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    Subject[PATCH V2] rtc: add RTC driver for TPS80031/TPS80032
    Date
    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.

    Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
    ---
    Changes from V1:
    - remvoe the checks for alarm time whether this is past or not in set_alarm.
    - add error prints if rtc registration failed.
    - add include of pm.h

    drivers/rtc/Kconfig | 8 +
    drivers/rtc/Makefile | 1 +
    drivers/rtc/rtc-tps80031.c | 349 ++++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 358 insertions(+), 0 deletions(-)
    create mode 100644 drivers/rtc/rtc-tps80031.c

    diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
    index 923a9da..adf8a97 100644
    --- a/drivers/rtc/Kconfig
    +++ b/drivers/rtc/Kconfig
    @@ -370,6 +370,14 @@ 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 4418ef3..9881e35 100644
    --- a/drivers/rtc/Makefile
    +++ b/drivers/rtc/Makefile
    @@ -113,6 +113,7 @@ 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 0000000..8e45cb4
    --- /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 __devinit 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 __devexit 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 = __devexit_p(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");
    --
    1.7.1.1


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