[PATCH v2 2/2] ARM: sun4i/sun7i: RTC driver
Carlo Caione
carlo.caione at gmail.com
Wed Oct 16 14:30:27 EDT 2013
This patch introduces the driver for the RTC in the Allwinner A10 and
A20 SoCs.
Signed-off-by: Carlo Caione <carlo.caione at gmail.com>
---
v1->v2:
- Patch split in two
- Fix coding style
- New driver description
- Rework macros
- Add comments
- Change while in for cycles
---
drivers/rtc/Kconfig | 7 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-sunxi.c | 487 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 495 insertions(+)
create mode 100644 drivers/rtc/rtc-sunxi.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 9654aa3..ef45e0b 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1076,6 +1076,13 @@ config RTC_DRV_SUN4V
If you say Y here you will get support for the Hypervisor
based RTC on SUN4V systems.
+config RTC_DRV_SUNXI
+ tristate "Allwinner sun4i/sun7i RTC"
+ depends on ARCH_SUNXI
+ help
+ If you say Y here you will get support for the RTC found on
+ Allwinner A10/A20.
+
config RTC_DRV_STARFIRE
bool "Starfire RTC"
depends on SPARC64
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 2dff3d2..8b52b5a 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -115,6 +115,7 @@ 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-$(CONFIG_RTC_DRV_SUNXI) += rtc-sunxi.o
obj-$(CONFIG_RTC_DRV_TEGRA) += rtc-tegra.o
obj-$(CONFIG_RTC_DRV_TEST) += rtc-test.o
obj-$(CONFIG_RTC_DRV_TILE) += rtc-tile.o
diff --git a/drivers/rtc/rtc-sunxi.c b/drivers/rtc/rtc-sunxi.c
new file mode 100644
index 0000000..ccd48ae
--- /dev/null
+++ b/drivers/rtc/rtc-sunxi.c
@@ -0,0 +1,487 @@
+/*
+ * An RTC driver for Allwinner A10/A20
+ *
+ * Copyright (c) 2013, Carlo Caione <carlo.caione at 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#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>
+
+#define SUNXI_LOSC_CTRL 0x0000
+#define SUNXI_LOSC_CTRL_RTC_HMS_ACC BIT(8)
+#define SUNXI_LOSC_CTRL_RTC_YMD_ACC BIT(7)
+
+#define SUNXI_RTC_YMD 0x0004
+
+#define SUNXI_RTC_HMS 0x0008
+
+#define SUNXI_ALRM_DHMS 0x000c
+
+#define SUNXI_ALRM_EN 0x0014
+#define SUNXI_ALRM_EN_CNT_EN BIT(8)
+
+#define SUNXI_ALRM_IRQ_EN 0x0018
+#define SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN BIT(0)
+
+#define SUNXI_ALRM_IRQ_STA 0x001c
+#define SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND BIT(0)
+
+#define SUNXI_LOSC_CTRL_RTC_ACC \
+ (SUNXI_LOSC_CTRL_RTC_HMS_ACC | SUNXI_LOSC_CTRL_RTC_YMD_ACC)
+
+#define SUNXI_MASK_DH 0x0000001f
+#define SUNXI_MASK_SM 0x0000003f
+#define SUNXI_MASK_M 0x0000000f
+#define SUNXI_MASK_LY 0x00000001
+#define SUNXI_MASK_D 0x00000ffe
+#define SUNXI_MASK_M 0x0000000f
+
+#define SUNXI_GET(x, mask, shift) (((x) & ((mask) << (shift))) \
+ >> (shift))
+
+#define SUNXI_SET(x, mask, shift) (((x) & (mask)) << (shift))
+
+/* Get date values */
+#define SUNXI_DATE_GET_DAY_VALUE(x) SUNXI_GET(x, SUNXI_MASK_DH, 0)
+#define SUNXI_DATE_GET_MON_VALUE(x) SUNXI_GET(x, SUNXI_MASK_M, 8)
+#define SUNXI_DATE_GET_YEAR_VALUE(x, mask) SUNXI_GET(x, mask, 16)
+
+/* Get time values */
+#define SUNXI_TIME_GET_SEC_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 0)
+#define SUNXI_TIME_GET_MIN_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 8)
+#define SUNXI_TIME_GET_HOUR_VALUE(x) SUNXI_GET(x, SUNXI_MASK_DH, 16)
+
+/* Get alarm values */
+#define SUNXI_ALRM_GET_SEC_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 0)
