Re: [PATCH v7 3/5] RTC: RK808: add RTC driver for RK808

[Doug Anderson <dianders@chromium.org>]

Chris,

On Mon, Sep 1, 2014 at 2:43 AM, Chris Zhong <zyw@rock-chips.com> wrote:
> Adding RTC driver for supporting RTC device present inside RK808 PMIC.
>
> Signed-off-by: Chris Zhong <zyw@rock-chips.com>
> Signed-off-by: Zhang Qing <zhangqing@rock-chips.com>
>
> ---
>
> Changes in v7:
> Adviced by doug
> - read rtc time from shadowed registers
> Adviced by Dmitry
> - use CONFIG_PM_SLEEP replace CONFIG_PM
> - use SIMPLE_DEV_PM_OPS replace dev_pm_ops
> - fix dev_warn
> - coding style
> Adviced by Heiko
> - remove rtc_ctl
>
> Changes in v6:
> Adviced by doug
> - move RTC_READSEL setting into probe
>
> Changes in v5:
> - fixed a bug about set_time failed
>
> Changes in v4:
> - use &client->dev replace rk808->dev
>
> Changes in v3: None
> Changes in v2:
> Adviced by javier.martinez
> - Add a separate clock driver, rather than in RTC driver
>
>  drivers/rtc/Kconfig     |   10 ++
>  drivers/rtc/Makefile    |    1 +
>  drivers/rtc/rtc-rk808.c |  419 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 430 insertions(+)
>  create mode 100644 drivers/rtc/rtc-rk808.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index a168e96..aeab9d9 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -288,6 +288,16 @@ config RTC_DRV_MAX77686
>           This driver can also be built as a module. If so, the module
>           will be called rtc-max77686.
>
> +config RTC_DRV_RK808
> +       tristate "Rockchip RK808 RTC"
> +       depends on MFD_RK808
> +       help
> +         If you say yes here you will get support for the
> +         RTC of RK808 PMIC.
> +
> +         This driver can also be built as a module. If so, the module
> +         will be called rk808-rtc.
> +
>  config RTC_DRV_RS5C372
>         tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"
>         help
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 56f061c..91fe4647 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -109,6 +109,7 @@ obj-$(CONFIG_RTC_DRV_PUV3)  += rtc-puv3.o
>  obj-$(CONFIG_RTC_DRV_PXA)      += rtc-pxa.o
>  obj-$(CONFIG_RTC_DRV_R9701)    += rtc-r9701.o
>  obj-$(CONFIG_RTC_DRV_RC5T583)  += rtc-rc5t583.o
> +obj-$(CONFIG_RTC_DRV_RK808)    += rtc-rk808.o
>  obj-$(CONFIG_RTC_DRV_RP5C01)   += rtc-rp5c01.o
>  obj-$(CONFIG_RTC_DRV_RS5C313)  += rtc-rs5c313.o
>  obj-$(CONFIG_RTC_DRV_RS5C348)  += rtc-rs5c348.o
> diff --git a/drivers/rtc/rtc-rk808.c b/drivers/rtc/rtc-rk808.c
> new file mode 100644
> index 0000000..3de78e8
> --- /dev/null
> +++ b/drivers/rtc/rtc-rk808.c
> @@ -0,0 +1,419 @@
> +/*
> + * RTC driver for Rockchip RK808
> + *
> + * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/rtc.h>
> +#include <linux/bcd.h>
> +#include <linux/mfd/rk808.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +
> +/* RTC_CTRL_REG bitfields */
> +#define BIT_RTC_CTRL_REG_STOP_RTC_M            BIT(0)
> +
> +/* RK808 has a shadowed register for saving a "frozen" RTC time.
> + * When user setting "GET_TIME" to 1, the time will save in this shadowed
> + * register. If set "READSEL" to 1, user read rtc time register, actually
> + * get the time of that moment. If we need the real time, clr this bit.
> + */
> +#define BIT_RTC_CTRL_REG_RTC_GET_TIME          BIT(6)
> +#define BIT_RTC_CTRL_REG_RTC_READSEL_M         BIT(7)
> +#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M      BIT(3)
> +#define RTC_STATUS_MASK                0xFE
> +
> +#define SECONDS_REG_MSK                0x7F
> +#define MINUTES_REG_MAK                0x7F
> +#define HOURS_REG_MSK          0x3F
> +#define DAYS_REG_MSK           0x3F
> +#define MONTHS_REG_MSK         0x1F
> +#define YEARS_REG_MSK          0xFF
> +#define WEEKS_REG_MSK          0x7
> +
> +/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
> +
> +#define NUM_TIME_REGS  (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
> +#define NUM_ALARM_REGS (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
> +
> +struct rk808_rtc {
> +       struct rk808 *rk808;
> +       struct rtc_device *rtc;
> +       int irq;
> +};
> +
> +/* Read current time and date in RTC */
> +static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
> +{
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       u8 rtc_data[NUM_TIME_REGS];
> +       int ret;
> +
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +                                BIT_RTC_CTRL_REG_RTC_GET_TIME,
> +                                BIT_RTC_CTRL_REG_RTC_GET_TIME);
> +       if (ret) {
> +               dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
> +               return ret;
> +       }
> +
> +       ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG,
> +                              rtc_data, NUM_TIME_REGS);
> +       if (ret) {
> +               dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
> +               goto reset_read_sel;
> +       }
> +
> +       tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
> +       tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
> +       tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
> +       tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
> +       tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
> +       tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
> +       tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
> +       dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +               1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
> +               tm->tm_wday, tm->tm_hour , tm->tm_min, tm->tm_sec);
> +
> +reset_read_sel:
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +                                BIT_RTC_CTRL_REG_RTC_GET_TIME, 0);
> +       if (ret)
> +               dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
> +       return ret;

