rtc: da9063: RTC driver

Add the RTC driver for DA9063.

[akpm@linux-foundation.org: coding-style tweaks]
Signed-off-by: Opensource [Steve Twiss] <stwiss.opensource@diasemi.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Mark Brown <broonie@linaro.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: David Dajun Chen <david.chen@diasemi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 333 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-da9063.c b/drivers/rtc/rtc-da9063.c
new file mode 100644
index 000000000000..595393098b09
--- /dev/null
+++ b/drivers/rtc/rtc-da9063.c
@@ -0,0 +1,333 @@
+/* rtc-da9063.c - Real time clock device driver for DA9063
+ * Copyright (C) 2013-14  Dialog Semiconductor Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/regmap.h>
+#include <linux/mfd/da9063/registers.h>
+#include <linux/mfd/da9063/core.h>
+
+#define YEARS_TO_DA9063(year)		((year) - 100)
+#define MONTHS_TO_DA9063(month)		((month) + 1)
+#define YEARS_FROM_DA9063(year)		((year) + 100)
+#define MONTHS_FROM_DA9063(month)	((month) - 1)
+
+#define RTC_DATA_LEN	(DA9063_REG_COUNT_Y - DA9063_REG_COUNT_S + 1)
+#define RTC_SEC		0
+#define RTC_MIN		1
+#define RTC_HOUR	2
+#define RTC_DAY		3
+#define RTC_MONTH	4
+#define RTC_YEAR	5
+
+struct da9063_rtc {
+	struct rtc_device	*rtc_dev;
+	struct da9063		*hw;
+	struct rtc_time		alarm_time;
+	bool			rtc_sync;
+};
+
+static void da9063_data_to_tm(u8 *data, struct rtc_time *tm)
+{
+	tm->tm_sec  = data[RTC_SEC]  & DA9063_COUNT_SEC_MASK;
+	tm->tm_min  = data[RTC_MIN]  & DA9063_COUNT_MIN_MASK;
+	tm->tm_hour = data[RTC_HOUR] & DA9063_COUNT_HOUR_MASK;
+	tm->tm_mday = data[RTC_DAY]  & DA9063_COUNT_DAY_MASK;
+	tm->tm_mon  = MONTHS_FROM_DA9063(data[RTC_MONTH] &
+					 DA9063_COUNT_MONTH_MASK);
+	tm->tm_year = YEARS_FROM_DA9063(data[RTC_YEAR] &
+					DA9063_COUNT_YEAR_MASK);
+}
+
+static void da9063_tm_to_data(struct rtc_time *tm, u8 *data)
+{
+	data[RTC_SEC] &= ~DA9063_COUNT_SEC_MASK;
+	data[RTC_SEC] |= tm->tm_sec & DA9063_COUNT_SEC_MASK;
+
+	data[RTC_MIN] &= ~DA9063_COUNT_MIN_MASK;
+	data[RTC_MIN] |= tm->tm_min & DA9063_COUNT_MIN_MASK;
+
+	data[RTC_HOUR] &= ~DA9063_COUNT_HOUR_MASK;
+	data[RTC_HOUR] |= tm->tm_hour & DA9063_COUNT_HOUR_MASK;
+
+	data[RTC_DAY] &= ~DA9063_COUNT_DAY_MASK;
+	data[RTC_DAY] |= tm->tm_mday & DA9063_COUNT_DAY_MASK;
+
+	data[RTC_MONTH] &= ~DA9063_COUNT_MONTH_MASK;
+	data[RTC_MONTH] |= MONTHS_TO_DA9063(tm->tm_mon) &
+				DA9063_COUNT_MONTH_MASK;
+
+	data[RTC_YEAR] &= ~DA9063_COUNT_YEAR_MASK;
+	data[RTC_YEAR] |= YEARS_TO_DA9063(tm->tm_year) &
+				DA9063_COUNT_YEAR_MASK;
+}
+
+static int da9063_rtc_stop_alarm(struct device *dev)
+{
+	struct da9063_rtc *rtc = dev_get_drvdata(dev);
+
+	return regmap_update_bits(rtc->hw->regmap, DA9063_REG_ALARM_Y,
+				  DA9063_ALARM_ON, 0);
+}
+
+static int da9063_rtc_start_alarm(struct device *dev)
+{
+	struct da9063_rtc *rtc = dev_get_drvdata(dev);
+
+	return regmap_update_bits(rtc->hw->regmap, DA9063_REG_ALARM_Y,
+				  DA9063_ALARM_ON, DA9063_ALARM_ON);
+}
+
+static int da9063_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct da9063_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long tm_secs;
+	unsigned long al_secs;
+	u8 data[RTC_DATA_LEN];
+	int ret;
+
+	ret = regmap_bulk_read(rtc->hw->regmap, DA9063_REG_COUNT_S,
+			       data, RTC_DATA_LEN);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read RTC time data: %d\n", ret);
+		return ret;
+	}
+
+	if (!(data[RTC_SEC] & DA9063_RTC_READ)) {
+		dev_dbg(dev, "RTC not yet ready to be read by the host\n");
+		return -EINVAL;
+	}
+
+	da9063_data_to_tm(data, tm);
+
+	rtc_tm_to_time(tm, &tm_secs);
+	rtc_tm_to_time(&rtc->alarm_time, &al_secs);
+
+	/* handle the rtc synchronisation delay */
+	if (rtc->rtc_sync == true && al_secs - tm_secs == 1)
+		memcpy(tm, &rtc->alarm_time, sizeof(struct rtc_time));
+	else
+		rtc->rtc_sync = false;
+
+	return rtc_valid_tm(tm);
+}
+
+static int da9063_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct da9063_rtc *rtc = dev_get_drvdata(dev);
+	u8 data[RTC_DATA_LEN];
+	int ret;
+
+	da9063_tm_to_data(tm, data);
+	ret = regmap_bulk_write(rtc->hw->regmap, DA9063_REG_COUNT_S,
+				data, RTC_DATA_LEN);
+	if (ret < 0)
+		dev_err(dev, "Failed to set RTC time data: %d\n", ret);
+
+	return ret;
+}
+
+static int da9063_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct da9063_rtc *rtc = dev_get_drvdata(dev);
+	u8 data[RTC_DATA_LEN];
+	int ret;
+	unsigned int val;
+
