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linux/drivers/i2c/busses/i2c-bfin-twi.c
Jean Delvare e1995f65be i2c: Drop I2C_CLASS_ALL
I2C_CLASS_ALL is almost never what bus driver authors really want.
These i2c classes are really only about which devices must be probed,
not what devices can be present. As device drivers get converted to the
new i2c device driver model, only a few device types will keep relying
on probing.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Sonic Zhang <sonic.zhang@analog.com>
2009-01-07 14:29:16 +01:00

758 lines
19 KiB
C

/*
* Blackfin On-Chip Two Wire Interface Driver
*
* Copyright 2005-2007 Analog Devices Inc.
*
* Enter bugs at http://blackfin.uclinux.org/
*
* Licensed under the GPL-2 or later.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/blackfin.h>
#include <asm/portmux.h>
#include <asm/irq.h>
#define POLL_TIMEOUT (2 * HZ)
/* SMBus mode*/
#define TWI_I2C_MODE_STANDARD 1
#define TWI_I2C_MODE_STANDARDSUB 2
#define TWI_I2C_MODE_COMBINED 3
#define TWI_I2C_MODE_REPEAT 4
struct bfin_twi_iface {
int irq;
spinlock_t lock;
char read_write;
u8 command;
u8 *transPtr;
int readNum;
int writeNum;
int cur_mode;
int manual_stop;
int result;
int timeout_count;
struct timer_list timeout_timer;
struct i2c_adapter adap;
struct completion complete;
struct i2c_msg *pmsg;
int msg_num;
int cur_msg;
u16 saved_clkdiv;
u16 saved_control;
void __iomem *regs_base;
};
#define DEFINE_TWI_REG(reg, off) \
static inline u16 read_##reg(struct bfin_twi_iface *iface) \
{ return bfin_read16(iface->regs_base + (off)); } \
static inline void write_##reg(struct bfin_twi_iface *iface, u16 v) \
{ bfin_write16(iface->regs_base + (off), v); }
DEFINE_TWI_REG(CLKDIV, 0x00)
DEFINE_TWI_REG(CONTROL, 0x04)
DEFINE_TWI_REG(SLAVE_CTL, 0x08)
DEFINE_TWI_REG(SLAVE_STAT, 0x0C)
DEFINE_TWI_REG(SLAVE_ADDR, 0x10)
DEFINE_TWI_REG(MASTER_CTL, 0x14)
DEFINE_TWI_REG(MASTER_STAT, 0x18)
DEFINE_TWI_REG(MASTER_ADDR, 0x1C)
DEFINE_TWI_REG(INT_STAT, 0x20)
DEFINE_TWI_REG(INT_MASK, 0x24)
DEFINE_TWI_REG(FIFO_CTL, 0x28)
DEFINE_TWI_REG(FIFO_STAT, 0x2C)
DEFINE_TWI_REG(XMT_DATA8, 0x80)
DEFINE_TWI_REG(XMT_DATA16, 0x84)
DEFINE_TWI_REG(RCV_DATA8, 0x88)
DEFINE_TWI_REG(RCV_DATA16, 0x8C)
static const u16 pin_req[2][3] = {
{P_TWI0_SCL, P_TWI0_SDA, 0},
{P_TWI1_SCL, P_TWI1_SDA, 0},
};
static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface)
{
unsigned short twi_int_status = read_INT_STAT(iface);
unsigned short mast_stat = read_MASTER_STAT(iface);
if (twi_int_status & XMTSERV) {
/* Transmit next data */
if (iface->writeNum > 0) {
write_XMT_DATA8(iface, *(iface->transPtr++));
iface->writeNum--;
}
/* start receive immediately after complete sending in
* combine mode.
*/
else if (iface->cur_mode == TWI_I2C_MODE_COMBINED)
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | MDIR | RSTART);
else if (iface->manual_stop)
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | STOP);
else if (iface->cur_mode == TWI_I2C_MODE_REPEAT &&
iface->cur_msg+1 < iface->msg_num)
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | RSTART);
SSYNC();
/* Clear status */
write_INT_STAT(iface, XMTSERV);
SSYNC();
}
if (twi_int_status & RCVSERV) {
if (iface->readNum > 0) {
/* Receive next data */
*(iface->transPtr) = read_RCV_DATA8(iface);
if (iface->cur_mode == TWI_I2C_MODE_COMBINED) {
/* Change combine mode into sub mode after
* read first data.
*/
iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
/* Get read number from first byte in block
* combine mode.
