1====================== 2Kernel driver i2c-i801 3====================== 4 5 6Supported adapters: 7 * Intel 82801AA and 82801AB (ICH and ICH0 - part of the 8 '810' and '810E' chipsets) 9 * Intel 82801BA (ICH2 - part of the '815E' chipset) 10 * Intel 82801CA/CAM (ICH3) 11 * Intel 82801DB (ICH4) (HW PEC supported) 12 * Intel 82801EB/ER (ICH5) (HW PEC supported) 13 * Intel 6300ESB 14 * Intel 82801FB/FR/FW/FRW (ICH6) 15 * Intel 82801G (ICH7) 16 * Intel 631xESB/632xESB (ESB2) 17 * Intel 82801H (ICH8) 18 * Intel 82801I (ICH9) 19 * Intel EP80579 (Tolapai) 20 * Intel 82801JI (ICH10) 21 * Intel 5/3400 Series (PCH) 22 * Intel 6 Series (PCH) 23 * Intel Patsburg (PCH) 24 * Intel DH89xxCC (PCH) 25 * Intel Panther Point (PCH) 26 * Intel Lynx Point (PCH) 27 * Intel Avoton (SOC) 28 * Intel Wellsburg (PCH) 29 * Intel Coleto Creek (PCH) 30 * Intel Wildcat Point (PCH) 31 * Intel BayTrail (SOC) 32 * Intel Braswell (SOC) 33 * Intel Sunrise Point (PCH) 34 * Intel Kaby Lake (PCH) 35 * Intel DNV (SOC) 36 * Intel Broxton (SOC) 37 * Intel Lewisburg (PCH) 38 * Intel Gemini Lake (SOC) 39 * Intel Cannon Lake (PCH) 40 * Intel Cedar Fork (PCH) 41 * Intel Ice Lake (PCH) 42 * Intel Comet Lake (PCH) 43 * Intel Elkhart Lake (PCH) 44 * Intel Tiger Lake (PCH) 45 * Intel Jasper Lake (SOC) 46 * Intel Emmitsburg (PCH) 47 * Intel Alder Lake (PCH) 48 * Intel Raptor Lake (PCH) 49 * Intel Meteor Lake (SOC and PCH) 50 * Intel Birch Stream (SOC) 51 * Intel Arrow Lake (SOC) 52 * Intel Panther Lake (SOC) 53 * Intel Wildcat Lake (SOC) 54 * Intel Diamond Rapids (SOC) 55 * Intel Nova Lake (PCH) 56 57 Datasheets: Publicly available at the Intel website 58 59On Intel Patsburg and later chipsets, both the normal host SMBus controller 60and the additional 'Integrated Device Function' controllers are supported. 61 62Authors: 63 - Mark Studebaker <mdsxyz123@yahoo.com> 64 - Jean Delvare <jdelvare@suse.de> 65 66 67Module Parameters 68----------------- 69 70* disable_features (bit vector) 71 72Disable selected features normally supported by the device. This makes it 73possible to work around possible driver or hardware bugs if the feature in 74question doesn't work as intended for whatever reason. Bit values: 75 76 ==== ========================================= 77 0x01 disable SMBus PEC 78 0x02 disable the block buffer 79 0x08 disable the I2C block read functionality 80 0x10 don't use interrupts 81 0x20 disable SMBus Host Notify 82 ==== ========================================= 83 84 85Description 86----------- 87 88The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA), 89ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of 90Intel's '810' chipset for Celeron-based PCs, '810E' chipset for 91Pentium-based PCs, '815E' chipset, and others. 92 93The ICH chips contain at least SEVEN separate PCI functions in TWO logical 94PCI devices. An output of lspci will show something similar to the 95following:: 96 97 00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01) 98 00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01) 99 00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01) 100 00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01) 101 00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01) 102 103The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial 104Controller. 105 106The ICH chips are quite similar to Intel's PIIX4 chip, at least in the 107SMBus controller. 108 109 110Process Call Support 111-------------------- 112 113Block process call is supported on the 82801EB (ICH5) and later chips. 114 115 116I2C Block Read Support 117---------------------- 118 119I2C block read is supported on the 82801EB (ICH5) and later chips. 120 121 122SMBus 2.0 Support 123----------------- 124 125The 82801DB (ICH4) and later chips support several SMBus 2.0 features. 126 127 128Interrupt Support 129----------------- 130 131PCI interrupt support is supported on the 82801EB (ICH5) and later chips. 132 133 134Hidden ICH SMBus 135---------------- 136 137If your system has an Intel ICH south bridge, but you do NOT see the 138SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the 139BIOS to enable it, it means it has been hidden by the BIOS code. Asus is 140well known for first doing this on their P4B motherboard, and many other 141boards after that. Some vendor machines are affected as well. 142 143The first thing to try is the "i2c-scmi" ACPI driver. It could be that the 144SMBus was hidden on purpose because it'll be driven by ACPI. If the 145i2c-scmi driver works for you, just forget about the i2c-i801 driver and 146don't try to unhide the ICH SMBus. Even if i2c-scmi doesn't work, you 147better make sure that the SMBus isn't used by the ACPI code. Try loading 148the "fan" and "thermal" drivers, and check in /sys/class/thermal. If you 149find a thermal zone with type "acpitz", it's likely that the ACPI is 150accessing the SMBus and it's safer not to unhide it. Only once you are 151certain that ACPI isn't using the SMBus, you can attempt to unhide it. 152 153In order to unhide the SMBus, we need to change the value of a PCI 154register before the kernel enumerates the PCI devices. This is done in 155drivers/pci/quirks.c, where all affected boards must be listed (see 156function asus_hides_smbus_hostbridge.) If the SMBus device is missing, 157and you think there's something interesting on the SMBus (e.g. a 158hardware monitoring chip), you need to add your board to the list. 159 160The motherboard is identified using the subvendor and subdevice IDs of the 161host bridge PCI device. Get yours with ``lspci -n -v -s 00:00.0``:: 162 163 00:00.0 Class 0600: 8086:2570 (rev 02) 164 Subsystem: 1043:80f2 165 Flags: bus master, fast devsel, latency 0 166 Memory at fc000000 (32-bit, prefetchable) [size=32M] 167 Capabilities: [e4] #09 [2106] 168 Capabilities: [a0] AGP version 3.0 169 170Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043 171(Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic 172names for the bridge ID and the subvendor ID in include/linux/pci_ids.h, 173and then add a case for your subdevice ID at the right place in 174drivers/pci/quirks.c. Then please give it very good testing, to make sure 175that the unhidden SMBus doesn't conflict with e.g. ACPI. 176 177If it works, proves useful (i.e. there are usable chips on the SMBus) 178and seems safe, please submit a patch for inclusion into the kernel. 179 180Note: There's a useful script in lm_sensors 2.10.2 and later, named 181unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to 182temporarily unhide the SMBus without having to patch and recompile your 183kernel. It's very convenient if you just want to check if there's 184anything interesting on your hidden ICH SMBus. 185 186 187---------------------------------------------------------------------------- 188 189The lm_sensors project gratefully acknowledges the support of Texas 190Instruments in the initial development of this driver. 191 192The lm_sensors project gratefully acknowledges the support of Intel in the 193development of SMBus 2.0 / ICH4 features of this driver. 194