Patchwork [3/3] drivers: rtc: Add support for Qualcomm PMIC8xxx RTC

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Submitter Anirudh Ghayal
Date March 26, 2011, 4:52 p.m.
Message ID <1301158345-22206-4-git-send-email-aghayal@codeaurora.org>
Download mbox | patch
Permalink /patch/88468/
State New
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Anirudh Ghayal - March 26, 2011, 4:52 p.m.
PMIC8xxx is Qualcomm's power management IC. A
32-bit RTC is housed inside this PMIC. The RTC driver
uses SSBI to communicate with the RTC module.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>
---
 drivers/rtc/Kconfig            |    9 +
 drivers/rtc/Makefile           |    1 +
 drivers/rtc/rtc-pm8xxx.c       |  567 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/pm8xxx/rtc.h |   25 ++
 4 files changed, 602 insertions(+), 0 deletions(-)
 create mode 100644 drivers/rtc/rtc-pm8xxx.c
 create mode 100644 include/linux/mfd/pm8xxx/rtc.h
Wan ZongShun - March 31, 2011, 4:48 p.m.
Hi Anirudh,

Some advice below:

2011/3/27 Anirudh Ghayal <aghayal@codeaurora.org>:
> PMIC8xxx is Qualcomm's power management IC. A
> 32-bit RTC is housed inside this PMIC. The RTC driver
> uses SSBI to communicate with the RTC module.
>
> Cc: Alessandro Zummo <a.zummo@towertech.it>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
> Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>
> ---
>  drivers/rtc/Kconfig            |    9 +
>  drivers/rtc/Makefile           |    1 +
>  drivers/rtc/rtc-pm8xxx.c       |  567 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/pm8xxx/rtc.h |   25 ++
>  4 files changed, 602 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/rtc/rtc-pm8xxx.c
>  create mode 100644 include/linux/mfd/pm8xxx/rtc.h
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index e187887..a66672a 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -995,4 +995,13 @@ config RTC_DRV_TEGRA
>          This drive can also be built as a module. If so, the module
>          will be called rtc-tegra.
>
> +config RTC_DRV_PM8XXX
> +       tristate "Qualcomm PMIC8XXX RTC"
> +       depends on MFD_PM8XXX
> +       help
> +         Say Y here if you want to support the Qualcomm PMIC8XXX RTC.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called rtc-pm8xxx.
> +
>  endif # RTC_CLASS
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index ca91c3c..ff40366 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -72,6 +72,7 @@ obj-$(CONFIG_RTC_DRV_PCF8563) += rtc-pcf8563.o
>  obj-$(CONFIG_RTC_DRV_PCF8583)  += rtc-pcf8583.o
>  obj-$(CONFIG_RTC_DRV_PCF2123)  += rtc-pcf2123.o
>  obj-$(CONFIG_RTC_DRV_PCF50633) += rtc-pcf50633.o
> +obj-$(CONFIG_RTC_DRV_PM8XXX)    += rtc-pm8xxx.o
>  obj-$(CONFIG_RTC_DRV_PL030)    += rtc-pl030.o
>  obj-$(CONFIG_RTC_DRV_PL031)    += rtc-pl031.o
>  obj-$(CONFIG_RTC_DRV_PS3)      += rtc-ps3.o
> diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
> new file mode 100644
> index 0000000..ce2dad3
> --- /dev/null
> +++ b/drivers/rtc/rtc-pm8xxx.c
> @@ -0,0 +1,567 @@
> +/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that 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.
> + */
> +
> +#define pr_fmt(fmt) "%s: " fmt, __func__
> +

 why add pr_fmt here?

> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/rtc.h>
> +#include <linux/pm.h>
> +#include <linux/slab.h>
> +#include<linux/spinlock.h>
> +
> +#include <linux/mfd/pm8xxx/core.h>
> +#include <linux/mfd/pm8xxx/rtc.h>
> +
> +/* RTC Register offsets from RTC CTRL REG */
> +#define PM8XXX_ALARM_CTRL_OFFSET 0x01
> +#define PM8XXX_RTC_WRITE_OFFSET 0x02
> +#define PM8XXX_RTC_READ_OFFSET 0x06
> +#define PM8XXX_ALARM_RW_OFFSET 0x0A
> +
> +/* RTC_CTRL register bit fields */
> +#define PM8xxx_RTC_ENABLE      BIT(7)
> +#define PM8xxx_RTC_ALARM_ENABLE        BIT(1)
> +#define PM8xxx_RTC_ALARM_CLEAR  BIT(0)
> +
> +#define NUM_8_BIT_RTC_REGS     0x4
> +
> +/**
> + * struct pm8xxx_rtc - rtc driver internal structure
> + * @rtc: rtc device for this driver
> + * @rtc_alarm_irq: rtc alarm irq number
> + */
> +struct pm8xxx_rtc {
> +       struct rtc_device *rtc;
> +       int rtc_alarm_irq;
> +       int rtc_base;
> +       int rtc_read_base;
> +       int rtc_write_base;
> +       int alarm_rw_base;
> +       u8  ctrl_reg;
> +       struct device *parent;
> +       spinlock_t ctrl_reg_lock;
> +};
> +
> +/*
> + * The RTC registers need to be read/written one byte at a time. This is a
> + * hardware limitation.
> + */
> +static int pm8xxx_read_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
> +                       int base, int count)
> +{
> +       int i, rc;
> +
> +       for (i = 0; i < count; i++) {
> +               rc = pm8xxx_readb(rtc_dd->parent, base + i, &rtc_val[i]);
> +               if (rc < 0) {
> +                       pr_err("PM8xxx read failed\n");

All pr_err are not so good, please try to use dev_err.

