u-boot/drivers/i2c/omap24xx_i2c.c
Patil, Rachna 498cbdfe62 ARM: AM33XX: Add AM33XX I2C driver support
1. Compliant with Philips I2C specification version 2.1
2. Supports upto 100Kbps in standard mode

Signed-off-by: Chandan Nath <chandan.nath@ti.com>
Signed-off-by: Patil, Rachna <rachna@ti.com>
2012-01-23 11:57:31 +01:00

579 lines
13 KiB
C

/*
* Basic I2C functions
*
* Copyright (c) 2004 Texas Instruments
*
* This package is free software; you can redistribute it and/or
* modify it under the terms of the license found in the file
* named COPYING that should have accompanied this file.
*
* THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Author: Jian Zhang jzhang@ti.com, Texas Instruments
*
* Copyright (c) 2003 Wolfgang Denk, wd@denx.de
* Rewritten to fit into the current U-Boot framework
*
* Adapted for OMAP2420 I2C, r-woodruff2@ti.com
*
*/
#include <common.h>
#include <asm/arch/i2c.h>
#include <asm/io.h>
#include "omap24xx_i2c.h"
DECLARE_GLOBAL_DATA_PTR;
#define I2C_STAT_TIMEO (1 << 31)
#define I2C_TIMEOUT 10
static u32 wait_for_bb(void);
static u32 wait_for_status_mask(u16 mask);
static void flush_fifo(void);
/*
* For SPL boot some boards need i2c before SDRAM is initialised so force
* variables to live in SRAM
*/
static struct i2c __attribute__((section (".data"))) *i2c_base =
(struct i2c *)I2C_DEFAULT_BASE;
static unsigned int __attribute__((section (".data"))) bus_initialized[I2C_BUS_MAX] =
{ [0 ... (I2C_BUS_MAX-1)] = 0 };
static unsigned int __attribute__((section (".data"))) current_bus = 0;
void i2c_init(int speed, int slaveadd)
{
int psc, fsscll, fssclh;
int hsscll = 0, hssclh = 0;
u32 scll, sclh;
/* Only handle standard, fast and high speeds */
if ((speed != OMAP_I2C_STANDARD) &&
(speed != OMAP_I2C_FAST_MODE) &&
(speed != OMAP_I2C_HIGH_SPEED)) {
printf("Error : I2C unsupported speed %d\n", speed);
return;
}
psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
psc -= 1;
if (psc < I2C_PSC_MIN) {
printf("Error : I2C unsupported prescalar %d\n", psc);
return;
}
if (speed == OMAP_I2C_HIGH_SPEED) {
/* High speed */
/* For first phase of HS mode */
fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK /
(2 * OMAP_I2C_FAST_MODE);
fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
if (((fsscll < 0) || (fssclh < 0)) ||
((fsscll > 255) || (fssclh > 255))) {
puts("Error : I2C initializing first phase clock\n");
return;
}
/* For second phase of HS mode */
hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
if (((fsscll < 0) || (fssclh < 0)) ||
((fsscll > 255) || (fssclh > 255))) {
puts("Error : I2C initializing second phase clock\n");
return;
}
scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
} else {
/* Standard and fast speed */
fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
fsscll -= I2C_FASTSPEED_SCLL_TRIM;
fssclh -= I2C_FASTSPEED_SCLH_TRIM;
if (((fsscll < 0) || (fssclh < 0)) ||
((fsscll > 255) || (fssclh > 255))) {
puts("Error : I2C initializing clock\n");
return;
}
scll = (unsigned int)fsscll;
sclh = (unsigned int)fssclh;
}
if (gd->flags & GD_FLG_RELOC)
bus_initialized[current_bus] = 1;
if (readw(&i2c_base->con) & I2C_CON_EN) {
writew(0, &i2c_base->con);
udelay(50000);
}
writew(psc, &i2c_base->psc);
writew(scll, &i2c_base->scll);
writew(sclh, &i2c_base->sclh);
/* own address */
writew(slaveadd, &i2c_base->oa);
writew(I2C_CON_EN, &i2c_base->con);
/* have to enable intrrupts or OMAP i2c module doesn't work */
writew(I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
udelay(1000);
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
}
static void flush_fifo(void)
{ u16 stat;
/* note: if you try and read data when its not there or ready
* you get a bus error
*/
while (1) {
stat = readw(&i2c_base->stat);
if (stat == I2C_STAT_RRDY) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX)
readb(&i2c_base->data);
#else
readw(&i2c_base->data);
#endif
writew(I2C_STAT_RRDY, &i2c_base->stat);
udelay(1000);
} else
break;
}
}
int i2c_probe(uchar chip)
{
u32 status;
int res = 1; /* default = fail */
if (chip == readw(&i2c_base->oa))
return res;
/* wait until bus not busy */
status = wait_for_bb();
/* exit on BUS busy */
