path: root/Documentation/i2c/busses/i2c-ali15x3
diff options
Diffstat (limited to 'Documentation/i2c/busses/i2c-ali15x3')
1 files changed, 112 insertions, 0 deletions
diff --git a/Documentation/i2c/busses/i2c-ali15x3 b/Documentation/i2c/busses/i2c-ali15x3
new file mode 100644
index 00000000000..ff28d381beb
--- /dev/null
+++ b/Documentation/i2c/busses/i2c-ali15x3
@@ -0,0 +1,112 @@
+Kernel driver i2c-ali15x3
+Supported adapters:
+ * Acer Labs, Inc. ALI 1533 and 1543C (south bridge)
+ Datasheet: Now under NDA
+ Frodo Looijaard <>,
+ Philip Edelbrock <>,
+ Mark D. Studebaker <>
+Module Parameters
+* force_addr: int
+ Initialize the base address of the i2c controller
+The force_addr parameter is useful for boards that don't set the address in
+the BIOS. Does not do a PCI force; the device must still be present in
+lspci. Don't use this unless the driver complains that the base address is
+not set.
+Example: 'modprobe i2c-ali15x3 force_addr=0xe800'
+SMBus periodically hangs on ASUS P5A motherboards and can only be cleared
+by a power cycle. Cause unknown (see Issues below).
+This is the driver for the SMB Host controller on Acer Labs Inc. (ALI)
+M1541 and M1543C South Bridges.
+The M1543C is a South bridge for desktop systems.
+The M1541 is a South bridge for portable systems.
+They are part of the following ALI chipsets:
+ * "Aladdin Pro 2" includes the M1621 Slot 1 North bridge with AGP and
+ 100MHz CPU Front Side bus
+ * "Aladdin V" includes the M1541 Socket 7 North bridge with AGP and 100MHz
+ CPU Front Side bus
+ Some Aladdin V motherboards:
+ Asus P5A
+ Atrend ATC-5220
+ BCM/GVC VP1541
+ Biostar M5ALA
+ Gigabyte GA-5AX (** Generally doesn't work because the BIOS doesn't
+ enable the 7101 device! **)
+ Iwill XA100 Plus
+ Micronics C200
+ Microstar (MSI) MS-5169
+ * "Aladdin IV" includes the M1541 Socket 7 North bridge
+ with host bus up to 83.3 MHz.
+For an overview of these chips see At this time the
+full data sheets on the web site are password protected, however if you
+contact the ALI office in San Jose they may give you the password.
+The M1533/M1543C devices appear as FOUR separate devices on the PCI bus. An
+output of lspci will show something similar to the following:
+ 00:02.0 USB Controller: Acer Laboratories Inc. M5237 (rev 03)
+ 00:03.0 Bridge: Acer Laboratories Inc. M7101 <= THIS IS THE ONE WE NEED
+ 00:07.0 ISA bridge: Acer Laboratories Inc. M1533 (rev c3)
+ 00:0f.0 IDE interface: Acer Laboratories Inc. M5229 (rev c1)
+** If you have a M1533 or M1543C on the board and you get
+** "ali15x3: Error: Can't detect ali15x3!"
+** then run lspci.
+** If you see the 1533 and 5229 devices but NOT the 7101 device,
+** then you must enable ACPI, the PMU, SMB, or something similar
+** in the BIOS.
+** The driver won't work if it can't find the M7101 device.
+The SMB controller is part of the M7101 device, which is an ACPI-compliant
+Power Management Unit (PMU).
+The whole M7101 device has to be enabled for the SMB to work. You can't
+just enable the SMB alone. The SMB and the ACPI have separate I/O spaces.
+We make sure that the SMB is enabled. We leave the ACPI alone.
+This driver controls the SMB Host only. The SMB Slave
+controller on the M15X3 is not enabled. This driver does not use
+This driver requests the I/O space for only the SMB
+registers. It doesn't use the ACPI region.
+On the ASUS P5A motherboard, there are several reports that
+the SMBus will hang and this can only be resolved by
+powering off the computer. It appears to be worse when the board
+gets hot, for example under heavy CPU load, or in the summer.
+There may be electrical problems on this board.
+On the P5A, the W83781D sensor chip is on both the ISA and
+SMBus. Therefore the SMBus hangs can generally be avoided
+by accessing the W83781D on the ISA bus only.