> +                       return rc;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static int pm8xxx_write_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
> +                       int base, int count)
> +{
> +       int i, rc;
> +
> +       for (i = 0; i < count; i++) {
> +               rc = pm8xxx_writeb(rtc_dd->parent, base + i, rtc_val[i]);
> +               if (rc < 0) {
> +                       pr_err("PM8xxx write failed\n");
> +                       return rc;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +
> +/*
> + * Steps to write the RTC registers.
> + * 1. Disable alarm if enabled.
> + * 2. Write 0x00 to LSB.
> + * 3. Write Byte[1], Byte[2], Byte[3] then Byte[0].
> + * 4. Enable alarm if disabled in step 1.
> + */
> +static int
> +pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +       int rc;
> +       unsigned long secs, irq_flags;
> +       u8 value[4], reg = 0, alarm_enabled = 0, ctrl_reg;
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +
> +       rtc_tm_to_time(tm, &secs);
> +
> +       value[0] = secs & 0xFF;
> +       value[1] = (secs >> 8) & 0xFF;
> +       value[2] = (secs >> 16) & 0xFF;
> +       value[3] = (secs >> 24) & 0xFF;
> +
> +       dev_dbg(dev, "Seconds value to be written to RTC = %lu\n", secs);
> +
> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
> +       ctrl_reg = rtc_dd->ctrl_reg;
> +
> +       if (ctrl_reg & PM8xxx_RTC_ALARM_ENABLE) {
> +               alarm_enabled = 1;
> +               ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE;
> +               rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
> +                                                                       1);
> +               if (rc < 0) {
> +                       dev_err(dev, "PM8xxx write failed\n");
> +                       goto rtc_rw_fail;
> +               }
> +       } else
> +               spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
> +
> +       /* Write Byte[1], Byte[2], Byte[3], Byte[0] */
> +       /* Write 0 to Byte[0] */
> +       reg = 0;
> +       rc = pm8xxx_write_wrapper(rtc_dd, &reg, rtc_dd->rtc_write_base, 1);
> +       if (rc < 0) {
> +               dev_err(dev, "PM8xxx write failed\n");
> +               goto rtc_rw_fail;
> +       }
> +
> +       /* Write Byte[1], Byte[2], Byte[3] */
> +       rc = pm8xxx_write_wrapper(rtc_dd, value + 1,
> +                                       rtc_dd->rtc_write_base + 1, 3);
> +       if (rc < 0) {
> +               dev_err(dev, "Write to RTC registers failed\n");
> +               goto rtc_rw_fail;
> +       }
> +
> +       /* Write Byte[0] */
> +       rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->rtc_write_base, 1);
> +       if (rc < 0) {
> +               dev_err(dev, "Write to RTC register failed\n");
> +               goto rtc_rw_fail;
> +       }
> +
> +       if (alarm_enabled) {
> +               ctrl_reg |= PM8xxx_RTC_ALARM_ENABLE;
> +               rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
> +                                                                       1);
> +               if (rc < 0) {
> +                       dev_err(dev, "PM8xxx write failed\n");
> +                       goto rtc_rw_fail;
> +               }
> +       }
> +
> +       rtc_dd->ctrl_reg = ctrl_reg;
> +
> +rtc_rw_fail:
> +       if (alarm_enabled)
> +               spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
> +
> +       return rc;
> +}
> +
> +static int
> +pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +       int rc;
> +       u8 value[4], reg;
> +       unsigned long secs;
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +
> +       rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->rtc_read_base,
> +                                                       NUM_8_BIT_RTC_REGS);
> +       if (rc < 0) {
> +               dev_err(dev, "RTC time read failed\n");
> +               return rc;
> +       }
> +
> +       /*
> +        * Read the LSB again and check if there has been a carry over.
> +        * If there is, redo the read operation.
> +        */
> +       rc = pm8xxx_read_wrapper(rtc_dd, &reg, rtc_dd->rtc_read_base, 1);
> +       if (rc < 0) {
> +               dev_err(dev, "PM8xxx read failed\n");
> +               return rc;
> +       }
> +
> +       if (unlikely(reg < value[0])) {
> +               rc = pm8xxx_read_wrapper(rtc_dd, value,
> +                               rtc_dd->rtc_read_base, NUM_8_BIT_RTC_REGS);
> +               if (rc < 0) {
> +                       dev_err(dev, "RTC time read failed\n");
> +                       return rc;
> +               }
> +       }
> +
> +       secs = value[0] | (value[1] << 8) | (value[2] << 16) \
> +                                               | (value[3] << 24);
> +
> +       rtc_time_to_tm(secs, tm);
> +
> +       rc = rtc_valid_tm(tm);
> +       if (rc < 0) {
> +               dev_err(dev, "Invalid time read from PM8xxx\n");
> +               return rc;
> +       }
> +
> +       dev_dbg(dev, "secs = %lu, h:m:s == %d:%d:%d, d/m/y = %d/%d/%d\n",
> +                       secs, tm->tm_hour, tm->tm_min, tm->tm_sec,
> +                       tm->tm_mday, tm->tm_mon, tm->tm_year);
> +
> +       return 0;
> +}
> +
> +static int
> +pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
> +{
> +       int rc;
> +       u8 value[4], ctrl_reg;
> +       unsigned long secs, secs_rtc, irq_flags;
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +       struct rtc_time rtc_tm;
> +
> +       rtc_tm_to_time(&alarm->time, &secs);
> +
> +       /*
> +        * Read the current RTC time and verify if the alarm time is in the
> +        * past. If yes, return invalid.
> +        */
> +       rc = pm8xxx_rtc_read_time(dev, &rtc_tm);
> +       if (rc < 0) {
> +               dev_err(dev, "Unamble to read RTC time\n");
> +               return -EINVAL;
> +       }
> +
> +       rtc_tm_to_time(&rtc_tm, &secs_rtc);
> +       if (secs < secs_rtc) {
> +               dev_err(dev, "Trying to set alarm in the past\n");
> +               return -EINVAL;
> +       }
> +
> +       value[0] = secs & 0xFF;
> +       value[1] = (secs >> 8) & 0xFF;
> +       value[2] = (secs >> 16) & 0xFF;
> +       value[3] = (secs >> 24) & 0xFF;
> +
> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
> +
> +       rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
> +                                                       NUM_8_BIT_RTC_REGS);
> +       if (rc < 0) {
> +               dev_err(dev, "Write to RTC ALARM registers failed\n");
> +               goto rtc_rw_fail;
> +       }
> +
> +       ctrl_reg = rtc_dd->ctrl_reg;
> +       ctrl_reg = (alarm->enabled) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
> +                                       (ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE);
> +
> +       rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
> +       if (rc < 0) {
> +               dev_err(dev, "PM8xxx write failed\n");
> +               goto rtc_rw_fail;
> +       }
> +
> +       rtc_dd->ctrl_reg = ctrl_reg;
> +
> +       dev_dbg(dev, "Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
> +                       alarm->time.tm_hour, alarm->time.tm_min,
> +                       alarm->time.tm_sec, alarm->time.tm_mday,
> +                       alarm->time.tm_mon, alarm->time.tm_year);
> +rtc_rw_fail:
> +       spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
> +       return rc;
> +}
> +
> +static int
> +pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
> +{
> +       int rc;
> +       u8 value[4];
> +       unsigned long secs;
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +
> +       rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
> +                       NUM_8_BIT_RTC_REGS);
> +       if (rc < 0) {
> +               dev_err(dev, "RTC alarm time read failed\n");
> +               return rc;
> +       }
> +
> +       secs = value[0] | (value[1] << 8) | (value[2] << 16) | \
> +                                                (value[3] << 24);
> +
> +       rtc_time_to_tm(secs, &alarm->time);
> +
> +       rc = rtc_valid_tm(&alarm->time);
> +       if (rc < 0) {
> +               dev_err(dev, "Invalid time read from PM8xxx\n");
> +               return rc;
> +       }
> +
> +       dev_dbg(dev, "Alarm set for - h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
> +               alarm->time.tm_hour, alarm->time.tm_min,
> +                               alarm->time.tm_sec, alarm->time.tm_mday,
> +                               alarm->time.tm_mon, alarm->time.tm_year);
> +
> +       return 0;
> +}
> +
> +
> +static int
> +pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
> +{
> +       int rc;
> +       unsigned long irq_flags;
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +       u8 ctrl_reg;
> +
> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
> +       ctrl_reg = rtc_dd->ctrl_reg;
> +       ctrl_reg = (enabled) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
> +                               (ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE);
> +
> +       rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
> +       if (rc < 0) {
> +               dev_err(dev, "PM8xxx write failed\n");
> +               goto rtc_rw_fail;
> +       }
> +
> +       rtc_dd->ctrl_reg = ctrl_reg;
> +
> +rtc_rw_fail:
> +       spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
> +       return rc;
> +}
> +
> +static struct rtc_class_ops pm8xxx_rtc_ops = {
> +       .read_time      = pm8xxx_rtc_read_time,
> +       .set_alarm      = pm8xxx_rtc_set_alarm,
> +       .read_alarm     = pm8xxx_rtc_read_alarm,
> +       .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
> +};
> +
> +static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
> +{
> +       struct pm8xxx_rtc *rtc_dd = dev_id;
> +       u8 ctrl_reg;
> +       int rc;
> +       unsigned long irq_flags;
> +
> +       rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF);
> +
> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
> +
> +       /* Clear the alarm enable bit */
> +       ctrl_reg = rtc_dd->ctrl_reg;
> +       ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE;
> +
> +       rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
> +       if (rc < 0) {
> +               spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
> +               pr_err("PM8xxx write failed!\n");
> +               goto rtc_alarm_handled;
> +       }
> +
> +       rtc_dd->ctrl_reg = ctrl_reg;
> +       spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
> +
> +       /* Clear RTC alarm register */
> +       rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base +
> +                                               PM8XXX_ALARM_CTRL_OFFSET, 1);
> +       if (rc < 0) {
> +               pr_err("PM8xxx write failed!\n");
> +               goto rtc_alarm_handled;
> +       }
> +
> +       ctrl_reg &= ~PM8xxx_RTC_ALARM_CLEAR;
> +       rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base +
> +                                               PM8XXX_ALARM_CTRL_OFFSET, 1);
> +       if (rc < 0)
> +               pr_err("PM8xxx write failed!\n");
> +
> +rtc_alarm_handled:
> +       return IRQ_HANDLED;
> +}
> +
> +static int __devinit pm8xxx_rtc_probe(struct platform_device *pdev)
> +{
> +       int rc;
> +       u8 ctrl_reg;
> +       bool rtc_write_enable = false;
> +       struct pm8xxx_rtc *rtc_dd;
> +       struct resource *rtc_resource;
> +       const struct pm8xxx_rtc_platform_data *pdata =
> +               pdev->dev.platform_data;
> +
> +       if (pdata != NULL)
> +               rtc_write_enable = pdata->rtc_write_enable;
> +
> +       rtc_dd = kzalloc(sizeof(*rtc_dd), GFP_KERNEL);
> +       if (rtc_dd == NULL) {
> +               dev_err(&pdev->dev, "Unable to allocate memory!\n");
> +               return -ENOMEM;
> +       }
> +
> +       /* Initialise spinlock to protect RTC cntrol register */
> +       spin_lock_init(&rtc_dd->ctrl_reg_lock);
> +
> +       rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 0);
> +       if (!rtc_dd->rtc_alarm_irq) {
> +               dev_err(&pdev->dev, "Alarm IRQ resource absent!\n");
> +               rc = -ENXIO;
> +               goto fail_rtc_enable;
> +       }
> +

In fact, the 'platform_get_irq' maybe return -ENXIO, so you should use
the 'if (rtc_dd->rtc_alarm_irq < 0)' instead of  '!' to judge
the get irq action.