+#define SUNXI_ALRM_GET_MIN_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 8)
+#define SUNXI_ALRM_GET_HOUR_VALUE(x) SUNXI_GET(x, SUNXI_MASK_DH, 16)
+
+/* Set date values */
+#define SUNXI_DATE_SET_DAY_VALUE(x) SUNXI_DATE_GET_DAY_VALUE(x)
+#define SUNXI_DATE_SET_MON_VALUE(x) SUNXI_SET(x, SUNXI_MASK_M, 8)
+#define SUNXI_DATE_SET_YEAR_VALUE(x, mask) SUNXI_SET(x, mask, 16)
+#define SUNXI_LEAP_SET_VALUE(x, shift) SUNXI_SET(x, SUNXI_MASK_LY, shift)
+
+/* Set time values */
+#define SUNXI_TIME_SET_SEC_VALUE(x) SUNXI_TIME_GET_SEC_VALUE(x)
+#define SUNXI_TIME_SET_MIN_VALUE(x) SUNXI_SET(x, SUNXI_MASK_SM, 8)
+#define SUNXI_TIME_SET_HOUR_VALUE(x) SUNXI_SET(x, SUNXI_MASK_DH, 16)
+
+/* set alarm values */
+#define SUNXI_ALRM_SET_SEC_VALUE(x) SUNXI_ALRM_GET_SEC_VALUE(x)
+#define SUNXI_ALRM_SET_MIN_VALUE(x) SUNXI_SET(x, SUNXI_MASK_SM, 8)
+#define SUNXI_ALRM_SET_HOUR_VALUE(x) SUNXI_SET(x, SUNXI_MASK_DH, 16)
+#define SUNXI_ALRM_SET_DAY_VALUE(x) SUNXI_SET(x, SUNXI_MASK_D, 21)
+
+/* time unit conversions */
+#define SEC_IN_MIN 60
+#define SEC_IN_HOUR (60 * SEC_IN_MIN)
+#define SEC_IN_DAY (24 * SEC_IN_HOUR)
+
+struct sunxi_rtc_data_year {
+ unsigned int min; /* min year allowed */
+ unsigned int max; /* max year allowed */
+ unsigned int off; /* data year offset */
+ unsigned int mask;
+ unsigned char leap_shift; /* bit shift to get the leap year */
+};
+
+static struct sunxi_rtc_data_year data_year_param[] = {
+ [0] = {
+ .min = 1970,
+ .max = 2100,
+ .off = 0,
+ .mask = 0x000000ff,
+ .leap_shift = 24,
+ },
+ [1] = {
+ .min = 2010,
+ .max = 2073,
+ .off = 110,
+ .mask = 0x0000003f,
+ .leap_shift = 22,
+ },
+};
+
+struct sunxi_rtc_dev {
+ struct rtc_device *rtc;
+ struct device *dev;
+ struct sunxi_rtc_data_year *data_year;
+ void __iomem *base;
+ int irq;
+};
+
+static irqreturn_t sunxi_rtc_alarmirq(int irq, void *id)
+{
+ struct sunxi_rtc_dev *chip = (struct sunxi_rtc_dev *) id;
+ u32 val;
+
+ val = readl(chip->base + SUNXI_ALRM_IRQ_STA);
+
+ if (val & SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND) {
+ val |= SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND;
+ writel(val, chip->base + SUNXI_ALRM_IRQ_STA);
+
+ rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
+
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static void sunxi_rtc_setaie(int to, struct sunxi_rtc_dev *chip)
+{
+ u32 alarm_val = 0;
+ u32 alarm_irq_val = 0;
+
+ if (to) {
+ alarm_val = readl(chip->base + SUNXI_ALRM_EN);
+ alarm_val |= SUNXI_ALRM_EN_CNT_EN;
+
+ alarm_irq_val = readl(chip->base + SUNXI_ALRM_IRQ_EN);
+ alarm_irq_val |= SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN;
+ } else {
+ writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND,
+ chip->base + SUNXI_ALRM_IRQ_STA);
+ }
+
+ writel(alarm_val, chip->base + SUNXI_ALRM_EN);
+ writel(alarm_irq_val, chip->base + SUNXI_ALRM_IRQ_EN);
+}
+
+static int sunxi_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
+ struct rtc_time *alrm_tm = &alrm->time;
+ u32 alarm;
+ u32 alarm_en;
+ u32 date;
+
+ alarm = readl(chip->base + SUNXI_ALRM_DHMS);
+ date = readl(chip->base + SUNXI_RTC_YMD);
+
+ alrm_tm->tm_sec = SUNXI_ALRM_GET_SEC_VALUE(alarm);
+ alrm_tm->tm_min = SUNXI_ALRM_GET_MIN_VALUE(alarm);
+ alrm_tm->tm_hour = SUNXI_ALRM_GET_HOUR_VALUE(alarm);
+
+ alrm_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
+ alrm_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
+ alrm_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
