mirror of https://github.com/ipxe/ipxe.git
58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
/*
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* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stddef.h>
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#include <byteswap.h>
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#include <gpxe/spi.h>
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#include <gpxe/threewire.h>
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/** @file
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*
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* Three-wire serial devices
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*
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*/
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/**
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* Read from a three-wire device
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*
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* @v three Three-wire device
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* @v address Address
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* @ret data Data
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*/
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unsigned long threewire_read ( struct threewire_device *three,
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unsigned long address ) {
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struct spi_interface *spi = three->spi;
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uint32_t data;
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/* Activate chip select line */
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spi->select_slave ( spi, three->slave );
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/* Send command and address */
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data = cpu_to_le32 ( threewire_cmd_read ( three, address ) );
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spi->transfer ( spi, &data, NULL, threewire_cmd_len ( three ) );
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/* Read back data */
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data = 0;
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spi->transfer ( spi, NULL, &data, three->datasize );
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/* Deactivate chip select line */
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spi->deselect_slave ( spi );
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return le32_to_cpu ( data );;
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}
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