mirror of https://gitee.com/openkylin/linux.git
140 lines
5.3 KiB
C
140 lines
5.3 KiB
C
/*
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I2C API, implementation depends on board specifics
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Copyright (c), 2004-2005,2007-2010 Trident Microsystems, Inc.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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* Neither the name of Trident Microsystems nor Hauppauge Computer Works
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nor the names of its contributors may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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This module encapsulates I2C access.In some applications several devices
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share one I2C bus. If these devices have the same I2C address some kind
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off "switch" must be implemented to ensure error free communication with
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one device. In case such a "switch" is used, the device ID can be used
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to implement control over this "switch".
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*/
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#ifndef __BSPI2C_H__
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#define __BSPI2C_H__
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#include "bsp_types.h"
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/*
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* This structure contains the I2C address, the device ID and a user_data pointer.
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* The user_data pointer can be used for application specific purposes.
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*/
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struct i2c_device_addr {
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u16 i2c_addr; /* The I2C address of the device. */
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u16 i2c_dev_id; /* The device identifier. */
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void *user_data; /* User data pointer */
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};
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/**
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* \def IS_I2C_10BIT( addr )
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* \brief Determine if I2C address 'addr' is a 10 bits address or not.
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* \param addr The I2C address.
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* \return int.
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* \retval 0 if address is not a 10 bits I2C address.
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* \retval 1 if address is a 10 bits I2C address.
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*/
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#define IS_I2C_10BIT(addr) \
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(((addr) & 0xF8) == 0xF0)
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/*------------------------------------------------------------------------------
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Exported FUNCTIONS
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------------------------------------------------------------------------------*/
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/**
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* \fn drxbsp_i2c_init()
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* \brief Initialize I2C communication module.
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* \return drx_status_t Return status.
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* \retval 0 Initialization successful.
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* \retval -EIO Initialization failed.
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*/
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drx_status_t drxbsp_i2c_init(void);
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/**
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* \fn drxbsp_i2c_term()
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* \brief Terminate I2C communication module.
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* \return drx_status_t Return status.
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* \retval 0 Termination successful.
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* \retval -EIO Termination failed.
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*/
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drx_status_t drxbsp_i2c_term(void);
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/**
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* \fn drx_status_t drxbsp_i2c_write_read( struct i2c_device_addr *w_dev_addr,
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* u16 w_count,
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* u8 *wData,
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* struct i2c_device_addr *r_dev_addr,
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* u16 r_count,
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* u8 *r_data)
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* \brief Read and/or write count bytes from I2C bus, store them in data[].
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* \param w_dev_addr The device i2c address and the device ID to write to
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* \param w_count The number of bytes to write
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* \param wData The array to write the data to
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* \param r_dev_addr The device i2c address and the device ID to read from
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* \param r_count The number of bytes to read
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* \param r_data The array to read the data from
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* \return drx_status_t Return status.
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* \retval 0 Succes.
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* \retval -EIO Failure.
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* \retval -EINVAL Parameter 'wcount' is not zero but parameter
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* 'wdata' contains NULL.
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* Idem for 'rcount' and 'rdata'.
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* Both w_dev_addr and r_dev_addr are NULL.
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*
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* This function must implement an atomic write and/or read action on the I2C bus
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* No other process may use the I2C bus when this function is executing.
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* The critical section of this function runs from and including the I2C
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* write, up to and including the I2C read action.
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*
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* The device ID can be useful if several devices share an I2C address.
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* It can be used to control a "switch" on the I2C bus to the correct device.
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*/
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drx_status_t drxbsp_i2c_write_read(struct i2c_device_addr *w_dev_addr,
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u16 w_count,
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u8 *w_data,
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struct i2c_device_addr *r_dev_addr,
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u16 r_count, u8 *r_data);
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/**
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* \fn drxbsp_i2c_error_text()
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* \brief Returns a human readable error.
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* Counter part of numerical drx_i2c_error_g.
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*
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* \return char* Pointer to human readable error text.
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*/
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char *drxbsp_i2c_error_text(void);
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/**
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* \var drx_i2c_error_g;
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* \brief I2C specific error codes, platform dependent.
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*/
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extern int drx_i2c_error_g;
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#endif /* __BSPI2C_H__ */
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