*/
if (iface->readNum == 1 && iface->manual_stop)
iface->readNum = *iface->transPtr + 1;
}
iface->transPtr++;
iface->readNum--;
} else if (iface->manual_stop) {
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | STOP);
SSYNC();
} else if (iface->cur_mode == TWI_I2C_MODE_REPEAT &&
iface->cur_msg+1 < iface->msg_num) {
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | RSTART);
SSYNC();
}
/* Clear interrupt source */
write_INT_STAT(iface, RCVSERV);
SSYNC();
}
if (twi_int_status & MERR) {
write_INT_STAT(iface, MERR);
write_INT_MASK(iface, 0);
write_MASTER_STAT(iface, 0x3e);
write_MASTER_CTL(iface, 0);
SSYNC();
iface->result = -EIO;
/* if both err and complete int stats are set, return proper
* results.
*/
if (twi_int_status & MCOMP) {
write_INT_STAT(iface, MCOMP);
write_INT_MASK(iface, 0);
write_MASTER_CTL(iface, 0);
SSYNC();
/* If it is a quick transfer, only address bug no data,
* not an err, return 1.
*/
if (iface->writeNum == 0 && (mast_stat & BUFRDERR))
iface->result = 1;
/* If address not acknowledged return -1,
* else return 0.
*/
else if (!(mast_stat & ANAK))
iface->result = 0;
}
complete(&iface->complete);
return;
}
if (twi_int_status & MCOMP) {
write_INT_STAT(iface, MCOMP);
SSYNC();
if (iface->cur_mode == TWI_I2C_MODE_COMBINED) {
if (iface->readNum == 0) {
/* set the read number to 1 and ask for manual
* stop in block combine mode
*/
iface->readNum = 1;
iface->manual_stop = 1;
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | (0xff << 6));
} else {
/* set the readd number in other
* combine mode.
*/
write_MASTER_CTL(iface,
(read_MASTER_CTL(iface) &
(~(0xff << 6))) |
(iface->readNum << 6));
}
/* remove restart bit and enable master receive */
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) & ~RSTART);
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | MEN | MDIR);
SSYNC();
} else if (iface->cur_mode == TWI_I2C_MODE_REPEAT &&
iface->cur_msg+1 < iface->msg_num) {
iface->cur_msg++;
iface->transPtr = iface->pmsg[iface->cur_msg].buf;
iface->writeNum = iface->readNum =
iface->pmsg[iface->cur_msg].len;
/* Set Transmit device address */
write_MASTER_ADDR(iface,
iface->pmsg[iface->cur_msg].addr);
if (iface->pmsg[iface->cur_msg].flags & I2C_M_RD)
iface->read_write = I2C_SMBUS_READ;
else {
iface->read_write = I2C_SMBUS_WRITE;
/* Transmit first data */
if (iface->writeNum > 0) {
write_XMT_DATA8(iface,
*(iface->transPtr++));
iface->writeNum--;
SSYNC();
}
}
if (iface->pmsg[iface->cur_msg].len <= 255)
write_MASTER_CTL(iface,
iface->pmsg[iface->cur_msg].len << 6);
else {
write_MASTER_CTL(iface, 0xff << 6);
iface->manual_stop = 1;
}
/* remove restart bit and enable master receive */
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) & ~RSTART);
write_MASTER_CTL(iface, read_MASTER_CTL(iface) |
MEN | ((iface->read_write == I2C_SMBUS_READ) ?
