[PATCH v3 4/8] rtc: ac100: Add RTC driver for X-Powers AC100

Chen-Yu Tsai
2016-06-20T02:52:14Z

X-Powers AC100 is a codec / RTC combo chip. This driver supports
the RTC sub-device.

The RTC block also has clock outputs and non-volatile storage.
Non-volatile storage wthin the RTC hardware is not supported.
Clock output support is added in the next patch.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
Changes since v2:

- Fixed off-by-1 errors in register mask macros
- Fixed copy-paste error in set_alarm function
- Drop uie_unsupported, since the alarm works now
- Fixed up copyright notice
- Changed license to GPL v2, matching mfd driver

---
drivers/rtc/Kconfig | 10 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-ac100.c | 365 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 376 insertions(+)
create mode 100644 drivers/rtc/rtc-ac100.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 18639e0cb6e2..b9d7cbb6bd76 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -183,6 +183,16 @@ config RTC_DRV_ABX80X
This driver can also be built as a module. If so, the module
will be called rtc-abx80x.

+config RTC_DRV_AC100
+ tristate "X-Powers AC100"
+ depends on MFD_AC100
+ help
+ If you say yes here you get support for the real-time clock found
+ in X-Powers AC100 family peripheral ICs.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-ac100.
+
config RTC_DRV_AS3722
tristate "ams AS3722 RTC driver"
depends on MFD_AS3722
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index ea2833723fa9..b07c28779573 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_RTC_DRV_AB3100) += rtc-ab3100.o
obj-$(CONFIG_RTC_DRV_AB8500) += rtc-ab8500.o
obj-$(CONFIG_RTC_DRV_ABB5ZES3) += rtc-ab-b5ze-s3.o
obj-$(CONFIG_RTC_DRV_ABX80X) += rtc-abx80x.o
+obj-$(CONFIG_RTC_DRV_AC100) += rtc-ac100.o
obj-$(CONFIG_RTC_DRV_ARMADA38X) += rtc-armada38x.o
obj-$(CONFIG_RTC_DRV_AS3722) += rtc-as3722.o
obj-$(CONFIG_RTC_DRV_ASM9260) += rtc-asm9260.o
diff --git a/drivers/rtc/rtc-ac100.c b/drivers/rtc/rtc-ac100.c
new file mode 100644
index 000000000000..752bc0771d71
--- /dev/null
+++ b/drivers/rtc/rtc-ac100.c
@@ -0,0 +1,365 @@
+/*
+ * RTC Driver for X-Powers AC100
+ *
+ * Copyright (c) 2016 Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens@csie.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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/bcd.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/ac100.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+
+/* Control register */
+#define AC100_RTC_CTRL_24HOUR BIT(0)
+
+/* RTC */
+#define AC100_RTC_SEC_MASK GENMASK(6, 0)
+#define AC100_RTC_MIN_MASK GENMASK(6, 0)
+#define AC100_RTC_HOU_MASK GENMASK(5, 0)
+#define AC100_RTC_WEE_MASK GENMASK(2, 0)
+#define AC100_RTC_DAY_MASK GENMASK(5, 0)
+#define AC100_RTC_MON_MASK GENMASK(4, 0)
+#define AC100_RTC_YEA_MASK GENMASK(7, 0)
+#define AC100_RTC_YEA_LEAP BIT(15)
+#define AC100_RTC_UPD_TRIGGER BIT(15)
+
+/* Alarm (wall clock) */
+#define AC100_ALM_INT_ENABLE BIT(0)
+
+#define AC100_ALM_SEC_MASK GENMASK(6, 0)
+#define AC100_ALM_MIN_MASK GENMASK(6, 0)
+#define AC100_ALM_HOU_MASK GENMASK(5, 0)
+#define AC100_ALM_WEE_MASK GENMASK(2, 0)
+#define AC100_ALM_DAY_MASK GENMASK(5, 0)
+#define AC100_ALM_MON_MASK GENMASK(4, 0)
+#define AC100_ALM_YEA_MASK GENMASK(7, 0)
+#define AC100_ALM_ENABLE_FLAG BIT(15)
+#define AC100_ALM_UPD_TRIGGER BIT(15)
+
+/*
+ * 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 - 2069. This range is selected to match Allwinner's
+ * driver.
+ */
+#define AC100_YEAR_MIN 1970
+#define AC100_YEAR_MAX 2069
+#define AC100_YEAR_OFF (AC100_YEAR_MIN - 1900)
+
+struct ac100_rtc_dev {
+ struct rtc_device *rtc;
+ struct device *dev;
+ struct regmap *regmap;
+ struct mutex mutex;
+ int irq;
+ unsigned long alarm;