> +       rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
> +                                                       "pmic_rtc_base");
> +       if (rtc_resource)
> +               rtc_dd->rtc_base = rtc_resource->start;
> +       if (!rtc_dd->rtc_base) {
> +               dev_err(&pdev->dev, "RTC IO resource absent!\n");
> +               rc = -ENXIO;
> +               goto fail_rtc_enable;
> +       }


      rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
                                                       "pmic_rtc_base");
       if !(rtc_resource && rtc_resource->start) {
               dev_err(&pdev->dev, "RTC IO resource absent!\n");
               rc = -ENXIO;
               goto fail_rtc_enable;
       }
     rtc_dd->rtc_base = rtc_resource->start;

Do you think above code style is better?

> +
> +       /* Setup RTC register addresses */
> +       rtc_dd->rtc_write_base = rtc_dd->rtc_base + PM8XXX_RTC_WRITE_OFFSET;
> +       rtc_dd->rtc_read_base = rtc_dd->rtc_base + PM8XXX_RTC_READ_OFFSET;
> +       rtc_dd->alarm_rw_base = rtc_dd->rtc_base + PM8XXX_ALARM_RW_OFFSET;
> +
> +       rtc_dd->parent = pdev->dev.parent;
> +
> +       /* Check if the RTC is on, else turn it on */
> +       rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
> +       if (rc < 0) {
> +               dev_err(&pdev->dev, "PM8xxx read failed!\n");
> +               goto fail_rtc_enable;
> +       }
> +
> +       if (!(ctrl_reg & PM8xxx_RTC_ENABLE)) {
> +               ctrl_reg |= PM8xxx_RTC_ENABLE;
> +               rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
> +                                                                       1);
> +               if (rc < 0) {
> +                       dev_err(&pdev->dev, "PM8xxx write failed!\n");
> +                       goto fail_rtc_enable;
> +               }
> +       }
> +
> +       rtc_dd->ctrl_reg = ctrl_reg;
> +       if (rtc_write_enable == true)
> +               pm8xxx_rtc_ops.set_time = pm8xxx_rtc_set_time,
> +
> +       platform_set_drvdata(pdev, rtc_dd);
> +
> +       /* Register the RTC device */
> +       rtc_dd->rtc = rtc_device_register("pm8xxx_rtc", &pdev->dev,
> +                               &pm8xxx_rtc_ops, THIS_MODULE);
> +       if (IS_ERR(rtc_dd->rtc)) {
> +               dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n",
> +                                       __func__, PTR_ERR(rtc_dd->rtc));
> +               rc = PTR_ERR(rtc_dd->rtc);
> +               goto fail_rtc_enable;
> +       }
> +
> +       /* Request the alarm IRQ */
> +       rc = request_any_context_irq(rtc_dd->rtc_alarm_irq,
> +                                pm8xxx_alarm_trigger, IRQF_TRIGGER_RISING,
> +                                "pm8xxx_rtc_alarm", rtc_dd);
> +       if (rc < 0) {
> +               dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc);
> +               goto fail_req_irq;
> +       }
> +
> +       device_init_wakeup(&pdev->dev, 1);
> +
> +       dev_dbg(&pdev->dev, "Probe success !!\n");
> +
> +       return 0;
> +
> +fail_req_irq:
> +       rtc_device_unregister(rtc_dd->rtc);
> +fail_rtc_enable:
> +       platform_set_drvdata(pdev, NULL);
> +       kfree(rtc_dd);
> +       return rc;
> +}
> +
> +#ifdef CONFIG_PM
> +static int pm8xxx_rtc_resume(struct device *dev)
> +{
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +
> +       if (device_may_wakeup(dev))
> +               disable_irq_wake(rtc_dd->rtc_alarm_irq);
> +
> +       return 0;
> +}
> +
> +static int pm8xxx_rtc_suspend(struct device *dev)
> +{
> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
> +
> +       if (device_may_wakeup(dev))
> +               enable_irq_wake(rtc_dd->rtc_alarm_irq);
> +
> +       return 0;
> +}
> +
> +static const struct dev_pm_ops pm8xxx_rtc_pm_ops = {
> +       .suspend = pm8xxx_rtc_suspend,
> +       .resume = pm8xxx_rtc_resume,
> +};
> +#endif
> +static int __devexit pm8xxx_rtc_remove(struct platform_device *pdev)
> +{
> +       struct pm8xxx_rtc *rtc_dd = platform_get_drvdata(pdev);
> +
> +       device_init_wakeup(&pdev->dev, 0);
> +       free_irq(rtc_dd->rtc_alarm_irq, rtc_dd);
> +       rtc_device_unregister(rtc_dd->rtc);
> +       platform_set_drvdata(pdev, NULL);
> +       kfree(rtc_dd);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver pm8xxx_rtc_driver = {
> +       .probe          = pm8xxx_rtc_probe,
> +       .remove         = __devexit_p(pm8xxx_rtc_remove),
> +       .driver = {
> +               .name   = PM8XXX_RTC_DEV_NAME,
> +               .owner  = THIS_MODULE,
> +#ifdef CONFIG_PM
> +               .pm     = &pm8xxx_rtc_pm_ops,
> +#endif
> +       },
> +};
> +
> +static int __init pm8xxx_rtc_init(void)
> +{
> +       return platform_driver_register(&pm8xxx_rtc_driver);
> +}
> +module_init(pm8xxx_rtc_init);
> +
> +static void __exit pm8xxx_rtc_exit(void)
> +{
> +       platform_driver_unregister(&pm8xxx_rtc_driver);
> +}
> +module_exit(pm8xxx_rtc_exit);
> +
> +MODULE_ALIAS("platform:rtc-pm8xxx");
> +MODULE_DESCRIPTION("PMIC8xxx RTC driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Anirudh Ghayal <aghayal@codeaurora.org>");
> diff --git a/include/linux/mfd/pm8xxx/rtc.h b/include/linux/mfd/pm8xxx/rtc.h
> new file mode 100644
> index 0000000..2528e1d
> --- /dev/null
> +++ b/include/linux/mfd/pm8xxx/rtc.h
> @@ -0,0 +1,25 @@
> +/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that 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.
> + */
> +
> +#ifndef __RTC_PM8XXX_H__
> +#define __RTC_PM8XXX_H__
> +
> +#define PM8XXX_RTC_DEV_NAME     "rtc-pm8xxx"
> +/**
> + * struct pm8058_rtc_pdata - RTC driver platform data
> + * @rtc_write_enable: variable stating RTC write capability
> + */
> +struct pm8xxx_rtc_platform_data {
> +       bool rtc_write_enable;
> +};
> +
> +#endif /* __RTC_PM8XXX_H__ */
> --
> 1.7.3.5
>
> --
> You received this message because you are subscribed to "rtc-linux".
> Membership options at http://groups.google.com/group/rtc-linux .
> Please read http://groups.google.com/group/rtc-linux/web/checklist
> before submitting a driver.
Anirudh Ghayal - April 1, 2011, 8:49 a.m.
Hi Wan,

Thank you for reviewing this. I will submit a V2 patch with the changes.