+	ret = regmap_bulk_read(rtc->hw->regmap, DA9063_REG_ALARM_S,
+			       &data[RTC_SEC], RTC_DATA_LEN);
+	if (ret < 0)
+		return ret;
+
+	da9063_data_to_tm(data, &alrm->time);
+
+	alrm->enabled = !!(data[RTC_YEAR] & DA9063_ALARM_ON);
+
+	ret = regmap_read(rtc->hw->regmap, DA9063_REG_EVENT_A, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val & (DA9063_E_ALARM))
+		alrm->pending = 1;
+	else
+		alrm->pending = 0;
+
+	return 0;
+}
+
+static int da9063_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct da9063_rtc *rtc = dev_get_drvdata(dev);
+	u8 data[RTC_DATA_LEN];
+	int ret;
+
+	da9063_tm_to_data(&alrm->time, data);
+
+	ret = da9063_rtc_stop_alarm(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to stop alarm: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_bulk_write(rtc->hw->regmap, DA9063_REG_ALARM_S,
+				data, RTC_DATA_LEN);
+	if (ret < 0) {
+		dev_err(dev, "Failed to write alarm: %d\n", ret);
+		return ret;
+	}
+
+	rtc->alarm_time = alrm->time;
+
+	if (alrm->enabled) {
+		ret = da9063_rtc_start_alarm(dev);
+		if (ret < 0) {
+			dev_err(dev, "Failed to start alarm: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+static int da9063_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	if (enabled)
+		return da9063_rtc_start_alarm(dev);
+	else
+		return da9063_rtc_stop_alarm(dev);
+}
+
+static irqreturn_t da9063_alarm_event(int irq, void *data)
+{
+	struct da9063_rtc *rtc = data;
+
+	regmap_update_bits(rtc->hw->regmap, DA9063_REG_ALARM_Y,
+			   DA9063_ALARM_ON, 0);
+
+	rtc->rtc_sync = true;
+	rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
+
+	return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops da9063_rtc_ops = {
+	.read_time = da9063_rtc_read_time,
+	.set_time = da9063_rtc_set_time,
+	.read_alarm = da9063_rtc_read_alarm,
+	.set_alarm = da9063_rtc_set_alarm,
+	.alarm_irq_enable = da9063_rtc_alarm_irq_enable,
+};
+
+static int da9063_rtc_probe(struct platform_device *pdev)
+{
+	struct da9063 *da9063 = dev_get_drvdata(pdev->dev.parent);
+	struct da9063_rtc *rtc;
+	int irq_alarm;
+	u8 data[RTC_DATA_LEN];
+	int ret;
+
+	ret = regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_E,
+				 DA9063_RTC_EN, DA9063_RTC_EN);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to enable RTC\n");
+		goto err;
+	}
+
+	ret = regmap_update_bits(da9063->regmap, DA9063_REG_EN_32K,
+				 DA9063_CRYSTAL, DA9063_CRYSTAL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to run 32kHz oscillator\n");
+		goto err;
+	}
+
+	ret = regmap_update_bits(da9063->regmap, DA9063_REG_ALARM_S,
+			DA9063_ALARM_STATUS_TICK | DA9063_ALARM_STATUS_ALARM,
+			0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to access RTC alarm register\n");
+		goto err;
+	}
+
+	ret = regmap_update_bits(da9063->regmap, DA9063_REG_ALARM_S,
+				 DA9063_ALARM_STATUS_ALARM,
+				 DA9063_ALARM_STATUS_ALARM);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to access RTC alarm register\n");
+		goto err;
+	}
+
+	ret = regmap_update_bits(da9063->regmap, DA9063_REG_ALARM_Y,
+				 DA9063_TICK_ON, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to disable TICKs\n");
+		goto err;
+	}
+
+	ret = regmap_bulk_read(da9063->regmap, DA9063_REG_ALARM_S,
+			       data, RTC_DATA_LEN);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to read initial alarm data: %d\n",
+			ret);
+		goto err;
+	}
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rtc);
+
+	irq_alarm = platform_get_irq_byname(pdev, "ALARM");
+	ret = devm_request_threaded_irq(&pdev->dev, irq_alarm, NULL,
+					da9063_alarm_event,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					"ALARM", rtc);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request ALARM IRQ %d: %d\n",
+			irq_alarm, ret);
+		goto err;
+	}
+
+	rtc->hw = da9063;
+	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, DA9063_DRVNAME_RTC,
+					   &da9063_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc_dev))
+		return PTR_ERR(rtc->rtc_dev);
+
+	da9063_data_to_tm(data, &rtc->alarm_time);
+	rtc->rtc_sync = false;
+err:
+	return ret;
+}
+
+static struct platform_driver da9063_rtc_driver = {
+	.probe		= da9063_rtc_probe,
+	.driver		= {
+		.name	= DA9063_DRVNAME_RTC,
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_platform_driver(da9063_rtc_driver);
+
+MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
+MODULE_DESCRIPTION("Real time clock device driver for Dialog DA9063");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DA9063_DRVNAME_RTC);