MDIR : 0));
SSYNC();
} else {
iface->result = 1;
write_INT_MASK(iface, 0);
write_MASTER_CTL(iface, 0);
SSYNC();
complete(&iface->complete);
}
}
}
/* Interrupt handler */
static irqreturn_t bfin_twi_interrupt_entry(int irq, void *dev_id)
{
struct bfin_twi_iface *iface = dev_id;
unsigned long flags;
spin_lock_irqsave(&iface->lock, flags);
del_timer(&iface->timeout_timer);
bfin_twi_handle_interrupt(iface);
spin_unlock_irqrestore(&iface->lock, flags);
return IRQ_HANDLED;
}
static void bfin_twi_timeout(unsigned long data)
{
struct bfin_twi_iface *iface = (struct bfin_twi_iface *)data;
unsigned long flags;
spin_lock_irqsave(&iface->lock, flags);
bfin_twi_handle_interrupt(iface);
if (iface->result == 0) {
iface->timeout_count--;
if (iface->timeout_count > 0) {
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
} else {
iface->result = -1;
complete(&iface->complete);
}
}
spin_unlock_irqrestore(&iface->lock, flags);
}
/*
* Generic i2c master transfer entrypoint
*/
static int bfin_twi_master_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct bfin_twi_iface *iface = adap->algo_data;
struct i2c_msg *pmsg;
int rc = 0;
if (!(read_CONTROL(iface) & TWI_ENA))
return -ENXIO;
while (read_MASTER_STAT(iface) & BUSBUSY)
yield();
iface->pmsg = msgs;
iface->msg_num = num;
iface->cur_msg = 0;
pmsg = &msgs[0];
if (pmsg->flags & I2C_M_TEN) {
dev_err(&adap->dev, "10 bits addr not supported!\n");
return -EINVAL;
}
iface->cur_mode = TWI_I2C_MODE_REPEAT;
iface->manual_stop = 0;
iface->transPtr = pmsg->buf;
iface->writeNum = iface->readNum = pmsg->len;
iface->result = 0;
iface->timeout_count = 10;
init_completion(&(iface->complete));
/* Set Transmit device address */
write_MASTER_ADDR(iface, pmsg->addr);
/* FIFO Initiation. Data in FIFO should be
* discarded before start a new operation.
*/
write_FIFO_CTL(iface, 0x3);
SSYNC();
write_FIFO_CTL(iface, 0);
SSYNC();
if (pmsg->flags & I2C_M_RD)
iface->read_write = I2C_SMBUS_READ;
else {
iface->read_write = I2C_SMBUS_WRITE;
/* Transmit first data */
if (iface->writeNum > 0) {
write_XMT_DATA8(iface, *(iface->transPtr++));
iface->writeNum--;
SSYNC();
}
}
/* clear int stat */
write_INT_STAT(iface, MERR | MCOMP | XMTSERV | RCVSERV);
/* Interrupt mask . Enable XMT, RCV interrupt */
write_INT_MASK(iface, MCOMP | MERR | RCVSERV | XMTSERV);
SSYNC();
if (pmsg->len <= 255)
write_MASTER_CTL(iface, pmsg->len << 6);
else {
write_MASTER_CTL(iface, 0xff << 6);
iface->manual_stop = 1;
}
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
/* Master enable */
write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN |
((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) |
((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ > 100) ? FAST : 0));
SSYNC();
wait_for_completion(&iface->complete);
rc = iface->result;
if (rc == 1)
return num;
else
return rc;
}
/*
* SMBus type transfer entrypoint
*/
int bfin_twi_smbus_xfer(struct i2c_adapter *adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size, union i2c_smbus_data *data)
{
struct bfin_twi_iface *iface = adap->algo_data;
int rc = 0;
if (!(read_CONTROL(iface) & TWI_ENA))
return -ENXIO;
while (read_MASTER_STAT(iface) & BUSBUSY)
yield();
iface->writeNum = 0;
iface->readNum = 0;
/* Prepare datas & select mode */
switch (size) {
case I2C_SMBUS_QUICK:
iface->transPtr = NULL;
iface->cur_mode = TWI_I2C_MODE_STANDARD;
break;
case I2C_SMBUS_BYTE:
if (data == NULL)
iface->transPtr = NULL;
else {
if (read_write == I2C_SMBUS_READ)
iface->readNum = 1;
else
iface->writeNum = 1;
iface->transPtr = &data->byte;
}
iface->cur_mode = TWI_I2C_MODE_STANDARD;
break;
case I2C_SMBUS_BYTE_DATA:
if (read_write == I2C_SMBUS_READ) {
iface->readNum = 1;
iface->cur_mode = TWI_I2C_MODE_COMBINED;
} else {
iface->writeNum = 1;
iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
}
iface->transPtr = &data->byte;
break;
case I2C_SMBUS_WORD_DATA:
if (read_write == I2C_SMBUS_READ) {
iface->readNum = 2;
iface->cur_mode = TWI_I2C_MODE_COMBINED;
} else {
iface->writeNum = 2;
iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
}
iface->transPtr = (u8 *)&data->word;
break;
case I2C_SMBUS_PROC_CALL:
iface->writeNum = 2;
iface->readNum = 2;
iface->cur_mode = TWI_I2C_MODE_COMBINED;
iface->transPtr = (u8 *)&data->word;
break;
case I2C_SMBUS_BLOCK_DATA:
if (read_write == I2C_SMBUS_READ) {
iface->readNum = 0;
iface->cur_mode = TWI_I2C_MODE_COMBINED;
} else {
iface->writeNum = data->block[0] + 1;
iface->cur_mode = TWI_I2C_MODE_STANDARDSUB;
}
iface->transPtr = data->block;
break;
default:
return -1;
}
iface->result = 0;
iface->manual_stop = 0;
iface->read_write = read_write;
iface->command = command;
iface->timeout_count = 10;
init_completion(&(iface->complete));
/* FIFO Initiation. Data in FIFO should be discarded before
* start a new operation.
