0001 =========================
0002 Kernel driver i2c-ali15x3
0003 =========================
0004
0005 Supported adapters:
0006 * Acer Labs, Inc. ALI 1533 and 1543C (south bridge)
0007
0008 Datasheet: Now under NDA
0009 http://www.ali.com.tw/
0010
0011 Authors:
0012 - Frodo Looijaard <frodol@dds.nl>,
0013 - Philip Edelbrock <phil@netroedge.com>,
0014 - Mark D. Studebaker <mdsxyz123@yahoo.com>
0015
0016 Module Parameters
0017 -----------------
0018
0019 * force_addr: int
0020 Initialize the base address of the i2c controller
0021
0022
0023 Notes
0024 -----
0025
0026 The force_addr parameter is useful for boards that don't set the address in
0027 the BIOS. Does not do a PCI force; the device must still be present in
0028 lspci. Don't use this unless the driver complains that the base address is
0029 not set.
0030
0031 Example::
0032
0033 modprobe i2c-ali15x3 force_addr=0xe800
0034
0035 SMBus periodically hangs on ASUS P5A motherboards and can only be cleared
0036 by a power cycle. Cause unknown (see Issues below).
0037
0038
0039 Description
0040 -----------
0041
0042 This is the driver for the SMB Host controller on Acer Labs Inc. (ALI)
0043 M1541 and M1543C South Bridges.
0044
0045 The M1543C is a South bridge for desktop systems.
0046
0047 The M1541 is a South bridge for portable systems.
0048
0049 They are part of the following ALI chipsets:
0050
0051 * "Aladdin Pro 2" includes the M1621 Slot 1 North bridge with AGP and
0052 100MHz CPU Front Side bus
0053 * "Aladdin V" includes the M1541 Socket 7 North bridge with AGP and 100MHz
0054 CPU Front Side bus
0055
0056 Some Aladdin V motherboards:
0057 - Asus P5A
0058 - Atrend ATC-5220
0059 - BCM/GVC VP1541
0060 - Biostar M5ALA
0061 - Gigabyte GA-5AX (Generally doesn't work because the BIOS doesn't
0062 enable the 7101 device!)
0063 - Iwill XA100 Plus
0064 - Micronics C200
0065 - Microstar (MSI) MS-5169
0066
0067 * "Aladdin IV" includes the M1541 Socket 7 North bridge
0068 with host bus up to 83.3 MHz.
0069
0070 For an overview of these chips see http://www.acerlabs.com. At this time the
0071 full data sheets on the web site are password protected, however if you
0072 contact the ALI office in San Jose they may give you the password.
0073
0074 The M1533/M1543C devices appear as FOUR separate devices on the PCI bus. An
0075 output of lspci will show something similar to the following::
0076
0077 00:02.0 USB Controller: Acer Laboratories Inc. M5237 (rev 03)
0078 00:03.0 Bridge: Acer Laboratories Inc. M7101 <= THIS IS THE ONE WE NEED
0079 00:07.0 ISA bridge: Acer Laboratories Inc. M1533 (rev c3)
0080 00:0f.0 IDE interface: Acer Laboratories Inc. M5229 (rev c1)
0081
0082 .. important::
0083
0084 If you have a M1533 or M1543C on the board and you get
0085 "ali15x3: Error: Can't detect ali15x3!"
0086 then run lspci.
0087
0088 If you see the 1533 and 5229 devices but NOT the 7101 device,
0089 then you must enable ACPI, the PMU, SMB, or something similar
0090 in the BIOS.
0091
0092 The driver won't work if it can't find the M7101 device.
0093
0094 The SMB controller is part of the M7101 device, which is an ACPI-compliant
0095 Power Management Unit (PMU).
0096
0097 The whole M7101 device has to be enabled for the SMB to work. You can't
0098 just enable the SMB alone. The SMB and the ACPI have separate I/O spaces.
0099 We make sure that the SMB is enabled. We leave the ACPI alone.
0100
0101 Features
0102 --------
0103
0104 This driver controls the SMB Host only. The SMB Slave
0105 controller on the M15X3 is not enabled. This driver does not use
0106 interrupts.
0107
0108
0109 Issues
0110 ------
0111
0112 This driver requests the I/O space for only the SMB
0113 registers. It doesn't use the ACPI region.
0114
0115 On the ASUS P5A motherboard, there are several reports that
0116 the SMBus will hang and this can only be resolved by
0117 powering off the computer. It appears to be worse when the board
0118 gets hot, for example under heavy CPU load, or in the summer.
0119 There may be electrical problems on this board.
0120 On the P5A, the W83781D sensor chip is on both the ISA and
0121 SMBus. Therefore the SMBus hangs can generally be avoided
0122 by accessing the W83781D on the ISA bus only.
