rtc: rc5t583: add ricoh rc5t583 RTC driver

Add an RTC driver for the RTC device on Ricoh MFD Rc5t583.  Ricoh RTC has
3 types of alarms.  The current patch adds support for the Y-Alarm of
RC5t583 RTC.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 342 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index f92d17bc9566..94764560d110 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -350,6 +350,16 @@ config RTC_DRV_TPS65910
           This driver can also be built as a module. If so, the module
           will be called rtc-tps65910.
 
+config RTC_DRV_RC5T583
+        tristate "RICOH 5T583 RTC driver"
+        depends on MFD_RC5T583
+        help
+          If you say yes here you get support for the RTC on the
+          RICOH 5T583 chips.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-rc5t583.
+
 config RTC_DRV_S35390A
         tristate "Seiko Instruments S-35390A"
         select BITREVERSE
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index d9526b549f87..56297f0fd388 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_RTC_DRV_PS3)	+= rtc-ps3.o
 obj-$(CONFIG_RTC_DRV_PUV3)      += rtc-puv3.o
 obj-$(CONFIG_RTC_DRV_PXA)       += rtc-pxa.o
 obj-$(CONFIG_RTC_DRV_R9701)     += rtc-r9701.o
+obj-$(CONFIG_RTC_DRV_RC5T583)   += rtc-rc5t583.o
 obj-$(CONFIG_RTC_DRV_RP5C01)    += rtc-rp5c01.o
 obj-$(CONFIG_RTC_DRV_RS5C313)   += rtc-rs5c313.o
 obj-$(CONFIG_RTC_DRV_RS5C348)   += rtc-rs5c348.o
diff --git a/drivers/rtc/rtc-rc5t583.c b/drivers/rtc/rtc-rc5t583.c
new file mode 100644
index 000000000000..cdb140c29c56
--- /dev/null
+++ b/drivers/rtc/rtc-rc5t583.c
@@ -0,0 +1,331 @@
+/*
+ * rtc-rc5t583.c -- RICOH RC5T583 Real Time Clock
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#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/rc5t583.h>
+
+struct rc5t583_rtc {
+        struct rtc_device       *rtc;
+        /* To store the list of enabled interrupts, during system suspend */
+        u32 irqen;
+};
+
+/* Total number of RTC registers needed to set time*/
+#define NUM_TIME_REGS   (RC5T583_RTC_YEAR - RC5T583_RTC_SEC + 1)
+
+/* Total number of RTC registers needed to set Y-Alarm*/
+#define NUM_YAL_REGS    (RC5T583_RTC_AY_YEAR - RC5T583_RTC_AY_MIN + 1)
+
+/* Set Y-Alarm interrupt */
+#define SET_YAL BIT(5)
+
+/* Get Y-Alarm interrupt status*/
+#define GET_YAL_STATUS BIT(3)
+
+static int rc5t583_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        u8 val;
+
+        /* Set Y-Alarm, based on 'enabled' */
+        val = enabled ? SET_YAL : 0;
+
+        return regmap_update_bits(rc5t583->regmap, RC5T583_RTC_CTL1, SET_YAL,
+                val);
+}
+
+/*
+ * Gets current rc5t583 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 rc5t583_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        u8 rtc_data[NUM_TIME_REGS];
+        int ret;
+
+        ret = regmap_bulk_read(rc5t583->regmap, RC5T583_RTC_SEC, rtc_data,
+                NUM_TIME_REGS);
+        if (ret < 0) {
+                dev_err(dev, "RTC read time 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_wday = bcd2bin(rtc_data[3]);
+        tm->tm_mday = bcd2bin(rtc_data[4]);
+        tm->tm_mon = bcd2bin(rtc_data[5]) - 1;
+        tm->tm_year = bcd2bin(rtc_data[6]) + 100;
+
+        return ret;
+}
+
+static int rc5t583_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        unsigned char rtc_data[NUM_TIME_REGS];
+        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_wday);
