recv.c

QNX ADS BSP code for i.MX27 chips

/*
 * $QNXLicenseC: 
 * Copyright 2007, QNX Software Systems.  
 *  
 * Licensed under the Apache License, Version 2.0 (the "License"). You  
 * may not reproduce, modify or distribute this software except in  
 * compliance with the License. You may obtain a copy of the License  
 * at: http://www.apache.org/licenses/LICENSE-2.0  
 *  
 * Unless required by applicable law or agreed to in writing, software  
 * distributed under the License is distributed on an "AS IS" basis,  
 * WITHOUT WARRANTIES OF ANY KIND, either express or implied. 
 * 
 * This file may contain contributions from others, either as  
 * contributors under the License or as licensors under other terms.   
 * Please review this entire file for other proprietary rights or license  
 * notices, as well as the QNX Development Suite License Guide at  
 * http://licensing.qnx.com/license-guide/ for other information. 
 * $
 */


#include "proto.h"

i2c_status_t
mx21_recv(void *hdl, void *buf, unsigned int len, unsigned int stop)
{
	mx21_dev_t		*dev = hdl;
	uint8_t			*data = buf;
	uint16_t		cr;
	int				i;
//	i2c_status_t	ret = I2C_STATUS_ERROR;

	if (len <= 0) 
		return I2C_STATUS_DONE;

	mx21_i2c_enable(dev);

   if(dev->stop) /* check whether the stop bit is generated, if not, skip busy check*/
   {
		if (in16(dev->regbase + MX21_I2C_SR) & MX21_I2SR_IBB) {
			mx21_i2c_disable(dev);
	        return I2C_STATUS_BUSY;
		}
   }

	mx21_i2c_start(dev, 1);
	/* Wait for the address cycle to complete */
	if (mx21_wait_complete(dev, 1)) {
		mx21_i2c_stop(dev);
		mx21_i2c_disable(dev);
		return I2C_STATUS_ERROR;
	}

	cr = in16(dev->regbase + MX21_I2C_CR);
	/*
	 * Clear MTX to switch to receive mode.
	 */
	cr &= ~MX21_I2CR_MTX;

	/*
	 * Clear the TXAK bit to gen an ack when receiving only one byte.
	 */
	if (len == 1)
		cr |= MX21_I2CR_TXAK;
	else
		cr &= ~MX21_I2CR_TXAK;

	out16(dev->regbase + MX21_I2C_CR, cr);

	/*
	 * Dummy read only at the end of an address cycle
	 */
	in16(dev->regbase + MX21_I2C_DR);

	for (i = 0; i < len; i++) {
		/*
		 * Wait for data transmission to complete
		 */
		if (mx21_wait_complete(dev, 1)) {
			mx21_i2c_stop(dev);
			return I2C_STATUS_ERROR;
		}
		/*
		 * Do not generate an ACK for the last byte
		 */
		if (i == (len - 2)) {
			cr = in16(dev->regbase + MX21_I2C_CR) | MX21_I2CR_TXAK;
			out16(dev->regbase + MX21_I2C_CR, cr);
		}
		else if (i == (len - 1)) {
  			dev->stop = stop;
			if (dev->stop)
				mx21_i2c_stop(dev);
		}
		/* Read the data */
		*data++ = in16(dev->regbase + MX21_I2C_DR);
	}
    return I2C_STATUS_DONE;
}