On 3/31/2011 10:18 PM, Wan ZongShun wrote:
> Hi Anirudh,
>
> Some advice below:
>
> 2011/3/27 Anirudh Ghayal<aghayal@codeaurora.org>:
>> PMIC8xxx is Qualcomm's power management IC. A
>> 32-bit RTC is housed inside this PMIC. The RTC driver
>> uses SSBI to communicate with the RTC module.
>>
>> Cc: Alessandro Zummo<a.zummo@towertech.it>
>> Cc: Lars-Peter Clausen<lars@metafoo.de>
>> Signed-off-by: Anirudh Ghayal<aghayal@codeaurora.org>
>> ---
>>   drivers/rtc/Kconfig            |    9 +
>>   drivers/rtc/Makefile           |    1 +
>>   drivers/rtc/rtc-pm8xxx.c       |  567 ++++++++++++++++++++++++++++++++++++++++
>>   include/linux/mfd/pm8xxx/rtc.h |   25 ++
>>   4 files changed, 602 insertions(+), 0 deletions(-)
>>   create mode 100644 drivers/rtc/rtc-pm8xxx.c
>>   create mode 100644 include/linux/mfd/pm8xxx/rtc.h
>>
>> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
>> index e187887..a66672a 100644
>> --- a/drivers/rtc/Kconfig
>> +++ b/drivers/rtc/Kconfig
>> @@ -995,4 +995,13 @@ config RTC_DRV_TEGRA
>>           This drive can also be built as a module. If so, the module
>>           will be called rtc-tegra.
>>
>> +config RTC_DRV_PM8XXX
>> +       tristate "Qualcomm PMIC8XXX RTC"
>> +       depends on MFD_PM8XXX
>> +       help
>> +         Say Y here if you want to support the Qualcomm PMIC8XXX RTC.
>> +
>> +         To compile this driver as a module, choose M here: the
>> +         module will be called rtc-pm8xxx.
>> +
>>   endif # RTC_CLASS
>> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
>> index ca91c3c..ff40366 100644
>> --- a/drivers/rtc/Makefile
>> +++ b/drivers/rtc/Makefile
>> @@ -72,6 +72,7 @@ obj-$(CONFIG_RTC_DRV_PCF8563) += rtc-pcf8563.o
>>   obj-$(CONFIG_RTC_DRV_PCF8583)  += rtc-pcf8583.o
>>   obj-$(CONFIG_RTC_DRV_PCF2123)  += rtc-pcf2123.o
>>   obj-$(CONFIG_RTC_DRV_PCF50633) += rtc-pcf50633.o
>> +obj-$(CONFIG_RTC_DRV_PM8XXX)    += rtc-pm8xxx.o
>>   obj-$(CONFIG_RTC_DRV_PL030)    += rtc-pl030.o
>>   obj-$(CONFIG_RTC_DRV_PL031)    += rtc-pl031.o
>>   obj-$(CONFIG_RTC_DRV_PS3)      += rtc-ps3.o
>> diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
>> new file mode 100644
>> index 0000000..ce2dad3
>> --- /dev/null
>> +++ b/drivers/rtc/rtc-pm8xxx.c
>> @@ -0,0 +1,567 @@
>> +/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 and
>> + * only version 2 as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that 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.
>> + */
>> +
>> +#define pr_fmt(fmt) "%s: " fmt, __func__
>> +
>
>   why add pr_fmt here?
Will not need this after I move to dev_* calls.
>
>> +#include<linux/module.h>
>> +#include<linux/init.h>
>> +#include<linux/rtc.h>
>> +#include<linux/pm.h>
>> +#include<linux/slab.h>
>> +#include<linux/spinlock.h>
>> +
>> +#include<linux/mfd/pm8xxx/core.h>
>> +#include<linux/mfd/pm8xxx/rtc.h>
>> +
>> +/* RTC Register offsets from RTC CTRL REG */
>> +#define PM8XXX_ALARM_CTRL_OFFSET 0x01
>> +#define PM8XXX_RTC_WRITE_OFFSET 0x02
>> +#define PM8XXX_RTC_READ_OFFSET 0x06
>> +#define PM8XXX_ALARM_RW_OFFSET 0x0A
>> +
>> +/* RTC_CTRL register bit fields */
>> +#define PM8xxx_RTC_ENABLE      BIT(7)
>> +#define PM8xxx_RTC_ALARM_ENABLE        BIT(1)
>> +#define PM8xxx_RTC_ALARM_CLEAR  BIT(0)
>> +
>> +#define NUM_8_BIT_RTC_REGS     0x4
>> +
>> +/**
>> + * struct pm8xxx_rtc - rtc driver internal structure
>> + * @rtc: rtc device for this driver
>> + * @rtc_alarm_irq: rtc alarm irq number
>> + */
>> +struct pm8xxx_rtc {
>> +       struct rtc_device *rtc;
>> +       int rtc_alarm_irq;
>> +       int rtc_base;
>> +       int rtc_read_base;
>> +       int rtc_write_base;
>> +       int alarm_rw_base;
>> +       u8  ctrl_reg;
>> +       struct device *parent;
>> +       spinlock_t ctrl_reg_lock;
>> +};
>> +
>> +/*
>> + * The RTC registers need to be read/written one byte at a time. This is a
>> + * hardware limitation.
>> + */
>> +static int pm8xxx_read_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
>> +                       int base, int count)
>> +{
>> +       int i, rc;
>> +
>> +       for (i = 0; i<  count; i++) {
>> +               rc = pm8xxx_readb(rtc_dd->parent, base + i,&rtc_val[i]);
>> +               if (rc<  0) {
>> +                       pr_err("PM8xxx read failed\n");
>
> All pr_err are not so good, please try to use dev_err.

Ok.

