[PATCH v2 0/2] pcf85363: support for quartz-load-femtofarads

From: Javier Carrasco
Date: Wed Feb 15 2023 - 03:18:55 EST


These patches add support for the quartz-load-femtofarads property in
the pcf85363 device driver and new bindings for the pcf85263 and
pcf85363 Real Time Clocks.

The driver has been tested with a PCF85263ATT RTC and a CTS3-32.768-12.5-20
oscillator that needs a 12.5 pF load capacitor. With no property
support the 7 pF default value leads to at least 2 Hz output frequency
deviations, while setting the right value the deviation decreased to
0.15 Hz. These measurements were made with a high precision oscilloscope
(SIGLENT SDS5104X).

This modification does not affect existing designs where the
quartz-load-femtofarads is not defined because in that case the default
value is used.

Javier Carrasco (2):
dt-bindings: rtc: nxp,pcf8563: move pcf85263/pcf85363 to a dedicated
binding
rtc: pcf85363: add support for the quartz-load-femtofarads property

.../devicetree/bindings/rtc/nxp,pcf85363.yaml | 60 +++++++++++++++++++
.../devicetree/bindings/rtc/nxp,pcf8563.yaml | 2 -
drivers/rtc/rtc-pcf85363.c | 37 +++++++++++-
3 files changed, 96 insertions(+), 3 deletions(-)
create mode 100644 Documentation/devicetree/bindings/rtc/nxp,pcf85363.yaml

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2.37.2