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It turns out that as documented, PCF8563_R_SECOND_VL (i.e. battery low)
doesn't automatically clear when VDD rises above Vlow again and needs to be cleared manually. However, apparently this needs all of the time registers to be set, i.e. pcf8563_settime(), and not just PCF8563_R_SECOND in order for PCF8563_R_SECOND_VL to stick. Thus, we just issue a warning during pcf8563_attach() rather than failing with ENXIO in case it is set. MFC after: 3 days
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parent
470797ab8e
commit
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=241679
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@ -83,6 +83,16 @@ pcf8563_attach(device_t dev)
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if (sc->sc_addr == 0)
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sc->sc_addr = PCF8563_ADDR;
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/*
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* NB: PCF8563_R_SECOND_VL doesn't automatically clear when VDD
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* rises above Vlow again and needs to be cleared manually.
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* However, apparently this needs all of the time registers to be
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* set, i.e. pcf8563_settime(), and not just PCF8563_R_SECOND in
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* order for PCF8563_R_SECOND_VL to stick. Thus, we just issue a
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* warning here rather than failing with ENXIO in case it is set.
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* Note that pcf8563_settime() will also clear PCF8563_R_SECOND_VL
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* as a side-effect.
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*/
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msgs[0].slave = msgs[1].slave = sc->sc_addr;
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error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
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sizeof(*msgs));
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@ -90,10 +100,8 @@ pcf8563_attach(device_t dev)
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device_printf(dev, "%s: cannot read RTC\n", __func__);
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return (error);
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}
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if ((val & PCF8563_R_SECOND_VL) != 0) {
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if ((val & PCF8563_R_SECOND_VL) != 0)
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device_printf(dev, "%s: battery low\n", __func__);
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return (ENXIO);
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}
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sc->sc_year0 = 1900;
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clock_register(dev, 1000000); /* 1 second resolution */
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