>
>> +                       return rc;
>> +               }
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int pm8xxx_write_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
>> +                       int base, int count)
>> +{
>> +       int i, rc;
>> +
>> +       for (i = 0; i<  count; i++) {
>> +               rc = pm8xxx_writeb(rtc_dd->parent, base + i, rtc_val[i]);
>> +               if (rc<  0) {
>> +                       pr_err("PM8xxx write failed\n");
>> +                       return rc;
>> +               }
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +
>> +/*
>> + * Steps to write the RTC registers.
>> + * 1. Disable alarm if enabled.
>> + * 2. Write 0x00 to LSB.
>> + * 3. Write Byte[1], Byte[2], Byte[3] then Byte[0].
>> + * 4. Enable alarm if disabled in step 1.
>> + */
>> +static int
>> +pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
>> +{
>> +       int rc;
>> +       unsigned long secs, irq_flags;
>> +       u8 value[4], reg = 0, alarm_enabled = 0, ctrl_reg;
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +
>> +       rtc_tm_to_time(tm,&secs);
>> +
>> +       value[0] = secs&  0xFF;
>> +       value[1] = (secs>>  8)&  0xFF;
>> +       value[2] = (secs>>  16)&  0xFF;
>> +       value[3] = (secs>>  24)&  0xFF;
>> +
>> +       dev_dbg(dev, "Seconds value to be written to RTC = %lu\n", secs);
>> +
>> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +       ctrl_reg = rtc_dd->ctrl_reg;
>> +
>> +       if (ctrl_reg&  PM8xxx_RTC_ALARM_ENABLE) {
>> +               alarm_enabled = 1;
>> +               ctrl_reg&= ~PM8xxx_RTC_ALARM_ENABLE;
>> +               rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base,
>> +                                                                       1);
>> +               if (rc<  0) {
>> +                       dev_err(dev, "PM8xxx write failed\n");
>> +                       goto rtc_rw_fail;
>> +               }
>> +       } else
>> +               spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +
>> +       /* Write Byte[1], Byte[2], Byte[3], Byte[0] */
>> +       /* Write 0 to Byte[0] */
>> +       reg = 0;
>> +       rc = pm8xxx_write_wrapper(rtc_dd,&reg, rtc_dd->rtc_write_base, 1);
>> +       if (rc<  0) {
>> +               dev_err(dev, "PM8xxx write failed\n");
>> +               goto rtc_rw_fail;
>> +       }
>> +
>> +       /* Write Byte[1], Byte[2], Byte[3] */
>> +       rc = pm8xxx_write_wrapper(rtc_dd, value + 1,
>> +                                       rtc_dd->rtc_write_base + 1, 3);
>> +       if (rc<  0) {
>> +               dev_err(dev, "Write to RTC registers failed\n");
>> +               goto rtc_rw_fail;
>> +       }
>> +
>> +       /* Write Byte[0] */
>> +       rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->rtc_write_base, 1);
>> +       if (rc<  0) {
>> +               dev_err(dev, "Write to RTC register failed\n");
>> +               goto rtc_rw_fail;
>> +       }
>> +
>> +       if (alarm_enabled) {
>> +               ctrl_reg |= PM8xxx_RTC_ALARM_ENABLE;
>> +               rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base,
>> +                                                                       1);
>> +               if (rc<  0) {
>> +                       dev_err(dev, "PM8xxx write failed\n");
>> +                       goto rtc_rw_fail;
>> +               }
>> +       }
>> +
>> +       rtc_dd->ctrl_reg = ctrl_reg;
>> +
>> +rtc_rw_fail:
>> +       if (alarm_enabled)
>> +               spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +
>> +       return rc;
>> +}
>> +
>> +static int
>> +pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
>> +{
>> +       int rc;
>> +       u8 value[4], reg;
>> +       unsigned long secs;
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +
>> +       rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->rtc_read_base,
>> +                                                       NUM_8_BIT_RTC_REGS);
>> +       if (rc<  0) {
>> +               dev_err(dev, "RTC time read failed\n");
>> +               return rc;
>> +       }
>> +
>> +       /*
>> +        * Read the LSB again and check if there has been a carry over.
>> +        * If there is, redo the read operation.
>> +        */
>> +       rc = pm8xxx_read_wrapper(rtc_dd,&reg, rtc_dd->rtc_read_base, 1);
>> +       if (rc<  0) {
>> +               dev_err(dev, "PM8xxx read failed\n");
>> +               return rc;
>> +       }
>> +
>> +       if (unlikely(reg<  value[0])) {
>> +               rc = pm8xxx_read_wrapper(rtc_dd, value,
>> +                               rtc_dd->rtc_read_base, NUM_8_BIT_RTC_REGS);
>> +               if (rc<  0) {
>> +                       dev_err(dev, "RTC time read failed\n");
>> +                       return rc;
>> +               }
>> +       }
>> +
>> +       secs = value[0] | (value[1]<<  8) | (value[2]<<  16) \
>> +                                               | (value[3]<<  24);
>> +
>> +       rtc_time_to_tm(secs, tm);
>> +
>> +       rc = rtc_valid_tm(tm);
>> +       if (rc<  0) {
>> +               dev_err(dev, "Invalid time read from PM8xxx\n");
>> +               return rc;
>> +       }
>> +
>> +       dev_dbg(dev, "secs = %lu, h:m:s == %d:%d:%d, d/m/y = %d/%d/%d\n",
>> +                       secs, tm->tm_hour, tm->tm_min, tm->tm_sec,
>> +                       tm->tm_mday, tm->tm_mon, tm->tm_year);
>> +
>> +       return 0;
>> +}
>> +
>> +static int
>> +pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>> +{
>> +       int rc;
>> +       u8 value[4], ctrl_reg;
>> +       unsigned long secs, secs_rtc, irq_flags;
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +       struct rtc_time rtc_tm;
>> +
>> +       rtc_tm_to_time(&alarm->time,&secs);
>> +
>> +       /*
>> +        * Read the current RTC time and verify if the alarm time is in the
>> +        * past. If yes, return invalid.
>> +        */
>> +       rc = pm8xxx_rtc_read_time(dev,&rtc_tm);
>> +       if (rc<  0) {
>> +               dev_err(dev, "Unamble to read RTC time\n");
>> +               return -EINVAL;
>> +       }
>> +
>> +       rtc_tm_to_time(&rtc_tm,&secs_rtc);
>> +       if (secs<  secs_rtc) {
>> +               dev_err(dev, "Trying to set alarm in the past\n");
>> +               return -EINVAL;
>> +       }
>> +
>> +       value[0] = secs&  0xFF;
>> +       value[1] = (secs>>  8)&  0xFF;
>> +       value[2] = (secs>>  16)&  0xFF;
>> +       value[3] = (secs>>  24)&  0xFF;
>> +
>> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +
>> +       rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
>> +                                                       NUM_8_BIT_RTC_REGS);
>> +       if (rc<  0) {
>> +               dev_err(dev, "Write to RTC ALARM registers failed\n");
>> +               goto rtc_rw_fail;
>> +       }
>> +
>> +       ctrl_reg = rtc_dd->ctrl_reg;
>> +       ctrl_reg = (alarm->enabled) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
>> +                                       (ctrl_reg&  ~PM8xxx_RTC_ALARM_ENABLE);
>> +
>> +       rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base, 1);
>> +       if (rc<  0) {
>> +               dev_err(dev, "PM8xxx write failed\n");
>> +               goto rtc_rw_fail;
>> +       }
>> +
>> +       rtc_dd->ctrl_reg = ctrl_reg;
>> +
>> +       dev_dbg(dev, "Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
>> +                       alarm->time.tm_hour, alarm->time.tm_min,
>> +                       alarm->time.tm_sec, alarm->time.tm_mday,
>> +                       alarm->time.tm_mon, alarm->time.tm_year);
>> +rtc_rw_fail:
>> +       spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +       return rc;
>> +}
>> +
>> +static int
>> +pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>> +{
>> +       int rc;
>> +       u8 value[4];
>> +       unsigned long secs;
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +
>> +       rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
>> +                       NUM_8_BIT_RTC_REGS);
>> +       if (rc<  0) {
>> +               dev_err(dev, "RTC alarm time read failed\n");
>> +               return rc;
>> +       }
>> +
>> +       secs = value[0] | (value[1]<<  8) | (value[2]<<  16) | \
>> +                                                (value[3]<<  24);
>> +
>> +       rtc_time_to_tm(secs,&alarm->time);
>> +
>> +       rc = rtc_valid_tm(&alarm->time);
>> +       if (rc<  0) {
>> +               dev_err(dev, "Invalid time read from PM8xxx\n");
>> +               return rc;
>> +       }
>> +
>> +       dev_dbg(dev, "Alarm set for - h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
>> +               alarm->time.tm_hour, alarm->time.tm_min,
>> +                               alarm->time.tm_sec, alarm->time.tm_mday,
>> +                               alarm->time.tm_mon, alarm->time.tm_year);
>> +
>> +       return 0;
>> +}
>> +
>> +
>> +static int
>> +pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
>> +{
>> +       int rc;
>> +       unsigned long irq_flags;
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +       u8 ctrl_reg;
>> +
>> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +       ctrl_reg = rtc_dd->ctrl_reg;
>> +       ctrl_reg = (enabled) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
>> +                               (ctrl_reg&  ~PM8xxx_RTC_ALARM_ENABLE);
>> +
>> +       rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base, 1);
>> +       if (rc<  0) {
>> +               dev_err(dev, "PM8xxx write failed\n");
>> +               goto rtc_rw_fail;
>> +       }
>> +
>> +       rtc_dd->ctrl_reg = ctrl_reg;
>> +
>> +rtc_rw_fail:
>> +       spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +       return rc;
>> +}
>> +
>> +static struct rtc_class_ops pm8xxx_rtc_ops = {
>> +       .read_time      = pm8xxx_rtc_read_time,
>> +       .set_alarm      = pm8xxx_rtc_set_alarm,
>> +       .read_alarm     = pm8xxx_rtc_read_alarm,
>> +       .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
>> +};
>> +
>> +static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
>> +{
>> +       struct pm8xxx_rtc *rtc_dd = dev_id;
>> +       u8 ctrl_reg;
>> +       int rc;
>> +       unsigned long irq_flags;
>> +
>> +       rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF);
>> +
>> +       spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +
>> +       /* Clear the alarm enable bit */
>> +       ctrl_reg = rtc_dd->ctrl_reg;
>> +       ctrl_reg&= ~PM8xxx_RTC_ALARM_ENABLE;
>> +
>> +       rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base, 1);
>> +       if (rc<  0) {
>> +               spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +               pr_err("PM8xxx write failed!\n");
>> +               goto rtc_alarm_handled;
>> +       }
>> +
>> +       rtc_dd->ctrl_reg = ctrl_reg;
>> +       spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
>> +
>> +       /* Clear RTC alarm register */
>> +       rc = pm8xxx_read_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base +
>> +                                               PM8XXX_ALARM_CTRL_OFFSET, 1);
>> +       if (rc<  0) {
>> +               pr_err("PM8xxx write failed!\n");
>> +               goto rtc_alarm_handled;
>> +       }
>> +
>> +       ctrl_reg&= ~PM8xxx_RTC_ALARM_CLEAR;
>> +       rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base +
>> +                                               PM8XXX_ALARM_CTRL_OFFSET, 1);
>> +       if (rc<  0)
>> +               pr_err("PM8xxx write failed!\n");
>> +
>> +rtc_alarm_handled:
>> +       return IRQ_HANDLED;
>> +}
>> +
>> +static int __devinit pm8xxx_rtc_probe(struct platform_device *pdev)
>> +{
>> +       int rc;
>> +       u8 ctrl_reg;
>> +       bool rtc_write_enable = false;
>> +       struct pm8xxx_rtc *rtc_dd;
>> +       struct resource *rtc_resource;
>> +       const struct pm8xxx_rtc_platform_data *pdata =
>> +               pdev->dev.platform_data;
>> +
>> +       if (pdata != NULL)
>> +               rtc_write_enable = pdata->rtc_write_enable;
>> +
>> +       rtc_dd = kzalloc(sizeof(*rtc_dd), GFP_KERNEL);
>> +       if (rtc_dd == NULL) {
>> +               dev_err(&pdev->dev, "Unable to allocate memory!\n");
>> +               return -ENOMEM;
>> +       }
>> +
>> +       /* Initialise spinlock to protect RTC cntrol register */
>> +       spin_lock_init(&rtc_dd->ctrl_reg_lock);
>> +
>> +       rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 0);
>> +       if (!rtc_dd->rtc_alarm_irq) {
>> +               dev_err(&pdev->dev, "Alarm IRQ resource absent!\n");
>> +               rc = -ENXIO;
>> +               goto fail_rtc_enable;
>> +       }
>> +
>
> In fact, the 'platform_get_irq' maybe return -ENXIO, so you should use
> the 'if (rtc_dd->rtc_alarm_irq<  0)' instead of  '!' to judge
> the get irq action.
>

Right. Thanks for pointing this out. Will correct this in my V2 patch.

>> +       rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
>> +                                                       "pmic_rtc_base");
>> +       if (rtc_resource)
>> +               rtc_dd->rtc_base = rtc_resource->start;
>> +       if (!rtc_dd->rtc_base) {
>> +               dev_err(&pdev->dev, "RTC IO resource absent!\n");
>> +               rc = -ENXIO;
>> +               goto fail_rtc_enable;
>> +       }
>
>
>        rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
>                                                         "pmic_rtc_base");
>         if !(rtc_resource&&  rtc_resource->start) {
>                 dev_err(&pdev->dev, "RTC IO resource absent!\n");
>                 rc = -ENXIO;
>                 goto fail_rtc_enable;
>         }
>       rtc_dd->rtc_base = rtc_resource->start;
>
> Do you think above code style is better?
Yes, looks better.