+};
+
+static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)
+{
+ struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
+ struct regmap *regmap = chip->regmap;
+ u16 reg[7];
+ int ret;
+
+ ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);
+ if (ret)
+ return ret;
+
+ rtc_tm->tm_sec = bcd2bin(reg[0] & AC100_RTC_SEC_MASK);
+ rtc_tm->tm_min = bcd2bin(reg[1] & AC100_RTC_MIN_MASK);
+ rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK);
+ rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK);
+ rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK);
+ rtc_tm->tm_mon = bcd2bin(reg[5] & AC100_RTC_MON_MASK);
+ rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK);
+
+ rtc_tm->tm_mon -= 1;
+
+ /*
+ * switch from (data_year->min)-relative offset to
+ * a (1900)-relative one
+ */
+ rtc_tm->tm_year += AC100_YEAR_OFF;
+
+ return rtc_valid_tm(rtc_tm);
+}
+
+static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
+{
+ struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
+ struct regmap *regmap = chip->regmap;
+ int year;
+ u16 reg[8];
+
+ /* our RTC has a limited year range... */
+ year = rtc_tm->tm_year + 1900;
+ if (year < AC100_YEAR_MIN || year > AC100_YEAR_MAX) {
+ dev_err(dev, "rtc only supports year in range %d - %d\n",
+ AC100_YEAR_MIN, AC100_YEAR_MAX);
+ return -EINVAL;
+ }
+
+ /* correct offsets */
+ rtc_tm->tm_year -= AC100_YEAR_OFF;
+ rtc_tm->tm_mon += 1;
+
+ /* convert to BCD */
+ reg[0] = bin2bcd(rtc_tm->tm_sec) & AC100_RTC_SEC_MASK;
+ reg[1] = bin2bcd(rtc_tm->tm_min) & AC100_RTC_MIN_MASK;
+ reg[2] = bin2bcd(rtc_tm->tm_hour) & AC100_RTC_HOU_MASK;
+ reg[3] = bin2bcd(rtc_tm->tm_wday) & AC100_RTC_WEE_MASK;
+ reg[4] = bin2bcd(rtc_tm->tm_mday) & AC100_RTC_DAY_MASK;
+ reg[5] = bin2bcd(rtc_tm->tm_mon) & AC100_RTC_MON_MASK;
+ reg[6] = bin2bcd(rtc_tm->tm_year) & AC100_RTC_YEA_MASK;
+ /* trigger write */
+ reg[7] = AC100_RTC_UPD_TRIGGER;
+
+ /* Is it a leap year? */
+ if (is_leap_year(year))
+ reg[6] |= AC100_RTC_YEA_LEAP;
+
+ return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);
+}
+
+static int _ac100_rtc_alarm_irq_enable(struct ac100_rtc_dev *chip,
+ unsigned int en)
+{
+ struct regmap *regmap = chip->regmap;
+ unsigned int val;
+
+ val = en ? AC100_ALM_INT_ENABLE : 0;
+
+ return regmap_write(regmap, AC100_ALM_INT_ENA, val);
+}
+
+static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
+{
+ struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
+ int ret;
+
+ mutex_lock(&chip->mutex);
+ ret = _ac100_rtc_alarm_irq_enable(chip, en);
+ mutex_unlock(&chip->mutex);
+
+ return ret;
+}
+
+static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
+ struct regmap *regmap = chip->regmap;
+ struct rtc_time *alrm_tm = &alrm->time;
+ u16 reg[7];
+ unsigned int val;
+ int ret;
+
+ mutex_lock(&chip->mutex);
+
+ ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);
+ if (ret)
+ goto out;
+
+ alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);
+
+ ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);
+ if (ret)
+ goto out;
+
+ alrm_tm->tm_sec = bcd2bin(reg[0] & AC100_ALM_SEC_MASK);
+ alrm_tm->tm_min = bcd2bin(reg[1] & AC100_ALM_MIN_MASK);
+ alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK);
+ alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK);
+ alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK);
+ alrm_tm->tm_mon = bcd2bin(reg[5] & AC100_ALM_MON_MASK);
+ alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK);
+
+ alrm_tm->tm_mon -= 1;
+
+ /*
+ * switch from (data_year->min)-relative offset to
+ * a (1900)-relative one
+ */
+ alrm_tm->tm_year += AC100_YEAR_OFF;
+
+out:
+ mutex_unlock(&chip->mutex);
+ return ret;
+}
+
+static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
+ struct regmap *regmap = chip->regmap;