if (status & I2C_STAT_TIMEO)
return res;
/* try to write one byte */
writew(1, &i2c_base->cnt);
/* set slave address */
writew(chip, &i2c_base->sa);
/* stop bit needed here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT
| I2C_CON_STP, &i2c_base->con);
/* enough delay for the NACK bit set */
udelay(9000);
if (!(readw(&i2c_base->stat) & I2C_STAT_NACK)) {
res = 0; /* success case */
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
} else {
/* failure, clear sources*/
writew(0xFFFF, &i2c_base->stat);
/* finish up xfer */
writew(readw(&i2c_base->con) | I2C_CON_STP, &i2c_base->con);
status = wait_for_bb();
/* exit on BUS busy */
if (status & I2C_STAT_TIMEO)
return res;
}
flush_fifo();
/* don't allow any more data in... we don't want it. */
writew(0, &i2c_base->cnt);
writew(0xFFFF, &i2c_base->stat);
return res;
}
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int i2c_error = 0, i;
u32 status;
if ((alen > 2) || (alen < 0))
return 1;
if (alen < 2) {
if (addr + len > 256)
return 1;
} else if (addr + len > 0xFFFF) {
return 1;
}
/* wait until bus not busy */
status = wait_for_bb();
/* exit on BUS busy */
if (status & I2C_STAT_TIMEO)
return 1;
writew((alen & 0xFF), &i2c_base->cnt);
/* set slave address */
writew(chip, &i2c_base->sa);
/* Clear the Tx & Rx FIFOs */
writew((readw(&i2c_base->buf) | I2C_RXFIFO_CLEAR |
I2C_TXFIFO_CLEAR), &i2c_base->buf);
/* no stop bit needed here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_TRX |
I2C_CON_STT, &i2c_base->con);
/* wait for Transmit ready condition */
status = wait_for_status_mask(I2C_STAT_XRDY | I2C_STAT_NACK);
if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
i2c_error = 1;
if (!i2c_error) {
if (status & I2C_STAT_XRDY) {
switch (alen) {
case 2:
/* Send address MSByte */
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_AM33XX)
writew(((addr >> 8) & 0xFF), &i2c_base->data);
/* Clearing XRDY event */
writew((status & I2C_STAT_XRDY),
&i2c_base->stat);
/* wait for Transmit ready condition */
status = wait_for_status_mask(I2C_STAT_XRDY |
I2C_STAT_NACK);
if (status & (I2C_STAT_NACK |
I2C_STAT_TIMEO)) {
i2c_error = 1;
break;
}
#endif
case 1:
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_AM33XX)
/* Send address LSByte */
writew((addr & 0xFF), &i2c_base->data);
#else
/* Send address Short word */
writew((addr & 0xFFFF), &i2c_base->data);
#endif
/* Clearing XRDY event */
writew((status & I2C_STAT_XRDY),
&i2c_base->stat);
/*wait for Transmit ready condition */
status = wait_for_status_mask(I2C_STAT_ARDY |
I2C_STAT_NACK);
if (status & (I2C_STAT_NACK |
I2C_STAT_TIMEO)) {
i2c_error = 1;
break;
}
}
} else
i2c_error = 1;
}
/* Wait for ARDY to set */
status = wait_for_status_mask(I2C_STAT_ARDY | I2C_STAT_NACK
| I2C_STAT_AL);
if (!i2c_error) {
/* set slave address */
writew(chip, &i2c_base->sa);
writew((len & 0xFF), &i2c_base->cnt);
/* Clear the Tx & Rx FIFOs */
writew((readw(&i2c_base->buf) | I2C_RXFIFO_CLEAR |
I2C_TXFIFO_CLEAR), &i2c_base->buf);
/* need stop bit here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
&i2c_base->con);
for (i = 0; i < len; i++) {
/* wait for Receive condition */
status = wait_for_status_mask(I2C_STAT_RRDY |
I2C_STAT_NACK);
if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO)) {
i2c_error = 1;
break;
}
if (status & I2C_STAT_RRDY) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_AM33XX)
buffer[i] = readb(&i2c_base->data);
#else
*((u16 *)&buffer[i]) =
readw(&i2c_base->data) & 0xFFFF;
i++;
#endif
writew((status & I2C_STAT_RRDY),
&i2c_base->stat);
udelay(1000);
} else {
i2c_error = 1;
}
}
}
/* Wait for ARDY to set */
status = wait_for_status_mask(I2C_STAT_ARDY | I2C_STAT_NACK
| I2C_STAT_AL);
if (i2c_error) {
writew(0, &i2c_base->con);
return 1;
}
writew(I2C_CON_EN, &i2c_base->con);
while (readw(&i2c_base->stat)
|| (readw(&i2c_base->con) & I2C_CON_MST)) {
udelay(10000);
writew(0xFFFF, &i2c_base->stat);
}
writew(I2C_CON_EN, &i2c_base->con);
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
return 0;
}
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int i, i2c_error = 0;
u32 status;
u16 writelen;
if (alen > 2)
return 1;
if (alen < 2) {
if (addr + len > 256)
