rtc: palmas: Add RTC driver Palmas series PMIC

TI Palmas series PMIC support the RTC and alarm functionality.
Add RTC driver with alarm support for this device.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 339 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c
new file mode 100644
index 0000000..59c4298
--- /dev/null
+++ b/drivers/rtc/rtc-palmas.c
@@ -0,0 +1,339 @@
+/*
+ * rtc-palmas.c -- Palmas Real Time Clock driver.
+
+ * RTC driver for TI Palma series devices like TPS65913,
+ * TPS65914 power management IC.
+ *
+ * Copyright (c) 2012, NVIDIA Corporation.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
+ * whether express or implied; 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., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307, USA
+ */
+
+#include <linux/bcd.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/palmas.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+
+struct palmas_rtc {
+	struct rtc_device	*rtc;
+	struct device		*dev;
+	unsigned int		irq;
+};
+
+/* Total number of RTC registers needed to set time*/
+#define PALMAS_NUM_TIME_REGS	(PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
+
+static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	/* Copy RTC counting registers to static registers or latches */
+	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
+		PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
+	if (ret < 0) {
+		dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret);
+		return ret;
+	}
+
+	ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
+			rtc_data, PALMAS_NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret);
+		return ret;
+	}
+
+	tm->tm_sec = bcd2bin(rtc_data[0]);
+	tm->tm_min = bcd2bin(rtc_data[1]);
+	tm->tm_hour = bcd2bin(rtc_data[2]);
+	tm->tm_mday = bcd2bin(rtc_data[3]);
+	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
+	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
+
+	return ret;
+}
+
+static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	rtc_data[0] = bin2bcd(tm->tm_sec);
+	rtc_data[1] = bin2bcd(tm->tm_min);
+	rtc_data[2] = bin2bcd(tm->tm_hour);
+	rtc_data[3] = bin2bcd(tm->tm_mday);
+	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
+	rtc_data[5] = bin2bcd(tm->tm_year - 100);
+
+	/* Stop RTC while updating the RTC time registers */
+	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
+		PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
+	if (ret < 0) {
+		dev_err(dev, "RTC stop failed, err = %d\n", ret);
+		return ret;
+	}
+
+	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
+		rtc_data, PALMAS_NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret);
+		return ret;
+	}
+
+	/* Start back RTC */
+	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
+		PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC);
+	if (ret < 0)
+		dev_err(dev, "RTC start failed, err = %d\n", ret);
+	return ret;
+}
+
+static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
+{
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	u8 val;
+
+	val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0;
+	return palmas_write(palmas, PALMAS_RTC_BASE,
+		PALMAS_RTC_INTERRUPTS_REG, val);
+}
+
+static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
+	u32 int_val;
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE,
+			PALMAS_ALARM_SECONDS_REG,
+			alarm_data, PALMAS_NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret);
+		return ret;
+	}
+
+	alm->time.tm_sec = bcd2bin(alarm_data[0]);
+	alm->time.tm_min = bcd2bin(alarm_data[1]);
+	alm->time.tm_hour = bcd2bin(alarm_data[2]);
+	alm->time.tm_mday = bcd2bin(alarm_data[3]);
+	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
+	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
+
+	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
+			&int_val);
+	if (ret < 0) {
+		dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret);
+		return ret;
+	}
+
+	if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
+		alm->enabled = 1;
+	return ret;
+}
+
+static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	ret = palmas_rtc_alarm_irq_enable(dev, 0);
+	if (ret < 0) {
+		dev_err(dev, "Disable RTC alarm failed\n");
