rtc: add RTC driver for TPS80031/TPS80032

Add an RTC driver for TPS80031/TPS80032 chips by TI.  This driver
supports:
 - Setting and getting time and date.
 - Setting and reading alarm time.
 - Alarm and interrupt functionlity.

[akpm@linux-foundation.org: remove obsolete __devinit/__devexit]
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 349 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-tps80031.c b/drivers/rtc/rtc-tps80031.c
new file mode 100644
index 000000000000..97406411d58c
--- /dev/null
+++ b/drivers/rtc/rtc-tps80031.c
@@ -0,0 +1,349 @@
+/*
+ * rtc-tps80031.c -- TI TPS80031/TPS80032 RTC driver
+ *
+ * RTC driver for TI TPS80031/TPS80032 Fully Integrated
+ * Power Management with Power Path and Battery Charger
+ *
+ * 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/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/tps80031.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+#define ENABLE_ALARM_INT                        0x08
+#define ALARM_INT_STATUS                        0x40
+
+/**
+ * Setting bit to 1 in STOP_RTC will run the RTC and
+ * setting this bit to 0 will freeze RTC.
+ */
+#define STOP_RTC                                0x1
+
+/* Power on reset Values of RTC registers */
+#define TPS80031_RTC_POR_YEAR                   0
+#define TPS80031_RTC_POR_MONTH                  1
+#define TPS80031_RTC_POR_DAY                    1
+
+/* Numbers of registers for time and alarms */
+#define TPS80031_RTC_TIME_NUM_REGS              7
+#define TPS80031_RTC_ALARM_NUM_REGS             6
+
+/**
+ * PMU RTC have only 2 nibbles to store year information, so using an
+ * offset of 100 to set the base year as 2000 for our driver.
+ */
+#define RTC_YEAR_OFFSET 100
+
+struct tps80031_rtc {
+        struct rtc_device       *rtc;
+        int                     irq;
+};
+
+static int tps80031_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        u8 buff[TPS80031_RTC_TIME_NUM_REGS];
+        int ret;
+
+        ret = tps80031_reads(dev->parent, TPS80031_SLAVE_ID1,
+                        TPS80031_SECONDS_REG, TPS80031_RTC_TIME_NUM_REGS, buff);
+        if (ret < 0) {
+                dev_err(dev, "reading RTC_SECONDS_REG failed, err = %d\n", ret);
+                return ret;
+        }
+
+        tm->tm_sec = bcd2bin(buff[0]);
+        tm->tm_min = bcd2bin(buff[1]);
+        tm->tm_hour = bcd2bin(buff[2]);
+        tm->tm_mday = bcd2bin(buff[3]);
+        tm->tm_mon = bcd2bin(buff[4]) - 1;
+        tm->tm_year = bcd2bin(buff[5]) + RTC_YEAR_OFFSET;
+        tm->tm_wday = bcd2bin(buff[6]);
+        return 0;
+}
+
+static int tps80031_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        u8 buff[7];
+        int ret;
+
+        buff[0] = bin2bcd(tm->tm_sec);
+        buff[1] = bin2bcd(tm->tm_min);
+        buff[2] = bin2bcd(tm->tm_hour);
+        buff[3] = bin2bcd(tm->tm_mday);
+        buff[4] = bin2bcd(tm->tm_mon + 1);
+        buff[5] = bin2bcd(tm->tm_year % RTC_YEAR_OFFSET);
+        buff[6] = bin2bcd(tm->tm_wday);
+
+        /* Stop RTC while updating the RTC time registers */
+        ret = tps80031_clr_bits(dev->parent, TPS80031_SLAVE_ID1,
+                                TPS80031_RTC_CTRL_REG, STOP_RTC);
+        if (ret < 0) {
