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mxc_i2c: don't disable controller after every transaction

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This helps in a multiple bus master environment which
is why I also added a wait for bus idle.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
This commit is contained in:
Troy Kisky 2012-07-19 08:18:13 +00:00 • committed by Heiko Schocher
parent 83a1a19038
commit 90a5b70f59
1 changed files with 13 additions and 15 deletions
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24
drivers/i2c/mxc_i2c.c
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@ -192,24 +192,19 @@ static int tx_byte(struct mxc_i2c_regs *i2c_regs, u8 byte)
} }
/* /*
* Stop the controller * Stop I2C transaction
*/ */
void i2c_imx_stop(void) void i2c_imx_stop(void)
{ {
int ret; int ret;
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
unsigned int temp = 0; unsigned int temp = readb(&i2c_regs->i2cr);
/* Stop I2C transaction */
temp = readb(&i2c_regs->i2cr);
temp &= ~(I2CR_MSTA | I2CR_MTX); temp &= ~(I2CR_MSTA | I2CR_MTX);
writeb(temp, &i2c_regs->i2cr); writeb(temp, &i2c_regs->i2cr);
ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
if (ret < 0) if (ret < 0)
printf("%s:trigger stop failed\n", __func__); printf("%s:trigger stop failed\n", __func__);
/* Disable I2C controller */
writeb(0, &i2c_regs->i2cr);
} }
/* /*
@ -223,11 +218,15 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
int ret; int ret;
/* Enable I2C controller */ /* Enable I2C controller */
writeb(0, &i2c_regs->i2sr); if (!(readb(&i2c_regs->i2cr) & I2CR_IEN)) {
writeb(I2CR_IEN, &i2c_regs->i2cr); writeb(I2CR_IEN, &i2c_regs->i2cr);
/* Wait for controller to be stable */ /* Wait for controller to be stable */
udelay(50); udelay(50);
}
writeb(0, &i2c_regs->i2sr);
ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
if (ret < 0)
goto exit;
/* Start I2C transaction */ /* Start I2C transaction */
temp = readb(&i2c_regs->i2cr); temp = readb(&i2c_regs->i2cr);
@ -254,6 +253,8 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
return 0; return 0;
exit: exit:
i2c_imx_stop(); i2c_imx_stop();
/* Disable I2C controller */
writeb(0, &i2c_regs->i2cr);
return ret; return ret;
} }
@ -303,10 +304,7 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
* controller from generating another clock cycle * controller from generating another clock cycle
*/ */
if (i == (len - 1)) { if (i == (len - 1)) {
temp = readb(&i2c_regs->i2cr); i2c_imx_stop();
temp &= ~(I2CR_MSTA | I2CR_MTX);
writeb(temp, &i2c_regs->i2cr);
wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
} else if (i == (len - 2)) { } else if (i == (len - 2)) {
temp = readb(&i2c_regs->i2cr); temp = readb(&i2c_regs->i2cr);
temp |= I2CR_TX_NO_AK; temp |= I2CR_TX_NO_AK;