[v6,2/2] MAX8997/8966 RTC Driver Initial Release

This patch adds support for RTC functionality for MAX8997/8966 chips.

The 16ms delay is somehow required by MAX8997 chips (at least for the
initial releases) and it can be enabled by .delay in platform_data.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/rtc/Kconfig         |   10 +
 drivers/rtc/Makefile        |    1 +
 drivers/rtc/rtc-max8997.c   |  476 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/max8997.h |    5 +-
 4 files changed, 491 insertions(+), 1 deletions(-)
 create mode 100644 drivers/rtc/rtc-max8997.c

Hi MyungJoo,

On Wed, Mar 16, 2011 at 10:39:11AM +0900, MyungJoo Ham wrote:
> This patch adds support for RTC functionality for MAX8997/8966 chips.
> 
> The 16ms delay is somehow required by MAX8997 chips (at least for the
> initial releases) and it can be enabled by .delay in platform_data.
I'll wait for Alessandro's ACK before pushing this one.

Cheers,
Samuel.

Hi MyungJoo,

Some comments inline.

On Wed, Mar 16, 2011 at 7:09 AM, MyungJoo Ham <myungjoo.ham@samsung.com>wrote:

> This patch adds support for RTC functionality for MAX8997/8966 chips.
>
> The 16ms delay is somehow required

by MAX8997 chips (at least for the
> initial releases) and it can be enabled by .delay in platform_data.
>
> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  drivers/rtc/Kconfig         |   10 +
>  drivers/rtc/Makefile        |    1 +
>  drivers/rtc/rtc-max8997.c   |  476
> +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/max8997.h |    5 +-
>  4 files changed, 491 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/rtc/rtc-max8997.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 4941cad..8dc93e8 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -196,6 +196,16 @@ config RTC_DRV_MAX8925
>          This driver can also be built as a module. If so, the module
>          will be called rtc-max8925.
>
> +config RTC_DRV_MAX8997
> +       tristate "Maxim MAX8997/8966"
> +       depends on MFD_MAX8997
> +       help
> +         If you say yes here you will get support for the
> +         RTC of Maxim MAX8997 and MAX8966 PMIC.
> +
> +         This driver can also be built as a module. If so, the module
> +         will be called rtc-max8997.
> +
>  config RTC_DRV_MAX8998
>        tristate "Maxim MAX8998"
>        depends on MFD_MAX8998
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 2afdaf3..8b74d41 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_RTC_DRV_M48T86)  += rtc-m48t86.o
>  obj-$(CONFIG_RTC_MXC)          += rtc-mxc.o
>  obj-$(CONFIG_RTC_DRV_MAX6900)  += rtc-max6900.o
>  obj-$(CONFIG_RTC_DRV_MAX8925)  += rtc-max8925.o
> +obj-$(CONFIG_RTC_DRV_MAX8997)  += rtc-max8997.o
>  obj-$(CONFIG_RTC_DRV_MAX8998)  += rtc-max8998.o
>  obj-$(CONFIG_RTC_DRV_MAX6902)  += rtc-max6902.o
>  obj-$(CONFIG_RTC_DRV_MC13XXX)  += rtc-mc13xxx.o
> diff --git a/drivers/rtc/rtc-max8997.c b/drivers/rtc/rtc-max8997.c
> new file mode 100644
> index 0000000..b1a4b66
> --- /dev/null
> +++ b/drivers/rtc/rtc-max8997.c
> @@ -0,0 +1,476 @@
> +/*
> + * rtc-max8997.c - RTC driver for Maxim 8966 and 8997
> + *
> + * Copyright (C) 2011 Samsung Electronics
> + * MyungJoo Ham <myungjoo.ham@samsung.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; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * 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.
> + *
> + * 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/delay.h>
> +#include <linux/mutex.h>
> +#include <linux/printk.h>


Do you really need the above include?