Nit: blank line before "return ret;"

> +}
> +
> +/* Set current time and date in RTC */
> +static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       u8 rtc_data[NUM_TIME_REGS];
> +       int ret;
> +
> +       rtc_data[0] = bin2bcd(tm->tm_sec);
> +       rtc_data[1] = bin2bcd(tm->tm_min);
> +       rtc_data[2] = bin2bcd(tm->tm_hour);
> +       rtc_data[3] = bin2bcd(tm->tm_mday);
> +       rtc_data[4] = bin2bcd(tm->tm_mon + 1);
> +       rtc_data[5] = bin2bcd(tm->tm_year - 100);
> +       rtc_data[6] = bin2bcd(tm->tm_wday);
> +       dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +               1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
> +               tm->tm_wday, tm->tm_hour , tm->tm_min, tm->tm_sec);
> +
> +       /* Stop RTC while updating the RTC registers */
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +                                BIT_RTC_CTRL_REG_STOP_RTC_M,
> +                                BIT_RTC_CTRL_REG_STOP_RTC_M);
> +       if (ret) {
> +               dev_err(dev, "Failed to update RTC control: %d\n", ret);
> +               return ret;
> +       }
> +
> +       ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
> +                               rtc_data, NUM_TIME_REGS);
> +       if (ret) {
> +               dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
> +               return ret;
> +       }
> +       /* Start RTC again */
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +                                BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
> +       if (ret) {
> +               dev_err(dev, "Failed to update RTC control: %d\n", ret);
> +               return ret;
> +       }
> +       return 0;
> +}
> +
> +/* Read alarm time and date in RTC */
> +static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       u8 alrm_data[NUM_ALARM_REGS];
> +       uint32_t int_reg;
> +       int ret;
> +
> +       ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
> +                              alrm_data, NUM_ALARM_REGS);
> +
> +       alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
> +       alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
> +       alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
> +       alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
> +       alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
> +       alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
> +
> +       ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
> +       if (ret) {
> +               dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
> +               return ret;
> +       }
> +
> +       dev_dbg(dev, "alrm read RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +               1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
> +               alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
> +               alrm->time.tm_min, alrm->time.tm_sec);
> +
> +       alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
> +
> +       return 0;
> +}
> +
> +static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
> +{
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       int ret;
> +
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
> +                                BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
> +
> +       return ret;
> +}
> +
> +static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
> +{
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       int ret;
> +
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
> +                                BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
> +                                BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> +
> +       return ret;
> +}
> +
> +static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       u8 alrm_data[NUM_ALARM_REGS];
> +       int ret;
> +
> +       ret = rk808_rtc_stop_alarm(rk808_rtc);
> +       if (ret) {
> +               dev_err(dev, "Failed to stop alarm: %d\n", ret);
> +               return ret;
> +       }
> +       dev_dbg(dev, "alrm set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +               1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
> +               alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
> +               alrm->time.tm_min, alrm->time.tm_sec);
> +