*/
write_FIFO_CTL(iface, 0x3);
SSYNC();
write_FIFO_CTL(iface, 0);
/* clear int stat */
write_INT_STAT(iface, MERR | MCOMP | XMTSERV | RCVSERV);
/* Set Transmit device address */
write_MASTER_ADDR(iface, addr);
SSYNC();
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
switch (iface->cur_mode) {
case TWI_I2C_MODE_STANDARDSUB:
write_XMT_DATA8(iface, iface->command);
write_INT_MASK(iface, MCOMP | MERR |
((iface->read_write == I2C_SMBUS_READ) ?
RCVSERV : XMTSERV));
SSYNC();
if (iface->writeNum + 1 <= 255)
write_MASTER_CTL(iface, (iface->writeNum + 1) << 6);
else {
write_MASTER_CTL(iface, 0xff << 6);
iface->manual_stop = 1;
}
/* Master enable */
write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN |
((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0));
break;
case TWI_I2C_MODE_COMBINED:
write_XMT_DATA8(iface, iface->command);
write_INT_MASK(iface, MCOMP | MERR | RCVSERV | XMTSERV);
SSYNC();
if (iface->writeNum > 0)
write_MASTER_CTL(iface, (iface->writeNum + 1) << 6);
else
write_MASTER_CTL(iface, 0x1 << 6);
/* Master enable */
write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN |
((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0));
break;
default:
write_MASTER_CTL(iface, 0);
if (size != I2C_SMBUS_QUICK) {
/* Don't access xmit data register when this is a
* read operation.
*/
if (iface->read_write != I2C_SMBUS_READ) {
if (iface->writeNum > 0) {
write_XMT_DATA8(iface,
*(iface->transPtr++));
if (iface->writeNum <= 255)
write_MASTER_CTL(iface,
iface->writeNum << 6);
else {
write_MASTER_CTL(iface,
0xff << 6);
iface->manual_stop = 1;
}
iface->writeNum--;
} else {
write_XMT_DATA8(iface, iface->command);
write_MASTER_CTL(iface, 1 << 6);
}
} else {
if (iface->readNum > 0 && iface->readNum <= 255)
write_MASTER_CTL(iface,
iface->readNum << 6);
else if (iface->readNum > 255) {
write_MASTER_CTL(iface, 0xff << 6);
iface->manual_stop = 1;
} else {
del_timer(&iface->timeout_timer);
break;
}
}
}
write_INT_MASK(iface, MCOMP | MERR |
((iface->read_write == I2C_SMBUS_READ) ?
RCVSERV : XMTSERV));
SSYNC();
/* Master enable */
write_MASTER_CTL(iface, read_MASTER_CTL(iface) | MEN |
((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) |
((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ > 100) ? FAST : 0));
break;
}
SSYNC();
wait_for_completion(&iface->complete);
rc = (iface->result >= 0) ? 0 : -1;
return rc;
}
/*
* Return what the adapter supports
*/
static u32 bfin_twi_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
I2C_FUNC_I2C;
}
static struct i2c_algorithm bfin_twi_algorithm = {
.master_xfer = bfin_twi_master_xfer,
.smbus_xfer = bfin_twi_smbus_xfer,
.functionality = bfin_twi_functionality,
};
static int i2c_bfin_twi_suspend(struct platform_device *pdev, pm_message_t state)
{
struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
iface->saved_clkdiv = read_CLKDIV(iface);
iface->saved_control = read_CONTROL(iface);
free_irq(iface->irq, iface);
/* Disable TWI */
write_CONTROL(iface, iface->saved_control & ~TWI_ENA);
return 0;
}
static int i2c_bfin_twi_resume(struct platform_device *pdev)
{
struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
int rc = request_irq(iface->irq, bfin_twi_interrupt_entry,
IRQF_DISABLED, pdev->name, iface);
if (rc) {
dev_err(&pdev->dev, "Can't get IRQ %d !\n", iface->irq);
return -ENODEV;
}
/* Resume TWI interface clock as specified */
write_CLKDIV(iface, iface->saved_clkdiv);
/* Resume TWI */
write_CONTROL(iface, iface->saved_control);
return 0;
}
