Kernel driver smsc47b397

Supported chips:

  • SMSC LPC47B397-NC

  • SMSC SCH5307-NS

  • SMSC SCH5317

    Prefix: ‘smsc47b397’

    Addresses scanned: none, address read from Super I/O config space

    Datasheet: In this file

Authors:

November 23, 2004

The following specification describes the SMSC LPC47B397-NC[1] sensor chip(for which there is no public datasheet available). This document wasprovided by Craig Kelly (In-Store Broadcast Network) and edited/correctedby Mark M. Hoffman <mhoffman@lightlink.com>.

[1]And SMSC SCH5307-NS and SCH5317, which have different device IDs but areotherwise compatible.

Methods for detecting the HP SIO and reading the thermal data on a dc7100

The thermal information on the dc7100 is contained in the SIO Hardware Monitor(HWM). The information is accessed through an index/data pair. The index/datapair is located at the HWM Base Address + 0 and the HWM Base Address + 1. TheHWM Base address can be obtained from Logical Device 8, registers 0x60 (MSB)and 0x61 (LSB). Currently we are using 0x480 for the HWM Base Address and0x480 and 0x481 for the index/data pair.

Reading temperature information.The temperature information is located in the following registers:

Temp10x25(Currently, this reflects the CPU temp on all systems).
Temp20x26 
Temp30x27 
Temp40x80 

Programming ExampleThe following is an example of how to read the HWM temperature registers:

MOV     DX,480HMOV     AX,25HOUT     DX,ALMOV     DX,481HIN      AL,DX

AL contains the data in hex, the temperature in Celsius is the decimalequivalent.

Ex: If AL contains 0x2A, the temperature is 42 degrees C.

Reading tach information.The fan speed information is located in the following registers:

Tach10x280x29(Currently, this reflects the CPUfan speed on all systems).
Tach20x2A0x2B 
Tach30x2C0x2D 
Tach40x2E0x2F 

Important

Reading the tach LSB locks the tach MSB.The LSB Must be read first.

How to convert the tach reading to RPM

The tach reading (TCount) is given by: (Tach MSB * 256) + (Tach LSB)The SIO counts the number of 90kHz (11.111us) pulses per revolution.RPM = 60/(TCount * 11.111us)

Example:

Reg 0x28 = 0x9BReg 0x29 = 0x08

TCount = 0x89B = 2203

RPM = 60 / (2203 * 11.11111 E-6) = 2451 RPM

Obtaining the SIO version.

Configuration Sequence

To program the configuration registers, the following sequence must be followed:1. Enter Configuration Mode2. Configure the Configuration Registers3. Exit Configuration Mode.

Enter Configuration Mode

To place the chip into the Configuration State The config key (0x55) is writtento the CONFIG PORT (0x2E).

Configuration Mode

In configuration mode, the INDEX PORT is located at the CONFIG PORT address andthe DATA PORT is at INDEX PORT address + 1.

The desired configuration registers are accessed in two steps:

  1. Write the index of the Logical Device Number Configuration Register(i.e., 0x07) to the INDEX PORT and then write the number of thedesired logical device to the DATA PORT.
  2. Write the address of the desired configuration register within thelogical device to the INDEX PORT and then write or read the config-uration register through the DATA PORT.
Note:
If accessing the Global Configuration Registers, step (a) is not required.

Exit Configuration Mode

To exit the Configuration State the write 0xAA to the CONFIG PORT (0x2E).The chip returns to the RUN State. (This is important).

Programming Example

The following is an example of how to read the SIO Device ID located at 0x20:

; ENTER CONFIGURATION MODEMOV DX,02EHMOV AX,055HOUT DX,AL; GLOBAL CONFIGURATION REGISTERMOV DX,02EHMOV AL,20HOUT DX,AL; READ THE DATAMOV DX,02FHIN AL,DX; EXIT CONFIGURATION MODEMOV DX,02EHMOV AX,0AAHOUT DX,AL

The registers of interest for identifying the SIO on the dc7100 are Device ID(0x20) and Device Rev (0x21).

The Device ID will read 0x6F (0x81 for SCH5307-NS, and 0x85 for SCH5317)The Device Rev currently reads 0x01

Obtaining the HWM Base Address

The following is an example of how to read the HWM Base Address located inLogical Device 8:

; ENTER CONFIGURATION MODEMOV     DX,02EHMOV     AX,055HOUT     DX,AL; CONFIGURE REGISTER CRE0,; LOGICAL DEVICE 8MOV     DX,02EHMOV     AL,07HOUT     DX,AL ;Point to LD# Config RegMOV     DX,02FHMOV     AL, 08HOUT     DX,AL;Point to Logical Device 8;MOV     DX,02EHMOV     AL,60HOUT     DX,AL   ; Point to HWM Base Addr MSBMOV     DX,02FHIN      AL,DX   ; Get MSB of HWM Base Addr; EXIT CONFIGURATION MODEMOV     DX,02EHMOV     AX,0AAHOUT     DX,AL