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gpio: Clarify API

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Clarify the behaviour of gpio read and write functions.

Change-Id: Ib64f9e4bfc6e908a945fd7e17ba4073d3c707fc6
Signed-off-by: Marcus Shawcroft <marcus.shawcroft@arm.com>
This commit is contained in:
Marcus Shawcroft 2017-01-31 15:05:41 +00:00 committed by Anas Nashif
parent fd74c0c5a6
commit f88824a0f2
1 changed files with 18 additions and 0 deletions
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18
include/gpio.h
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@ -1,4 +1,5 @@
/*
* Copyright (c) 2017 ARM Ltd
* Copyright (c) 2015-2016 Intel Corporation.
*
* SPDX-License-Identifier: Apache-2.0
@ -304,6 +305,9 @@ static inline int gpio_pin_write(struct device *port, uint32_t pin,
/**
* @brief Read the data value of a single pin.
*
* Read the input state of a pin, returning the value 0 or 1.
*
* @param port Pointer to the device structure for the driver instance.
* @param pin Pin number where data is read.
* @param value Integer pointer to receive the data values from the pin.
@ -418,6 +422,13 @@ static inline int gpio_port_configure(struct device *port, int flags)
/**
* @brief Write a data value to the port.
*
* Write the output state of a port. The state of each pin is
* represented by one bit in the value. Pin 0 corresponds to the
* least signficiant bit, pin 31 corresponds to the most significant
* bit. For ports with less that 32 physical pins the most signficant
* bits which do not correspond to a physical pin are ignored.
*
* @param port Pointer to the device structure for the driver instance.
* @param value Value to set on the port.
* @return 0 if successful, negative errno code on failure.
@ -431,6 +442,13 @@ static inline int gpio_port_write(struct device *port, uint32_t value)
/**
* @brief Read data value from the port.
*
* Read the input state of a port. The state of each pin is
* represented by one bit in the returned value. Pin 0 corresponds to
* the least signficiant bit, pin 31 corresponds to the most
* significant bit. Unused bits for ports with less that 32 physical
* pins are returned as 0.
*
* @param port Pointer to the device structure for the driver instance.
* @param value Integer pointer to receive the data value from the port.
* @return 0 if successful, negative errno code on failure.