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Based on kernel version 4.13.3. Page generated on 2017-09-23 13:55 EST.

1	Kernel driver i2c-i801
2	
3	Supported adapters:
4	  * Intel 82801AA and 82801AB (ICH and ICH0 - part of the
5	    '810' and '810E' chipsets)
6	  * Intel 82801BA (ICH2 - part of the '815E' chipset)
7	  * Intel 82801CA/CAM (ICH3)
8	  * Intel 82801DB (ICH4) (HW PEC supported)
9	  * Intel 82801EB/ER (ICH5) (HW PEC supported)
10	  * Intel 6300ESB
11	  * Intel 82801FB/FR/FW/FRW (ICH6)
12	  * Intel 82801G (ICH7)
13	  * Intel 631xESB/632xESB (ESB2)
14	  * Intel 82801H (ICH8)
15	  * Intel 82801I (ICH9)
16	  * Intel EP80579 (Tolapai)
17	  * Intel 82801JI (ICH10)
18	  * Intel 5/3400 Series (PCH)
19	  * Intel 6 Series (PCH)
20	  * Intel Patsburg (PCH)
21	  * Intel DH89xxCC (PCH)
22	  * Intel Panther Point (PCH)
23	  * Intel Lynx Point (PCH)
24	  * Intel Lynx Point-LP (PCH)
25	  * Intel Avoton (SOC)
26	  * Intel Wellsburg (PCH)
27	  * Intel Coleto Creek (PCH)
28	  * Intel Wildcat Point (PCH)
29	  * Intel Wildcat Point-LP (PCH)
30	  * Intel BayTrail (SOC)
31	  * Intel Sunrise Point-H (PCH)
32	  * Intel Sunrise Point-LP (PCH)
33	  * Intel DNV (SOC)
34	  * Intel Broxton (SOC)
35	  * Intel Lewisburg (PCH)
36	  * Intel Gemini Lake (SOC)
37	  * Intel Cannon Lake-H (PCH)
38	  * Intel Cannon Lake-LP (PCH)
39	   Datasheets: Publicly available at the Intel website
40	
41	On Intel Patsburg and later chipsets, both the normal host SMBus controller
42	and the additional 'Integrated Device Function' controllers are supported.
43	
44	Authors: 
45		Mark Studebaker <mdsxyz123@yahoo.com>
46		Jean Delvare <jdelvare@suse.de>
47	
48	
49	Module Parameters
50	-----------------
51	
52	* disable_features (bit vector)
53	Disable selected features normally supported by the device. This makes it
54	possible to work around possible driver or hardware bugs if the feature in
55	question doesn't work as intended for whatever reason. Bit values:
56	 0x01  disable SMBus PEC
57	 0x02  disable the block buffer
58	 0x08  disable the I2C block read functionality
59	 0x10  don't use interrupts
60	
61	
62	Description
63	-----------
64	
65	The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
66	ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
67	Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
68	Pentium-based PCs, '815E' chipset, and others.
69	
70	The ICH chips contain at least SEVEN separate PCI functions in TWO logical
71	PCI devices. An output of lspci will show something similar to the
72	following:
73	
74	  00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
75	  00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
76	  00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
77	  00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
78	  00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
79	
80	The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
81	Controller.
82	
83	The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
84	SMBus controller.
85	
86	
87	Process Call Support
88	--------------------
89	
90	Not supported.
91	
92	
93	I2C Block Read Support
94	----------------------
95	
96	I2C block read is supported on the 82801EB (ICH5) and later chips.
97	
98	
99	SMBus 2.0 Support
100	-----------------
101	
102	The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
103	
104	
105	Interrupt Support
106	-----------------
107	
108	PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
109	
110	
111	Hidden ICH SMBus
112	----------------
113	
114	If your system has an Intel ICH south bridge, but you do NOT see the
115	SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
116	BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
117	well known for first doing this on their P4B motherboard, and many other
118	boards after that. Some vendor machines are affected as well.
119	
120	The first thing to try is the "i2c_ec" ACPI driver. It could be that the
121	SMBus was hidden on purpose because it'll be driven by ACPI. If the
122	i2c_ec driver works for you, just forget about the i2c-i801 driver and
123	don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you
124	better make sure that the SMBus isn't used by the ACPI code. Try loading
125	the "fan" and "thermal" drivers, and check in /proc/acpi/fan and
126	/proc/acpi/thermal_zone. If you find anything there, it's likely that
127	the ACPI is accessing the SMBus and it's safer not to unhide it. Only
128	once you are certain that ACPI isn't using the SMBus, you can attempt
129	to unhide it.
130	
131	In order to unhide the SMBus, we need to change the value of a PCI
132	register before the kernel enumerates the PCI devices. This is done in
133	drivers/pci/quirks.c, where all affected boards must be listed (see
134	function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
135	and you think there's something interesting on the SMBus (e.g. a
136	hardware monitoring chip), you need to add your board to the list.
137	
138	The motherboard is identified using the subvendor and subdevice IDs of the
139	host bridge PCI device. Get yours with "lspci -n -v -s 00:00.0":
140	
141	00:00.0 Class 0600: 8086:2570 (rev 02)
142	        Subsystem: 1043:80f2
143	        Flags: bus master, fast devsel, latency 0
144	        Memory at fc000000 (32-bit, prefetchable) [size=32M]
145	        Capabilities: [e4] #09 [2106]
146	        Capabilities: [a0] AGP version 3.0
147	
148	Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
149	(Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
150	names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
151	and then add a case for your subdevice ID at the right place in
152	drivers/pci/quirks.c. Then please give it very good testing, to make sure
153	that the unhidden SMBus doesn't conflict with e.g. ACPI.
154	
155	If it works, proves useful (i.e. there are usable chips on the SMBus)
156	and seems safe, please submit a patch for inclusion into the kernel.
157	
158	Note: There's a useful script in lm_sensors 2.10.2 and later, named
159	unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
160	temporarily unhide the SMBus without having to patch and recompile your
161	kernel. It's very convenient if you just want to check if there's
162	anything interesting on your hidden ICH SMBus.
163	
164	
165	**********************
166	The lm_sensors project gratefully acknowledges the support of Texas
167	Instruments in the initial development of this driver.
168	
169	The lm_sensors project gratefully acknowledges the support of Intel in the
170	development of SMBus 2.0 / ICH4 features of this driver.
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