static int i2c_bfin_twi_probe(struct platform_device *pdev)
{
struct bfin_twi_iface *iface;
struct i2c_adapter *p_adap;
struct resource *res;
int rc;
iface = kzalloc(sizeof(struct bfin_twi_iface), GFP_KERNEL);
if (!iface) {
dev_err(&pdev->dev, "Cannot allocate memory\n");
rc = -ENOMEM;
goto out_error_nomem;
}
spin_lock_init(&(iface->lock));
/* Find and map our resources */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
rc = -ENOENT;
goto out_error_get_res;
}
iface->regs_base = ioremap(res->start, res->end - res->start + 1);
if (iface->regs_base == NULL) {
dev_err(&pdev->dev, "Cannot map IO\n");
rc = -ENXIO;
goto out_error_ioremap;
}
iface->irq = platform_get_irq(pdev, 0);
if (iface->irq < 0) {
dev_err(&pdev->dev, "No IRQ specified\n");
rc = -ENOENT;
goto out_error_no_irq;
}
init_timer(&(iface->timeout_timer));
iface->timeout_timer.function = bfin_twi_timeout;
iface->timeout_timer.data = (unsigned long)iface;
p_adap = &iface->adap;
p_adap->id = I2C_HW_BLACKFIN;
p_adap->nr = pdev->id;
strlcpy(p_adap->name, pdev->name, sizeof(p_adap->name));
p_adap->algo = &bfin_twi_algorithm;
p_adap->algo_data = iface;
p_adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
p_adap->dev.parent = &pdev->dev;
rc = peripheral_request_list(pin_req[pdev->id], "i2c-bfin-twi");
if (rc) {
dev_err(&pdev->dev, "Can't setup pin mux!\n");
goto out_error_pin_mux;
}
rc = request_irq(iface->irq, bfin_twi_interrupt_entry,
IRQF_DISABLED, pdev->name, iface);
if (rc) {
dev_err(&pdev->dev, "Can't get IRQ %d !\n", iface->irq);
rc = -ENODEV;
goto out_error_req_irq;
}
/* Set TWI internal clock as 10MHz */
write_CONTROL(iface, ((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
/* Set Twi interface clock as specified */
write_CLKDIV(iface, ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
<< 8) | ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
& 0xFF));
/* Enable TWI */
write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);
SSYNC();
rc = i2c_add_numbered_adapter(p_adap);
if (rc < 0) {
dev_err(&pdev->dev, "Can't add i2c adapter!\n");
goto out_error_add_adapter;
}
platform_set_drvdata(pdev, iface);
dev_info(&pdev->dev, "Blackfin BF5xx on-chip I2C TWI Contoller, "
"regs_base@%p\n", iface->regs_base);
return 0;
out_error_add_adapter:
free_irq(iface->irq, iface);
out_error_req_irq:
out_error_no_irq:
peripheral_free_list(pin_req[pdev->id]);
out_error_pin_mux:
iounmap(iface->regs_base);
out_error_ioremap:
out_error_get_res:
kfree(iface);
out_error_nomem:
return rc;
}
static int i2c_bfin_twi_remove(struct platform_device *pdev)
{
struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
platform_set_drvdata(pdev, NULL);
i2c_del_adapter(&(iface->adap));
free_irq(iface->irq, iface);
peripheral_free_list(pin_req[pdev->id]);
iounmap(iface->regs_base);
kfree(iface);
return 0;
}
static struct platform_driver i2c_bfin_twi_driver = {
.probe = i2c_bfin_twi_probe,
.remove = i2c_bfin_twi_remove,
.suspend = i2c_bfin_twi_suspend,
.resume = i2c_bfin_twi_resume,
.driver = {
.name = "i2c-bfin-twi",
.owner = THIS_MODULE,
},
};
static int __init i2c_bfin_twi_init(void)
{
return platform_driver_register(&i2c_bfin_twi_driver);
}
static void __exit i2c_bfin_twi_exit(void)
{
platform_driver_unregister(&i2c_bfin_twi_driver);
}
module_init(i2c_bfin_twi_init);
module_exit(i2c_bfin_twi_exit);
MODULE_AUTHOR("Bryan Wu, Sonic Zhang");
MODULE_DESCRIPTION("Blackfin BF5xx on-chip I2C TWI Contoller Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-bfin-twi");