+ chip->data_year->mask);
+
+ alrm_tm->tm_year += chip->data_year->off;
+ alrm_tm->tm_mon -= 1;
+
+ alarm_en = readl(chip->base + SUNXI_ALRM_IRQ_EN);
+ if (alarm_en & SUNXI_ALRM_EN_CNT_EN)
+ alrm->enabled = 1;
+
+ return 0;
+}
+
+static int sunxi_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
+{
+ struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
+ u32 date, time;
+ int t;
+
+ /* read again if the system was mid-updated
+ */
+ for (t = 0; t < 2; t++) {
+ date = readl(chip->base + SUNXI_RTC_YMD);
+ time = readl(chip->base + SUNXI_RTC_HMS);
+
+ rtc_tm->tm_sec = SUNXI_TIME_GET_SEC_VALUE(time);
+ rtc_tm->tm_min = SUNXI_TIME_GET_MIN_VALUE(time);
+ rtc_tm->tm_hour = SUNXI_TIME_GET_HOUR_VALUE(time);
+
+ rtc_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
+ rtc_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
+ rtc_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
+ chip->data_year->mask);
+
+ if (rtc_tm->tm_sec == 0)
+ msleep(500);
+ else
+ break;
+ }
+
+ rtc_tm->tm_year += chip->data_year->off;
+ rtc_tm->tm_mon -= 1;
+
+ return rtc_valid_tm(rtc_tm);
+}
+
+static int sunxi_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
+ struct rtc_time *alrm_tm = &alrm->time;
+ struct rtc_time tm_now;
+ u32 alarm = 0;
+ unsigned long time_now = 0;
+ unsigned long time_set = 0;
+ unsigned long time_gap = 0;
+ unsigned long time_gap_day = 0;
+ unsigned long time_gap_hour = 0;
+ unsigned long time_gap_min = 0;
+ int ret = 0;
+
+ ret = sunxi_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;
+ time_gap_day = time_gap / SEC_IN_DAY;
+ time_gap -= time_gap_day * SEC_IN_DAY;
+ time_gap_hour = time_gap / SEC_IN_HOUR;
+ time_gap -= time_gap_hour * SEC_IN_HOUR;
+ time_gap_min = time_gap / SEC_IN_MIN;
+ time_gap -= time_gap_min * SEC_IN_MIN;
+
+ if (time_gap_day > 255) {
+ dev_err(dev, "Day must be in the range 0 - 255\n");
+ return -EINVAL;
+ }
+
+ sunxi_rtc_setaie(0, chip);
+ writel(0, chip->base + SUNXI_ALRM_DHMS);
+ usleep_range(100, 300);
+
+ alarm = SUNXI_ALRM_SET_SEC_VALUE(time_gap) |
+ SUNXI_ALRM_SET_MIN_VALUE(time_gap_min) |
+ SUNXI_ALRM_SET_HOUR_VALUE(time_gap_hour) |
+ SUNXI_ALRM_SET_DAY_VALUE(time_gap_day);
+ writel(alarm, chip->base + SUNXI_ALRM_DHMS);
+
+ writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
+ writel(SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN, chip->base + SUNXI_ALRM_IRQ_EN);
+
+ sunxi_rtc_setaie(alrm->enabled, chip);
+
+ return 0;
+}
+
+static int sunxi_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
+{
+ struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
+ u32 date = 0;
+ u32 time = 0;
+ int year;
+ int t;
+
+ year = rtc_tm->tm_year + 1900;
+ if (year < chip->data_year->min || year > chip->data_year->max) {
+ dev_err(dev, "rtc only supports year in range %d - %d\n",
+ chip->data_year->min, chip->data_year->max);
+ return -EINVAL;
+ }
+
+ rtc_tm->tm_year -= chip->data_year->off;
+ rtc_tm->tm_mon += 1;
+
+ date = SUNXI_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
+ SUNXI_DATE_SET_MON_VALUE(rtc_tm->tm_mon) |
+ SUNXI_DATE_SET_YEAR_VALUE(rtc_tm->tm_year,
+ chip->data_year->mask);
+
+ if (is_leap_year(year))
+ date |= SUNXI_LEAP_SET_VALUE(1, chip->data_year->leap_shift);
+
+ time = SUNXI_TIME_SET_SEC_VALUE(rtc_tm->tm_sec) |
+ SUNXI_TIME_SET_MIN_VALUE(rtc_tm->tm_min) |
+ SUNXI_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
+
+ writel(0, chip->base + SUNXI_RTC_HMS);
