i2c-ali15x3.rst

  1=========================
  2Kernel driver i2c-ali15x3
  3=========================
  4
  5Supported adapters:
  6  * Acer Labs, Inc. ALI 1533 and 1543C (south bridge)
  7
  8    Datasheet: Now under NDA
  9	http://www.ali.com.tw/
 10
 11Authors:
 12	- Frodo Looijaard <frodol@dds.nl>,
 13	- Philip Edelbrock <phil@netroedge.com>,
 14	- Mark D. Studebaker <mdsxyz123@yahoo.com>
 15
 16Module Parameters
 17-----------------
 18
 19* force_addr: int
 20    Initialize the base address of the i2c controller
 21
 22
 23Notes
 24-----
 25
 26The force_addr parameter is useful for boards that don't set the address in
 27the BIOS. Does not do a PCI force; the device must still be present in
 28lspci. Don't use this unless the driver complains that the base address is
 29not set.
 30
 31Example::
 32
 33    modprobe i2c-ali15x3 force_addr=0xe800
 34
 35SMBus periodically hangs on ASUS P5A motherboards and can only be cleared
 36by a power cycle. Cause unknown (see Issues below).
 37
 38
 39Description
 40-----------
 41
 42This is the driver for the SMB Host controller on Acer Labs Inc. (ALI)
 43M1541 and M1543C South Bridges.
 44
 45The M1543C is a South bridge for desktop systems.
 46
 47The M1541 is a South bridge for portable systems.
 48
 49They are part of the following ALI chipsets:
 50
 51 * "Aladdin Pro 2" includes the M1621 Slot 1 North bridge with AGP and
 52   100MHz CPU Front Side bus
 53 * "Aladdin V" includes the M1541 Socket 7 North bridge with AGP and 100MHz
 54   CPU Front Side bus
 55
 56   Some Aladdin V motherboards:
 57	- Asus P5A
 58	- Atrend ATC-5220
 59	- BCM/GVC VP1541
 60	- Biostar M5ALA
 61	- Gigabyte GA-5AX (Generally doesn't work because the BIOS doesn't
 62	  enable the 7101 device!)
 63	- Iwill XA100 Plus
 64	- Micronics C200
 65	- Microstar (MSI) MS-5169
 66
 67  * "Aladdin IV" includes the M1541 Socket 7 North bridge
 68    with host bus up to 83.3 MHz.
 69
 70For an overview of these chips see http://www.acerlabs.com. At this time the
 71full data sheets on the web site are password protected, however if you
 72contact the ALI office in San Jose they may give you the password.
 73
 74The M1533/M1543C devices appear as FOUR separate devices on the PCI bus. An
 75output of lspci will show something similar to the following::
 76
 77  00:02.0 USB Controller: Acer Laboratories Inc. M5237 (rev 03)
 78  00:03.0 Bridge: Acer Laboratories Inc. M7101      <= THIS IS THE ONE WE NEED
 79  00:07.0 ISA bridge: Acer Laboratories Inc. M1533 (rev c3)
 80  00:0f.0 IDE interface: Acer Laboratories Inc. M5229 (rev c1)
 81
 82.. important::
 83
 84   If you have a M1533 or M1543C on the board and you get
 85   "ali15x3: Error: Can't detect ali15x3!"
 86   then run lspci.
 87
 88   If you see the 1533 and 5229 devices but NOT the 7101 device,
 89   then you must enable ACPI, the PMU, SMB, or something similar
 90   in the BIOS.
 91
 92   The driver won't work if it can't find the M7101 device.
 93
 94The SMB controller is part of the M7101 device, which is an ACPI-compliant
 95Power Management Unit (PMU).
 96
 97The whole M7101 device has to be enabled for the SMB to work. You can't
 98just enable the SMB alone. The SMB and the ACPI have separate I/O spaces.
 99We make sure that the SMB is enabled. We leave the ACPI alone.
100
101Features
102--------
103
104This driver controls the SMB Host only. The SMB Slave
105controller on the M15X3 is not enabled. This driver does not use
106interrupts.
107
108
109Issues
110------
111
112This driver requests the I/O space for only the SMB
113registers. It doesn't use the ACPI region.
114
115On the ASUS P5A motherboard, there are several reports that
116the SMBus will hang and this can only be resolved by
117powering off the computer. It appears to be worse when the board
118gets hot, for example under heavy CPU load, or in the summer.
119There may be electrical problems on this board.
120On the P5A, the W83781D sensor chip is on both the ISA and
121SMBus. Therefore the SMBus hangs can generally be avoided
122by accessing the W83781D on the ISA bus only.