[PATCH resend v5 1/2] rtc: sun6i: Add sun6i RTC driver

From: Chen-Yu Tsai
Date: Mon Aug 25 2014 - 23:55:30 EST

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@xxxxxxxx>
Reviewed-by: Varka Bhadram <varkabhadram@xxxxxxxxx>
Acked-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
.../devicetree/bindings/rtc/sun6i-rtc.txt | 17 +
drivers/rtc/Kconfig | 7 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-sun6i.c | 447 +++++++++++++++++++++
4 files changed, 472 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
create mode 100644 drivers/rtc/rtc-sun6i.c

diff --git a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
new file mode 100644
index 0000000..f007e42
--- /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 a168e96..f2300b4 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 56f061c..9055b7d 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 0000000..c169a2c
--- /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@xxxxxxxx>
+ *
+ * based on rtc-sunxi.c
+ *
+ * An RTC driver for Allwinner A10/A20
+ *
+ * Copyright (c) 2013, Carlo Caione <carlo.caione@xxxxxxxxx>
+ *
+ * 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@xxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.1.0

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