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ccf988b66d
Convert each file at I2C subsystem, renaming them to .rst and adding to the driver-api book. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
123 lines
3.6 KiB
ReStructuredText
123 lines
3.6 KiB
ReStructuredText
=========================
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Kernel driver i2c-ali15x3
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=========================
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Supported adapters:
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* Acer Labs, Inc. ALI 1533 and 1543C (south bridge)
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Datasheet: Now under NDA
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http://www.ali.com.tw/
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Authors:
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- Frodo Looijaard <frodol@dds.nl>,
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- Philip Edelbrock <phil@netroedge.com>,
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- Mark D. Studebaker <mdsxyz123@yahoo.com>
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Module Parameters
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-----------------
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* force_addr: int
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Initialize the base address of the i2c controller
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Notes
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-----
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The force_addr parameter is useful for boards that don't set the address in
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the BIOS. Does not do a PCI force; the device must still be present in
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lspci. Don't use this unless the driver complains that the base address is
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not set.
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Example::
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modprobe i2c-ali15x3 force_addr=0xe800
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SMBus periodically hangs on ASUS P5A motherboards and can only be cleared
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by a power cycle. Cause unknown (see Issues below).
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Description
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-----------
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This is the driver for the SMB Host controller on Acer Labs Inc. (ALI)
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M1541 and M1543C South Bridges.
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The M1543C is a South bridge for desktop systems.
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The M1541 is a South bridge for portable systems.
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They are part of the following ALI chipsets:
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* "Aladdin Pro 2" includes the M1621 Slot 1 North bridge with AGP and
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100MHz CPU Front Side bus
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* "Aladdin V" includes the M1541 Socket 7 North bridge with AGP and 100MHz
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CPU Front Side bus
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Some Aladdin V motherboards:
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- Asus P5A
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- Atrend ATC-5220
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- BCM/GVC VP1541
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- Biostar M5ALA
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- Gigabyte GA-5AX (Generally doesn't work because the BIOS doesn't
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enable the 7101 device!)
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- Iwill XA100 Plus
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- Micronics C200
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- Microstar (MSI) MS-5169
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* "Aladdin IV" includes the M1541 Socket 7 North bridge
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with host bus up to 83.3 MHz.
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For an overview of these chips see http://www.acerlabs.com. At this time the
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full data sheets on the web site are password protected, however if you
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contact the ALI office in San Jose they may give you the password.
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The M1533/M1543C devices appear as FOUR separate devices on the PCI bus. An
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output of lspci will show something similar to the following::
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00:02.0 USB Controller: Acer Laboratories Inc. M5237 (rev 03)
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00:03.0 Bridge: Acer Laboratories Inc. M7101 <= THIS IS THE ONE WE NEED
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00:07.0 ISA bridge: Acer Laboratories Inc. M1533 (rev c3)
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00:0f.0 IDE interface: Acer Laboratories Inc. M5229 (rev c1)
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.. important::
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If you have a M1533 or M1543C on the board and you get
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"ali15x3: Error: Can't detect ali15x3!"
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then run lspci.
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If you see the 1533 and 5229 devices but NOT the 7101 device,
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then you must enable ACPI, the PMU, SMB, or something similar
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in the BIOS.
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The driver won't work if it can't find the M7101 device.
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The SMB controller is part of the M7101 device, which is an ACPI-compliant
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Power Management Unit (PMU).
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The whole M7101 device has to be enabled for the SMB to work. You can't
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just enable the SMB alone. The SMB and the ACPI have separate I/O spaces.
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We make sure that the SMB is enabled. We leave the ACPI alone.
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Features
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--------
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This driver controls the SMB Host only. The SMB Slave
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controller on the M15X3 is not enabled. This driver does not use
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interrupts.
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Issues
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------
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This driver requests the I/O space for only the SMB
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registers. It doesn't use the ACPI region.
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On the ASUS P5A motherboard, there are several reports that
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the SMBus will hang and this can only be resolved by
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powering off the computer. It appears to be worse when the board
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gets hot, for example under heavy CPU load, or in the summer.
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There may be electrical problems on this board.
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On the P5A, the W83781D sensor chip is on both the ISA and
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SMBus. Therefore the SMBus hangs can generally be avoided
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by accessing the W83781D on the ISA bus only.
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