Re: [PATCH 2/3] rtc: pcf2127: add alarm support

[Bruno Thomsen <bruno.thomsen@gmail.com>]

Hi Liam,

See comments below.

Den søn. 7. jun. 2020 kl. 19.06 skrev <liambeguin@gmail.com>:
>
> From: Liam Beguin <lvb@xiphos.com>
>
> From: Liam Beguin <lvb@xiphos.com>
>
> Add alarm support for the pcf2127 RTC chip family.
> Tested on pca2129.
>
> Signed-off-by: Liam Beguin <lvb@xiphos.com>
> ---
>  drivers/rtc/rtc-pcf2127.c | 120 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 117 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 396a1144a213..3eeb085a7c72 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -28,7 +28,9 @@
>  #define PCF2127_BIT_CTRL1_TSF1                 BIT(4)
>  /* Control register 2 */
>  #define PCF2127_REG_CTRL2              0x01
> +#define PCF2127_BIT_CTRL2_AIE                  BIT(1)
>  #define PCF2127_BIT_CTRL2_TSIE                 BIT(2)
> +#define PCF2127_BIT_CTRL2_AF                   BIT(4)
>  #define PCF2127_BIT_CTRL2_TSF2                 BIT(5)
>  /* Control register 3 */
>  #define PCF2127_REG_CTRL3              0x02
> @@ -46,6 +48,12 @@
>  #define PCF2127_REG_DW                 0x07
>  #define PCF2127_REG_MO                 0x08
>  #define PCF2127_REG_YR                 0x09
> +/* Alarm registers */
> +#define PCF2127_REG_ALARM_SC           0x0A
> +#define PCF2127_REG_ALARM_MN           0x0B
> +#define PCF2127_REG_ALARM_HR           0x0C
> +#define PCF2127_REG_ALARM_DM           0x0D
> +#define PCF2127_REG_ALARM_DW           0x0E
>  /* Watchdog registers */
>  #define PCF2127_REG_WD_CTL             0x10
>  #define PCF2127_BIT_WD_CTL_TF0                 BIT(0)
> @@ -185,6 +193,107 @@ static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
>         return 0;
>  }
>
> +static int pcf2127_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +       struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> +       unsigned int buf[5], ctrl2;
> +       int ret;
> +
> +       ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
> +       if (ret) {
> +               dev_err(dev, "%s: ctrl2 read error\n", __func__);
> +               return ret;
> +       }

Reading CTRL2 register causes watchdog to stop.

Aways call pcf2127_wdt_active_ping() after CTRL2 access to ensure the watchdog
is running if enabled.

> +       ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf, 5);

Replace 5 with sizeof(buf).

> +       if (ret) {
> +               dev_err(dev, "%s: alarm read error\n", __func__);
> +               return ret;
> +       }
> +
> +       alrm->enabled = ctrl2 & PCF2127_BIT_CTRL2_AIE;
> +       alrm->pending = ctrl2 & PCF2127_BIT_CTRL2_AF;
> +
> +       alrm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
> +       alrm->time.tm_min = bcd2bin(buf[1] & 0x7F);
> +       alrm->time.tm_hour = bcd2bin(buf[2] & 0x3F);
> +       alrm->time.tm_mday = bcd2bin(buf[3] & 0x3F);
> +       alrm->time.tm_wday = buf[4] & 0x07;
> +
> +       dev_dbg(dev, "%s: alarm is %d:%d:%d, mday=%d, wday=%d\n", __func__,
> +               alrm->time.tm_hour, alrm->time.tm_min, alrm->time.tm_sec,
> +               alrm->time.tm_mday, alrm->time.tm_wday);
> +
> +       return 0;
> +}
> +
> +static int pcf2127_rtc_alarm_irq_enable(struct device *dev, u32 enable)
> +{
> +       struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> +       unsigned int ctrl2;
> +       int ret;
> +
> +       dev_dbg(dev, "%s: %s\n", __func__, enable ? "enable" : "disable");

Delete debug trace.

