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Based on kernel version 3.19. Page generated on 2015-02-13 21:21 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	   Datasheets: Publicly available at the Intel website
34	
35	On Intel Patsburg and later chipsets, both the normal host SMBus controller
36	and the additional 'Integrated Device Function' controllers are supported.
37	
38	Authors: 
39		Mark Studebaker <mdsxyz123@yahoo.com>
40		Jean Delvare <jdelvare@suse.de>
41	
42	
43	Module Parameters
44	-----------------
45	
46	* disable_features (bit vector)
47	Disable selected features normally supported by the device. This makes it
48	possible to work around possible driver or hardware bugs if the feature in
49	question doesn't work as intended for whatever reason. Bit values:
50	 0x01  disable SMBus PEC
51	 0x02  disable the block buffer
52	 0x08  disable the I2C block read functionality
53	 0x10  don't use interrupts
54	
55	
56	Description
57	-----------
58	
59	The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
60	ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
61	Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
62	Pentium-based PCs, '815E' chipset, and others.
63	
64	The ICH chips contain at least SEVEN separate PCI functions in TWO logical
65	PCI devices. An output of lspci will show something similar to the
66	following:
67	
68	  00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
69	  00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
70	  00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
71	  00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
72	  00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
73	
74	The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
75	Controller.
76	
77	The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
78	SMBus controller.
79	
80	
81	Process Call Support
82	--------------------
83	
84	Not supported.
85	
86	
87	I2C Block Read Support
88	----------------------
89	
90	I2C block read is supported on the 82801EB (ICH5) and later chips.
91	
92	
93	SMBus 2.0 Support
94	-----------------
95	
96	The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
97	
98	
99	Interrupt Support
100	-----------------
101	
102	PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
103	
104	
105	Hidden ICH SMBus
106	----------------
107	
108	If your system has an Intel ICH south bridge, but you do NOT see the
109	SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
110	BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
111	well known for first doing this on their P4B motherboard, and many other
112	boards after that. Some vendor machines are affected as well.
113	
114	The first thing to try is the "i2c_ec" ACPI driver. It could be that the
115	SMBus was hidden on purpose because it'll be driven by ACPI. If the
116	i2c_ec driver works for you, just forget about the i2c-i801 driver and
117	don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you
118	better make sure that the SMBus isn't used by the ACPI code. Try loading
119	the "fan" and "thermal" drivers, and check in /proc/acpi/fan and
120	/proc/acpi/thermal_zone. If you find anything there, it's likely that
121	the ACPI is accessing the SMBus and it's safer not to unhide it. Only
122	once you are certain that ACPI isn't using the SMBus, you can attempt
123	to unhide it.
124	
125	In order to unhide the SMBus, we need to change the value of a PCI
126	register before the kernel enumerates the PCI devices. This is done in
127	drivers/pci/quirks.c, where all affected boards must be listed (see
128	function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
129	and you think there's something interesting on the SMBus (e.g. a
130	hardware monitoring chip), you need to add your board to the list.
131	
132	The motherboard is identified using the subvendor and subdevice IDs of the
133	host bridge PCI device. Get yours with "lspci -n -v -s 00:00.0":
134	
135	00:00.0 Class 0600: 8086:2570 (rev 02)
136	        Subsystem: 1043:80f2
137	        Flags: bus master, fast devsel, latency 0
138	        Memory at fc000000 (32-bit, prefetchable) [size=32M]
139	        Capabilities: [e4] #09 [2106]
140	        Capabilities: [a0] AGP version 3.0
141	
142	Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
143	(Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
144	names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
145	and then add a case for your subdevice ID at the right place in
146	drivers/pci/quirks.c. Then please give it very good testing, to make sure
147	that the unhidden SMBus doesn't conflict with e.g. ACPI.
148	
149	If it works, proves useful (i.e. there are usable chips on the SMBus)
150	and seems safe, please submit a patch for inclusion into the kernel.
151	
152	Note: There's a useful script in lm_sensors 2.10.2 and later, named
153	unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
154	temporarily unhide the SMBus without having to patch and recompile your
155	kernel. It's very convenient if you just want to check if there's
156	anything interesting on your hidden ICH SMBus.
157	
158	
159	**********************
160	The lm_sensors project gratefully acknowledges the support of Texas
161	Instruments in the initial development of this driver.
162	
163	The lm_sensors project gratefully acknowledges the support of Intel in the
164	development of SMBus 2.0 / ICH4 features of this driver.
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