rtc: tps65910: add RTC driver for TPS65910 PMIC RTC

TPS65910 PMIC is a MFD with RTC as one of the device.  Adding RTC driver
for supporting RTC device present inside TPS65910 PMIC.

Only support for RTC alarm is implemented as part of this patch.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.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>

3 files changed, 363 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index f87bfea6718c..6309df4e2654 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -335,6 +335,16 @@ config RTC_DRV_TWL4030
           This driver can also be built as a module. If so, the module
           will be called rtc-twl.
 
+config RTC_DRV_TPS65910
+        tristate "TI TPS65910 RTC driver"
+        depends on RTC_CLASS && MFD_TPS65910
+        help
+          If you say yes here you get support for the RTC on the
+          TPS65910 chips.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-tps65910.
+
 config RTC_DRV_S35390A
         tristate "Seiko Instruments S-35390A"
         select BITREVERSE
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 6056f71033db..5c8f106237da 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -107,6 +107,7 @@ obj-$(CONFIG_RTC_DRV_TEGRA)	+= rtc-tegra.o
 obj-$(CONFIG_RTC_DRV_TEST)      += rtc-test.o
 obj-$(CONFIG_RTC_DRV_TILE)      += rtc-tile.o
 obj-$(CONFIG_RTC_DRV_TWL4030)   += rtc-twl.o
+obj-$(CONFIG_RTC_DRV_TPS65910)  += rtc-tps65910.o
 obj-$(CONFIG_RTC_DRV_TX4939)    += rtc-tx4939.o
 obj-$(CONFIG_RTC_DRV_V3020)     += rtc-v3020.o
 obj-$(CONFIG_RTC_DRV_VR41XX)    += rtc-vr41xx.o
diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c
new file mode 100644
index 000000000000..7c4ca8605741
--- /dev/null
+++ b/drivers/rtc/rtc-tps65910.c
@@ -0,0 +1,352 @@
+/*
+ * rtc-tps65910.c -- TPS65910 Real Time Clock interface
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
+ *
+ * Based on original TI driver rtc-twl.c
+ *   Copyright (C) 2007 MontaVista Software, Inc
+ *   Author: Alexandre Rusev <source@mvista.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/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/tps65910.h>
+
+struct tps65910_rtc {
+        struct rtc_device       *rtc;
+        /* To store the list of enabled interrupts */
+        u32 irqstat;
+};
+
+/* Total number of RTC registers needed to set time*/
+#define NUM_TIME_REGS   (TPS65910_YEARS - TPS65910_SECONDS + 1)
+
+static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
+{
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+        u8 val = 0;
+
+        if (enabled)
+                val = TPS65910_RTC_INTERRUPTS_IT_ALARM;
+
+        return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
+}
+
+/*
+ * Gets current tps65910 RTC time and date parameters.
+ *
+ * The RTC's time/alarm representation is not what gmtime(3) requires
+ * Linux to use:
+ *
+ *  - Months are 1..12 vs Linux 0-11
+ *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
+ */
+static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        unsigned char rtc_data[NUM_TIME_REGS];
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+        int ret;
+
+        /* Copy RTC counting registers to static registers or latches */
+        ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
+                TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
+        if (ret < 0) {
+                dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
+                return ret;
+        }
+
+        ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
+                NUM_TIME_REGS);
+        if (ret < 0) {
+                dev_err(dev, "reading from RTC failed with 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 tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        unsigned char rtc_data[NUM_TIME_REGS];
+        struct tps65910 *tps = 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 = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
+                TPS65910_RTC_CTRL_STOP_RTC, 0);
+        if (ret < 0) {
+                dev_err(dev, "RTC stop failed with err:%d\n", ret);
+                return ret;
+        }
+
+        /* update all the time registers in one shot */
+        ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
+                NUM_TIME_REGS);
+        if (ret < 0) {
+                dev_err(dev, "rtc_set_time error %d\n", ret);
+                return ret;
+        }
+
+        /* Start back RTC */
+        ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
+                TPS65910_RTC_CTRL_STOP_RTC, 1);
+        if (ret < 0)
+                dev_err(dev, "RTC start failed with err:%d\n", ret);
+
+        return ret;
+}
+
+/*
+ * Gets current tps65910 RTC alarm time.
+ */
+static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        unsigned char alarm_data[NUM_TIME_REGS];
+        u32 int_val;
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+        int ret;
+
+        ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
+                NUM_TIME_REGS);
+        if (ret < 0) {
+                dev_err(dev, "rtc_read_alarm error %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 = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
+        if (ret < 0)
+                return ret;
+
+        if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
+                alm->enabled = 1;
+
+        return ret;
+}
+
+static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        unsigned char alarm_data[NUM_TIME_REGS];
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+        int ret;
+