+                dev_err(dev->parent, "Stop RTC failed, err = %d\n", ret);
+                return ret;
+        }
+
+        ret = tps80031_writes(dev->parent, TPS80031_SLAVE_ID1,
+                        TPS80031_SECONDS_REG,
+                        TPS80031_RTC_TIME_NUM_REGS, buff);
+        if (ret < 0) {
+                dev_err(dev, "writing RTC_SECONDS_REG failed, err %d\n", ret);
+                return ret;
+        }
+
+        ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
+                                TPS80031_RTC_CTRL_REG, STOP_RTC);
+        if (ret < 0)
+                dev_err(dev->parent, "Start RTC failed, err = %d\n", ret);
+        return ret;
+}
+
+static int tps80031_rtc_alarm_irq_enable(struct device *dev,
+                                         unsigned int enable)
+{
+        int ret;
+
+        if (enable)
+                ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
+                                TPS80031_RTC_INTERRUPTS_REG, ENABLE_ALARM_INT);
+        else
+                ret = tps80031_clr_bits(dev->parent, TPS80031_SLAVE_ID1,
+                                TPS80031_RTC_INTERRUPTS_REG, ENABLE_ALARM_INT);
+        if (ret < 0) {
+                dev_err(dev, "Update on RTC_INT failed, err = %d\n", ret);
+                return ret;
+        }
+        return 0;
+}
+
+static int tps80031_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        u8 buff[TPS80031_RTC_ALARM_NUM_REGS];
+        int ret;
+
+        buff[0] = bin2bcd(alrm->time.tm_sec);
+        buff[1] = bin2bcd(alrm->time.tm_min);
+        buff[2] = bin2bcd(alrm->time.tm_hour);
+        buff[3] = bin2bcd(alrm->time.tm_mday);
+        buff[4] = bin2bcd(alrm->time.tm_mon + 1);
+        buff[5] = bin2bcd(alrm->time.tm_year % RTC_YEAR_OFFSET);
+        ret = tps80031_writes(dev->parent, TPS80031_SLAVE_ID1,
+                        TPS80031_ALARM_SECONDS_REG,
+                        TPS80031_RTC_ALARM_NUM_REGS, buff);
+        if (ret < 0) {
+                dev_err(dev, "Writing RTC_ALARM failed, err %d\n", ret);
+                return ret;
+        }
+        return tps80031_rtc_alarm_irq_enable(dev, alrm->enabled);
+}
+
+static int tps80031_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        u8 buff[6];
+        int ret;
+
+        ret = tps80031_reads(dev->parent, TPS80031_SLAVE_ID1,
+                        TPS80031_ALARM_SECONDS_REG,
+                        TPS80031_RTC_ALARM_NUM_REGS, buff);
+        if (ret < 0) {
+                dev_err(dev->parent,
+                        "reading RTC_ALARM failed, err = %d\n", ret);
+                return ret;
+        }
+
+        alrm->time.tm_sec = bcd2bin(buff[0]);
+        alrm->time.tm_min = bcd2bin(buff[1]);
+        alrm->time.tm_hour = bcd2bin(buff[2]);
+        alrm->time.tm_mday = bcd2bin(buff[3]);
+        alrm->time.tm_mon = bcd2bin(buff[4]) - 1;
+        alrm->time.tm_year = bcd2bin(buff[5]) + RTC_YEAR_OFFSET;
+        return 0;
+}
+
+static int clear_alarm_int_status(struct device *dev, struct tps80031_rtc *rtc)
+{
+        int ret;
+        u8 buf;
+
+        /**
+         * As per datasheet, A dummy read of this  RTC_STATUS_REG register
+         * is necessary before each I2C read in order to update the status
+         * register value.
