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>

3 files changed, 358 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e94ae65af171..d52183440691 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -396,6 +396,14 @@ 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_TPS80031
+        tristate "TI TPS80031/TPS80032 RTC driver"
+        depends on MFD_TPS80031
+        help
+          TI Power Managment IC TPS80031 supports RTC functionality
+          along with alarm. This driver supports the RTC driver for
+          the TPS80031 RTC module.
+
 config RTC_DRV_RC5T583
         tristate "RICOH 5T583 RTC driver"
         depends on MFD_RC5T583
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 1a837767b68d..cd03fb33c14c 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -116,6 +116,7 @@ obj-$(CONFIG_RTC_DRV_TILE)	+= rtc-tile.o
 obj-$(CONFIG_RTC_DRV_TWL4030)   += rtc-twl.o
 obj-$(CONFIG_RTC_DRV_TPS6586X)  += rtc-tps6586x.o
 obj-$(CONFIG_RTC_DRV_TPS65910)  += rtc-tps65910.o
+obj-$(CONFIG_RTC_DRV_TPS80031)  += rtc-tps80031.o
 obj-$(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-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;
+        }