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194684e596
Low priority thread holding the i2c bus mutex could block higher priority threads to access the bus resulting in unacceptable latencies. Change the mutex type to rt_mutex preventing priority inversion. Tested-by: Peter Ujfalusi <peter.ujfalusi@nokia.com> Signed-off-by: Mika Kuoppala <mika.kuoppala@nokia.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
100 lines
3.1 KiB
Plaintext
100 lines
3.1 KiB
Plaintext
#
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# I2C subsystem configuration
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#
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menuconfig I2C
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tristate "I2C support"
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depends on HAS_IOMEM
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select RT_MUTEXES
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---help---
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I2C (pronounce: I-square-C) is a slow serial bus protocol used in
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many micro controller applications and developed by Philips. SMBus,
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or System Management Bus is a subset of the I2C protocol. More
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information is contained in the directory <file:Documentation/i2c/>,
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especially in the file called "summary" there.
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Both I2C and SMBus are supported here. You will need this for
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hardware sensors support, and also for Video For Linux support.
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If you want I2C support, you should say Y here and also to the
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specific driver for your bus adapter(s) below.
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This I2C support can also be built as a module. If so, the module
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will be called i2c-core.
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if I2C
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config I2C_BOARDINFO
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boolean
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default y
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config I2C_COMPAT
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boolean "Enable compatibility bits for old user-space"
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default y
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help
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Say Y here if you intend to run lm-sensors 3.1.1 or older, or any
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other user-space package which expects i2c adapters to be class
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devices. If you don't know, say Y.
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config I2C_CHARDEV
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tristate "I2C device interface"
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help
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Say Y here to use i2c-* device files, usually found in the /dev
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directory on your system. They make it possible to have user-space
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programs use the I2C bus. Information on how to do this is
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contained in the file <file:Documentation/i2c/dev-interface>.
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This support is also available as a module. If so, the module
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will be called i2c-dev.
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config I2C_HELPER_AUTO
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bool "Autoselect pertinent helper modules"
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default y
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help
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Some I2C bus drivers require so-called "I2C algorithm" modules
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to work. These are basically software-only abstractions of generic
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I2C interfaces. This option will autoselect them so that you don't
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have to care.
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Unselect this only if you need to enable additional helper
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modules, for example for use with external I2C bus drivers.
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In doubt, say Y.
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source drivers/i2c/algos/Kconfig
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source drivers/i2c/busses/Kconfig
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source drivers/i2c/chips/Kconfig
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config I2C_DEBUG_CORE
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bool "I2C Core debugging messages"
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help
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Say Y here if you want the I2C core to produce a bunch of debug
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messages to the system log. Select this if you are having a
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problem with I2C support and want to see more of what is going on.
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config I2C_DEBUG_ALGO
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bool "I2C Algorithm debugging messages"
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help
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Say Y here if you want the I2C algorithm drivers to produce a bunch
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of debug messages to the system log. Select this if you are having
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a problem with I2C support and want to see more of what is going
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on.
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config I2C_DEBUG_BUS
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bool "I2C Bus debugging messages"
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help
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Say Y here if you want the I2C bus drivers to produce a bunch of
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debug messages to the system log. Select this if you are having
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a problem with I2C support and want to see more of what is going
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on.
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config I2C_DEBUG_CHIP
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bool "I2C Chip debugging messages"
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help
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Say Y here if you want the I2C chip drivers to produce a bunch of
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debug messages to the system log. Select this if you are having
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a problem with I2C support and want to see more of what is going
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on.
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endif # I2C
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