233 lines
8.6 KiB
C
233 lines
8.6 KiB
C
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/*
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* Copyright (c) 2011-2012, Freescale Semiconductor, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* o Redistributions of source code must retain the above copyright notice, this list
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* of conditions and the following disclaimer.
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*
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* o Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* o Neither the name of Freescale Semiconductor, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __IMX_I2C_H__
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#define __IMX_I2C_H__
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#include "sdk_types.h"
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//! @addtogroup diag_i2c
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//! @{
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////////////////////////////////////////////////////////////////////////////////
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// Definitions
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////////////////////////////////////////////////////////////////////////////////
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//! @brief Read/write address bits
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//!
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//! Bit 0 of the i2c device address cycle to indicate r/w. 0 is for write, 1 is for read.
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enum _i2c_rq {
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I2C_WRITE = 0,
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I2C_READ = 1
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};
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//! @brief I2C Error Codes
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enum _i2c_err {
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ERR_TX = -1,
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ERR_RX = -2,
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ERR_ARB_LOST = -3,
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ERR_NO_ACK = -4,
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ERR_XFER = -5,
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ERR_RX_ACK = -6,
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ERR_NO_ACK_ON_START = -7,
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ERR_INVALID_REQUEST = -8
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};
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//! Default slave address used for the MX6.
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enum _i2c_slave_id {
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IMX6_DEFAULT_SLAVE_ID = 0x60
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};
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//! @brief Info required to talk to an I2C device.
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//!
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//! Pairs an I2C port number with a device address.
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//!
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//! While the device address is often fixed and known in advance by the driver,
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//! some devices have configurable addresses that can be changed with pin
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//! settings. Thus, the same device may have different adresses on different
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//! boards depending on how these pins are tied.
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//!
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//! Note that the @a address member's value is @i not pre-shifted. The 7-bit
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//! address is right aligned within the byte, and the top bit is always set to 0.
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typedef struct i2c_device_info {
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uint8_t port; //!< I2C controller instance to which the device is connected. Starts at 1.
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uint8_t address; //!< I2C device address in lower 7 bits.
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uint32_t freq; //!< Maximum transfer speed in bits per second.
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} i2c_device_info_t;
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/*!
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* @brief An I2C transfer descriptor.
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*
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* To perform an I2C transfer, the caller first fills in an instance of this struct. Then
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* i2c_xfer() is called, passing a pointer to the #imx_i2c_request_t struct.
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*
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* @a ctl_addr should be set to either a valid controller instance number from 1 through
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* the number of I2C instances on the chip, or the base address of the controller.
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*
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* If @a device is set to a non-NULL value, it is a pointer to an #i2c_device_info_t struct
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* to use instead of the @a ctl_addr and @a dev_addr members of this struct.
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*/
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typedef struct imx_i2c_request {
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uint32_t ctl_addr; //!< Either the I2C controller base address or instance number starting at 1.
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uint32_t dev_addr; //!< The I2C device address.
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uint32_t reg_addr; //!< The register address within the target device.
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uint32_t reg_addr_sz; //!< Number of bytes for the address of I2C device register.
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uint8_t *buffer; //!< Buffer to hold the data.
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uint32_t buffer_sz; //!< The number of bytes for read/write.
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int32_t (*slave_receive) (const struct imx_i2c_request *rq); //!< Function for slave to receive data from master.
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int32_t (*slave_transmit) (const struct imx_i2c_request *rq); //!< Function for slave to transmit data to master.
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const i2c_device_info_t * device; //!< Optional pointer to device info struct. Overrides @a ctl_addr and @a dev_addr if set.
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} imx_i2c_request_t;
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////////////////////////////////////////////////////////////////////////////////
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// API
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////////////////////////////////////////////////////////////////////////////////
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/*!
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* @brief Initialize the I2C module
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*
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* Mainly enable the I2C clock, module itself and the I2C clock prescaler.
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*
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* @param base Either the base address of I2C module or the module's instance number. (also assigned for I2Cx_CLK)
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* @param baud The desired data rate in bits per second.