+         */
+        ret = tps80031_read(dev->parent, TPS80031_SLAVE_ID1,
+                                TPS80031_RTC_STATUS_REG, &buf);
+        if (ret < 0) {
+                dev_err(dev, "reading RTC_STATUS failed. err = %d\n", ret);
+                return ret;
+        }
+
+        /* clear Alarm status bits.*/
+        ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
+                        TPS80031_RTC_STATUS_REG, ALARM_INT_STATUS);
+        if (ret < 0) {
+                dev_err(dev, "clear Alarm INT failed, err = %d\n", ret);
+                return ret;
+        }
+        return 0;
+}
+
+static irqreturn_t tps80031_rtc_irq(int irq, void *data)
+{
+        struct device *dev = data;
+        struct tps80031_rtc *rtc = dev_get_drvdata(dev);
+        int ret;
+
+        ret = clear_alarm_int_status(dev, rtc);
+        if (ret < 0)
+                return ret;
+
+        rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
+        return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops tps80031_rtc_ops = {
+        .read_time = tps80031_rtc_read_time,
+        .set_time = tps80031_rtc_set_time,
+        .set_alarm = tps80031_rtc_set_alarm,
+        .read_alarm = tps80031_rtc_read_alarm,
+        .alarm_irq_enable = tps80031_rtc_alarm_irq_enable,
+};
+
+static int tps80031_rtc_probe(struct platform_device *pdev)
+{
+        struct tps80031_rtc *rtc;
+        struct rtc_time tm;
+        int ret;
+
+        rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+        if (!rtc)
+                return -ENOMEM;
+
+        rtc->irq = platform_get_irq(pdev, 0);
+        platform_set_drvdata(pdev, rtc);
+
+        /* Start RTC */
+        ret = tps80031_set_bits(pdev->dev.parent, TPS80031_SLAVE_ID1,
+                        TPS80031_RTC_CTRL_REG, STOP_RTC);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "failed to start RTC. err = %d\n", ret);
+                return ret;
+        }
+
+        /* If RTC have POR values, set time 01:01:2000 */
+        tps80031_rtc_read_time(&pdev->dev, &tm);
+        if ((tm.tm_year == RTC_YEAR_OFFSET + TPS80031_RTC_POR_YEAR) &&
+                (tm.tm_mon == (TPS80031_RTC_POR_MONTH - 1)) &&
+                (tm.tm_mday == TPS80031_RTC_POR_DAY)) {
+                tm.tm_year = 2000;
+                tm.tm_mday = 1;
+                tm.tm_mon = 1;
+                ret = tps80031_rtc_set_time(&pdev->dev, &tm);
+                if (ret < 0) {
+                        dev_err(&pdev->dev,
+                                "RTC set time failed, err = %d\n", ret);
+                        return ret;
+                }
+        }
+
+        /* Clear alarm intretupt status if it is there */
+        ret = clear_alarm_int_status(&pdev->dev, rtc);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Clear alarm int failed, err = %d\n", ret);
+                return ret;
+        }
+
+        rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+                               &tps80031_rtc_ops, THIS_MODULE);
+        if (IS_ERR(rtc->rtc)) {
+                ret = PTR_ERR(rtc->rtc);
+                dev_err(&pdev->dev, "RTC registration failed, err %d\n", ret);
+                return ret;
+        }
+
+        ret = request_threaded_irq(rtc->irq, NULL, tps80031_rtc_irq,
+                        IRQF_ONESHOT | IRQF_EARLY_RESUME,
+                        dev_name(&pdev->dev), rtc);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "request IRQ:%d failed, err = %d\n",
+                         rtc->irq, ret);
+                rtc_device_unregister(rtc->rtc);
+                return ret;
+        }
+        device_set_wakeup_capable(&pdev->dev, 1);
+        return 0;
+}
+
+static int tps80031_rtc_remove(struct platform_device *pdev)
+{
+        struct tps80031_rtc *rtc = platform_get_drvdata(pdev);
+
+        free_irq(rtc->irq, rtc);
+        rtc_device_unregister(rtc->rtc);
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tps80031_rtc_suspend(struct device *dev)
+{
+        struct tps80031_rtc *rtc = dev_get_drvdata(dev);
+
+        if (device_may_wakeup(dev))
+                enable_irq_wake(rtc->irq);
+        return 0;
+}
+
+static int tps80031_rtc_resume(struct device *dev)
+{
+        struct tps80031_rtc *rtc = dev_get_drvdata(dev);
+
+        if (device_may_wakeup(dev))
+                disable_irq_wake(rtc->irq);
+        return 0;
+};
+#endif
+
+static const struct dev_pm_ops tps80031_pm_ops = {
+        SET_SYSTEM_SLEEP_PM_OPS(tps80031_rtc_suspend, tps80031_rtc_resume)
+};
+
+static struct platform_driver tps80031_rtc_driver = {
+        .driver = {
+                .name   = "tps80031-rtc",
+                .owner  = THIS_MODULE,
+                .pm     = &tps80031_pm_ops,
+        },
+        .probe  = tps80031_rtc_probe,
+        .remove = tps80031_rtc_remove,
+};
+
+module_platform_driver(tps80031_rtc_driver);
+
+MODULE_ALIAS("platform:tps80031-rtc");
+MODULE_DESCRIPTION("TI TPS80031/TPS80032 RTC driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");