rtc: sun6i: Add sun6i RTC driver
authorChen-Yu Tsai <wens@csie.org>
Tue, 26 Aug 2014 03:54:55 +0000 (11:54 +0800)
committerMaxime Ripard <maxime.ripard@free-electrons.com>
Fri, 19 Sep 2014 10:39:19 +0000 (12:39 +0200)
This patch introduces the driver for the RTC in the Allwinner A31 and
A23 SoCs.

Unlike the RTC found in A10/A20 SoCs, which was part of the timer, the
RTC in A31/A23 are a separate hardware block, which also contain a few
controls for the RTC block hardware (a regulator and RTC block GPIO pin
latches), while also having separate interrupts for the alarms.

The hardware is different enough to make a different driver for it.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Documentation/devicetree/bindings/rtc/sun6i-rtc.txt [new file with mode: 0644]
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-sun6i.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
new file mode 100644 (file)
index 0000000..f007e42
--- /dev/null
@@ -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>;
+};
index a168e96142b95001f5ece9585cfff8a07c1bb489..f2300b4e9b1754b43820dea55949cbff5ffeec50 100644 (file)
@@ -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
index 56f061c7c815b9ad9a8ca1408484beccadf8a549..9055b7dd3dc5b93655088bd83f7911ca678e9d50 100644 (file)
@@ -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 (file)
index 0000000..c169a2c
--- /dev/null
@@ -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");