>
>> +
>> +       /* Setup RTC register addresses */
>> +       rtc_dd->rtc_write_base = rtc_dd->rtc_base + PM8XXX_RTC_WRITE_OFFSET;
>> +       rtc_dd->rtc_read_base = rtc_dd->rtc_base + PM8XXX_RTC_READ_OFFSET;
>> +       rtc_dd->alarm_rw_base = rtc_dd->rtc_base + PM8XXX_ALARM_RW_OFFSET;
>> +
>> +       rtc_dd->parent = pdev->dev.parent;
>> +
>> +       /* Check if the RTC is on, else turn it on */
>> +       rc = pm8xxx_read_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base, 1);
>> +       if (rc<  0) {
>> +               dev_err(&pdev->dev, "PM8xxx read failed!\n");
>> +               goto fail_rtc_enable;
>> +       }
>> +
>> +       if (!(ctrl_reg&  PM8xxx_RTC_ENABLE)) {
>> +               ctrl_reg |= PM8xxx_RTC_ENABLE;
>> +               rc = pm8xxx_write_wrapper(rtc_dd,&ctrl_reg, rtc_dd->rtc_base,
>> +                                                                       1);
>> +               if (rc<  0) {
>> +                       dev_err(&pdev->dev, "PM8xxx write failed!\n");
>> +                       goto fail_rtc_enable;
>> +               }
>> +       }
>> +
>> +       rtc_dd->ctrl_reg = ctrl_reg;
>> +       if (rtc_write_enable == true)
>> +               pm8xxx_rtc_ops.set_time = pm8xxx_rtc_set_time,
>> +
>> +       platform_set_drvdata(pdev, rtc_dd);
>> +
>> +       /* Register the RTC device */
>> +       rtc_dd->rtc = rtc_device_register("pm8xxx_rtc",&pdev->dev,
>> +&pm8xxx_rtc_ops, THIS_MODULE);
>> +       if (IS_ERR(rtc_dd->rtc)) {
>> +               dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n",
>> +                                       __func__, PTR_ERR(rtc_dd->rtc));
>> +               rc = PTR_ERR(rtc_dd->rtc);
>> +               goto fail_rtc_enable;
>> +       }
>> +
>> +       /* Request the alarm IRQ */
>> +       rc = request_any_context_irq(rtc_dd->rtc_alarm_irq,
>> +                                pm8xxx_alarm_trigger, IRQF_TRIGGER_RISING,
>> +                                "pm8xxx_rtc_alarm", rtc_dd);
>> +       if (rc<  0) {
>> +               dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc);
>> +               goto fail_req_irq;
>> +       }
>> +
>> +       device_init_wakeup(&pdev->dev, 1);
>> +
>> +       dev_dbg(&pdev->dev, "Probe success !!\n");
>> +
>> +       return 0;
>> +
>> +fail_req_irq:
>> +       rtc_device_unregister(rtc_dd->rtc);
>> +fail_rtc_enable:
>> +       platform_set_drvdata(pdev, NULL);
>> +       kfree(rtc_dd);
>> +       return rc;
>> +}
>> +
>> +#ifdef CONFIG_PM
>> +static int pm8xxx_rtc_resume(struct device *dev)
>> +{
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +
>> +       if (device_may_wakeup(dev))
>> +               disable_irq_wake(rtc_dd->rtc_alarm_irq);
>> +
>> +       return 0;
>> +}
>> +
>> +static int pm8xxx_rtc_suspend(struct device *dev)
>> +{
>> +       struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
>> +
>> +       if (device_may_wakeup(dev))
>> +               enable_irq_wake(rtc_dd->rtc_alarm_irq);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct dev_pm_ops pm8xxx_rtc_pm_ops = {
>> +       .suspend = pm8xxx_rtc_suspend,
>> +       .resume = pm8xxx_rtc_resume,
>> +};
>> +#endif
>> +static int __devexit pm8xxx_rtc_remove(struct platform_device *pdev)
>> +{
>> +       struct pm8xxx_rtc *rtc_dd = platform_get_drvdata(pdev);
>> +
>> +       device_init_wakeup(&pdev->dev, 0);
>> +       free_irq(rtc_dd->rtc_alarm_irq, rtc_dd);
>> +       rtc_device_unregister(rtc_dd->rtc);
>> +       platform_set_drvdata(pdev, NULL);
>> +       kfree(rtc_dd);
>> +
>> +       return 0;
>> +}
>> +
>> +static struct platform_driver pm8xxx_rtc_driver = {
>> +       .probe          = pm8xxx_rtc_probe,
>> +       .remove         = __devexit_p(pm8xxx_rtc_remove),
>> +       .driver = {
>> +               .name   = PM8XXX_RTC_DEV_NAME,
>> +               .owner  = THIS_MODULE,
>> +#ifdef CONFIG_PM
>> +               .pm     =&pm8xxx_rtc_pm_ops,
>> +#endif
>> +       },
>> +};
>> +
>> +static int __init pm8xxx_rtc_init(void)
>> +{
>> +       return platform_driver_register(&pm8xxx_rtc_driver);
>> +}
>> +module_init(pm8xxx_rtc_init);
>> +
>> +static void __exit pm8xxx_rtc_exit(void)
>> +{
>> +       platform_driver_unregister(&pm8xxx_rtc_driver);
>> +}
>> +module_exit(pm8xxx_rtc_exit);
>> +
>> +MODULE_ALIAS("platform:rtc-pm8xxx");
>> +MODULE_DESCRIPTION("PMIC8xxx RTC driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("Anirudh Ghayal<aghayal@codeaurora.org>");
>> diff --git a/include/linux/mfd/pm8xxx/rtc.h b/include/linux/mfd/pm8xxx/rtc.h
>> new file mode 100644
>> index 0000000..2528e1d
>> --- /dev/null
>> +++ b/include/linux/mfd/pm8xxx/rtc.h
>> @@ -0,0 +1,25 @@
>> +/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 and
>> + * only version 2 as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that 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.
>> + */
>> +
>> +#ifndef __RTC_PM8XXX_H__
>> +#define __RTC_PM8XXX_H__
>> +
>> +#define PM8XXX_RTC_DEV_NAME     "rtc-pm8xxx"
>> +/**
>> + * struct pm8058_rtc_pdata - RTC driver platform data
>> + * @rtc_write_enable: variable stating RTC write capability
>> + */
>> +struct pm8xxx_rtc_platform_data {
>> +       bool rtc_write_enable;
>> +};
>> +
>> +#endif /* __RTC_PM8XXX_H__ */
>> --
>> 1.7.3.5
>>
>> --
>> You received this message because you are subscribed to "rtc-linux".
>> Membership options at http://groups.google.com/group/rtc-linux .
>> Please read http://groups.google.com/group/rtc-linux/web/checklist
>> before submitting a driver.
>
>
>

Thank you,
~Anirudh

Patch

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e187887..a66672a 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -995,4 +995,13 @@  config RTC_DRV_TEGRA
 	  This drive can also be built as a module. If so, the module
 	  will be called rtc-tegra.
 
