e645e2dcf2
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12229 a1c6a512-1295-4272-9138-f99709370657
135 lines
3.2 KiB
C
135 lines
3.2 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2006 by Linus Nielsen Feltzing
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "cpu.h"
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#include <stdbool.h>
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#include "kernel.h"
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#include "system.h"
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#include "hwcompat.h"
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#include "logf.h"
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#include "debug.h"
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#include "string.h"
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#include "generic_i2c.h"
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static void i2c_sda_output(void)
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{
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GPECON |= (1 << 30);
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}
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static void i2c_sda_input(void)
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{
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GPECON &= ~(3 << 30);
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}
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static void i2c_sda_lo(void)
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{
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GPEDAT &= ~(1 << 15);
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}
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static void i2c_sda_hi(void)
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{
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GPEDAT |= (1 << 15);
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}
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static int i2c_sda(void)
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{
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return GPEDAT & (1 << 15);
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}
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static void i2c_scl_output(void)
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{
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GPECON |= (1 << 28);
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}
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static void i2c_scl_input(void)
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{
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GPECON &= ~(3 << 28);
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}
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static void i2c_scl_lo(void)
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{
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GPEDAT &= ~(1 << 14);
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}
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static int i2c_scl(void)
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{
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return GPEDAT & (1 << 14);
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}
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static void i2c_scl_hi(void)
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{
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i2c_scl_input();
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while(!i2c_scl());
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GPEDAT |= (1 << 14);
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i2c_scl_output();
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}
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static void i2c_delay(void)
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{
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unsigned _x;
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/* The i2c can clock at 500KHz: 2uS period -> 1uS half period */
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/* about 30 cycles overhead + X * 7 */
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/* 300MHz: 1000nS @3.36nS/cyc = 297cyc: X = 38*/
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/* 100MHz: 1000nS @10nS/cyc = 100cyc : X = 10 */
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for (_x = 38; _x; _x--)
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{
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/* burn CPU cycles */
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/* gcc makes it an inc loop - check with objdump for asm timing */
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}
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}
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struct i2c_interface s3c2440_i2c = {
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0x34, /* Address */
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/* Bit-banged interface definitions */
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i2c_scl_hi, /* Drive SCL high, might sleep on clk stretch */
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i2c_scl_lo, /* Drive SCL low */
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i2c_sda_hi, /* Drive SDA high */
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i2c_sda_lo, /* Drive SDA low */
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i2c_sda_input, /* Set SDA as input */
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i2c_sda_output, /* Set SDA as output */
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i2c_scl_input, /* Set SCL as input */
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i2c_scl_output, /* Set SCL as output */
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i2c_scl, /* Read SCL, returns 0 or nonzero */
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i2c_sda, /* Read SDA, returns 0 or nonzero */
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i2c_delay, /* START SDA hold time (tHD:SDA) */
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i2c_delay, /* SDA hold time (tHD:DAT) */
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i2c_delay, /* SDA setup time (tSU:DAT) */
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i2c_delay, /* STOP setup time (tSU:STO) */
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i2c_delay, /* Rep. START setup time (tSU:STA) */
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i2c_delay, /* SCL high period (tHIGH) */
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};
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void i2c_init(void)
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{
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/* Set GPE15 (SDA) and GPE14 (SCL) to 1 */
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GPECON = (GPECON & ~(0xF<<28)) | 5<<28;
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i2c_add_node(&s3c2440_i2c);
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}
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void i2c_send(int bus_address, int reg_address, const unsigned char buf)
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{
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i2c_write_data(bus_address, reg_address, &buf, 1);
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}
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