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authorTroy Kisky <troy.kisky@boundarydevices.com>2012-07-19 08:18:13 +0000
committerHeiko Schocher <hs@denx.de>2012-07-31 07:51:22 +0200
commit90a5b70f5914a3ac79cac3dd386cc98ce42bfd8e (patch)
tree1c43dd1c828f9b59a4d7fb9104bb0e685cce584c
parent83a1a19038b0bf36c966b7c7b67708e19b45c3b5 (diff)
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mxc_i2c: don't disable controller after every transaction
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>
-rw-r--r--drivers/i2c/mxc_i2c.c28
1 files changed, 13 insertions, 15 deletions
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index 717bc7a..1a5e379 100644
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -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)
{
int ret;
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);
writeb(temp, &i2c_regs->i2cr);
-
ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
if (ret < 0)
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;
/* Enable I2C controller */
+ if (!(readb(&i2c_regs->i2cr) & I2CR_IEN)) {
+ writeb(I2CR_IEN, &i2c_regs->i2cr);
+ /* Wait for controller to be stable */
+ udelay(50);
+ }
writeb(0, &i2c_regs->i2sr);
- writeb(I2CR_IEN, &i2c_regs->i2cr);
-
- /* Wait for controller to be stable */
- udelay(50);
+ ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
+ if (ret < 0)
+ goto exit;
/* Start I2C transaction */
temp = readb(&i2c_regs->i2cr);
@@ -254,6 +253,8 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
return 0;
exit:
i2c_imx_stop();
+ /* Disable I2C controller */
+ writeb(0, &i2c_regs->i2cr);
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
*/
if (i == (len - 1)) {
- temp = readb(&i2c_regs->i2cr);
- temp &= ~(I2CR_MSTA | I2CR_MTX);
- writeb(temp, &i2c_regs->i2cr);
- wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
+ i2c_imx_stop();
} else if (i == (len - 2)) {
temp = readb(&i2c_regs->i2cr);
temp |= I2CR_TX_NO_AK;