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Based on kernel version 4.7.2. Page generated on 2016-08-22 22:46 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	   Datasheets: Publicly available at the Intel website
37	
38	On Intel Patsburg and later chipsets, both the normal host SMBus controller
39	and the additional 'Integrated Device Function' controllers are supported.
40	
41	Authors: 
42		Mark Studebaker <mdsxyz123@yahoo.com>
43		Jean Delvare <jdelvare@suse.de>
44	
45	
46	Module Parameters
47	-----------------
48	
49	* disable_features (bit vector)
50	Disable selected features normally supported by the device. This makes it
51	possible to work around possible driver or hardware bugs if the feature in
52	question doesn't work as intended for whatever reason. Bit values:
53	 0x01  disable SMBus PEC
54	 0x02  disable the block buffer
55	 0x08  disable the I2C block read functionality
56	 0x10  don't use interrupts
57	
58	
59	Description
60	-----------
61	
62	The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
63	ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
64	Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
65	Pentium-based PCs, '815E' chipset, and others.
66	
67	The ICH chips contain at least SEVEN separate PCI functions in TWO logical
68	PCI devices. An output of lspci will show something similar to the
69	following:
70	
71	  00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
72	  00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
73	  00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
74	  00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
75	  00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
76	
77	The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
78	Controller.
79	
80	The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
81	SMBus controller.
82	
83	
84	Process Call Support
85	--------------------
86	
87	Not supported.
88	
89	
90	I2C Block Read Support
91	----------------------
92	
93	I2C block read is supported on the 82801EB (ICH5) and later chips.
94	
95	
96	SMBus 2.0 Support
97	-----------------
98	
99	The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
100	
101	
102	Interrupt Support
103	-----------------
104	
105	PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
106	
107	
108	Hidden ICH SMBus
109	----------------
110	
111	If your system has an Intel ICH south bridge, but you do NOT see the
112	SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
113	BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
114	well known for first doing this on their P4B motherboard, and many other
115	boards after that. Some vendor machines are affected as well.
116	
117	The first thing to try is the "i2c_ec" ACPI driver. It could be that the
118	SMBus was hidden on purpose because it'll be driven by ACPI. If the
119	i2c_ec driver works for you, just forget about the i2c-i801 driver and
120	don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you
121	better make sure that the SMBus isn't used by the ACPI code. Try loading
122	the "fan" and "thermal" drivers, and check in /proc/acpi/fan and
123	/proc/acpi/thermal_zone. If you find anything there, it's likely that
124	the ACPI is accessing the SMBus and it's safer not to unhide it. Only
125	once you are certain that ACPI isn't using the SMBus, you can attempt
126	to unhide it.
127	
128	In order to unhide the SMBus, we need to change the value of a PCI
129	register before the kernel enumerates the PCI devices. This is done in
130	drivers/pci/quirks.c, where all affected boards must be listed (see
131	function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
132	and you think there's something interesting on the SMBus (e.g. a
133	hardware monitoring chip), you need to add your board to the list.
134	
135	The motherboard is identified using the subvendor and subdevice IDs of the
136	host bridge PCI device. Get yours with "lspci -n -v -s 00:00.0":
137	
138	00:00.0 Class 0600: 8086:2570 (rev 02)
139	        Subsystem: 1043:80f2
140	        Flags: bus master, fast devsel, latency 0
141	        Memory at fc000000 (32-bit, prefetchable) [size=32M]
142	        Capabilities: [e4] #09 [2106]
143	        Capabilities: [a0] AGP version 3.0
144	
145	Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
146	(Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
147	names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
148	and then add a case for your subdevice ID at the right place in
149	drivers/pci/quirks.c. Then please give it very good testing, to make sure
150	that the unhidden SMBus doesn't conflict with e.g. ACPI.
151	
152	If it works, proves useful (i.e. there are usable chips on the SMBus)
153	and seems safe, please submit a patch for inclusion into the kernel.
154	
155	Note: There's a useful script in lm_sensors 2.10.2 and later, named
156	unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
157	temporarily unhide the SMBus without having to patch and recompile your
158	kernel. It's very convenient if you just want to check if there's
159	anything interesting on your hidden ICH SMBus.
160	
161	
162	**********************
163	The lm_sensors project gratefully acknowledges the support of Texas
164	Instruments in the initial development of this driver.
165	
166	The lm_sensors project gratefully acknowledges the support of Intel in the
167	development of SMBus 2.0 / ICH4 features of this driver.
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