.\"	$NetBSD: bq4802rtc.4,v 1.1 2026/07/07 12:36:01 jdc Exp $
.\"
.\" Copyright (c) 2026 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Julian Coleman.
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.Dd June 8, 2026
.Dt BQ4802RTC 4
.Os
.Sh NAME
.Nm bq4802rtc
.Nd Texas Instruments bq4802Y/bq4802LY Real-Time Clock
.Sh SYNOPSIS
.Cd "bq4802rtc* at ebus?  # sparc64"
.Sh DESCRIPTION
The
.Nm
driver provides access to the Texas Instruments bq4802Y/bq4802LY
real-time clock.
Access methods to retrieve and set date and time
are provided through the
.Em TODR
interface defined in
.Xr todr 9 .
.Pp
The chip supports stopping the oscillator to conserve battery life
if the computer will be stored for an extended period.
The
.Nm
driver
makes the oscillator control available via
.Xr sysctl 8 .
For example:
.Bd -literal -offset indent
hw.bq4802rtc0.stop_oscillator = 0
.Ed
.Pp
A value of
.Dq 0
means that the oscillator is running when the computer is powered off,
and a value of
.Dq 1
means that the oscillator is stopped.
If the oscillator is stopped, then the driver will output a warning message
at attach time, but does not automatically restart the oscillator.
.Sh SEE ALSO
.Xr sysctl 8,
.Xr todr 9
.Sh HISTORY
The
.Nm
driver first appeared in
.Nx 11.1 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Julian Coleman Aq Mt jcoleman@NetBSD.org .