u-boot/drivers/i2c/ppc4xx_i2c.c

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/*
* (C) Copyright 2007-2009
* Stefan Roese, DENX Software Engineering, sr@denx.de.
*
* based on work by Anne Sophie Harnois <anne-sophie.harnois@nextream.fr>
*
* (C) Copyright 2001
* Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
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#include <common.h>
#include <asm/ppc4xx.h>
#include <asm/ppc4xx-i2c.h>
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#include <i2c.h>
#include <asm/io.h>
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#ifdef CONFIG_HARD_I2C
DECLARE_GLOBAL_DATA_PTR;
#if defined(CONFIG_I2C_MULTI_BUS)
/*
* Initialize the bus pointer to whatever one the SPD EEPROM is on.
* Default is bus 0. This is necessary because the DDR initialization
* runs from ROM, and we can't switch buses because we can't modify
* the global variables.
*/
#ifndef CONFIG_SYS_SPD_BUS_NUM
#define CONFIG_SYS_SPD_BUS_NUM 0
#endif
static unsigned int i2c_bus_num __attribute__ ((section (".data"))) =
CONFIG_SYS_SPD_BUS_NUM;
#endif /* CONFIG_I2C_MULTI_BUS */
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static void _i2c_bus_reset(void)
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{
struct ppc4xx_i2c *i2c = (struct ppc4xx_i2c *)I2C_BASE_ADDR;
int i;
u8 dc;
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/* Reset status register */
/* write 1 in SCMP and IRQA to clear these fields */
out_8(&i2c->sts, 0x0A);
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/* write 1 in IRQP IRQD LA ICT XFRA to clear these fields */
out_8(&i2c->extsts, 0x8F);
/* Place chip in the reset state */
out_8(&i2c->xtcntlss, IIC_XTCNTLSS_SRST);
/* Check if bus is free */
dc = in_8(&i2c->directcntl);
if (!DIRCTNL_FREE(dc)){
/* Try to set bus free state */
out_8(&i2c->directcntl, IIC_DIRCNTL_SDAC | IIC_DIRCNTL_SCC);
/* Wait until we regain bus control */
for (i = 0; i < 100; ++i) {
dc = in_8(&i2c->directcntl);
if (DIRCTNL_FREE(dc))
break;
/* Toggle SCL line */
dc ^= IIC_DIRCNTL_SCC;
out_8(&i2c->directcntl, dc);
udelay(10);
dc ^= IIC_DIRCNTL_SCC;
out_8(&i2c->directcntl, dc);
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}
}
/* Remove reset */
out_8(&i2c->xtcntlss, 0);
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}
void i2c_init(int speed, int slaveaddr)
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{
struct ppc4xx_i2c *i2c;
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int val, divisor;
int bus;
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#ifdef CONFIG_SYS_I2C_INIT_BOARD
/*
* Call board specific i2c bus reset routine before accessing the
* environment, which might be in a chip on that bus. For details
* about this problem see doc/I2C_Edge_Conditions.
