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authorTroy Kisky <troy.kisky@boundarydevices.com>2012-07-19 08:18:16 +0000
committerHeiko Schocher <hs@denx.de>2012-07-31 07:53:36 +0200
commita7f1a0051078052cb81ba1ff5985b908f39cefd5 (patch)
tree56236eb45ce4de4f0b4710a7f35e80e044dea07f /drivers
parentd5383a63cd1286392a9792f3bd9e9b0d87e02171 (diff)
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mxc_i2c: add retries
Retry unexpected hardware errors. This will not retry a received NAK. Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/i2c/mxc_i2c.c36
1 files changed, 27 insertions, 9 deletions
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index 093a73f..cbb0fff 100644
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -218,7 +218,7 @@ void i2c_imx_stop(void)
* Send start signal, chip address and
* write register address
*/
-static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
+static int i2c_init_transfer_(struct mxc_i2c_regs *i2c_regs,
uchar chip, uint addr, int alen)
{
unsigned int temp;
@@ -235,7 +235,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
writeb(0, &i2c_regs->i2sr);
ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
if (ret < 0)
- goto exit;
+ return ret;
/* Start I2C transaction */
temp = readb(&i2c_regs->i2cr);
@@ -244,7 +244,7 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
ret = wait_for_sr_state(i2c_regs, ST_BUS_BUSY);
if (ret < 0)
- goto exit;
+ return ret;
temp |= I2CR_MTX | I2CR_TX_NO_AK;
writeb(temp, &i2c_regs->i2cr);
@@ -252,18 +252,36 @@ static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
/* write slave address */
ret = tx_byte(i2c_regs, chip << 1);
if (ret < 0)
- goto exit;
+ return ret;
while (alen--) {
ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff);
if (ret < 0)
- goto exit;
+ return ret;
}
return 0;
-exit:
- i2c_imx_stop();
- /* Disable I2C controller */
- writeb(0, &i2c_regs->i2cr);
+}
+
+static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
+ uchar chip, uint addr, int alen)
+{
+ int retry;
+ int ret;
+ for (retry = 0; retry < 3; retry++) {
+ ret = i2c_init_transfer_(i2c_regs, chip, addr, alen);
+ if (ret >= 0)
+ return 0;
+ i2c_imx_stop();
+ if (ret == -ENODEV)
+ return ret;
+
+ printf("%s: failed for chip 0x%x retry=%d\n", __func__, chip,
+ retry);
+ if (ret != -ERESTART)
+ writeb(0, &i2c_regs->i2cr); /* Disable controller */
+ udelay(100);
+ }
+ printf("%s: give up i2c_regs=%p\n", __func__, i2c_regs);
return ret;
}