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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* STM32 common I2C code for Chrome EC */
#include "i2c.h"
#include "util.h"
/* Maximum transfer of a SMBUS block transfer */
#define SMBUS_MAX_BLOCK 32
int i2c_read_string(int port, int slave_addr,
int offset, uint8_t *data, int len)
{
int rv;
uint8_t reg, block_length;
if ((len <= 0) || (len > SMBUS_MAX_BLOCK))
return EC_ERROR_INVAL;
i2c_lock(port, 1);
/* Read the counted string into the output buffer */
reg = offset;
rv = i2c_xfer(port, slave_addr, ®, 1, data, len, I2C_XFER_SINGLE);
if (rv == EC_SUCCESS) {
/* Block length is the first byte of the returned buffer */
block_length = MIN(data[0], len - 1);
/* Move data down, then null-terminate it */
memmove(data, data + 1, block_length);
data[block_length] = 0;
}
i2c_lock(port, 0);
return rv;
}
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