return 1;
} else if (addr + len > 0xFFFF) {
return 1;
}
/* wait until bus not busy */
status = wait_for_bb();
/* exiting on BUS busy */
if (status & I2C_STAT_TIMEO)
return 1;
writelen = (len & 0xFFFF) + alen;
/* two bytes */
writew((writelen & 0xFFFF), &i2c_base->cnt);
/* Clear the Tx & Rx FIFOs */
writew((readw(&i2c_base->buf) | I2C_RXFIFO_CLEAR |
I2C_TXFIFO_CLEAR), &i2c_base->buf);
/* set slave address */
writew(chip, &i2c_base->sa);
/* stop bit needed here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
I2C_CON_STP, &i2c_base->con);
/* wait for Transmit ready condition */
status = wait_for_status_mask(I2C_STAT_XRDY | I2C_STAT_NACK);
if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
i2c_error = 1;
if (!i2c_error) {
if (status & I2C_STAT_XRDY) {
switch (alen) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_AM33XX)
case 2:
/* send out MSB byte */
writeb(((addr >> 8) & 0xFF), &i2c_base->data);
#else
writeb((addr & 0xFFFF), &i2c_base->data);
break;
#endif
/* Clearing XRDY event */
writew((status & I2C_STAT_XRDY),
&i2c_base->stat);
/*waiting for Transmit ready * condition */
status = wait_for_status_mask(I2C_STAT_XRDY |
I2C_STAT_NACK);
if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO)) {
i2c_error = 1;
break;
}
case 1:
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_AM33XX)
/* send out MSB byte */
writeb((addr & 0xFF), &i2c_base->data);
#else
writew(((buffer[0] << 8) | (addr & 0xFF)),
&i2c_base->data);
#endif
}
/* Clearing XRDY event */
writew((status & I2C_STAT_XRDY), &i2c_base->stat);
}
/* waiting for Transmit ready condition */
status = wait_for_status_mask(I2C_STAT_XRDY | I2C_STAT_NACK);
if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
i2c_error = 1;
if (!i2c_error) {
for (i = ((alen > 1) ? 0 : 1); i < len; i++) {
if (status & I2C_STAT_XRDY) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_AM33XX)
writeb((buffer[i] & 0xFF),
&i2c_base->data);
#else
writew((((buffer[i] << 8) |
buffer[i + 1]) & 0xFFFF),
&i2c_base->data);
i++;
#endif
} else
i2c_error = 1;
/* Clearing XRDY event */
writew((status & I2C_STAT_XRDY),
&i2c_base->stat);
/* waiting for XRDY condition */
status = wait_for_status_mask(
I2C_STAT_XRDY |
I2C_STAT_ARDY |
I2C_STAT_NACK);
if (status & (I2C_STAT_NACK |
I2C_STAT_TIMEO)) {
i2c_error = 1;
break;
}
if (status & I2C_STAT_ARDY)
break;
}
}
}
status = wait_for_status_mask(I2C_STAT_ARDY | I2C_STAT_NACK |
I2C_STAT_AL);
if (status & (I2C_STAT_NACK | I2C_STAT_TIMEO))
i2c_error = 1;
if (i2c_error) {
writew(0, &i2c_base->con);
return 1;
}
if (!i2c_error) {
int eout = 200;
writew(I2C_CON_EN, &i2c_base->con);
while ((status = readw(&i2c_base->stat)) ||
(readw(&i2c_base->con) & I2C_CON_MST)) {
udelay(1000);
/* have to read to clear intrrupt */
writew(0xFFFF, &i2c_base->stat);
if (--eout == 0)
/* better leave with error than hang */
break;
}
}
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
return 0;
}
static u32 wait_for_bb(void)
{
int timeout = I2C_TIMEOUT;
u32 stat;
while ((stat = readw(&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
writew(stat, &i2c_base->stat);
udelay(1000);
}
if (timeout <= 0) {
printf("timed out in wait_for_bb: I2C_STAT=%x\n",
readw(&i2c_base->stat));
stat |= I2C_STAT_TIMEO;
}
writew(0xFFFF, &i2c_base->stat); /* clear delayed stuff*/
return stat;
}
static u32 wait_for_status_mask(u16 mask)
{
u32 status;
int timeout = I2C_TIMEOUT;
do {
udelay(1000);
status = readw(&i2c_base->stat);
} while (!(status & mask) && timeout--);
if (timeout <= 0) {
printf("timed out in wait_for_status_mask: I2C_STAT=%x\n",
readw(&i2c_base->stat));
writew(0xFFFF, &i2c_base->stat);
status |= I2C_STAT_TIMEO;
}
return status;
}
int i2c_set_bus_num(unsigned int bus)
{
if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
printf("Bad bus: %d\n", bus);
return -1;
}
#if I2C_BUS_MAX == 3
if (bus == 2)
i2c_base = (struct i2c *)I2C_BASE3;
else
#endif
if (bus == 1)
i2c_base = (struct i2c *)I2C_BASE2;
else
i2c_base = (struct i2c *)I2C_BASE1;
current_bus = bus;
if (!bus_initialized[current_bus])
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
int i2c_get_bus_num(void)
{
return (int) current_bus;
}