+        rtc_data[4] = bin2bcd(tm->tm_mday);
+        rtc_data[5] = bin2bcd(tm->tm_mon + 1);
+        rtc_data[6] = bin2bcd(tm->tm_year - 100);
+
+        ret = regmap_bulk_write(rc5t583->regmap, RC5T583_RTC_SEC, rtc_data,
+                NUM_TIME_REGS);
+        if (ret < 0) {
+                dev_err(dev, "RTC set time failed with error %d\n", ret);
+                return ret;
+        }
+
+        return ret;
+}
+
+static int rc5t583_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        unsigned char alarm_data[NUM_YAL_REGS];
+        u32 interrupt_enable;
+        int ret;
+
+        ret = regmap_bulk_read(rc5t583->regmap, RC5T583_RTC_AY_MIN, alarm_data,
+                NUM_YAL_REGS);
+        if (ret < 0) {
+                dev_err(dev, "rtc_read_alarm error %d\n", ret);
+                return ret;
+        }
+
+        alm->time.tm_min = bcd2bin(alarm_data[0]);
+        alm->time.tm_hour = bcd2bin(alarm_data[1]);
+        alm->time.tm_mday = bcd2bin(alarm_data[2]);
+        alm->time.tm_mon = bcd2bin(alarm_data[3]) - 1;
+        alm->time.tm_year = bcd2bin(alarm_data[4]) + 100;
+
+        ret = regmap_read(rc5t583->regmap, RC5T583_RTC_CTL1, &interrupt_enable);
+        if (ret < 0)
+                return ret;
+
+        /* check if YALE is set */
+        if (interrupt_enable & SET_YAL)
+                alm->enabled = 1;
+
+        return ret;
+}
+
+static int rc5t583_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        unsigned char alarm_data[NUM_YAL_REGS];
+        int ret;
+
+        ret = rc5t583_rtc_alarm_irq_enable(dev, 0);
+        if (ret)
+                return ret;
+
+        alarm_data[0] = bin2bcd(alm->time.tm_min);
+        alarm_data[1] = bin2bcd(alm->time.tm_hour);
+        alarm_data[2] = bin2bcd(alm->time.tm_mday);
+        alarm_data[3] = bin2bcd(alm->time.tm_mon + 1);
+        alarm_data[4] = bin2bcd(alm->time.tm_year - 100);
+
+        ret = regmap_bulk_write(rc5t583->regmap, RC5T583_RTC_AY_MIN, alarm_data,
+                NUM_YAL_REGS);
+        if (ret) {
+                dev_err(dev, "rtc_set_alarm error %d\n", ret);
+                return ret;
+        }
+
+        if (alm->enabled)
+                ret = rc5t583_rtc_alarm_irq_enable(dev, 1);
+
+        return ret;
+}
+
+static irqreturn_t rc5t583_rtc_interrupt(int irq, void *rtc)
+{
+        struct device *dev = rtc;
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(dev);
+        unsigned long events = 0;
+        int ret;
+        u32 rtc_reg;
+
+        ret = regmap_read(rc5t583->regmap, RC5T583_RTC_CTL2, &rtc_reg);
+        if (ret < 0)
+                return IRQ_NONE;
+
+        if (rtc_reg & GET_YAL_STATUS) {
+                events = RTC_IRQF | RTC_AF;
+                /* clear pending Y-alarm interrupt bit */
+                rtc_reg &= ~GET_YAL_STATUS;
+        }
+
+        ret = regmap_write(rc5t583->regmap, RC5T583_RTC_CTL2, rtc_reg);
+        if (ret)
+                return IRQ_NONE;
+
+        /* Notify RTC core on event */
+        rtc_update_irq(rc5t583_rtc->rtc, 1, events);
+
+        return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops rc5t583_rtc_ops = {
+        .read_time      = rc5t583_rtc_read_time,
+        .set_time       = rc5t583_rtc_set_time,
+        .read_alarm     = rc5t583_rtc_read_alarm,
+        .set_alarm      = rc5t583_rtc_set_alarm,
+        .alarm_irq_enable = rc5t583_rtc_alarm_irq_enable,