+config RTC_DRV_PM8XXX
+	tristate "Qualcomm PMIC8XXX RTC"
+	depends on MFD_PM8XXX
+	help
+	  Say Y here if you want to support the Qualcomm PMIC8XXX RTC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rtc-pm8xxx.
+
 endif # RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index ca91c3c..ff40366 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -72,6 +72,7 @@  obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)	+= rtc-pcf8583.o
 obj-$(CONFIG_RTC_DRV_PCF2123)	+= rtc-pcf2123.o
 obj-$(CONFIG_RTC_DRV_PCF50633)	+= rtc-pcf50633.o
+obj-$(CONFIG_RTC_DRV_PM8XXX)    += rtc-pm8xxx.o
 obj-$(CONFIG_RTC_DRV_PL030)	+= rtc-pl030.o
 obj-$(CONFIG_RTC_DRV_PL031)	+= rtc-pl031.o
 obj-$(CONFIG_RTC_DRV_PS3)	+= rtc-ps3.o
diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
new file mode 100644
index 0000000..ce2dad3
--- /dev/null
+++ b/drivers/rtc/rtc-pm8xxx.c
@@ -0,0 +1,567 @@ 
+/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include<linux/spinlock.h>
+
+#include <linux/mfd/pm8xxx/core.h>
+#include <linux/mfd/pm8xxx/rtc.h>
+
+/* RTC Register offsets from RTC CTRL REG */
+#define PM8XXX_ALARM_CTRL_OFFSET 0x01
+#define PM8XXX_RTC_WRITE_OFFSET 0x02
+#define PM8XXX_RTC_READ_OFFSET 0x06
+#define PM8XXX_ALARM_RW_OFFSET 0x0A
+
+/* RTC_CTRL register bit fields */
+#define PM8xxx_RTC_ENABLE	BIT(7)
+#define PM8xxx_RTC_ALARM_ENABLE	BIT(1)
+#define PM8xxx_RTC_ALARM_CLEAR  BIT(0)
+
+#define NUM_8_BIT_RTC_REGS	0x4
+
+/**
+ * struct pm8xxx_rtc - rtc driver internal structure
+ * @rtc: rtc device for this driver
+ * @rtc_alarm_irq: rtc alarm irq number
+ */
+struct pm8xxx_rtc {
+	struct rtc_device *rtc;
+	int rtc_alarm_irq;
+	int rtc_base;
+	int rtc_read_base;
+	int rtc_write_base;
+	int alarm_rw_base;
+	u8  ctrl_reg;
+	struct device *parent;
+	spinlock_t ctrl_reg_lock;
+};
+
+/*
+ * The RTC registers need to be read/written one byte at a time. This is a
+ * hardware limitation.
+ */
+static int pm8xxx_read_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
+			int base, int count)
+{
+	int i, rc;
+
+	for (i = 0; i < count; i++) {
+		rc = pm8xxx_readb(rtc_dd->parent, base + i, &rtc_val[i]);
+		if (rc < 0) {
+			pr_err("PM8xxx read failed\n");
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static int pm8xxx_write_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
+			int base, int count)
+{
+	int i, rc;
+
+	for (i = 0; i < count; i++) {
+		rc = pm8xxx_writeb(rtc_dd->parent, base + i, rtc_val[i]);
+		if (rc < 0) {
+			pr_err("PM8xxx write failed\n");
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+
+/*
+ * Steps to write the RTC registers.
+ * 1. Disable alarm if enabled.
+ * 2. Write 0x00 to LSB.
+ * 3. Write Byte[1], Byte[2], Byte[3] then Byte[0].
+ * 4. Enable alarm if disabled in step 1.
+ */
+static int
+pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	int rc;
+	unsigned long secs, irq_flags;
+	u8 value[4], reg = 0, alarm_enabled = 0, ctrl_reg;
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	rtc_tm_to_time(tm, &secs);
+
+	value[0] = secs & 0xFF;
+	value[1] = (secs >> 8) & 0xFF;
+	value[2] = (secs >> 16) & 0xFF;
+	value[3] = (secs >> 24) & 0xFF;
+
+	dev_dbg(dev, "Seconds value to be written to RTC = %lu\n", secs);
+
+	spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
+	ctrl_reg = rtc_dd->ctrl_reg;
+
+	if (ctrl_reg & PM8xxx_RTC_ALARM_ENABLE) {
+		alarm_enabled = 1;
+		ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE;
+		rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
+									1);
+		if (rc < 0) {
+			dev_err(dev, "PM8xxx write failed\n");
+			goto rtc_rw_fail;
+		}
+	} else
+		spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+
+	/* Write Byte[1], Byte[2], Byte[3], Byte[0] */
+	/* Write 0 to Byte[0] */
+	reg = 0;
+	rc = pm8xxx_write_wrapper(rtc_dd, &reg, rtc_dd->rtc_write_base, 1);
+	if (rc < 0) {
+		dev_err(dev, "PM8xxx write failed\n");
+		goto rtc_rw_fail;
+	}
+
+	/* Write Byte[1], Byte[2], Byte[3] */
+	rc = pm8xxx_write_wrapper(rtc_dd, value + 1,
+					rtc_dd->rtc_write_base + 1, 3);
+	if (rc < 0) {
+		dev_err(dev, "Write to RTC registers failed\n");
+		goto rtc_rw_fail;
+	}
+
+	/* Write Byte[0] */
+	rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->rtc_write_base, 1);
+	if (rc < 0) {
+		dev_err(dev, "Write to RTC register failed\n");
+		goto rtc_rw_fail;
+	}
+
+	if (alarm_enabled) {
+		ctrl_reg |= PM8xxx_RTC_ALARM_ENABLE;
+		rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
+									1);
+		if (rc < 0) {
+			dev_err(dev, "PM8xxx write failed\n");
+			goto rtc_rw_fail;
+		}
+	}
+
+	rtc_dd->ctrl_reg = ctrl_reg;
+
+rtc_rw_fail:
+	if (alarm_enabled)
+		spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+
+	return rc;
+}
+
+static int
+pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	int rc;
+	u8 value[4], reg;
+	unsigned long secs;
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->rtc_read_base,
+							NUM_8_BIT_RTC_REGS);
+	if (rc < 0) {
+		dev_err(dev, "RTC time read failed\n");
+		return rc;
+	}
+
+	/*
+	 * Read the LSB again and check if there has been a carry over.
+	 * If there is, redo the read operation.
+	 */
+	rc = pm8xxx_read_wrapper(rtc_dd, &reg, rtc_dd->rtc_read_base, 1);
+	if (rc < 0) {
+		dev_err(dev, "PM8xxx read failed\n");
+		return rc;
+	}
+
+	if (unlikely(reg < value[0])) {
+		rc = pm8xxx_read_wrapper(rtc_dd, value,
+				rtc_dd->rtc_read_base, NUM_8_BIT_RTC_REGS);
+		if (rc < 0) {
+			dev_err(dev, "RTC time read failed\n");
+			return rc;
+		}
+	}
+
+	secs = value[0] | (value[1] << 8) | (value[2] << 16) \
+						| (value[3] << 24);
+
+	rtc_time_to_tm(secs, tm);
+
+	rc = rtc_valid_tm(tm);
+	if (rc < 0) {
+		dev_err(dev, "Invalid time read from PM8xxx\n");
+		return rc;
+	}
+
+	dev_dbg(dev, "secs = %lu, h:m:s == %d:%d:%d, d/m/y = %d/%d/%d\n",
+			secs, tm->tm_hour, tm->tm_min, tm->tm_sec,
+			tm->tm_mday, tm->tm_mon, tm->tm_year);
+
+	return 0;
+}
+
+static int
+pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	int rc;
+	u8 value[4], ctrl_reg;
+	unsigned long secs, secs_rtc, irq_flags;
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+	struct rtc_time rtc_tm;
+
+	rtc_tm_to_time(&alarm->time, &secs);
+
+	/*
+	 * Read the current RTC time and verify if the alarm time is in the
+	 * past. If yes, return invalid.
+	 */
+	rc = pm8xxx_rtc_read_time(dev, &rtc_tm);
+	if (rc < 0) {
+		dev_err(dev, "Unamble to read RTC time\n");
+		return -EINVAL;
+	}
+
+	rtc_tm_to_time(&rtc_tm, &secs_rtc);
+	if (secs < secs_rtc) {
+		dev_err(dev, "Trying to set alarm in the past\n");
+		return -EINVAL;
+	}
+
+	value[0] = secs & 0xFF;
+	value[1] = (secs >> 8) & 0xFF;
+	value[2] = (secs >> 16) & 0xFF;
+	value[3] = (secs >> 24) & 0xFF;
+
+	spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
+
+	rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
+							NUM_8_BIT_RTC_REGS);
+	if (rc < 0) {
+		dev_err(dev, "Write to RTC ALARM registers failed\n");
+		goto rtc_rw_fail;
+	}
+
+	ctrl_reg = rtc_dd->ctrl_reg;
+	ctrl_reg = (alarm->enabled) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
+					(ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE);
+
+	rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
+	if (rc < 0) {
+		dev_err(dev, "PM8xxx write failed\n");
+		goto rtc_rw_fail;
+	}
+
+	rtc_dd->ctrl_reg = ctrl_reg;
+
+	dev_dbg(dev, "Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
+			alarm->time.tm_hour, alarm->time.tm_min,
+			alarm->time.tm_sec, alarm->time.tm_mday,
+			alarm->time.tm_mon, alarm->time.tm_year);
+rtc_rw_fail:
+	spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+	return rc;
+}
+
+static int
+pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	int rc;
+	u8 value[4];
+	unsigned long secs;
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
+			NUM_8_BIT_RTC_REGS);
+	if (rc < 0) {
+		dev_err(dev, "RTC alarm time read failed\n");
+		return rc;
+	}
+
+	secs = value[0] | (value[1] << 8) | (value[2] << 16) | \
+						 (value[3] << 24);
+
+	rtc_time_to_tm(secs, &alarm->time);
+
+	rc = rtc_valid_tm(&alarm->time);
+	if (rc < 0) {
+		dev_err(dev, "Invalid time read from PM8xxx\n");
+		return rc;
+	}
+
+	dev_dbg(dev, "Alarm set for - h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
+		alarm->time.tm_hour, alarm->time.tm_min,
+				alarm->time.tm_sec, alarm->time.tm_mday,
+				alarm->time.tm_mon, alarm->time.tm_year);
+
+	return 0;
+}
+
+
+static int
+pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	int rc;
+	unsigned long irq_flags;
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+	u8 ctrl_reg;
+
+	spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
+	ctrl_reg = rtc_dd->ctrl_reg;
+	ctrl_reg = (enabled) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
+				(ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE);
+
+	rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
+	if (rc < 0) {
+		dev_err(dev, "PM8xxx write failed\n");
+		goto rtc_rw_fail;
+	}
+
+	rtc_dd->ctrl_reg = ctrl_reg;
+
+rtc_rw_fail:
+	spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+	return rc;
+}
+
+static struct rtc_class_ops pm8xxx_rtc_ops = {
+	.read_time	= pm8xxx_rtc_read_time,
+	.set_alarm	= pm8xxx_rtc_set_alarm,
+	.read_alarm	= pm8xxx_rtc_read_alarm,
+	.alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
+{
+	struct pm8xxx_rtc *rtc_dd = dev_id;
+	u8 ctrl_reg;
+	int rc;
+	unsigned long irq_flags;
+
+	rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF);
+
+	spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
+
+	/* Clear the alarm enable bit */
+	ctrl_reg = rtc_dd->ctrl_reg;
+	ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE;
+
+	rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
+	if (rc < 0) {
+		spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+		pr_err("PM8xxx write failed!\n");
+		goto rtc_alarm_handled;
+	}
+
+	rtc_dd->ctrl_reg = ctrl_reg;
+	spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+
+	/* Clear RTC alarm register */
+	rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base +
+						PM8XXX_ALARM_CTRL_OFFSET, 1);
+	if (rc < 0) {
+		pr_err("PM8xxx write failed!\n");
+		goto rtc_alarm_handled;
+	}
+
+	ctrl_reg &= ~PM8xxx_RTC_ALARM_CLEAR;
+	rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base +
+						PM8XXX_ALARM_CTRL_OFFSET, 1);
+	if (rc < 0)
+		pr_err("PM8xxx write failed!\n");
+
+rtc_alarm_handled:
+	return IRQ_HANDLED;
+}
+
+static int __devinit pm8xxx_rtc_probe(struct platform_device *pdev)
+{
+	int rc;
+	u8 ctrl_reg;
+	bool rtc_write_enable = false;
+	struct pm8xxx_rtc *rtc_dd;
+	struct resource *rtc_resource;
+	const struct pm8xxx_rtc_platform_data *pdata =
+		pdev->dev.platform_data;
+
+	if (pdata != NULL)
+		rtc_write_enable = pdata->rtc_write_enable;
+
+	rtc_dd = kzalloc(sizeof(*rtc_dd), GFP_KERNEL);
+	if (rtc_dd == NULL) {
+		dev_err(&pdev->dev, "Unable to allocate memory!\n");
+		return -ENOMEM;
+	}
+
+	/* Initialise spinlock to protect RTC cntrol register */
+	spin_lock_init(&rtc_dd->ctrl_reg_lock);
+
+	rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 0);
+	if (!rtc_dd->rtc_alarm_irq) {
+		dev_err(&pdev->dev, "Alarm IRQ resource absent!\n");
+		rc = -ENXIO;
+		goto fail_rtc_enable;
+	}
+
+	rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
+							"pmic_rtc_base");
+	if (rtc_resource)
+		rtc_dd->rtc_base = rtc_resource->start;
+	if (!rtc_dd->rtc_base) {
+		dev_err(&pdev->dev, "RTC IO resource absent!\n");
+		rc = -ENXIO;
+		goto fail_rtc_enable;
+	}
+
+	/* Setup RTC register addresses */
+	rtc_dd->rtc_write_base = rtc_dd->rtc_base + PM8XXX_RTC_WRITE_OFFSET;
+	rtc_dd->rtc_read_base = rtc_dd->rtc_base + PM8XXX_RTC_READ_OFFSET;
+	rtc_dd->alarm_rw_base = rtc_dd->rtc_base + PM8XXX_ALARM_RW_OFFSET;
+
+	rtc_dd->parent = pdev->dev.parent;
+
+	/* Check if the RTC is on, else turn it on */
+	rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "PM8xxx read failed!\n");
+		goto fail_rtc_enable;
+	}
+
+	if (!(ctrl_reg & PM8xxx_RTC_ENABLE)) {
+		ctrl_reg |= PM8xxx_RTC_ENABLE;
+		rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
+									1);
+		if (rc < 0) {
+			dev_err(&pdev->dev, "PM8xxx write failed!\n");
+			goto fail_rtc_enable;
+		}
+	}
+
+	rtc_dd->ctrl_reg = ctrl_reg;
+	if (rtc_write_enable == true)
+		pm8xxx_rtc_ops.set_time = pm8xxx_rtc_set_time,
+
+	platform_set_drvdata(pdev, rtc_dd);
+
+	/* Register the RTC device */
+	rtc_dd->rtc = rtc_device_register("pm8xxx_rtc", &pdev->dev,
+				&pm8xxx_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc_dd->rtc)) {
+		dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n",
+					__func__, PTR_ERR(rtc_dd->rtc));
+		rc = PTR_ERR(rtc_dd->rtc);
+		goto fail_rtc_enable;
+	}
+
+	/* Request the alarm IRQ */
+	rc = request_any_context_irq(rtc_dd->rtc_alarm_irq,
+				 pm8xxx_alarm_trigger, IRQF_TRIGGER_RISING,
+				 "pm8xxx_rtc_alarm", rtc_dd);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc);
+		goto fail_req_irq;
+	}
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	dev_dbg(&pdev->dev, "Probe success !!\n");
+
+	return 0;
+
+fail_req_irq:
+	rtc_device_unregister(rtc_dd->rtc);
+fail_rtc_enable:
+	platform_set_drvdata(pdev, NULL);
+	kfree(rtc_dd);
+	return rc;
+}
+
+#ifdef CONFIG_PM
+static int pm8xxx_rtc_resume(struct device *dev)
+{
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(rtc_dd->rtc_alarm_irq);
+
+	return 0;
+}
+
+static int pm8xxx_rtc_suspend(struct device *dev)
+{
+	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(rtc_dd->rtc_alarm_irq);
+
+	return 0;
+}
+
+static const struct dev_pm_ops pm8xxx_rtc_pm_ops = {
+	.suspend = pm8xxx_rtc_suspend,
+	.resume = pm8xxx_rtc_resume,
+};
+#endif
+static int __devexit pm8xxx_rtc_remove(struct platform_device *pdev)
+{
+	struct pm8xxx_rtc *rtc_dd = platform_get_drvdata(pdev);
+
+	device_init_wakeup(&pdev->dev, 0);
+	free_irq(rtc_dd->rtc_alarm_irq, rtc_dd);
+	rtc_device_unregister(rtc_dd->rtc);
+	platform_set_drvdata(pdev, NULL);
+	kfree(rtc_dd);
+
+	return 0;
+}
+
+static struct platform_driver pm8xxx_rtc_driver = {
+	.probe		= pm8xxx_rtc_probe,
+	.remove		= __devexit_p(pm8xxx_rtc_remove),
+	.driver	= {
+		.name	= PM8XXX_RTC_DEV_NAME,
+		.owner	= THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm	= &pm8xxx_rtc_pm_ops,
+#endif
+	},
+};
+
+static int __init pm8xxx_rtc_init(void)
+{
+	return platform_driver_register(&pm8xxx_rtc_driver);
+}
+module_init(pm8xxx_rtc_init);
+
+static void __exit pm8xxx_rtc_exit(void)
+{
+	platform_driver_unregister(&pm8xxx_rtc_driver);
+}
+module_exit(pm8xxx_rtc_exit);
+
+MODULE_ALIAS("platform:rtc-pm8xxx");
+MODULE_DESCRIPTION("PMIC8xxx RTC driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Anirudh Ghayal <aghayal@codeaurora.org>");
diff --git a/include/linux/mfd/pm8xxx/rtc.h b/include/linux/mfd/pm8xxx/rtc.h
new file mode 100644
index 0000000..2528e1d
--- /dev/null
+++ b/include/linux/mfd/pm8xxx/rtc.h
@@ -0,0 +1,25 @@ 
+/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#ifndef __RTC_PM8XXX_H__
+#define __RTC_PM8XXX_H__
+
+#define PM8XXX_RTC_DEV_NAME     "rtc-pm8xxx"
+/**
+ * struct pm8058_rtc_pdata - RTC driver platform data
+ * @rtc_write_enable: variable stating RTC write capability
+ */
+struct pm8xxx_rtc_platform_data {
+	bool rtc_write_enable;
+};
+
+#endif /* __RTC_PM8XXX_H__ */