blob: 60f03d47a154f712585f99f9a0fc58a55d81454a [file] [log] [blame]
/*
* i2c.c - driver for Blackfin on-chip TWI/I2C
*
* Copyright (c) 2006-2008 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#ifdef CONFIG_HARD_I2C
#include <asm/blackfin.h>
#include <i2c.h>
#include <asm/io.h>
#include <asm/mach-common/bits/twi.h>
/* Two-Wire Interface (0xFFC01400 - 0xFFC014FF) */
#ifdef TWI0_CLKDIV
#define bfin_read_TWI_CLKDIV() bfin_read_TWI0_CLKDIV()
#define bfin_write_TWI_CLKDIV(val) bfin_write_TWI0_CLKDIV(val)
#define bfin_read_TWI_CONTROL() bfin_read_TWI0_CONTROL()
#define bfin_write_TWI_CONTROL(val) bfin_write_TWI0_CONTROL(val)
#define bfin_read_TWI_SLAVE_CTL() bfin_read_TWI0_SLAVE_CTL()
#define bfin_write_TWI_SLAVE_CTL(val) bfin_write_TWI0_SLAVE_CTL(val)
#define bfin_read_TWI_SLAVE_STAT() bfin_read_TWI0_SLAVE_STAT()
#define bfin_write_TWI_SLAVE_STAT(val) bfin_write_TWI0_SLAVE_STAT(val)
#define bfin_read_TWI_SLAVE_ADDR() bfin_read_TWI0_SLAVE_ADDR()
#define bfin_write_TWI_SLAVE_ADDR(val) bfin_write_TWI0_SLAVE_ADDR(val)
#define bfin_read_TWI_MASTER_CTL() bfin_read_TWI0_MASTER_CTL()
#define bfin_write_TWI_MASTER_CTL(val) bfin_write_TWI0_MASTER_CTL(val)
#define bfin_read_TWI_MASTER_STAT() bfin_read_TWI0_MASTER_STAT()
#define bfin_write_TWI_MASTER_STAT(val) bfin_write_TWI0_MASTER_STAT(val)
#define bfin_read_TWI_MASTER_ADDR() bfin_read_TWI0_MASTER_ADDR()
#define bfin_write_TWI_MASTER_ADDR(val) bfin_write_TWI0_MASTER_ADDR(val)
#define bfin_read_TWI_INT_STAT() bfin_read_TWI0_INT_STAT()
#define bfin_write_TWI_INT_STAT(val) bfin_write_TWI0_INT_STAT(val)
#define bfin_read_TWI_INT_MASK() bfin_read_TWI0_INT_MASK()
#define bfin_write_TWI_INT_MASK(val) bfin_write_TWI0_INT_MASK(val)
#define bfin_read_TWI_FIFO_CTL() bfin_read_TWI0_FIFO_CTL()
#define bfin_write_TWI_FIFO_CTL(val) bfin_write_TWI0_FIFO_CTL(val)
#define bfin_read_TWI_FIFO_STAT() bfin_read_TWI0_FIFO_STAT()
#define bfin_write_TWI_FIFO_STAT(val) bfin_write_TWI0_FIFO_STAT(val)
#define bfin_read_TWI_XMT_DATA8() bfin_read_TWI0_XMT_DATA8()
#define bfin_write_TWI_XMT_DATA8(val) bfin_write_TWI0_XMT_DATA8(val)
#define bfin_read_TWI_XMT_DATA_16() bfin_read_TWI0_XMT_DATA16()
#define bfin_write_TWI_XMT_DATA16(val) bfin_write_TWI0_XMT_DATA16(val)
#define bfin_read_TWI_RCV_DATA8() bfin_read_TWI0_RCV_DATA8()
#define bfin_write_TWI_RCV_DATA8(val) bfin_write_TWI0_RCV_DATA8(val)
#define bfin_read_TWI_RCV_DATA16() bfin_read_TWI0_RCV_DATA16()
#define bfin_write_TWI_RCV_DATA16(val) bfin_write_TWI0_RCV_DATA16(val)
#endif
#ifdef DEBUG_I2C
#define PRINTD(fmt,args...) do { \
DECLARE_GLOBAL_DATA_PTR; \
if (gd->have_console) \
printf(fmt ,##args); \
} while (0)
#else
#define PRINTD(fmt,args...)
