8636e6949e
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13114 a1c6a512-1295-4272-9138-f99709370657
134 lines
3.2 KiB
C
134 lines
3.2 KiB
C
/***************************************************************************
|
|
* __________ __ ___.
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
|
* \/ \/ \/ \/ \/
|
|
* $Id$
|
|
*
|
|
* Copyright (C) 2006 by Linus Nielsen Feltzing
|
|
*
|
|
* All files in this archive are subject to the GNU General Public License.
|
|
* See the file COPYING in the source tree root for full license agreement.
|
|
*
|
|
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
* KIND, either express or implied.
|
|
*
|
|
****************************************************************************/
|
|
#include "config.h"
|
|
#include "cpu.h"
|
|
#include <stdbool.h>
|
|
#include "kernel.h"
|
|
#include "system.h"
|
|
#include "logf.h"
|
|
#include "debug.h"
|
|
#include "string.h"
|
|
#include "generic_i2c.h"
|
|
|
|
static void i2c_sda_output(void)
|
|
{
|
|
GPECON |= (1 << 30);
|
|
}
|
|
|
|
static void i2c_sda_input(void)
|
|
{
|
|
GPECON &= ~(3 << 30);
|
|
}
|
|
|
|
static void i2c_sda_lo(void)
|
|
{
|
|
GPEDAT &= ~(1 << 15);
|
|
}
|
|
|
|
static void i2c_sda_hi(void)
|
|
{
|
|
GPEDAT |= (1 << 15);
|
|
}
|
|
|
|
static int i2c_sda(void)
|
|
{
|
|
return GPEDAT & (1 << 15);
|
|
}
|
|
|
|
static void i2c_scl_output(void)
|
|
{
|
|
GPECON |= (1 << 28);
|
|
}
|
|
|
|
static void i2c_scl_input(void)
|
|
{
|
|
GPECON &= ~(3 << 28);
|
|
}
|
|
|
|
static void i2c_scl_lo(void)
|
|
{
|
|
GPEDAT &= ~(1 << 14);
|
|
}
|
|
|
|
static int i2c_scl(void)
|
|
{
|
|
return GPEDAT & (1 << 14);
|
|
}
|
|
|
|
static void i2c_scl_hi(void)
|
|
{
|
|
i2c_scl_input();
|
|
while(!i2c_scl());
|
|
GPEDAT |= (1 << 14);
|
|
i2c_scl_output();
|
|
}
|
|
|
|
|
|
|
|
static void i2c_delay(void)
|
|
{
|
|
unsigned _x;
|
|
|
|
/* The i2c can clock at 500KHz: 2uS period -> 1uS half period */
|
|
/* about 30 cycles overhead + X * 7 */
|
|
/* 300MHz: 1000nS @3.36nS/cyc = 297cyc: X = 38*/
|
|
/* 100MHz: 1000nS @10nS/cyc = 100cyc : X = 10 */
|
|
for (_x = 38; _x; _x--)
|
|
{
|
|
/* burn CPU cycles */
|
|
/* gcc makes it an inc loop - check with objdump for asm timing */
|
|
}
|
|
}
|
|
|
|
|
|
|
|
struct i2c_interface s3c2440_i2c = {
|
|
0x34, /* Address */
|
|
|
|
/* Bit-banged interface definitions */
|
|
i2c_scl_hi, /* Drive SCL high, might sleep on clk stretch */
|
|
i2c_scl_lo, /* Drive SCL low */
|
|
i2c_sda_hi, /* Drive SDA high */
|
|
i2c_sda_lo, /* Drive SDA low */
|
|
i2c_sda_input, /* Set SDA as input */
|
|
i2c_sda_output, /* Set SDA as output */
|
|
i2c_scl_input, /* Set SCL as input */
|
|
i2c_scl_output, /* Set SCL as output */
|
|
i2c_scl, /* Read SCL, returns 0 or nonzero */
|
|
i2c_sda, /* Read SDA, returns 0 or nonzero */
|
|
|
|
i2c_delay, /* START SDA hold time (tHD:SDA) */
|
|
i2c_delay, /* SDA hold time (tHD:DAT) */
|
|
i2c_delay, /* SDA setup time (tSU:DAT) */
|
|
i2c_delay, /* STOP setup time (tSU:STO) */
|
|
i2c_delay, /* Rep. START setup time (tSU:STA) */
|
|
i2c_delay, /* SCL high period (tHIGH) */
|
|
};
|
|
|
|
void i2c_init(void)
|
|
{
|
|
/* Set GPE15 (SDA) and GPE14 (SCL) to 1 */
|
|
GPECON = (GPECON & ~(0xF<<28)) | 5<<28;
|
|
i2c_add_node(&s3c2440_i2c);
|
|
}
|
|
|
|
void i2c_send(int bus_address, int reg_address, const unsigned char buf)
|
|
{
|
|
i2c_write_data(bus_address, reg_address, &buf, 1);
|
|
}
|