+ writel(0, chip->base + SUNXI_RTC_YMD);
+
+ writel(time, chip->base + SUNXI_RTC_HMS);
+
+ /* After writing the RCT HH-MM-SS register, the
+ * SUNXI_LOSC_CTRL_RTC_HMS_ACC bit is set and it will be cleared until
+ * the real writing operation is finished
+ */
+ for (t = 0; t < 3; t++) {
+ if ((readl(chip->base + SUNXI_LOSC_CTRL) &
+ SUNXI_LOSC_CTRL_RTC_HMS_ACC) && --t)
+ break;
+ else
+ msleep(50);
+ }
+ if (t == 0) {
+ dev_err(dev, "Failed to set rtc time.\n");
+ return -1;
+ }
+
+ writel(date, chip->base + SUNXI_RTC_YMD);
+
+ /* After writing the RCT YY-MM-DD register, the
+ * SUNXI_LOSC_CTRL_RTC_YMD_ACC bit is set and it will be cleared until
+ * the real writing operation is finished
+ */
+ for (t = 0; t < 3; t++) {
+ if ((readl(chip->base + SUNXI_LOSC_CTRL) &
+ SUNXI_LOSC_CTRL_RTC_YMD_ACC) && --t)
+ break;
+ else
+ msleep(50);
+ }
+ if (t == 0) {
+ dev_err(dev, "Failed to set rtc date.\n");
+ return -1;
+ }
+
+ /* wait about 70us to make sure the the time is really written into
+ * target */
+ usleep_range(70, 100);
+
+ return 0;
+}
+
+static int sunxi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
+
+ if (!enabled)
+ sunxi_rtc_setaie(enabled, chip);
+
+ return 0;
+}
+
+static const struct rtc_class_ops sunxi_rtc_ops = {
+ .read_time = sunxi_rtc_gettime,
+ .set_time = sunxi_rtc_settime,
+ .read_alarm = sunxi_rtc_getalarm,
+ .set_alarm = sunxi_rtc_setalarm,
+ .alarm_irq_enable = sunxi_rtc_alarm_irq_enable
+};
+
+static const struct of_device_id sunxi_rtc_dt_ids[] = {
+ { .compatible = "allwinner,sun4i-rtc", .data = &data_year_param[0] },
+ { .compatible = "allwinner,sun7i-a20-rtc", .data = &data_year_param[1] },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);
+
+
+static int sunxi_rtc_probe(struct platform_device *pdev)
+{
+ struct sunxi_rtc_dev *chip;
+ struct resource *res;
+ const struct of_device_id *of_id;
+ 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, sunxi_rtc_alarmirq,
+ 0, dev_name(&pdev->dev), chip);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not request IRQ\n");
+ return ret;
+ }
+
+ of_id = of_match_device(sunxi_rtc_dt_ids, &pdev->dev);
+ if (!of_id) {
+ dev_err(&pdev->dev, "Unable to setup RTC data\n");
+ return -ENODEV;
+ }
+ chip->data_year = (struct sunxi_rtc_data_year *) of_id->data;
+
+ /* clear the alarm count value */
+ writel(0, chip->base + SUNXI_ALRM_DHMS);
+
+ /* disable alarm, not generate irq pending */
+ writel(0, chip->base + SUNXI_ALRM_EN);
+
+ /* disable alarm week/cnt irq, unset to cpu */
+ writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
+
+ /* clear alarm week/cnt irq pending */
+ writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base + SUNXI_ALRM_IRQ_STA);
+
+ chip->rtc = rtc_device_register("rtc-sunxi", &pdev->dev,
+ &sunxi_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 sunxi_rtc_remove(struct platform_device *pdev)
+{
+ struct sunxi_rtc_dev *chip = platform_get_drvdata(pdev);
+
+ rtc_device_unregister(chip->rtc);
+
+ return 0;
+}
+
+static struct platform_driver sunxi_rtc_driver = {
+ .probe = sunxi_rtc_probe,
+ .remove = sunxi_rtc_remove,
+ .driver = {
+ .name = "sunxi-rtc",
+ .owner = THIS_MODULE,
+ .of_match_table = sunxi_rtc_dt_ids,
+ },
+};
+
+module_platform_driver(sunxi_rtc_driver);
+
+MODULE_DESCRIPTION("sunxi RTC driver");
+MODULE_AUTHOR("Carlo Caione <carlo.caione at gmail.com>");
+MODULE_LICENSE("GPL");
--
1.8.4.1
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