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*
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* @return 0 if successful; non-zero otherwise
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*/
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int i2c_init(uint32_t base, uint32_t baud);
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/*!
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* @brief Perform a single I2C transfer in the selected direction.
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*
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* This is a rather simple function that can be used for most I2C devices.
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*
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* Common steps for both READ and WRITE:
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* - step 1: issue start signal
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* - step 2: put I2C device addr on the bus (always 1 byte write. the dir always I2C_WRITE)
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* - step 3: offset of the I2C device write (offset within the device. can be 1-4 bytes)
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*
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* For READ:
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* - step 4: do repeat-start
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* - step 5: send slave address again, but indicate a READ operation by setting LSB bit
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* - Step 6: change to receive mode
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* - Step 7: dummy read
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* - Step 8: reading
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*
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* For WRITE:
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* - Step 4: do data write
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* - Step 5: generate STOP by clearing MSTA bit
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*
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* @param rq Pointer to #imx_i2c_request_t.
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* @param dir #I2C_READ or #I2C_WRITE
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*
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* @return 0 on success; non-zero otherwise
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*/
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int i2c_xfer(const imx_i2c_request_t *rq, int dir);
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/*!
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* @brief Perform I2C read transfer.
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*
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* @param rq Pointer to #imx_i2c_request_t.
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*/
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int i2c_read(const imx_i2c_request_t *rq);
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/*!
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* @brief Perform I2C write transfer.
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*
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* @param rq Pointer to #imx_i2c_request_t.
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*/
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int i2c_write(const imx_i2c_request_t *rq);
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/*!
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* @brief I2C handler for the slave mode.
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*
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* The function is based on the flow chart for typical I2C polling routine described in the
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* I2C controller chapter of the reference manual.
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*
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* @param rq Pointer to #imx_i2c_request_t.
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*/
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void i2c_slave_handler(const imx_i2c_request_t *rq);
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/*!
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* @brief Handle the I2C transfers in slave mode.
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*
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* The slave mode behaves like any device with g_addr_cycle of address + g_data_cycle of data.
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* Master read =
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* START - SLAVE_ID/W - ACK - MEM_ADDR - ACK - START - SLAVE_ID/R - ACK - DATAx - NACK - STOP
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*
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* Example for a 16-bit address access:
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* - 1st IRQ - receive the slave address and Write flag from master.
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* - 2nd IRQ - receive the lower byte of the requested 16-bit address.
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* - 3rd IRQ - receive the higher byte of the requested 16-bit address.
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* - 4th IRQ - receive the slave address and Read flag from master.
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* - 5th and next IRQ - transmit the data as long as NACK and STOP is not asserted.
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*
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* Master write =
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* START - SLAVE_ID/W - ACK - MEM_ADDR - ACK - DATAx - NACK - STOP
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*
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* - 1st IRQ - receive the slave address and Write flag from master.
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* - 2nd IRQ - receive the lower byte of the requested 16-bit address.
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* - 3rd IRQ - receive the higher byte of the requested 16-bit address.
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* - 4th and next IRQ - receive the data as long STOP is not asserted.
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*
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* @param port Pointer to the I2C module structure.
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* @param rq Pointer to #imx_i2c_request_t.
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*/
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void i2c_slave_xfer(imx_i2c_request_t *rq);
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////////////////////////////////////////////////////////////////////////////////
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// Board support
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////////////////////////////////////////////////////////////////////////////////
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//! @name Board support functions
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//!
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//! These functions are called by the driver in order to factor out board
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//! specific functionality. They must be defined by the board support
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//! library or the application.
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//@{
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//! @brief Configure IOMUX for the I2C driver.
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void i2c_iomux_config(int instance);
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//@}
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#if defined(__cplusplus)
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}
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#endif
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//! @}
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#endif /* __IMX_I2C_H__ */
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////////////////////////////////////////////////////////////////////////////////
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// EOF
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////////////////////////////////////////////////////////////////////////////////
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