*/
i2c_init_board();
#endif
for (bus = 0; bus < CONFIG_SYS_MAX_I2C_BUS; bus++) {
I2C_SET_BUS(bus);
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/* Set i2c pointer after calling I2C_SET_BUS() */
i2c = (struct ppc4xx_i2c *)I2C_BASE_ADDR;
/* Handle possible failed I2C state */
/* FIXME: put this into i2c_init_board()? */
_i2c_bus_reset();
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/* clear lo master address */
out_8(&i2c->lmadr, 0);
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/* clear hi master address */
out_8(&i2c->hmadr, 0);
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/* clear lo slave address */
out_8(&i2c->lsadr, 0);
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/* clear hi slave address */
out_8(&i2c->hsadr, 0);
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/* Clock divide Register */
/* set divisor according to freq_opb */
divisor = (get_OPB_freq() - 1) / 10000000;
if (divisor == 0)
divisor = 1;
out_8(&i2c->clkdiv, divisor);
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/* no interrupts */
out_8(&i2c->intrmsk, 0);
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/* clear transfer count */
out_8(&i2c->xfrcnt, 0);
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/* clear extended control & stat */
/* write 1 in SRC SRS SWC SWS to clear these fields */
out_8(&i2c->xtcntlss, 0xF0);
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/* Mode Control Register
Flush Slave/Master data buffer */
out_8(&i2c->mdcntl, IIC_MDCNTL_FSDB | IIC_MDCNTL_FMDB);
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val = in_8(&i2c->mdcntl);
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/* Ignore General Call, slave transfers are ignored,
* disable interrupts, exit unknown bus state, enable hold
* SCL 100kHz normaly or FastMode for 400kHz and above
*/
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val |= IIC_MDCNTL_EUBS | IIC_MDCNTL_HSCL;
if (speed >= 400000)
val |= IIC_MDCNTL_FSM;
out_8(&i2c->mdcntl, val);
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/* clear control reg */
out_8(&i2c->cntl, 0x00);
}
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/* set to SPD bus as default bus upon powerup */
I2C_SET_BUS(CONFIG_SYS_SPD_BUS_NUM);
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}
/*
* This code tries to use the features of the 405GP i2c
* controller. It will transfer up to 4 bytes in one pass
* on the loop. It only does out_8((u8 *)lbz) to the buffer when it
* is possible to do out16(lhz) transfers.
*
* cmd_type is 0 for write 1 for read.
*
* addr_len can take any value from 0-255, it is only limited
* by the char, we could make it larger if needed. If it is
* 0 we skip the address write cycle.
*
* Typical case is a Write of an addr followd by a Read. The
* IBM FAQ does not cover this. On the last byte of the write
* we don't set the creg CHT bit, and on the first bytes of the
* read we set the RPST bit.
*
* It does not support address only transfers, there must be
* a data part. If you want to write the address yourself, put
* it in the data pointer.
*
* It does not support transfer to/from address 0.
*
* It does not check XFRCNT.
*/
static int i2c_transfer(unsigned char cmd_type,
unsigned char chip,
unsigned char addr[],
unsigned char addr_len,
unsigned char data[],
unsigned short data_len)
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{
struct ppc4xx_i2c *i2c = (struct ppc4xx_i2c *)I2C_BASE_ADDR;
u8 *ptr;
int reading;
int tran, cnt;
int result;
int status;
int i;
u8 creg;
if (data == 0 || data_len == 0) {
/* Don't support data transfer of no length or to address 0 */
printf( "i2c_transfer: bad call\n" );
return IIC_NOK;
}
if (addr && addr_len) {
ptr = addr;
cnt = addr_len;
reading = 0;
} else {
ptr = data;
cnt = data_len;
reading = cmd_type;
}
/* Clear Stop Complete Bit */
out_8(&i2c->sts, IIC_STS_SCMP);
/* Check init */
i = 10;
do {
/* Get status */
status = in_8(&i2c->sts);
i--;
} while ((status & IIC_STS_PT) && (i > 0));
if (status & IIC_STS_PT) {
result = IIC_NOK_TOUT;
return(result);
}
/* flush the Master/Slave Databuffers */
out_8(&i2c->mdcntl, in_8(&i2c->mdcntl) |
IIC_MDCNTL_FMDB | IIC_MDCNTL_FSDB);
/* need to wait 4 OPB clocks? code below should take that long */
/* 7-bit adressing */
out_8(&i2c->hmadr, 0);
out_8(&i2c->lmadr, chip);
tran = 0;
result = IIC_OK;
creg = 0;
while (tran != cnt && (result == IIC_OK)) {
int bc,j;
/*
* Control register =
* Normal transfer, 7-bits adressing, Transfer up to
* bc bytes, Normal start, Transfer is a sequence of transfers
*/
creg |= IIC_CNTL_PT;
bc = (cnt - tran) > 4 ? 4 : cnt - tran;
creg |= (bc - 1) << 4;
/* if the real cmd type is write continue trans */
if ((!cmd_type && (ptr == addr)) || ((tran + bc) != cnt))
creg |= IIC_CNTL_CHT;
if (reading) {
creg |= IIC_CNTL_READ;
} else {
for(j = 0; j < bc; j++) {
/* Set buffer */
out_8(&i2c->mdbuf, ptr[tran + j]);
}
}
out_8(&i2c->cntl, creg);
/*
* Transfer is in progress
* we have to wait for upto 5 bytes of data
* 1 byte chip address+r/w bit then bc bytes
* of data.
