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freebsd-dev/share/man/man4/lm75.4

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Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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.\"
.\" Copyright (c) 2014 Luiz Otavio O Souza <loos@freebsd.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
Update the FDT example for the lm75 sensor to match current devicetree standards and what the existing driver expects. Also change 'like' to 'such as' where the text is providing an example rather than a simile.
2017-12-26 18:34:07 +00:00
.Dd December 26, 2017
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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.Dt LM75 4
.Os
.Sh NAME
.Nm lm75
.Nd lm75 i2c digital temperature sensor driver
.Sh SYNOPSIS
.Cd "device iic"
.Cd "device iicbus"
.Cd "device lm75"
.Sh DESCRIPTION
The
.Nm
driver provides access to sensor data and configuration over the
.Xr iicbus 4 .
.Pp
It provides an easy and simple way to check the functionality of an i2c bus
as it provides read and write access to the
.Nm
configuration register.
.Pp
The access to
.Nm
data is made via the
.Xr sysctl 8
interface:
.Bd -literal
dev.lm75.0.%desc: LM75 temperature sensor
dev.lm75.0.%driver: lm75
dev.lm75.0.%location: addr=0x49
dev.lm75.0.%pnpinfo: name=lm750 compat=national,lm75
dev.lm75.0.%parent: iicbus3
dev.lm75.0.temperature: 27.1C
dev.lm75.0.thyst: 75.0C
dev.lm75.0.tos: 80.0C
dev.lm75.0.faults: 1
dev.lm75.0.mode: comparator
dev.lm75.0.polarity: active-low
dev.lm75.0.shutdown: 0
.Ed
.Bl -tag -width ".Va dev.lm75.%d.temperature"
.It Va dev.lm75.%d.temperature
Is the read-only value of the current temperature read by the sensor.
.It Va dev.lm75.%d.thyst
Sets the hysteresis temperature.
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
Once the temperature gets over the overtemperature shutdown value (tos)
it needs to drop below the hysteresis temperature to disable the output
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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(interrupt) pin again.
.It Va dev.lm75.%d.tos
Sets the overtemperature shutdown value.
Typo fixes and some language/punctuation improvements.
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Once the temperature gets over this value the output pin will be enabled.
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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The way the output (interrupt) pin works, depends on the mode configuration.
.It Va dev.lm75.%d.faults
Is the number of faults that must occur consecutively to activate the
interrupt (output) pin.
It can be set to 1, 2, 4, and 6.
.It Va dev.lm75.%d.mode
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
Sets the operation mode for the sensor interrupt pin.
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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It can be set to 'comparator' (default) or 'interrupt'.
.It Va dev.lm75.%d.polarity
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
Sets the polarity of the sensor interrupt pin.
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
It can be set to 'active-low' (default) or 'active-high'.
Please note that the output pin is an open-drain output and it needs a
proper pull-up resistor to work.
.It Va dev.lm75.%d.shutdown
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
When set to '1' it shuts down the sensor.
The temperature conversion stops but the sensor remains with its i2c bus
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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active, i.e., it can be woken up by setting this option to '0' again.
.El
.Pp
Please check the
.Nm
datasheet for more details.
.Pp
When used together with
.Xr snmp_lm75 3
it allows the monitoring of
.Nm
temperature data over SNMP.
.Pp
The
.Nm
driver supports both the low and the high resolution models.
.Pp
The low resolution model (lm75) provides a 9 bit output with the LSB
representing 0.5C.
.Pp
The high resolution model (lm75a) provides an 11 bit output with the LSB
representing 0.125C.
.Pp
The driver tries to auto-detect the
.Nm
model, but the detection of some
.Nm
clones may not work reliably.
.Pp
On a
.Xr device.hints 5
Update the FDT example for the lm75 sensor to match current devicetree standards and what the existing driver expects. Also change 'like' to 'such as' where the text is providing an example rather than a simile.
2017-12-26 18:34:07 +00:00
based system, such as
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
.Li MIPS ,
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
these values are configurable for
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
.Nm :
.Bl -tag -width ".Va hint.lm75.%d.addr"
.It Va hint.lm75.%d.at
Is the
.Xr iicbus 4
you are attaching to.
.It Va hint.lm75.%d.addr
Is the
.Nm
i2c address on the
.Xr iicbus 4 .
.El
.Pp
On a
.Xr FDT 4
Update the FDT example for the lm75 sensor to match current devicetree standards and what the existing driver expects. Also change 'like' to 'such as' where the text is providing an example rather than a simile.
2017-12-26 18:34:07 +00:00
based system, such as
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
.Li ARM ,
the DTS part for a
.Nm
device usually looks like:
.Bd -literal
i2c {
Update the FDT example for the lm75 sensor to match current devicetree standards and what the existing driver expects. Also change 'like' to 'such as' where the text is providing an example rather than a simile.
2017-12-26 18:34:07 +00:00
/* Properties describing the controller appear here. */
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
...
Update the FDT example for the lm75 sensor to match current devicetree standards and what the existing driver expects. Also change 'like' to 'such as' where the text is providing an example rather than a simile.
2017-12-26 18:34:07 +00:00
lm750@49 {
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
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compatible = "national,lm75";
Update the FDT example for the lm75 sensor to match current devicetree standards and what the existing driver expects. Also change 'like' to 'such as' where the text is providing an example rather than a simile.
2017-12-26 18:34:07 +00:00
reg = <0x49>;
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
};
};
.Ed
.Pp
Where:
Complete the changing of the old "i2c-address" property to the modern "reg" property by updating the description text to match the updated example. This should have been part of r327220
2017-12-26 18:42:29 +00:00
.Bl -tag -width ".Va compatible"
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
.It Va compatible
Should always be set to "national,lm75".
Complete the changing of the old "i2c-address" property to the modern "reg" property by updating the description text to match the updated example. This should have been part of r327220
2017-12-26 18:42:29 +00:00
.It Va reg
Indicates which 7-bit i2c address the
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
.Nm
is wired at.
.Nm
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
temperature sensors can be wired to 8 different addresses, allowing up to 8
Add the lm75 i2c digital temperature sensor driver. This driver supports the low and high precision models (9 and 11 bits) and it will auto-detect the both variants. The driver expose the temperature registers (actual temperature, shutdown and hysteresys temperature) and also the configuration register. It was tested on FDT systems: RPi, BBB and on non-FDT systems: AR71xx, with both, hardware i2c controllers (when available) and gpioiic(4). This provides a simple and cheap way for verifying the i2c bus on embedded systems.
2014-05-10 12:19:02 +00:00
sensors on the same
.Xr iicbus 4 .
.El
.Sh SEE ALSO
.Xr snmp_lm75 3 ,
.Xr fdt 4 ,
.Xr iic 4 ,
.Xr iicbus 4 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 11.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
Typo fixes and some language/punctuation improvements.
2014-05-11 10:06:27 +00:00
driver and this manual page were written by
use .Mt to mark up email addresses consistently (final part) PR: 191174 Submitted by: Franco Fichtner <franco at lastsummer.de>
2014-06-26 21:46:14 +00:00
.An Luiz Otavio O Souza Aq Mt loos@FreeBSD.org .
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