#endif
#ifndef CONFIG_TWICLK_KHZ
#define CONFIG_TWICLK_KHZ 50
#endif
/* All transfers are described by this data structure */
struct i2c_msg {
u16 addr; /* slave address */
u16 flags;
#define I2C_M_STOP 0x2
#define I2C_M_RD 0x1
u16 len; /* msg length */
u8 *buf; /* pointer to msg data */
};
/**
* i2c_reset: - reset the host controller
*/
static void i2c_reset(void)
{
/* Disable TWI */
bfin_write_TWI_CONTROL(0);
SSYNC();
/* Set TWI internal clock as 10MHz */
bfin_write_TWI_CONTROL(((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
/* Set Twi interface clock as specified */
if (CONFIG_TWICLK_KHZ > 400)
bfin_write_TWI_CLKDIV(((5 * 1024 / 400) << 8) | ((5 * 1024 /
400) & 0xFF));
else
bfin_write_TWI_CLKDIV(((5 * 1024 /
CONFIG_TWICLK_KHZ) << 8) | ((5 * 1024 /
CONFIG_TWICLK_KHZ)
& 0xFF));
/* Enable TWI */
bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() | TWI_ENA);
SSYNC();
}
int wait_for_completion(struct i2c_msg *msg, int timeout_count)
{
unsigned short twi_int_stat;
unsigned short mast_stat;
int i;
for (i = 0; i < timeout_count; i++) {
twi_int_stat = bfin_read_TWI_INT_STAT();
mast_stat = bfin_read_TWI_MASTER_STAT();
if (XMTSERV & twi_int_stat) {
/* Transmit next data */
if (msg->len > 0) {
bfin_write_TWI_XMT_DATA8(*(msg->buf++));
msg->len--;
} else if (msg->flags & I2C_M_STOP)
bfin_write_TWI_MASTER_CTL
(bfin_read_TWI_MASTER_CTL() | STOP);
SSYNC();
/* Clear status */
bfin_write_TWI_INT_STAT(XMTSERV);
SSYNC();
i = 0;
}
if (RCVSERV & twi_int_stat) {
if (msg->len > 0) {
/* Receive next data */
*(msg->buf++) = bfin_read_TWI_RCV_DATA8();
msg->len--;
} else if (msg->flags & I2C_M_STOP) {
bfin_write_TWI_MASTER_CTL
(bfin_read_TWI_MASTER_CTL() | STOP);
SSYNC();
}
/* Clear interrupt source */
bfin_write_TWI_INT_STAT(RCVSERV);
SSYNC();
i = 0;
}
if (MERR & twi_int_stat) {
bfin_write_TWI_INT_STAT(MERR);
bfin_write_TWI_INT_MASK(0);
bfin_write_TWI_MASTER_STAT(0x3e);
bfin_write_TWI_MASTER_CTL(0);
SSYNC();
/*
* if both err and complete int stats are set,
* return proper results.
*/
if (MCOMP & twi_int_stat) {
bfin_write_TWI_INT_STAT(MCOMP);
bfin_write_TWI_INT_MASK(0);
bfin_write_TWI_MASTER_CTL(0);
SSYNC();
/*
* If it is a quick transfer,
* only address bug no data, not an err.
*/
if (msg->len == 0 && mast_stat & BUFRDERR)
return 0;
/*
* If address not acknowledged return -3,
* else return 0.
*/
else if (!(mast_stat & ANAK))
return 0;
else
return -3;
}
return -1;
}
if (MCOMP & twi_int_stat) {
bfin_write_TWI_INT_STAT(MCOMP);
SSYNC();
bfin_write_TWI_INT_MASK(0);
bfin_write_TWI_MASTER_CTL(0);
SSYNC();
return 0;
}
}
if (msg->flags & I2C_M_RD)
return -4;
else
return -2;
}
/**
* i2c_transfer: - Transfer one byte over the i2c bus
*
* This function can tranfer a byte over the i2c bus in both directions.
* It is used by the public API functions.
*
* @return: 0: transfer successful
* -1: transfer fail
* -2: transmit timeout
* -3: ACK missing
* -4: receive timeout
* -5: controller not ready
*/
int i2c_transfer(struct i2c_msg *msg)
{
int ret = 0;
int timeout_count = 10000;
int len = msg->len;
if (!(bfin_read_TWI_CONTROL() & TWI_ENA)) {
ret = -5;
goto transfer_error;
}
while (bfin_read_TWI_MASTER_STAT() & BUSBUSY)
continue;
/* Set Transmit device address */
bfin_write_TWI_MASTER_ADDR(msg->addr);
/*
* FIFO Initiation.
* Data in FIFO should be discarded before start a new operation.
