         * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
+         * be cleared until the real writing operation is finished
+         */
+
+        if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
+                           SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
+                dev_err(dev, "Failed to set rtc time.\n");
+                return -ETIMEDOUT;
+        }
+
+        writel(date, chip->base + SUN6I_RTC_YMD);
+
+        /*
+         * After writing the RTC YY-MM-DD register, the
+         * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
+         * be cleared until the real writing operation is finished
+         */
+
+        if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
+                           SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
+                dev_err(dev, "Failed to set rtc time.\n");
+                return -ETIMEDOUT;
+        }
+
+        return 0;
+}
+
+static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+        struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+
+        if (!enabled)
+                sun6i_rtc_setaie(enabled, chip);
+
+        return 0;
+}
+
+static const struct rtc_class_ops sun6i_rtc_ops = {
+        .read_time              = sun6i_rtc_gettime,
+        .set_time               = sun6i_rtc_settime,
+        .read_alarm             = sun6i_rtc_getalarm,
+        .set_alarm              = sun6i_rtc_setalarm,
+        .alarm_irq_enable       = sun6i_rtc_alarm_irq_enable
+};
+
+static int sun6i_rtc_probe(struct platform_device *pdev)
+{
+        struct sun6i_rtc_dev *chip;
+        struct resource *res;
+        int ret;
+
+        chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+        if (!chip)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, chip);
+        chip->dev = &pdev->dev;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        chip->base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(chip->base))
+                return PTR_ERR(chip->base);
+
+        chip->irq = platform_get_irq(pdev, 0);
+        if (chip->irq < 0) {
+                dev_err(&pdev->dev, "No IRQ resource\n");
+                return chip->irq;
+        }
+
+        ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
+                               0, dev_name(&pdev->dev), chip);
+        if (ret) {
+                dev_err(&pdev->dev, "Could not request IRQ\n");
+                return ret;
+        }
+
+        /* clear the alarm counter value */
+        writel(0, chip->base + SUN6I_ALRM_COUNTER);
+
+        /* disable counter alarm */
+        writel(0, chip->base + SUN6I_ALRM_EN);
+
+        /* disable counter alarm interrupt */
+        writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
+
+        /* disable week alarm */
+        writel(0, chip->base + SUN6I_ALRM1_EN);
+
+        /* disable week alarm interrupt */
+        writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
+
+        /* clear counter alarm pending interrupts */
+        writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
+               chip->base + SUN6I_ALRM_IRQ_STA);
+
+        /* clear week alarm pending interrupts */
+        writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
+               chip->base + SUN6I_ALRM1_IRQ_STA);
+
+        /* disable alarm wakeup */
+        writel(0, chip->base + SUN6I_ALARM_CONFIG);
+
+        chip->rtc = rtc_device_register("rtc-sun6i", &pdev->dev,
+                                        &sun6i_rtc_ops, THIS_MODULE);
+        if (IS_ERR(chip->rtc)) {
+                dev_err(&pdev->dev, "unable to register device\n");
+                return PTR_ERR(chip->rtc);
+        }
+
+        dev_info(&pdev->dev, "RTC enabled\n");
+
+        return 0;
+}
+
+static int sun6i_rtc_remove(struct platform_device *pdev)
+{
+        struct sun6i_rtc_dev *chip = platform_get_drvdata(pdev);
+
+        rtc_device_unregister(chip->rtc);
+
+        return 0;
+}
+
+static const struct of_device_id sun6i_rtc_dt_ids[] = {
+        { .compatible = "allwinner,sun6i-a31-rtc" },
+        { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
+
+static struct platform_driver sun6i_rtc_driver = {
+        .probe          = sun6i_rtc_probe,
+        .remove         = sun6i_rtc_remove,
+        .driver         = {
+                .name           = "sun6i-rtc",
+                .of_match_table = sun6i_rtc_dt_ids,
+        },
+};
+
+module_platform_driver(sun6i_rtc_driver);
+
+MODULE_DESCRIPTION("sun6i RTC driver");
+MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
+MODULE_LICENSE("GPL");