xref: /OK3568_Linux_fs/kernel/Documentation/hwmon/w83l785ts.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunKernel driver w83l785ts
2*4882a593Smuzhiyun=======================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunSupported chips:
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun  * Winbond W83L785TS-S
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8*4882a593Smuzhiyun    Prefix: 'w83l785ts'
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun    Addresses scanned: I2C 0x2e
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12*4882a593Smuzhiyun    Datasheet: Publicly available at the Winbond USA website
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14*4882a593Smuzhiyun	       http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
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16*4882a593SmuzhiyunAuthors:
17*4882a593Smuzhiyun	Jean Delvare <jdelvare@suse.de>
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19*4882a593SmuzhiyunDescription
20*4882a593Smuzhiyun-----------
21*4882a593Smuzhiyun
22*4882a593SmuzhiyunThe W83L785TS-S is a digital temperature sensor. It senses the
23*4882a593Smuzhiyuntemperature of a single external diode. The high limit is
24*4882a593Smuzhiyuntheoretically defined as 85 or 100 degrees C through a combination
25*4882a593Smuzhiyunof external resistors, so the user cannot change it. Values seen so
26*4882a593Smuzhiyunfar suggest that the two possible limits are actually 95 and 110
27*4882a593Smuzhiyundegrees C. The datasheet is rather poor and obviously inaccurate
28*4882a593Smuzhiyunon several points including this one.
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30*4882a593SmuzhiyunAll temperature values are given in degrees Celsius. Resolution
31*4882a593Smuzhiyunis 1.0 degree. See the datasheet for details.
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33*4882a593SmuzhiyunThe w83l785ts driver will not update its values more frequently than
34*4882a593Smuzhiyunevery other second; reading them more often will do no harm, but will
35*4882a593Smuzhiyunreturn 'old' values.
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37*4882a593SmuzhiyunKnown Issues
38*4882a593Smuzhiyun------------
39*4882a593Smuzhiyun
40*4882a593SmuzhiyunOn some systems (Asus), the BIOS is known to interfere with the driver
41*4882a593Smuzhiyunand cause read errors. Or maybe the W83L785TS-S chip is simply unreliable,
42*4882a593Smuzhiyunwe don't really know. The driver will retry a given number of times
43*4882a593Smuzhiyun(5 by default) and then give up, returning the old value (or 0 if
44*4882a593Smuzhiyunthere is no old value). It seems to work well enough so that you should
45*4882a593Smuzhiyunnot notice anything. Thanks to James Bolt for helping test this feature.
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