Re: [PATCH v2 2/2] rtc: pcf2127: add alarm support

["Liam Beguin" <liambeguin@gmail.com>]

Hi Bruno,

On Tue Jun 16, 2020 at 10:38 AM Bruno Thomsen wrote:
> Hi Liam
> 
> Good updates, but you need to rebase patches on top of the latest mainline tree.

Thanks, I'll rebase before sending v3.

> 
> Den søn. 14. jun. 2020 kl. 06.04 skrev Liam Beguin <liambeguin@gmail.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>
> > ---
> > Changes since v1:
> > - Add calls to pcf2127_wdt_active_ping after accessing CTRL2
> > - Cleanup calls to regmap_{read,write,update_bits}
> > - Cleanup debug trace
> > - Add interrupt handler, untested because of hardware limitations
> > - Add wakeup-source devicetree option
> >
> >  drivers/rtc/rtc-pcf2127.c | 169 +++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 166 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> > index 396a1144a213..87ecb29247c6 100644
> > --- a/drivers/rtc/rtc-pcf2127.c
> > +++ b/drivers/rtc/rtc-pcf2127.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/slab.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> > +#include <linux/of_irq.h>
> >  #include <linux/regmap.h>
> >  #include <linux/watchdog.h>
> >
> > @@ -28,7 +29,9 @@
> >  #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 +49,12 @@
> >  #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)
> > @@ -79,6 +88,8 @@
> >  #define PCF2127_WD_VAL_MAX             255
> >  #define PCF2127_WD_VAL_DEFAULT         60
> >
> > +static int pcf2127_wdt_active_ping(struct watchdog_device *wdd);
> > +
> >  struct pcf2127 {
> >         struct rtc_device *rtc;
> >         struct watchdog_device wdd;
> > @@ -185,6 +196,140 @@ 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;
> > +       }
> > +
> > +       ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +       if (ret)
> > +               return ret;
> > +
> > +       ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf,
> > +                              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);
> > +       int ret;
> > +
> > +       ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
> > +                                PCF2127_BIT_CTRL2_AIE,
> > +                                enable ? PCF2127_BIT_CTRL2_AIE : 0);
> > +       if (ret) {
> > +               dev_err(dev, "%s: failed to %s alarm (%d)\n", __func__,
> > +                       enable ? "enable" : "disable",
> > +                       ret);
> > +               return ret;
> > +       }
> > +
> > +       ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return 0;
> 
> Just do "return ret;" unconditional.
> 
> > +}
> > +
> > +static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> > +{
> > +       struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> > +       uint8_t buf[5];
> > +       int ret;
> > +
> > +       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;
> > +       }
> > +
> > +       ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +       if (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,
> > +                               sizeof(buf));
> > +       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;
> > +}
> > +
> > +static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
> > +{
> > +       struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> > +       unsigned int ctrl2 = 0;
> > +       int ret = 0;
> > +
> > +       ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
> > +       if (ret) {
> > +               dev_err(dev, "%s: ctrl2 read error (%d)\n", __func__, ret);
> > +               goto irq_err;
> > +       }
> > +
> > +       ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +       if (ret)
> > +               goto irq_err;
> > +
> > +       if (ctrl2 & PCF2127_BIT_CTRL2_AF) {
> > +               regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
> > +                                  PCF2127_BIT_CTRL2_AF, 0);
> > +
> > +               ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +               if (ret)
> > +                       goto irq_err;
> > +
> > +               rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
> > +       }
> 
> Do pcf2127_wdt_active_ping() here to avoid having the same code twice
> in the function.

That looks better, I'll update.

Thanks,
Liam

> 
> /Bruno
> 
> > +
> > +       return IRQ_HANDLED;
> > +irq_err:
> > +       return IRQ_NONE;
> > +}
> > +
> >  #ifdef CONFIG_RTC_INTF_DEV
> >  static int pcf2127_rtc_ioctl(struct device *dev,
> >                                 unsigned int cmd, unsigned long arg)
> > @@ -211,9 +356,12 @@ 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,
> > @@ -415,6 +563,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> >                         const char *name, bool has_nvmem)
> >  {
> >         struct pcf2127 *pcf2127;
> > +       int alarm_irq = 0;
> >         u32 wdd_timeout;
> >         int ret = 0;
> >
> > @@ -434,6 +583,20 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> >
> >         pcf2127->rtc->ops = &pcf2127_rtc_ops;
> >
> > +       alarm_irq = of_irq_get_byname(dev->of_node, "alarm");
> > +       if (alarm_irq >= 0) {
> > +               ret = devm_request_irq(dev, alarm_irq, pcf2127_rtc_irq,
> > +                                      IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> > +                                      dev_name(dev), dev);
> > +               if (ret) {
> > +                       dev_err(dev, "failed to request alarm irq\n");
> > +                       return ret;
> > +               }
> > +       }
> > +
> > +       if (alarm_irq >= 0 || device_property_read_bool(dev, "wakeup-source"))
> > +               device_init_wakeup(dev, true);
> > +
> >         pcf2127->wdd.parent = dev;
> >         pcf2127->wdd.info = &pcf2127_wdt_info;
> >         pcf2127->wdd.ops = &pcf2127_watchdog_ops;
> > --
> > 2.27.0
> >