rtc: DA9055 RTC driver

A driver for the DA9055 PMIC.  This has a dependency upon the DA9055 MFD
core.

Functionally tested on Samsung SMDKV6410.

Signed-off-by: David Dajun Chen <dchen@diasemi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 413 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-da9055.c b/drivers/rtc/rtc-da9055.c
new file mode 100644
index 000000000000..96bafc5c3bf8
--- /dev/null
+++ b/drivers/rtc/rtc-da9055.c
@@ -0,0 +1,413 @@
+/*
+ * Real time clock driver for DA9055
+ *
+ * Copyright(c) 2012 Dialog Semiconductor Ltd.
+ *
+ * Author: Dajun Dajun Chen <dajun.chen@diasemi.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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#include <linux/mfd/da9055/core.h>
+#include <linux/mfd/da9055/reg.h>
+#include <linux/mfd/da9055/pdata.h>
+
+struct da9055_rtc {
+	struct rtc_device *rtc;
+	struct da9055 *da9055;
+	int alarm_enable;
+};
+
+static int da9055_rtc_enable_alarm(struct da9055_rtc *rtc, bool enable)
+{
+	int ret;
+	if (enable) {
+		ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y,
+					DA9055_RTC_ALM_EN,
+					DA9055_RTC_ALM_EN);
+		if (ret != 0)
+			dev_err(rtc->da9055->dev, "Failed to enable ALM: %d\n",
+				ret);
+		rtc->alarm_enable = 1;
+	} else {
+		ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y,
+					DA9055_RTC_ALM_EN, 0);
+		if (ret != 0)
+			dev_err(rtc->da9055->dev,
+				"Failed to disable ALM: %d\n", ret);
+		rtc->alarm_enable = 0;
+	}
+	return ret;
+}
+
+static irqreturn_t da9055_rtc_alm_irq(int irq, void *data)
+{
+	struct da9055_rtc *rtc = data;
+
+	da9055_rtc_enable_alarm(rtc, 0);
+	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
+
+	return IRQ_HANDLED;
+}
+
+static int da9055_read_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm)
+{
+	int ret;
+	uint8_t v[5];
+
+	ret = da9055_group_read(da9055, DA9055_REG_ALARM_MI, 5, v);
+	if (ret != 0) {
+		dev_err(da9055->dev, "Failed to group read ALM: %d\n", ret);
+		return ret;
+	}
+
+	rtc_tm->tm_year = (v[4] & DA9055_RTC_ALM_YEAR) + 100;
+	rtc_tm->tm_mon  = (v[3] & DA9055_RTC_ALM_MONTH) - 1;
+	rtc_tm->tm_mday = v[2] & DA9055_RTC_ALM_DAY;
+	rtc_tm->tm_hour = v[1] & DA9055_RTC_ALM_HOUR;
+	rtc_tm->tm_min  = v[0] & DA9055_RTC_ALM_MIN;
+
+	return rtc_valid_tm(rtc_tm);
+}
+
+static int da9055_set_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm)
+{
+	int ret;
+	uint8_t v[2];
+
+	rtc_tm->tm_year -= 100;
+	rtc_tm->tm_mon += 1;
+
+	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MI,
+				DA9055_RTC_ALM_MIN, rtc_tm->tm_min);
+	if (ret != 0) {
+		dev_err(da9055->dev, "Failed to write ALRM MIN: %d\n", ret);
+		return ret;
+	}
+
+	v[0] = rtc_tm->tm_hour;
+	v[1] = rtc_tm->tm_mday;
+
+	ret = da9055_group_write(da9055, DA9055_REG_ALARM_H, 2, v);
+	if (ret < 0)
+		return ret;
+
+	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO,
+				DA9055_RTC_ALM_MONTH, rtc_tm->tm_mon);
+	if (ret < 0)
+		dev_err(da9055->dev, "Failed to write ALM Month:%d\n", ret);
+
+	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_Y,
+				DA9055_RTC_ALM_YEAR, rtc_tm->tm_year);
+	if (ret < 0)
+		dev_err(da9055->dev, "Failed to write ALM Year:%d\n", ret);
+
+	return ret;
+}
+
+static int da9055_rtc_get_alarm_status(struct da9055 *da9055)
+{
+	int ret;
+
+	ret = da9055_reg_read(da9055, DA9055_REG_ALARM_Y);
+	if (ret < 0) {
+		dev_err(da9055->dev, "Failed to read ALM: %d\n", ret);