+#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +#include <linux/mfd/max8997.h>
> +#include <linux/mfd/max8997-private.h>
> +
> +/* Allow RTC Update */
> +#define MAX8997_RTC_UPDATE1_ENABLE_UPDATE      (1 << 0)
> +/*
> + * Set Interrupt Mode (about how the interrupt is cleared.)
> + * Set the bit in order to let inetrrupt be cleared with register read
> + * Unset the bit in order to let it be cleared by writing 0.
> + */
> +#define MAX8997_RTC_UPDATE1_INT_READ_CLEAR     (1 << 1)
> +
> +/* Mode between BCD(1) and Binary(0) */
> +#define MAX8997_RTC_CTRL_BCD                   (1 << 0)
> +/* Mode between 24hrs(1) and 12hrs(0) */
> +#define MAX8997_RTC_CTRL_Mode24_12             (1 << 1)
> +
> +struct rtc_data {
> +       struct mutex            lock;
> +       struct i2c_client       *i2c;
> +       struct max8997_dev      *iodev;
> +
> +       struct device           *dev;
> +       struct rtc_device       *rtc_dev;
> +
> +       int irq;
> +       bool delay;
> +};
> +
> +enum {
> +       RTC_SEC = 0,
> +       RTC_MIN,
> +       RTC_HOUR,
> +       RTC_WEEKDAY,
> +       RTC_MONTH,
> +       RTC_YEAR,
> +       RTC_MONTHDAY,
> +       RTC_DATA_SIZE,
> +};
> +
> +static inline int wday_8997_to_kernel(u8 shifted)
> +{
> +       int counter = -1;
> +       while (shifted) {
> +               shifted >>= 1;
> +               counter++;
> +       }
> +       return counter;
> +}
> +
> +static void __maybe_unused dump(struct rtc_data *rtc)
> +{
> +       int i;
> +       u8 buf[48];
> +
> +       for (i = 0; i < 48; i++)
> +               max8997_read_reg(rtc->i2c, i, &buf[i]);
> +       print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 1,
> +                       buf, sizeof(buf), false);
> +}
> +
> +static inline u8 wday_kernel_to_8997(u8 wday)
> +{
> +       return 1 << wday;
> +}
> +
> +static void data_to_tm(u8 *data, struct rtc_time *tm)
> +{
> +       /* Binary Mode (not BCD) */
> +       tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
> +       tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
> +       tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f); /* 24 hour mode */
> +       tm->tm_wday = wday_8997_to_kernel(data[RTC_WEEKDAY] & 0x7f);
> +       tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
> +       tm->tm_year = bcd2bin(data[RTC_YEAR] & 0x7f) + 100;
> +       tm->tm_mday = bcd2bin(data[RTC_MONTHDAY] & 0x3f);
> +       tm->tm_yday = 0;
> +       tm->tm_isdst = 0;
> +}
> +
> +static int tm_to_data(struct rtc_time *tm, u8 *data)
> +{
> +       data[RTC_SEC] = bin2bcd(tm->tm_sec) & 0x7f;
> +       data[RTC_MIN] = bin2bcd(tm->tm_min) & 0x7f;
> +       data[RTC_HOUR] = bin2bcd(tm->tm_hour) & 0x3f;
> +       data[RTC_WEEKDAY] = wday_kernel_to_8997(tm->tm_wday) & 0x7f;
> +       data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1) & 0x1f;
> +       data[RTC_YEAR] = bin2bcd((tm->tm_year > 100) ? (tm->tm_year - 100)
> : 0)
> +                       & 0x7f;
> +       data[RTC_MONTHDAY] = bin2bcd(tm->tm_mday) & 0x3f;
> +
> +       /* MAX8997 RTC cannot deal with years prior to 2000 */
> +       if (tm->tm_year < 100) {
> +               pr_err("MAX8997 RTC cannot handle the year %d. "
> +                               "Assume it's 2000.\n", 1900 + tm->tm_year);
> +               return -EINVAL;
> +       } else {
> +               return 0;
> +       }
> +}
> +
> +static int max8997_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +       struct rtc_data *rtc = dev_get_drvdata(dev);
> +       u8 data[RTC_DATA_SIZE];
> +       int ret;
> +
> +       mutex_lock(&rtc->lock);
> +       ret = max8997_bulk_read(rtc->i2c, MAX8997_RTC_SEC, RTC_DATA_SIZE,
> data);
> +       mutex_unlock(&rtc->lock);
> +
> +       if (ret < 0)
> +               return ret;
> +
> +       data_to_tm(data, tm);
> +
> +       return rtc_valid_tm(tm);
> +}
> +
> +static int max8997_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +       struct rtc_data *rtc = dev_get_drvdata(dev);
> +       u8 data[RTC_DATA_SIZE];
> +       int ret;
> +
> +       ret = tm_to_data(tm, data);
> +       if (ret)
> +               return ret;
> +
> +       mutex_lock(&rtc->lock);
> +
> +       /* Allow RTC Update */
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_UPDATE1,
> +                       MAX8997_RTC_UPDATE1_ENABLE_UPDATE |
> +                       MAX8997_RTC_UPDATE1_INT_READ_CLEAR);
> +
> +       ret = max8997_bulk_write(rtc->i2c, MAX8997_RTC_SEC,
> +                               RTC_DATA_SIZE, data);
> +
> +       if (rtc->delay)
> +               msleep(20);
> +
> +       mutex_unlock(&rtc->lock);
> +
> +       return ret;
> +}
> +
> +static int max8997_rtc_read_alarm(struct device *dev, struct rtc_wkalrm
> *alrm)
> +{
> +       struct rtc_data *rtc = dev_get_drvdata(dev);
> +       u8 data[RTC_DATA_SIZE];
> +       u8 val;
> +       int i;
> +       int ret;
> +
> +       mutex_lock(&rtc->lock);
>

