1.\" $NetBSD: mcp980x.4,v 1.7 2020/06/14 22:30:44 rkujawa Exp $ 2.\" 3.\" Copyright (c) 2013 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Radoslaw Kujawa. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd July 26, 2016 31.Dt MCP980X 4 32.Os 33.Sh NAME 34.Nm mcp980x 35.Nd Microchip 9800/1/2/3 I2C temperature sensor driver 36.Sh SYNOPSIS 37.Cd "mcp980x* at iic? addr 0x48" 38.Sh DESCRIPTION 39The 40.Nm 41driver provides support for the MCP980x series of temperature sensors. 42It allows reporting ambient temperature through the 43.Xr envsys 4 44API. 45.Sh SYSCTL VARIABLES 46The following 47.Xr sysctl 3 48variable are provided: 49.Bl -tag -width machdep.mcp980x0.hysteresis 50.It Va machdep.mcp980x0.res 51ADC resolution (integer). 52Valid values are 0-3, where 0 is 9-bit (0.5 Celsius degree) and 3 is 12-bit 53(0.0625 Celsius degree) resolution. 54.It Va machdep.mcp980x0.templimit 55If the ambient temperature exceeds this limit, the chip asserts an alert line 56(integer). 57.It Va machdep.mcp980x0.hysteresis 58Hysteresis for temperature limit (integer). 59.El 60.Sh SEE ALSO 61.Xr envsys 4 62.Sh HISTORY 63The 64.Nm 65device first appeared in 66.Nx 7.0 . 67.Sh AUTHORS 68.An -nosplit 69The 70.Nm 71driver was written by 72.An Radoslaw Kujawa Aq Mt radoslaw.kujawa@gmail.com . 73.Sh CAVEATS 74MCP9804 and MCP9805 chip are different and are supported by the 75.Xr sdtemp 4 76driver. 77.Pp 78The MCP980x chip supports hysteresis and temperature limit values with a 79resolution of 0.5 Celsius degree, however the 80.Nm 81driver supports setting only integer values. 82