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Two small updates to the pcf857x driver: (a) the max732[89] chips are also second sources for the pcf8574/a, and (b) add a mutex to prevent trashing the cached state. Adding the lock is effectively a bugfix, although it seems unlikely that anyone would have run into the issue it protects against. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
86 lines
2.5 KiB
Text
86 lines
2.5 KiB
Text
#
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# GPIO infrastructure and expanders
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#
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config HAVE_GPIO_LIB
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bool
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help
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Platforms select gpiolib if they use this infrastructure
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for all their GPIOs, usually starting with ones integrated
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into SOC processors.
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menu "GPIO Support"
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depends on HAVE_GPIO_LIB
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config DEBUG_GPIO
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bool "Debug GPIO calls"
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depends on DEBUG_KERNEL
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help
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Say Y here to add some extra checks and diagnostics to GPIO calls.
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The checks help ensure that GPIOs have been properly initialized
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before they are used and that sleeping calls aren not made from
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nonsleeping contexts. They can make bitbanged serial protocols
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slower. The diagnostics help catch the type of setup errors
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that are most common when setting up new platforms or boards.
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# put expanders in the right section, in alphabetical order
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comment "I2C GPIO expanders:"
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config GPIO_PCA953X
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tristate "PCA953x, PCA955x, and MAX7310 I/O ports"
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depends on I2C
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help
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Say yes here to provide access to several register-oriented
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SMBus I/O expanders, made mostly by NXP or TI. Compatible
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models include:
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4 bits: pca9536, pca9537
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8 bits: max7310, pca9534, pca9538, pca9554, pca9557
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16 bits: pca9535, pca9539, pca9555
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This driver can also be built as a module. If so, the module
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will be called pca953x.
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config GPIO_PCF857X
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tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
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depends on I2C
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help
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Say yes here to provide access to most "quasi-bidirectional" I2C
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GPIO expanders used for additional digital outputs or inputs.
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Most of these parts are from NXP, though TI is a second source for
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some of them. Compatible models include:
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8 bits: pcf8574, pcf8574a, pca8574, pca8574a,
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pca9670, pca9672, pca9674, pca9674a,
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max7328, max7329
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16 bits: pcf8575, pcf8575c, pca8575,
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pca9671, pca9673, pca9675
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Your board setup code will need to declare the expanders in
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use, and assign numbers to the GPIOs they expose. Those GPIOs
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can then be used from drivers and other kernel code, just like
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other GPIOs, but only accessible from task contexts.
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This driver provides an in-kernel interface to those GPIOs using
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platform-neutral GPIO calls.
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comment "SPI GPIO expanders:"
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config GPIO_MAX7301
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tristate "Maxim MAX7301 GPIO expander"
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depends on SPI_MASTER
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help
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gpio driver for Maxim MAX7301 SPI GPIO expander.
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config GPIO_MCP23S08
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tristate "Microchip MCP23S08 I/O expander"
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depends on SPI_MASTER
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help
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SPI driver for Microchip MCP23S08 I/O expander. This provides
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a GPIO interface supporting inputs and outputs.
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endmenu
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