Please explain the need the locks here and in the other ops ?
If this is for the I2C writes, I see that core driver already has mutexs for
read & writes.
If this is for RTC ops they are already serialized by the RTC core.
Please remove them if not required.



> +       ret = max8997_bulk_read(rtc->i2c, MAX8997_RTC_ALARM1_SEC,
> +                               RTC_DATA_SIZE, data);
> +
> +       if (ret < 0)
> +               goto exit;
> +
> +       data_to_tm(data, &alrm->time);
> +
> +       alrm->enabled = 0;
> +       for (i = 0; i < RTC_DATA_SIZE; i++)
> +               if (data[i] & (1 << 7)) {
> +                       alrm->enabled = 1;
> +                       break;
> +               }
> +
> +       alrm->pending = 0;
> +       ret = max8997_read_reg(rtc->iodev->i2c, MAX8997_REG_STATUS1, &val);
> +       if (val & (1 << 4)) /* "RTCA1" */
> +               alrm->pending = 1;
> +exit:
> +       mutex_unlock(&rtc->lock);
> +       return ret;
> +}
> +
> +static int max8997_rtc_start_alarm(struct rtc_data *rtc)
> +{
> +       u8 data[RTC_DATA_SIZE];
> +       int ret;
> +
> +       /* Should be locked before entering here */
> +       if (!mutex_is_locked(&rtc->lock))
> +               dev_warn(rtc->dev, "%s should have mutex locked.\n",
> __func__);
> +
> +       ret = max8997_bulk_read(rtc->i2c, MAX8997_RTC_ALARM1_SEC,
> +                               RTC_DATA_SIZE, data);
> +       if (rtc < 0)
> +               goto exit;
> +
> +       data[RTC_SEC] |= (1 << 7);
> +       data[RTC_MIN] |= (1 << 7);
> +       data[RTC_HOUR] |= (1 << 7);
> +       data[RTC_WEEKDAY] &= ~(1 << 7);
> +       if (data[RTC_MONTH] & 0x1f)
> +               data[RTC_MONTH] |= (1 << 7);
> +       if (data[RTC_YEAR] & 0x7f)
> +               data[RTC_YEAR] |= (1 << 7);
> +       if (data[RTC_MONTHDAY] & 0x3f)
> +               data[RTC_MONTHDAY] |= (1 << 7);
> +
> +       /* Allow RTC Update */
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_UPDATE1,
> +                       MAX8997_RTC_UPDATE1_ENABLE_UPDATE |
> +                       MAX8997_RTC_UPDATE1_INT_READ_CLEAR);
> +
> +       ret = max8997_bulk_write(rtc->i2c, MAX8997_RTC_ALARM1_SEC,
> +                               RTC_DATA_SIZE, data);
> +       if (ret < 0)
> +               goto exit;
> +       if (rtc->delay)
> +               msleep(20);
> +
> +exit:
> +       return ret;
> +}
> +
> +static int max8997_rtc_stop_alarm(struct rtc_data *rtc)
> +{
> +       u8 data[RTC_DATA_SIZE];
> +       int ret;
> +       int i;
> +
> +       /* Should be locked before entering here */
> +       if (!mutex_is_locked(&rtc->lock))
> +               dev_warn(rtc->dev, "%s should have mutex locked.\n",
> __func__);
> +
> +       ret = max8997_bulk_read(rtc->i2c, MAX8997_RTC_ALARM1_SEC,
> +                               RTC_DATA_SIZE, data);
> +       if (rtc < 0)
> +               goto exit;
> +
> +       for (i = 0; i < RTC_DATA_SIZE; i++)
> +               data[i] &= ~(1 << 7);
> +
> +       /* Allow RTC Update */
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_UPDATE1,
> +                       MAX8997_RTC_UPDATE1_ENABLE_UPDATE |
> +                       MAX8997_RTC_UPDATE1_INT_READ_CLEAR);
> +
> +       ret = max8997_bulk_write(rtc->i2c, MAX8997_RTC_ALARM1_SEC,
> +                               RTC_DATA_SIZE, data);
> +       if (ret < 0)
> +               goto exit;
> +       if (rtc->delay)
> +               msleep(20);
> +
> +exit:
> +       return ret;
> +}
> +
> +static int max8997_rtc_set_alarm(struct device *dev, struct rtc_wkalrm
> *alrm)
> +{
> +       struct rtc_data *rtc = dev_get_drvdata(dev);
> +       u8 data[RTC_DATA_SIZE];
> +       int ret;
> +
> +       ret = tm_to_data(&alrm->time, data);
> +       if (ret)
> +               return ret;
> +
> +       mutex_lock(&rtc->lock);

