rtc: pcf2127: fix alarm handling

Fix multiple issues when handling alarms:
 - Use threaded interrupt to avoid scheduling when atomic
 - Stop matching on week day as it may not be set correctly
 - Avoid parsing the DT interrupt and use what is provided by the i2c or
   spi subsystem
 - Avoid returning IRQ_NONE in case of error in the interrupt handler
 - Never write WDTF as specified in the datasheet
 - Set uie_unsupported, as for the pcf85063, setting alarms every seconds
   is not working correctly and confuses the RTC.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200812085114.474903-1-alexandre.belloni@bootlin.com

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 4e99c45..ed63169 100644 (file)
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -33,6 +33,7 @@
 #define PCF2127_BIT_CTRL2_TSIE                 BIT(2)
 #define PCF2127_BIT_CTRL2_AF                   BIT(4)
 #define PCF2127_BIT_CTRL2_TSF2                 BIT(5)
+#define PCF2127_BIT_CTRL2_WDTF                 BIT(6)
 /* Control register 3 */
 #define PCF2127_REG_CTRL3              0x02
 #define PCF2127_BIT_CTRL3_BLIE                 BIT(0)
@@ -55,6 +56,7 @@
 #define PCF2127_REG_ALARM_HR           0x0C
 #define PCF2127_REG_ALARM_DM           0x0D
 #define PCF2127_REG_ALARM_DW           0x0E
+#define PCF2127_BIT_ALARM_AE                   BIT(7)
 /* Watchdog registers */
 #define PCF2127_REG_WD_CTL             0x10
 #define PCF2127_BIT_WD_CTL_TF0                 BIT(0)
@@ -360,7 +362,6 @@ static int pcf2127_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
        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;
 }
@@ -398,7 +399,7 @@ static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
        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);
+       buf[4] = PCF2127_BIT_ALARM_AE; /* Do not match on week day */
 
        ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf,
                                sizeof(buf));
@@ -418,16 +419,15 @@ static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
        if (ret)
                return IRQ_NONE;
 
-       if (ctrl2 & PCF2127_BIT_CTRL2_AF) {
-               regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
-                            ctrl2 & ~PCF2127_BIT_CTRL2_AF);
+       if (!(ctrl2 & PCF2127_BIT_CTRL2_AF))
+               return IRQ_NONE;
 
-               rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
-       }
+       regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
+                    ctrl2 & ~(PCF2127_BIT_CTRL2_AF | PCF2127_BIT_CTRL2_WDTF));
 
-       ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
-       if (ret)
-               return IRQ_NONE;
+       rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
+
+       pcf2127_wdt_active_ping(&pcf2127->wdd);
 
        return IRQ_HANDLED;
 }
@@ -533,10 +533,9 @@ static const struct attribute_group pcf2127_attr_group = {
 };
 
 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
-                       const char *name, bool has_nvmem)
+                        int alarm_irq, const char *name, bool has_nvmem)
 {
        struct pcf2127 *pcf2127;
-       int alarm_irq = 0;
        u32 wdd_timeout;
        int ret = 0;
 
@@ -558,12 +557,13 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
        pcf2127->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
        pcf2127->rtc->range_max = RTC_TIMESTAMP_END_2099;
        pcf2127->rtc->set_start_time = true; /* Sets actual start to 1970 */
+       pcf2127->rtc->uie_unsupported = 1;
 
-       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);
+               ret = devm_request_threaded_irq(dev, alarm_irq, NULL,
+                                               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;
@@ -792,7 +792,7 @@ static int pcf2127_i2c_probe(struct i2c_client *client,
                return PTR_ERR(regmap);
        }
 
-       return pcf2127_probe(&client->dev, regmap,
+       return pcf2127_probe(&client->dev, regmap, client->irq,
                             pcf2127_i2c_driver.driver.name, id->driver_data);
 }
 
@@ -858,7 +858,8 @@ static int pcf2127_spi_probe(struct spi_device *spi)
                return PTR_ERR(regmap);
        }
 
-       return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
+       return pcf2127_probe(&spi->dev, regmap, spi->irq,
+                            pcf2127_spi_driver.driver.name,
                             spi_get_device_id(spi)->driver_data);
 }