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mpc83xx: Fix empty i2c reads/writes in fsl_i2c.c

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Fix empty i2c reads/writes, i2c_write(0x50, 0x00, 0, NULL, 0)
which is used to se if an slave will ACK after receiving its address.

Correct i2c probing to use this method as the old method could upset
a slave as it wrote a data byte to it.

Add a small delay in i2c_init() to let the controller
shutdown any ongoing I2C activity.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
This commit is contained in:
Joakim Tjernlund 2007-01-31 11:04:19 +01:00 committed by Kim Phillips
parent 7a78f148d6
commit f6f5f709e5
1 changed files with 14 additions and 13 deletions
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27
drivers/fsl_i2c.c
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@ -58,6 +58,7 @@ i2c_init(int speed, int slaveadd)
dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET);
writeb(0, &dev->cr); /* stop I2C controller */
udelay(5); /* let it shutdown in peace */
writeb(0x3F, &dev->fdr); /* set bus speed */
writeb(0x3F, &dev->dfsrr); /* set default filter */
writeb(slaveadd << 1, &dev->adr); /* write slave address */
@ -191,15 +192,17 @@ __i2c_read(u8 *data, int length)
int
i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
{
int i = 0;
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus() >= 0
&& i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0
&& __i2c_write(&a[4 - alen], alen) == alen
&& i2c_write_addr(dev, I2C_READ_BIT, 1) != 0) {
&& __i2c_write(&a[4 - alen], alen) == alen)
i = 0; /* No error so far */
if (length
&& i2c_write_addr(dev, I2C_READ_BIT, 1) != 0)
i = __i2c_read(data, length);
}
writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr);
@ -212,7 +215,7 @@ i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
int
i2c_write(u8 dev, uint addr, int alen, u8 *data, int length)
{
int i = 0;
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus() >= 0
@ -232,16 +235,14 @@ i2c_write(u8 dev, uint addr, int alen, u8 *data, int length)
int
i2c_probe(uchar chip)
{
int tmp;
/*
* Try to read the first location of the chip. The underlying
* driver doesn't appear to support sending just the chip address
* and looking for an <ACK> back.
/* For unknow reason the controller will ACK when
* probing for a slave with the same address, so skip
* it.
*/
udelay(10000);
if (chip == (readb(&i2c_dev[i2c_bus_num]->adr) >> 1))
return -1;
return i2c_read(chip, 0, 1, (uchar *)&tmp, 1);
return i2c_read(chip, 0, 0, NULL, 0);
}
uchar