+		return ret;
+	}
+	ret &= DA9055_RTC_ALM_EN;
+	return (ret > 0) ? 1 : 0;
+}
+
+static int da9055_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
+{
+	struct da9055_rtc *rtc = dev_get_drvdata(dev);
+	uint8_t v[6];
+	int ret;
+
+	ret = da9055_reg_read(rtc->da9055, DA9055_REG_COUNT_S);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Registers are only valid when RTC_READ
+	 * status bit is asserted
+	 */
+	if (!(ret & DA9055_RTC_READ))
+		return -EBUSY;
+
+	ret = da9055_group_read(rtc->da9055, DA9055_REG_COUNT_S, 6, v);
+	if (ret < 0) {
+		dev_err(rtc->da9055->dev, "Failed to read RTC time : %d\n",
+			ret);
+		return ret;
+	}
+
+	rtc_tm->tm_year = (v[5] & DA9055_RTC_YEAR) + 100;
+	rtc_tm->tm_mon  = (v[4] & DA9055_RTC_MONTH) - 1;
+	rtc_tm->tm_mday = v[3] & DA9055_RTC_DAY;
+	rtc_tm->tm_hour = v[2] & DA9055_RTC_HOUR;
+	rtc_tm->tm_min  = v[1] & DA9055_RTC_MIN;
+	rtc_tm->tm_sec  = v[0] & DA9055_RTC_SEC;
+
+	return rtc_valid_tm(rtc_tm);
+}
+
+static int da9055_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct da9055_rtc *rtc;
+	uint8_t v[6];
+
+	rtc = dev_get_drvdata(dev);
+
+	v[0] = tm->tm_sec;
+	v[1] = tm->tm_min;
+	v[2] = tm->tm_hour;
+	v[3] = tm->tm_mday;
+	v[4] = tm->tm_mon + 1;
+	v[5] = tm->tm_year - 100;
+
+	return da9055_group_write(rtc->da9055, DA9055_REG_COUNT_S, 6, v);
+}
+
+static int da9055_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	int ret;
+	struct rtc_time *tm = &alrm->time;
+	struct da9055_rtc *rtc = dev_get_drvdata(dev);
+
+	ret = da9055_read_alarm(rtc->da9055, tm);
+
+	if (ret)
+		return ret;
+
+	alrm->enabled = da9055_rtc_get_alarm_status(rtc->da9055);
+
+	return 0;
+}
+
+static int da9055_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	int ret;
+	struct rtc_time *tm = &alrm->time;
+	struct da9055_rtc *rtc = dev_get_drvdata(dev);
+
+	ret = da9055_rtc_enable_alarm(rtc, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = da9055_set_alarm(rtc->da9055, tm);
+	if (ret)
+		return ret;
+
+	ret = da9055_rtc_enable_alarm(rtc, 1);
+
+	return ret;
+}
+
+static int da9055_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct da9055_rtc *rtc = dev_get_drvdata(dev);
+
+	return da9055_rtc_enable_alarm(rtc, enabled);
+}
+
+static const struct rtc_class_ops da9055_rtc_ops = {
+	.read_time	= da9055_rtc_read_time,
+	.set_time	= da9055_rtc_set_time,
+	.read_alarm	= da9055_rtc_read_alarm,
+	.set_alarm	= da9055_rtc_set_alarm,
+	.alarm_irq_enable = da9055_rtc_alarm_irq_enable,
+};
+
+static int __init da9055_rtc_device_init(struct da9055 *da9055,
+					struct da9055_pdata *pdata)
+{
+	int ret;
+
+	/* Enable RTC and the internal Crystal */
+	ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
+				DA9055_RTC_EN, DA9055_RTC_EN);
+	if (ret < 0)
+		return ret;
+	ret = da9055_reg_update(da9055, DA9055_REG_EN_32K,
+				DA9055_CRYSTAL_EN, DA9055_CRYSTAL_EN);
+	if (ret < 0)
+		return ret;
+
+	/* Enable RTC in Power Down mode */
+	ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
+				DA9055_RTC_MODE_PD, DA9055_RTC_MODE_PD);
+	if (ret < 0)
+		return ret;
+
+	/* Enable RTC in Reset mode */
+	if (pdata && pdata->reset_enable) {
+		ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
+					DA9055_RTC_MODE_SD,
+					DA9055_RTC_MODE_SD <<
+					DA9055_RTC_MODE_SD_SHIFT);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Disable the RTC TICK ALM */
