Re: [PATCH v3 2/2] rtc: pcf2127: add alarm support

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

On Sat Jun 27, 2020 at 2:32 PM Bruno Thomsen wrote:
> Den fre. 19. jun. 2020 kl. 06.12 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
> >
> > Changes since v2:
> > - Avoid forward declaration of pcf2127_wdt_active_ping
> > - Remove dev_err strings
> > - Remove dev_dbg traces since they are now part of the core
> > - Remove redundant if in pcf2127_rtc_alarm_irq_enable
> > - Remove duplicate watchdog ping in pcf2127_rtc_irq
> > - Avoid unnecessary read in pcf2127_rtc_irq with regmap_write
> > - Add extra rtc_class_ops struct with alarm functions
> >
> >  drivers/rtc/rtc-pcf2127.c | 136 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 136 insertions(+)
> >
> > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> > index 4accee09bfad..df09d3c6c5c3 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)
> > @@ -324,6 +333,116 @@ static const struct watchdog_ops pcf2127_watchdog_ops = {
> >         .set_timeout = pcf2127_wdt_set_timeout,
> >  };
> >
> > +/* Alarm */
> > +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)
> > +               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)
> > +               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;
> > +
> > +       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)
> > +               return ret;
> > +
> > +       return pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +}
> > +
> > +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)
> > +               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);
> > +
> > +       ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf,
> > +                               sizeof(buf));
> > +       if (ret)
> > +               return ret;
> > +
> > +       return pcf2127_rtc_alarm_irq_enable(dev, alrm->enabled);
> > +}
> > +
> > +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)
> > +               goto irq_err;
> > +
> > +       if (ctrl2 & PCF2127_BIT_CTRL2_AF) {
> > +               regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> > +                            ctrl2 & ~PCF2127_BIT_CTRL2_AF);
> > +
> > +               rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
> > +       }
> > +
> > +       ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> > +       if (ret)
> > +               goto irq_err;
> > +
> > +       return IRQ_HANDLED;
> > +irq_err:
> > +       return IRQ_NONE;

Hi Bruno,

> 
> It's not really needed to use "goto irq_err;" syntax as there is no
> common error cleanup
> path and can simply be replaced by "return IRQ_NONE;".
> 
> Overall this feature looks good to me.
> 
> Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
> 
> /Bruno
> 

I'll send another revision getting rid of the goto. I'll also add your
Reviewed-by on both patches.

Thanks again for reviewing this,
Liam

> > +}
> > +
> > +static const struct rtc_class_ops pcf2127_rtc_alrm_ops = {
> > +       .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,
> > +};
> > +
> >  /* sysfs interface */
> >
> >  static ssize_t timestamp0_store(struct device *dev,
> > @@ -419,6 +538,7 @@ 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;
> >
> > @@ -441,6 +561,22 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> >         pcf2127->rtc->range_max = RTC_TIMESTAMP_END_2099;
> >         pcf2127->rtc->set_start_time = true; /* Sets actual start to 1970 */
> >
> > +       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->rtc->ops = &pcf2127_rtc_alrm_ops;
> > +       }
> > +
> >         pcf2127->wdd.parent = dev;
> >         pcf2127->wdd.info = &pcf2127_wdt_info;
> >         pcf2127->wdd.ops = &pcf2127_watchdog_ops;
> > --
> > 2.27.0
> >