+};
+
+static int __devinit rc5t583_rtc_probe(struct platform_device *pdev)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(pdev->dev.parent);
+        struct rc5t583_rtc *ricoh_rtc;
+        struct rc5t583_platform_data *pmic_plat_data;
+        int ret;
+        int irq;
+
+        ricoh_rtc = devm_kzalloc(&pdev->dev, sizeof(struct rc5t583_rtc),
+                        GFP_KERNEL);
+        if (!ricoh_rtc)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, ricoh_rtc);
+
+        /* Clear pending interrupts */
+        ret = regmap_write(rc5t583->regmap, RC5T583_RTC_CTL2, 0);
+        if (ret < 0)
+                return ret;
+
+        /* clear RTC Adjust register */
+        ret = regmap_write(rc5t583->regmap, RC5T583_RTC_ADJ, 0);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "unable to program rtc_adjust reg\n");
+                return -EBUSY;
+        }
+
+        pmic_plat_data = dev_get_platdata(rc5t583->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 += RC5T583_IRQ_YALE;
+        ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+                rc5t583_rtc_interrupt, IRQF_TRIGGER_LOW,
+                "rtc-rc5t583", &pdev->dev);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "IRQ is not free.\n");
+                return ret;
+        }
+        device_init_wakeup(&pdev->dev, 1);
+
+        ricoh_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+                &rc5t583_rtc_ops, THIS_MODULE);
+        if (IS_ERR(ricoh_rtc->rtc)) {
+                ret = PTR_ERR(ricoh_rtc->rtc);
+                dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+/*
+ * Disable rc5t583 RTC interrupts.
+ * Sets status flag to free.
+ */
+static int __devexit rc5t583_rtc_remove(struct platform_device *pdev)
+{
+        struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(&pdev->dev);
+
+        rc5t583_rtc_alarm_irq_enable(&rc5t583_rtc->rtc->dev, 0);
+
+        rtc_device_unregister(rc5t583_rtc->rtc);
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int rc5t583_rtc_suspend(struct device *dev)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(dev);
+        int ret;
+
+        /* Store current list of enabled interrupts*/
+        ret = regmap_read(rc5t583->regmap, RC5T583_RTC_CTL1,
+                &rc5t583_rtc->irqen);
+        return ret;
+}
+
+static int rc5t583_rtc_resume(struct device *dev)
+{
+        struct rc5t583 *rc5t583 = dev_get_drvdata(dev->parent);
+        struct rc5t583_rtc *rc5t583_rtc = dev_get_drvdata(dev);
+
+        /* Restore list of enabled interrupts before suspend */
+        return regmap_write(rc5t583->regmap, RC5T583_RTC_CTL1,
+                rc5t583_rtc->irqen);
+}
+
+static const struct dev_pm_ops rc5t583_rtc_pm_ops = {
+        .suspend        = rc5t583_rtc_suspend,
+        .resume         = rc5t583_rtc_resume,
+};
+
+#define DEV_PM_OPS     (&rc5t583_rtc_pm_ops)
+#else
+#define DEV_PM_OPS     NULL
+#endif
+
+static struct platform_driver rc5t583_rtc_driver = {
+        .probe          = rc5t583_rtc_probe,
+        .remove         = __devexit_p(rc5t583_rtc_remove),
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "rtc-rc5t583",
+                .pm     = DEV_PM_OPS,
+        },
+};
+
+module_platform_driver(rc5t583_rtc_driver);
+MODULE_ALIAS("platform:rtc-rc5t583");
+MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
+MODULE_LICENSE("GPL v2");