*/
bfin_write_TWI_FIFO_CTL(0x3);
SSYNC();
bfin_write_TWI_FIFO_CTL(0);
SSYNC();
if (!(msg->flags & I2C_M_RD)) {
/* Transmit first data */
if (msg->len > 0) {
PRINTD("1 in i2c_transfer: buf=%d, len=%d\n", *msg->buf,
len);
bfin_write_TWI_XMT_DATA8(*(msg->buf++));
msg->len--;
SSYNC();
}
}
/* clear int stat */
bfin_write_TWI_INT_STAT(MERR | MCOMP | XMTSERV | RCVSERV);
/* Interrupt mask . Enable XMT, RCV interrupt */
bfin_write_TWI_INT_MASK(MCOMP | MERR |
((msg->flags & I2C_M_RD) ? RCVSERV : XMTSERV));
SSYNC();
if (len > 0 && len <= 255)
bfin_write_TWI_MASTER_CTL((len << 6));
else if (msg->len > 255) {
bfin_write_TWI_MASTER_CTL((0xff << 6));
msg->flags &= I2C_M_STOP;
} else
bfin_write_TWI_MASTER_CTL(0);
/* Master enable */
bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN |
((msg->flags & I2C_M_RD)
? MDIR : 0) | ((CONFIG_TWICLK_KHZ >
100) ? FAST : 0));
SSYNC();
ret = wait_for_completion(msg, timeout_count);
PRINTD("3 in i2c_transfer: ret=%d\n", ret);
transfer_error:
switch (ret) {
case 1:
PRINTD(("i2c_transfer: error: transfer fail\n"));
break;
case 2:
PRINTD(("i2c_transfer: error: transmit timeout\n"));
break;
case 3:
PRINTD(("i2c_transfer: error: ACK missing\n"));
break;
case 4:
PRINTD(("i2c_transfer: error: receive timeout\n"));
break;
case 5:
PRINTD(("i2c_transfer: error: controller not ready\n"));
i2c_reset();
break;
default:
break;
}
return ret;
}
/* ---------------------------------------------------------------------*/
/* API Functions */
/* ---------------------------------------------------------------------*/
void i2c_init(int speed, int slaveaddr)
{
i2c_reset();
}
/**
* i2c_probe: - Test if a chip answers for a given i2c address
*
* @chip: address of the chip which is searched for
* @return: 0 if a chip was found, -1 otherwhise
*/
int i2c_probe(uchar chip)
{
struct i2c_msg msg;
u8 probebuf;
i2c_reset();
probebuf = 0;
msg.addr = chip;
msg.flags = 0;
msg.len = 1;
msg.buf = &probebuf;
if (i2c_transfer(&msg))
return -1;
msg.addr = chip;
msg.flags = I2C_M_RD;
msg.len = 1;
msg.buf = &probebuf;
if (i2c_transfer(&msg))
return -1;
return 0;
}
/**
* i2c_read: - Read multiple bytes from an i2c device
*
* chip: I2C chip address, range 0..127
* addr: Memory (register) address within the chip
* alen: Number of bytes to use for addr (typically 1, 2 for larger
* memories, 0 for register type devices with only one
* register)
* buffer: Where to read/write the data
* len: How many bytes to read/write
*
* Returns: 0 on success, not 0 on failure
*/
int i2c_read(uchar chip, uint addr, int alen, uchar * buffer, int len)
{
struct i2c_msg msg;
u8 addr_bytes[3]; /* lowest...highest byte of data address */
PRINTD("i2c_read: chip=0x%x, addr=0x%x, alen=0x%x, len=0x%x\n", chip,
addr, alen, len);
if (alen > 0) {
addr_bytes[0] = (u8) ((addr >> 0) & 0x000000FF);
addr_bytes[1] = (u8) ((addr >> 8) & 0x000000FF);
addr_bytes[2] = (u8) ((addr >> 16) & 0x000000FF);
msg.addr = chip;
msg.flags = 0;
msg.len = alen;
msg.buf = addr_bytes;
if (i2c_transfer(&msg))
return -1;
}
/* start read sequence */
PRINTD(("i2c_read: start read sequence\n"));
msg.addr = chip;
msg.flags = I2C_M_RD;
msg.len = len;
msg.buf = buffer;
if (i2c_transfer(&msg))
return -1;
return 0;
}
/**
* i2c_write: - Write multiple bytes to an i2c device
*
* chip: I2C chip address, range 0..127
* addr: Memory (register) address within the chip
* alen: Number of bytes to use for addr (typically 1, 2 for larger
* memories, 0 for register type devices with only one
* register)
* buffer: Where to read/write the data
* len: How many bytes to read/write
*
* Returns: 0 on success, not 0 on failure
*/
int i2c_write(uchar chip, uint addr, int alen, uchar * buffer, int len)
{
struct i2c_msg msg;
u8 addr_bytes[3]; /* lowest...highest byte of data address */
PRINTD
("i2c_write: chip=0x%x, addr=0x%x, alen=0x%x, len=0x%x, buf0=0x%x\n",
chip, addr, alen, len, buffer[0]);
/* chip address write */
if (alen > 0) {
addr_bytes[0] = (u8) ((addr >> 0) & 0x000000FF);
addr_bytes[1] = (u8) ((addr >> 8) & 0x000000FF);
addr_bytes[2] = (u8) ((addr >> 16) & 0x000000FF);
msg.addr = chip;
msg.flags = 0;
msg.len = alen;
msg.buf = addr_bytes;
if (i2c_transfer(&msg))
return -1;
}
/* start read sequence */
PRINTD(("i2c_write: start write sequence\n"));
msg.addr = chip;
msg.flags = 0;
msg.len = len;
msg.buf = buffer;
if (i2c_transfer(&msg))
return -1;
return 0;
}
uchar i2c_reg_read(uchar chip, uchar reg)
{
uchar buf;
PRINTD("i2c_reg_read: chip=0x%02x, reg=0x%02x\n", chip, reg);
i2c_read(chip, reg, 0, &buf, 1);
return (buf);
}
void i2c_reg_write(uchar chip, uchar reg, uchar val)
{
PRINTD("i2c_reg_write: chip=0x%02x, reg=0x%02x, val=0x%02x\n", chip,
reg, val);
i2c_write(chip, reg, 0, &val, 1);
}
#endif /* CONFIG_HARD_I2C */