> +
> +       ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
> +       if (ret) {
> +               dev_err(dev, "%s: ctrl2 read error\n", __func__);
> +               return ret;
> +       }
> +
> +       if (enable)
> +               ret = regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> +                                  ctrl2 | PCF2127_BIT_CTRL2_AIE);
> +       else
> +               ret = regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> +                                  ctrl2 & ~PCF2127_BIT_CTRL2_AIE);
> +
> +       if (ret) {
> +               dev_err(dev, "%s: failed to enable alarm (%d)\n", __func__,
> +                       ret);
> +               return ret;
> +       }

Replace regmap_read() and regmap_write() with a regmap_update_bits().

So something like:

ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
                                          enabled ? PCF2127_REG_CTRL2 : 0);

And remember to call pcf2127_wdt_active_ping().

> +
> +       return 0;
> +}
> +
> +static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +       struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> +       unsigned int ctrl2;
> +       uint8_t buf[5];
> +       int ret;
> +
> +       ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
> +                                PCF2127_BIT_CTRL2_AF,
> +                                (unsigned int)~PCF2127_BIT_CTRL2_AF);

If you just want to clear the AF bit in CTRL2, just do:

ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
                                           PCF2127_BIT_CTRL2_AF, 0);

> +       if (ret) {
> +               dev_err(dev, "%s: failed to clear alarm interrupt flag (%d)",
> +                       __func__, ret);
> +               return ret;
> +       }
> +
> +       buf[0] = bin2bcd(alrm->time.tm_sec);
> +       buf[1] = bin2bcd(alrm->time.tm_min);
> +       buf[2] = bin2bcd(alrm->time.tm_hour);
> +       buf[3] = bin2bcd(alrm->time.tm_mday);
> +       buf[4] = (alrm->time.tm_wday & 0x07);
> +
> +       dev_dbg(dev, "%s: alarm set for: %d:%d:%d, mday=%d, wday=%d\n",
> +               __func__, alrm->time.tm_hour, alrm->time.tm_min,
> +               alrm->time.tm_sec, alrm->time.tm_mday, alrm->time.tm_wday);
> +
> +       ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf, 5);

Replace 5 with sizeof(buf).

/Bruno

> +       if (ret) {
> +               dev_err(dev, "%s: failed to write alarm registers (%d)",
> +                       __func__, ret);
> +               return ret;
> +       }
> +
> +       pcf2127_rtc_alarm_irq_enable(dev, alrm->enabled);
> +
> +       return 0;
> +}
> +
>  #ifdef CONFIG_RTC_INTF_DEV
>  static int pcf2127_rtc_ioctl(struct device *dev,
>                                 unsigned int cmd, unsigned long arg)
> @@ -211,9 +320,12 @@ static int pcf2127_rtc_ioctl(struct device *dev,
>  #endif
>
>  static const struct rtc_class_ops pcf2127_rtc_ops = {
> -       .ioctl          = pcf2127_rtc_ioctl,
> -       .read_time      = pcf2127_rtc_read_time,
> -       .set_time       = pcf2127_rtc_set_time,
> +       .ioctl            = pcf2127_rtc_ioctl,
> +       .read_time        = pcf2127_rtc_read_time,
> +       .set_time         = pcf2127_rtc_set_time,
> +       .read_alarm       = pcf2127_rtc_read_alarm,
> +       .set_alarm        = pcf2127_rtc_set_alarm,
> +       .alarm_irq_enable = pcf2127_rtc_alarm_irq_enable,
>  };
>
>  static int pcf2127_nvmem_read(void *priv, unsigned int offset,
> @@ -434,6 +546,8 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>
>         pcf2127->rtc->ops = &pcf2127_rtc_ops;
>
> +       device_init_wakeup(dev, true);
> +
>         pcf2127->wdd.parent = dev;
>         pcf2127->wdd.info = &pcf2127_wdt_info;
>         pcf2127->wdd.ops = &pcf2127_watchdog_ops;
> --
> 2.27.0
>