+       ret = max8997_rtc_stop_alarm(rtc);
> +       if (ret < 0)
> +               goto exit;
> +
> +       if (alrm->enabled) {
> +               data[RTC_SEC] |= (1 << 7);
> +               data[RTC_MIN] |= (1 << 7);
> +               data[RTC_HOUR] |= (1 << 7);
> +               data[RTC_WEEKDAY] &= ~(1 << 7);
> +               if (data[RTC_MONTH] & 0x1f)
> +                       data[RTC_MONTH] |= (1 << 7);
> +               if (data[RTC_YEAR] & 0x7f)
> +                       data[RTC_YEAR] |= (1 << 7);
> +               if (data[RTC_MONTHDAY] & 0x3f)
> +                       data[RTC_MONTHDAY] |= (1 << 7);
> +       }
> +
> +       /* Allow RTC Update */
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_UPDATE1,
> +                       MAX8997_RTC_UPDATE1_ENABLE_UPDATE |
> +                       MAX8997_RTC_UPDATE1_INT_READ_CLEAR);
>
please handle the return error.

> +
> +       ret = max8997_bulk_write(rtc->i2c, MAX8997_RTC_ALARM1_SEC,
> +                               RTC_DATA_SIZE, data);
> +       if (ret < 0)
> +               goto exit;
> +       if (rtc->delay)
> +               msleep(20);
> +
> +exit:
> +       mutex_unlock(&rtc->lock);
> +       return ret;
> +}
> +
> +static int max8997_rtc_alarm_irq_enable(struct device *dev,
> +                                       unsigned int enabled)
> +{
> +       struct rtc_data *rtc = dev_get_drvdata(dev);
> +       int ret;
> +
> +       mutex_lock(&rtc->lock);
> +       if (enabled)
> +               ret = max8997_rtc_start_alarm(rtc);
> +       else
> +               ret = max8997_rtc_stop_alarm(rtc);
> +       mutex_unlock(&rtc->lock);
> +
> +       return ret;
> +}
> +
> +static irqreturn_t max8997_rtc_alarm_irq(int irq, void *data)
> +{
> +       struct rtc_data *rtc = data;
> +
> +       rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static const struct rtc_class_ops max8997_rtc_ops = {
> +       .read_time              = max8997_rtc_read_time,
> +       .set_time               = max8997_rtc_set_time,
> +       .read_alarm             = max8997_rtc_read_alarm,
> +       .set_alarm              = max8997_rtc_set_alarm,
> +       .alarm_irq_enable       = max8997_rtc_alarm_irq_enable,
> +};
> +
> +static __devinit int rtc_probe(struct platform_device *pdev)
> +{
> +       struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
> +       struct max8997_platform_data *pdata = dev_get_platdata(iodev->dev);


const struct ?