+	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO,
+				DA9055_RTC_TICK_WAKE_MASK, 0);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int da9055_rtc_probe(struct platform_device *pdev)
+{
+	struct da9055_rtc *rtc;
+	struct da9055_pdata *pdata = NULL;
+	int ret, alm_irq;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(struct da9055_rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	rtc->da9055 = dev_get_drvdata(pdev->dev.parent);
+	pdata = rtc->da9055->dev->platform_data;
+	platform_set_drvdata(pdev, rtc);
+
+	ret = da9055_rtc_device_init(rtc->da9055, pdata);
+	if (ret < 0)
+		goto err_rtc;
+
+	ret = da9055_reg_read(rtc->da9055, DA9055_REG_ALARM_Y);
+	if (ret < 0)
+		goto err_rtc;
+
+	if (ret & DA9055_RTC_ALM_EN)
+		rtc->alarm_enable = 1;
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+					&da9055_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc)) {
+		ret = PTR_ERR(rtc->rtc);
+		goto err_rtc;
+	}
+
+	alm_irq = platform_get_irq_byname(pdev, "ALM");
+	alm_irq = regmap_irq_get_virq(rtc->da9055->irq_data, alm_irq);
+	ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL,
+					da9055_rtc_alm_irq,
+					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+					"ALM", rtc);
+	if (ret != 0)
+		dev_err(rtc->da9055->dev, "irq registration failed: %d\n", ret);
+
+err_rtc:
+	return ret;
+
+}
+
+static int da9055_rtc_remove(struct platform_device *pdev)
+{
+	struct da9055_rtc *rtc = pdev->dev.platform_data;
+
+	rtc_device_unregister(rtc->rtc);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+/* Turn off the alarm if it should not be a wake source. */
+static int da9055_rtc_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
+	int ret;
+
+	if (!device_may_wakeup(&pdev->dev)) {
+		/* Disable the ALM IRQ */
+		ret = da9055_rtc_enable_alarm(rtc, 0);
+		if (ret < 0)
+			dev_err(&pdev->dev, "Failed to disable RTC ALM\n");
+	}
+
+	return 0;
+}
+
+/* Enable the alarm if it should be enabled (in case it was disabled to
+ * prevent use as a wake source).
+ */
+static int da9055_rtc_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
+	int ret;
+
+	if (!device_may_wakeup(&pdev->dev)) {
+		if (rtc->alarm_enable) {
+			ret = da9055_rtc_enable_alarm(rtc, 1);
+			if (ret < 0)
+				dev_err(&pdev->dev,
+					"Failed to restart RTC ALM\n");
+		}
+	}
+
+	return 0;
+}
+
+/* Unconditionally disable the alarm */
+static int da9055_rtc_freeze(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
+	int ret;
+
+	ret = da9055_rtc_enable_alarm(rtc, 0);
+	if (ret < 0)
+		dev_err(&pdev->dev, "Failed to freeze RTC ALMs\n");
+
+	return 0;
+
+}
+#else
+#define da9055_rtc_suspend NULL
+#define da9055_rtc_resume NULL
+#define da9055_rtc_freeze NULL
+#endif
+
+static const struct dev_pm_ops da9055_rtc_pm_ops = {
+	.suspend = da9055_rtc_suspend,
+	.resume = da9055_rtc_resume,
+
+	.freeze = da9055_rtc_freeze,
+	.thaw = da9055_rtc_resume,
+	.restore = da9055_rtc_resume,
+
+	.poweroff = da9055_rtc_suspend,
+};
+
+static struct platform_driver da9055_rtc_driver = {
+	.probe  = da9055_rtc_probe,
+	.remove = da9055_rtc_remove,
+	.driver = {
+		.name   = "da9055-rtc",
+		.owner  = THIS_MODULE,
+		.pm = &da9055_rtc_pm_ops,
+	},
+};
+
+module_platform_driver(da9055_rtc_driver);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
+MODULE_DESCRIPTION("RTC driver for Dialog DA9055 PMIC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9055-rtc");