+        ret = tps65910_rtc_alarm_irq_enable(dev, 0);
+        if (ret)
+                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);
+
+        /* update all the alarm registers in one shot */
+        ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
+                alarm_data, NUM_TIME_REGS);
+        if (ret) {
+                dev_err(dev, "rtc_set_alarm error %d\n", ret);
+                return ret;
+        }
+
+        if (alm->enabled)
+                ret = tps65910_rtc_alarm_irq_enable(dev, 1);
+
+        return ret;
+}
+
+static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
+{
+        struct device *dev = rtc;
+        unsigned long events = 0;
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+        struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
+        int ret;
+        u32 rtc_reg;
+
+        ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
+        if (ret)
+                return IRQ_NONE;
+
+        if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
+                events = RTC_IRQF | RTC_AF;
+
+        ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
+        if (ret)
+                return IRQ_NONE;
+
+        /* Notify RTC core on event */
+        rtc_update_irq(tps_rtc->rtc, 1, events);
+
+        return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops tps65910_rtc_ops = {
+        .read_time      = tps65910_rtc_read_time,
+        .set_time       = tps65910_rtc_set_time,
+        .read_alarm     = tps65910_rtc_read_alarm,
+        .set_alarm      = tps65910_rtc_set_alarm,
+        .alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
+};
+
+static int __devinit tps65910_rtc_probe(struct platform_device *pdev)
+{
+        struct tps65910 *tps65910 = NULL;
+        struct tps65910_rtc *tps_rtc = NULL;
+        struct tps65910_board *pmic_plat_data;
+        int ret;
+        int irq;
+        u32 rtc_reg;
+
+        tps65910 = dev_get_drvdata(pdev->dev.parent);
+
+        tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
+                        GFP_KERNEL);
+        if (!tps_rtc)
+                return -ENOMEM;
+
+        /* Clear pending interrupts */
+        ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
+        if (ret < 0)
+                return ret;
+
+        ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
+        if (ret < 0)
+                return ret;
+
+        dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");
+        rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
+        ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
+        if (ret < 0)
+                return ret;
+
+        pmic_plat_data = dev_get_platdata(tps65910->dev);
+        irq = pmic_plat_data->irq_base;
+        if (irq <= 0) {
+                dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
+                        irq);
+                return ret;
+        }
+
+        irq += TPS65910_IRQ_RTC_ALARM;
+        ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+                tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
+                "rtc-tps65910", &pdev->dev);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "IRQ is not free.\n");
+                return ret;
+        }
+        device_init_wakeup(&pdev->dev, 1);
+
+        tps_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+                &tps65910_rtc_ops, THIS_MODULE);
+        if (IS_ERR(tps_rtc->rtc)) {
+                ret = PTR_ERR(tps_rtc->rtc);
+                dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
+                return ret;
+        }
+
+        platform_set_drvdata(pdev, tps_rtc);
+
+        return 0;
+}
+
+/*
+ * Disable tps65910 RTC interrupts.
+ * Sets status flag to free.
+ */
+static int __devexit tps65910_rtc_remove(struct platform_device *pdev)
+{
+        /* leave rtc running, but disable irqs */
+        struct rtc_device *rtc = platform_get_drvdata(pdev);
+
+        tps65910_rtc_alarm_irq_enable(&rtc->dev, 0);
+
+        rtc_device_unregister(rtc);
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int tps65910_rtc_suspend(struct device *dev)
+{
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+        u8 alarm = TPS65910_RTC_INTERRUPTS_IT_ALARM;
+        int ret;
+
+        /* Store current list of enabled interrupts*/
+        ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS,
+                &tps->rtc->irqstat);
+        if (ret < 0)
+                return ret;
+
+        /* Enable RTC ALARM interrupt only */
+        return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, alarm);
+}
+
+static int tps65910_rtc_resume(struct device *dev)
+{
+        struct tps65910 *tps = dev_get_drvdata(dev->parent);
+
+        /* Restore list of enabled interrupts before suspend */
+        return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS,
+                tps->rtc->irqstat);
+}
+
+static const struct dev_pm_ops tps65910_rtc_pm_ops = {
+        .suspend        = tps65910_rtc_suspend,
+        .resume         = tps65910_rtc_resume,
+};
+
+#define DEV_PM_OPS     (&tps65910_rtc_pm_ops)
+#else
+#define DEV_PM_OPS     NULL
+#endif
+
+static struct platform_driver tps65910_rtc_driver = {
+        .probe          = tps65910_rtc_probe,
+        .remove         = __devexit_p(tps65910_rtc_remove),
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "tps65910-rtc",
+                .pm     = DEV_PM_OPS,
+        },
+};
+
+module_platform_driver(tps65910_rtc_driver);
+MODULE_ALIAS("platform:rtc-tps65910");
+MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
+MODULE_LICENSE("GPL");