* udelay(10) is 1 bit time at 100khz
* Doubled for slop. 20 is too small.
*/
i = 2 * 5 * 8;
do {
/* Get status */
status = in_8(&i2c->sts);
udelay(10);
i--;
} while ((status & IIC_STS_PT) && !(status & IIC_STS_ERR) &&
(i > 0));
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if (status & IIC_STS_ERR) {
result = IIC_NOK;
status = in_8(&i2c->extsts);
/* Lost arbitration? */
if (status & IIC_EXTSTS_LA)
result = IIC_NOK_LA;
/* Incomplete transfer? */
if (status & IIC_EXTSTS_ICT)
result = IIC_NOK_ICT;
/* Transfer aborted? */
if (status & IIC_EXTSTS_XFRA)
result = IIC_NOK_XFRA;
} else if ( status & IIC_STS_PT) {
result = IIC_NOK_TOUT;
}
/* Command is reading => get buffer */
if ((reading) && (result == IIC_OK)) {
/* Are there data in buffer */
if (status & IIC_STS_MDBS) {
/*
* even if we have data we have to wait 4OPB
* clocks for it to hit the front of the FIFO,
* after that we can just read. We should check
* XFCNT here and if the FIFO is full there is
* no need to wait.
*/
udelay(1);
for (j = 0; j < bc; j++)
ptr[tran + j] = in_8(&i2c->mdbuf);
} else
result = IIC_NOK_DATA;
}
creg = 0;
tran += bc;
if (ptr == addr && tran == cnt) {
ptr = data;
cnt = data_len;
tran = 0;
reading = cmd_type;
if (reading)
creg = IIC_CNTL_RPST;
}
}
return result;
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}
int i2c_probe(uchar chip)
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{
uchar buf[1];
buf[0] = 0;
/*
* What is needed is to send the chip address and verify that the
* address was <ACK>ed (i.e. there was a chip at that address which
* drove the data line low).
*/
return (i2c_transfer(1, chip << 1, 0, 0, buf, 1) != 0);
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}
static int ppc4xx_i2c_transfer(uchar chip, uint addr, int alen, uchar *buffer,
int len, int read)
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{
uchar xaddr[4];
int ret;
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if (alen > 4) {
printf("I2C: addr len %d not supported\n", alen);
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return 1;
}
if (alen > 0) {
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
}
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#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
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/*
* EEPROM chips that implement "address overflow" are ones
* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
* address and the extra bits end up in the "chip address"
* bit slots. This makes a 24WC08 (1Kbyte) chip look like
* four 256 byte chips.
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*
* Note that we consider the length of the address field to
* still be one byte because the extra address bits are
* hidden in the chip address.
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*/
if (alen > 0)
chip |= ((addr >> (alen * 8)) &
CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
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#endif
if ((ret = i2c_transfer(read, chip << 1, &xaddr[4 - alen], alen,
buffer, len)) != 0) {
printf("I2C %s: failed %d\n", read ? "read" : "write", ret);
return 1;
}
return 0;
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}
int i2c_read(uchar chip, uint addr, int alen, uchar * buffer, int len)
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{
return ppc4xx_i2c_transfer(chip, addr, alen, buffer, len, 1);
}
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int i2c_write(uchar chip, uint addr, int alen, uchar * buffer, int len)
{
return ppc4xx_i2c_transfer(chip, addr, alen, buffer, len, 0);
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}
#if defined(CONFIG_I2C_MULTI_BUS)
/*
* Functions for multiple I2C bus handling
*/
unsigned int i2c_get_bus_num(void)
{
return i2c_bus_num;
}
int i2c_set_bus_num(unsigned int bus)
{
if (bus >= CONFIG_SYS_MAX_I2C_BUS)
return -1;
i2c_bus_num = bus;
return 0;
}
#endif /* CONFIG_I2C_MULTI_BUS */
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#endif /* CONFIG_HARD_I2C */