+ struct rtc_time *alrm_tm = &alrm->time;
+ u16 reg[8];
+ int year;
+ int ret;
+
+ /* our alarm has a limited year range... */
+ year = alrm_tm->tm_year + 1900;
+ if (year < AC100_YEAR_MIN || year > AC100_YEAR_MAX) {
+ dev_err(dev, "alarm only supports year in range %d - %d\n",
+ AC100_YEAR_MIN, AC100_YEAR_MAX);
+ return -EINVAL;
+ }
+
+ /* correct offsets */
+ alrm_tm->tm_year -= AC100_YEAR_OFF;
+ alrm_tm->tm_mon += 1;
+
+ /* convert to BCD */
+ reg[0] = (bin2bcd(alrm_tm->tm_sec) & AC100_ALM_SEC_MASK) |
+ AC100_ALM_ENABLE_FLAG;
+ reg[1] = (bin2bcd(alrm_tm->tm_min) & AC100_ALM_MIN_MASK) |
+ AC100_ALM_ENABLE_FLAG;
+ reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) |
+ AC100_ALM_ENABLE_FLAG;
+ /* Do not enable weekday alarm */
+ reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK;
+ reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) |
+ AC100_ALM_ENABLE_FLAG;
+ reg[5] = (bin2bcd(alrm_tm->tm_mon) & AC100_ALM_MON_MASK) |
+ AC100_ALM_ENABLE_FLAG;
+ reg[6] = (bin2bcd(alrm_tm->tm_year) & AC100_ALM_YEA_MASK) |
+ AC100_ALM_ENABLE_FLAG;
+ /* trigger write */
+ reg[7] = AC100_ALM_UPD_TRIGGER;
+
+ mutex_lock(&chip->mutex);
+
+ ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);
+ if (ret)
+ goto out;
+
+ ret = _ac100_rtc_alarm_irq_enable(chip, alrm->enabled);
+
+out:
+ mutex_unlock(&chip->mutex);
+ return ret;
+}
+
+static irqreturn_t ac100_rtc_irq(int irq, void *data)
+{
+ struct ac100_rtc_dev *chip = data;
+ struct regmap *regmap = chip->regmap;
+ unsigned int val = 0;
+ int ret;
+
+ mutex_lock(&chip->mutex);
+
+ /* read status */
+ ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);
+ if (ret)
+ goto out;
+
+ if (val & AC100_ALM_INT_ENABLE) {
+ /* signal rtc framework */
+ rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
+
+ /* clear status */
+ ret = regmap_write(regmap, AC100_ALM_INT_STA, val);
+ if (ret)
+ goto out;
+
+ /* disable interrupt */
+ ret = _ac100_rtc_alarm_irq_enable(chip, 0);
+ if (ret)
+ goto out;
+ }
+
+out:
+ mutex_unlock(&chip->mutex);
+ return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops ac100_rtc_ops = {
+ .read_time = ac100_rtc_get_time,
+ .set_time = ac100_rtc_set_time,
+ .read_alarm = ac100_rtc_get_alarm,
+ .set_alarm = ac100_rtc_set_alarm,
+ .alarm_irq_enable = ac100_rtc_alarm_irq_enable,
+};
+
+static int ac100_rtc_probe(struct platform_device *pdev)
+{
+ struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);
+ struct ac100_rtc_dev *chip;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ platform_set_drvdata(pdev, chip);
+ chip->dev = &pdev->dev;
+ chip->regmap = ac100->regmap;
+ mutex_init(&chip->mutex);
+
+ chip->irq = of_irq_get(pdev->dev.of_node, 0);
+ if (chip->irq < 0) {
+ dev_err(&pdev->dev, "No IRQ resource\n");
+ return chip->irq;
+ }
+
+ ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL,
+ ac100_rtc_irq,
+ IRQF_SHARED | IRQF_ONESHOT,
+ dev_name(&pdev->dev), chip);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not request IRQ\n");
+ return ret;
+ }
+
+ /* always use 24 hour mode */
+ regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,
+ AC100_RTC_CTRL_24HOUR);
+
+ /* disable counter alarm interrupt */
+ regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);
+
+ /* clear counter alarm pending interrupts */
+ regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);
+
+ chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-ac100",
+ &ac100_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 struct platform_driver ac100_rtc_driver = {
+ .probe = ac100_rtc_probe,
+ .driver = {
+ .name = "ac100-rtc",
+ },
+};
+module_platform_driver(ac100_rtc_driver);
+
+MODULE_DESCRIPTION("X-Powers AC100 RTC driver");
+MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
+MODULE_LICENSE("GPL v2");
--
2.8.1