>

+       struct rtc_data *rtc;
> +       int ret = 0;
> +       u8 val;
> +
> +       if (!pdata) {
> +               dev_err(pdev->dev.parent, "No platform init data
> supplied.\n");
> +               return -ENODEV;
> +       }
> +
> +       rtc = kzalloc(sizeof(struct rtc_data), GFP_KERNEL);
> +       if (!rtc)
> +               return -ENOMEM;
> +
> +       mutex_init(&rtc->lock);
> +       mutex_lock(&rtc->lock);
> +       rtc->i2c = iodev->rtc;
> +       rtc->dev = &pdev->dev;
> +       rtc->iodev = iodev;
> +       rtc->irq = iodev->irq_base + MAX8997_PMICIRQ_RTCA1;
> +
> +       if (pdata->delay)
> +               rtc->delay = true;
> +
> +       platform_set_drvdata(pdev, rtc);
> +
> +       val = MAX8997_RTC_CTRL_BCD |
> +               MAX8997_RTC_CTRL_Mode24_12;
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_CTRLMASK, val);
>

please handle the error return for all  i2c read/write calls.


> +
> +       val = MAX8997_RTC_CTRL_BCD |
> +               MAX8997_RTC_CTRL_Mode24_12;
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_CTRL, val);
> +
> +       /* Allow RTC Update */
> +       val = MAX8997_RTC_UPDATE1_ENABLE_UPDATE |
> +               MAX8997_RTC_UPDATE1_INT_READ_CLEAR;
> +       max8997_write_reg(rtc->i2c, MAX8997_RTC_UPDATE1, val);
> +
> +       if (pdata->wakeup)
> +               device_init_wakeup(&pdev->dev, 1);
> +
> +       rtc->rtc_dev = rtc_device_register("max8997-rtc", &pdev->dev,
> +                       &max8997_rtc_ops, THIS_MODULE);
> +       if (IS_ERR_OR_NULL(rtc->rtc_dev)) {
> +               ret = PTR_ERR(rtc->rtc_dev);
> +
> +               dev_err(&pdev->dev, "Failed to register RTC device: %d\n",
> ret);
> +               if (ret == 0)
> +                       ret = -EINVAL;
> +               goto err;
> +       }
> +
> +       ret = request_threaded_irq(rtc->irq, NULL, max8997_rtc_alarm_irq,
> 0,
> +                       "max8997-rtc-alarm1", rtc);
> +       if (ret < 0) {
> +               dev_err(&pdev->dev, "Failed to request alarm IRQ %d
> (%d)\n",
> +                               rtc->irq, ret);
>

Please unregister the rtc device in this error path.


> +               goto err;
> +       }
> +
> +       goto exit;
> +err:
> +       kfree(rtc);
> +exit:
> +       mutex_unlock(&rtc->lock);
> +       return ret;
> +}
> +
> +static __devexit int rtc_remove(struct platform_device *pdev)
> +{
> +       struct rtc_data *rtc = platform_get_drvdata(pdev);
> +
> +       rtc_device_unregister(rtc->rtc_dev);
> +       free_irq(rtc->irq, rtc);
> +       kfree(rtc);
> +
> +       return 0;
> +}
> +
> +static const struct platform_device_id rtc_id[] = {
> +       { "max8997-rtc", 0 },
> +       { },
> +};
> +
> +static struct platform_driver max8997_rtc_driver = {
> +       .driver = {
> +               .name = "max8997-rtc",
> +               .owner = THIS_MODULE,
> +       },
> +       .probe = rtc_probe,
> +       .remove = __devexit_p(rtc_remove),
> +       .id_table = rtc_id,
> +};
> +
> +static int __init max8997_rtc_init(void)
> +{
> +       return platform_driver_register(&max8997_rtc_driver);
> +}
> +subsys_initcall(max8997_rtc_init);
> +
> +static void __exit max8997_rtc_cleanup(void)
> +{
> +       platform_driver_unregister(&max8997_rtc_driver);
> +}
> +module_exit(max8997_rtc_cleanup);
> +
> +MODULE_DESCRIPTION("MAXIM 8997/8966 RTC Driver");
> +MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:max8997-rtc");
> diff --git a/include/linux/mfd/max8997.h b/include/linux/mfd/max8997.h
> index 60931d0..83f39b7 100644
> --- a/include/linux/mfd/max8997.h
> +++ b/include/linux/mfd/max8997.h
> @@ -109,7 +109,10 @@ struct max8997_platform_data {
>
>        /* MUIC: Not implemented */
>        /* HAPTIC: Not implemented */
> -       /* RTC: Not implemented */
> +
> +       /* ---- RTC ---- */
> +       bool delay; /* The MAX8997 RTC write delay is requred. */

+
>        /* Flash: Not implemented */
>        /* Charger control: Not implemented */
>  };
> --
> 1.7.1
>
>
Thx,
~Anirudh


> --
> 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.