> +       alrm_data[0] = bin2bcd(alrm->time.tm_sec);
> +       alrm_data[1] = bin2bcd(alrm->time.tm_min);
> +       alrm_data[2] = bin2bcd(alrm->time.tm_hour);
> +       alrm_data[3] = bin2bcd(alrm->time.tm_mday);
> +       alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
> +       alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
> +
> +       ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG,
> +                               alrm_data, NUM_ALARM_REGS);
> +       if (ret) {
> +               dev_err(dev, "Failed to bulk write: %d\n", ret);
> +               return ret;
> +       }
> +       if (alrm->enabled) {
> +               ret = rk808_rtc_start_alarm(rk808_rtc);
> +               if (ret) {
> +                       dev_err(dev, "Failed to start alarm: %d\n", ret);
> +                       return ret;
> +               }
> +       }
> +       return 0;
> +}
> +
> +static int rk808_rtc_alarm_irq_enable(struct device *dev,
> +                                     unsigned int enabled)
> +{
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +
> +       if (enabled)
> +               return rk808_rtc_start_alarm(rk808_rtc);
> +
> +       return rk808_rtc_stop_alarm(rk808_rtc);
> +}
> +
> +/*
> + * We will just handle setting the frequency and make use the framework for
> + * reading the periodic interupts.
> + *
> + * @freq: Current periodic IRQ freq:
> + * bit 0: every second
> + * bit 1: every minute
> + * bit 2: every hour
> + * bit 3: every day
> + */
> +static irqreturn_t rk808_alarm_irq(int irq, void *data)
> +{
> +       struct rk808_rtc *rk808_rtc = data;
> +       struct rk808 *rk808 = rk808_rtc->rk808;
> +       struct i2c_client *client = rk808->i2c;
> +       int ret;
> +
> +       ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
> +                          RTC_STATUS_MASK);
> +       if (ret) {
> +               dev_err(&client->dev,
> +                       "%s:Failed to update RTC status: %d\n", __func__, ret);
> +               return ret;
> +       }
> +
> +       rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
> +       dev_dbg(&client->dev,
> +                "%s:irq=%d\n", __func__, irq);
> +       return IRQ_HANDLED;
> +}
> +
> +static const struct rtc_class_ops rk808_rtc_ops = {
> +       .read_time = rk808_rtc_readtime,
> +       .set_time = rk808_rtc_set_time,
> +       .read_alarm = rk808_rtc_readalarm,
> +       .set_alarm = rk808_rtc_setalarm,
> +       .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
> +};
> +
> +#ifdef CONFIG_PM_SLEEP
> +/* Turn off the alarm if it should not be a wake source. */
> +static int rk808_rtc_suspend(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
> +
> +       if (device_may_wakeup(dev))
> +               enable_irq_wake(rk808_rtc->irq);
> +
> +       return 0;
> +}
> +
> +/* Enable the alarm if it should be enabled (in case it was disabled to
> + * prevent use as a wake source).
> + */
> +static int rk808_rtc_resume(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
> +
> +       if (device_may_wakeup(dev))
> +               disable_irq_wake(rk808_rtc->irq);
> +
> +       return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
> +       rk808_rtc_suspend, rk808_rtc_resume);
> +
> +/* 2014.1.1 12:00:00 Saturday */
> +struct rtc_time tm_def = {
> +                       .tm_wday = 6,
> +                       .tm_year = 114,
> +                       .tm_mon = 0,
> +                       .tm_mday = 1,
> +                       .tm_hour = 12,
> +                       .tm_min = 0,
> +                       .tm_sec = 0,
> +};
> +
> +static int rk808_rtc_probe(struct platform_device *pdev)
> +{
> +       struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
> +       struct rk808_rtc *rk808_rtc;
> +       struct rtc_time tm;
> +       int ret;
> +
> +       rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
> +       if (rk808_rtc == NULL)
> +               return -ENOMEM;
> +
> +       platform_set_drvdata(pdev, rk808_rtc);
> +       rk808_rtc->rk808 = rk808;
> +
> +       /* start rtc running by default, and use shadowed timer. */
> +       ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +                                BIT_RTC_CTRL_REG_STOP_RTC_M |
> +                                BIT_RTC_CTRL_REG_RTC_READSEL_M,
> +                                BIT_RTC_CTRL_REG_RTC_READSEL_M);

