Lines Matching refs:GPIO

1 GPIO Interfaces
8 Due to the history of GPIO interfaces in the kernel, there are two different
21 What is a GPIO?
24 A "General Purpose Input/Output" (GPIO) is a flexible software-controlled
26 to Linux developers working with embedded and custom hardware. Each GPIO
33 non-dedicated pin can be configured as a GPIO; and most chips have at least
37 also "GPIO Expander" chips that connect using the I2C or SPI serial buses.
38 Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS
50     cases (to support bidirectional signaling). GPIO controllers may have
57   - Usually a GPIO will be configurable as either input or output, as needed
63 On a given board each GPIO is used for one specific purpose like monitoring
69 Common GPIO Properties
72 These properties are met through all the other documents of the GPIO interface
73 and it is useful to understand them, especially if you need to define GPIO
78 It is natural to assume that a GPIO is "active" when its output signal is 1
80 GPIO may be inverted before is reaches its destination, or a device could decide
82 be transparent to device drivers, therefore it is possible to define a GPIO as
99 Some GPIO controllers directly support open drain and open source outputs; many
101 support it, there's a common idiom you can use to emulate it with any GPIO pin
111 high signal and configuring the GPIO as input for low. This open drain/open
112 source emulation can be handled transparently by the GPIO framework.