+		return ret;
+	}
+
+	alarm_data[0] = bin2bcd(alm->time.tm_sec);
+	alarm_data[1] = bin2bcd(alm->time.tm_min);
+	alarm_data[2] = bin2bcd(alm->time.tm_hour);
+	alarm_data[3] = bin2bcd(alm->time.tm_mday);
+	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
+	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
+
+	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
+		PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret);
+		return ret;
+	}
+
+	if (alm->enabled)
+		ret = palmas_rtc_alarm_irq_enable(dev, 1);
+	return ret;
+}
+
+static int palmas_clear_interrupts(struct device *dev)
+{
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	unsigned int rtc_reg;
+	int ret;
+
+	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
+				&rtc_reg);
+	if (ret < 0) {
+		dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret);
+		return ret;
+	}
+
+	ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
+			rtc_reg);
+	if (ret < 0) {
+		dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static irqreturn_t palmas_rtc_interrupt(int irq, void *context)
+{
+	struct palmas_rtc *palmas_rtc = context;
+	struct device *dev = palmas_rtc->dev;
+	int ret;
+
+	ret = palmas_clear_interrupts(dev);
+	if (ret < 0) {
+		dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret);
+		return IRQ_NONE;
+	}
+
+	rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF);
+	return IRQ_HANDLED;
+}
+
+static struct rtc_class_ops palmas_rtc_ops = {
+	.read_time	= palmas_rtc_read_time,
+	.set_time	= palmas_rtc_set_time,
+	.read_alarm	= palmas_rtc_read_alarm,
+	.set_alarm	= palmas_rtc_set_alarm,
+	.alarm_irq_enable = palmas_rtc_alarm_irq_enable,
+};
+
+static int palmas_rtc_probe(struct platform_device *pdev)
+{
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+	struct palmas_rtc *palmas_rtc = NULL;
+	int ret;
+
+	palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
+			GFP_KERNEL);
+	if (!palmas_rtc)
+		return -ENOMEM;
+
+	/* Clear pending interrupts */
+	ret = palmas_clear_interrupts(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret);
+		return ret;
+	}
+
+	palmas_rtc->dev = &pdev->dev;
+	platform_set_drvdata(pdev, palmas_rtc);
+
+	/* Start RTC */
+	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
+			PALMAS_RTC_CTRL_REG_STOP_RTC,
+			PALMAS_RTC_CTRL_REG_STOP_RTC);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret);
+		return ret;
+	}
+
+	palmas_rtc->irq = platform_get_irq(pdev, 0);
+
+	palmas_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+				&palmas_rtc_ops, THIS_MODULE);
+	if (IS_ERR(palmas_rtc->rtc)) {
+		ret = PTR_ERR(palmas_rtc->rtc);
+		dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret);
+		return ret;
+	}
+
+	ret = request_threaded_irq(palmas_rtc->irq, NULL,
+			palmas_rtc_interrupt,
+			IRQF_TRIGGER_LOW | IRQF_ONESHOT |
+			IRQF_EARLY_RESUME,
+			dev_name(&pdev->dev), palmas_rtc);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret);
+		rtc_device_unregister(palmas_rtc->rtc);
+		return ret;
+	}
+
+	device_set_wakeup_capable(&pdev->dev, 1);
+	return 0;
+}
+
+static int palmas_rtc_remove(struct platform_device *pdev)
+{
+	struct palmas_rtc *palmas_rtc = platform_get_drvdata(pdev);
+
+	palmas_rtc_alarm_irq_enable(&pdev->dev, 0);
+	free_irq(palmas_rtc->irq, palmas_rtc);
+	rtc_device_unregister(palmas_rtc->rtc);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int palmas_rtc_suspend(struct device *dev)
+{
+	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(palmas_rtc->irq);
+	return 0;
+}
+
+static int palmas_rtc_resume(struct device *dev)
+{
+	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(palmas_rtc->irq);
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops palmas_rtc_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(palmas_rtc_suspend, palmas_rtc_resume)
+};
+
+static struct platform_driver palmas_rtc_driver = {
+	.probe		= palmas_rtc_probe,
+	.remove		= palmas_rtc_remove,
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "palmas-rtc",
+		.pm	= &palmas_rtc_pm_ops,
+	},
+};
+
+module_platform_driver(palmas_rtc_driver);
+
+MODULE_ALIAS("platform:palmas_rtc");
+MODULE_DESCRIPTION("TI PALMAS series RTC driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");