I think this should still be setting to 0, not to
BIT_RTC_CTRL_REG_RTC_READSEL_M.  Otherwise the first read of the time
will return that time that was frozen at probe time, right?  AKA: if
probe happens at 11:00:00 and then we read the time at 11:00:05 we'll
still read 11:00:00 the first time.


> +       if (ret) {
> +               dev_err(&pdev->dev,
> +                       "Failed to update RTC control: %d\n", ret);
> +               return ret;
> +       }
> +
> +       ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
> +                          RTC_STATUS_MASK);
> +       if (ret) {
> +               dev_err(&pdev->dev,
> +                       "Failed to write RTC status: %d\n", ret);
> +                       return ret;
> +       }
> +
> +       /* set init time */
> +       ret = rk808_rtc_readtime(&pdev->dev, &tm);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to read RTC time\n");
> +               return ret;
> +       }
> +       ret = rtc_valid_tm(&tm);
> +       if (ret) {
> +               dev_warn(&pdev->dev, "invalid date/time and init time\n");
> +               rk808_rtc_set_time(&pdev->dev, &tm_def);
> +       }
> +
> +       device_init_wakeup(&pdev->dev, 1);
> +
> +       rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc",
> +                                                 &rk808_rtc_ops, THIS_MODULE);
> +       if (IS_ERR(rk808_rtc->rtc)) {
> +               ret = PTR_ERR(rk808_rtc->rtc);
> +               return ret;
> +       }
> +
> +       rk808_rtc->irq = platform_get_irq(pdev, 0);
> +       if (rk808_rtc->irq <= 0) {
> +               dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
> +                       rk808_rtc->irq);
> +               return -ENXIO;
> +       }

I think you misinterpreted Dmitry.  He said this block was wrong, but
you didn't quite make the right fix.  I believe the correct fix is
that an IRQ of "0" is a valid IRQ.  Thus, you should have:

       rk808_rtc->irq = platform_get_irq(pdev, 0);
       if (rk808_rtc->irq < 0) {
               dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
                       rk808_rtc->irq);
               return rk808_rtc->irq;
       }


> +
> +       /* request alarm irq of rk808 */
> +       ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
> +                                       rk808_alarm_irq, 0,
> +                                       "RTC alarm", rk808_rtc);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
> +                       rk808_rtc->irq, ret);
> +       }
> +
> +       return ret;
> +}
> +
> +static struct platform_driver rk808_rtc_driver = {
> +       .probe = rk808_rtc_probe,
> +       .driver = {
> +               .name = "rk808-rtc",
> +               .pm = &rk808_rtc_pm_ops,
> +       },
> +};
> +
> +module_platform_driver(rk808_rtc_driver);
> +
> +MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
> +MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
> +MODULE_AUTHOR("Zhang Qing <zhanqging@rock-chips.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:rk808-rtc");
> --
> 1.7.9.5
>