This fixes MAL (arbitration lost) bug caused by illegal use of
RSTA (repeated START) after STOP condition generated after last byte
of reads. With this patch, it is possible to do an i2c_transfer() with
additional i2c_msg's following the I2C_M_RD messages.
It still needs to be resolved if it is possible to fix this issue
by removing the STOP condition after reads in a robust way.
Signed-off-by: Esben Haabendal <eha@xxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-mpc.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 4af5c09..0199f9a 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -456,17 +456,22 @@ static int mpc_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
}
for (i = 0; ret >= 0 && i < num; i++) {
+ int restart = i;
pmsg = &msgs[i];
dev_dbg(i2c->dev,
"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, pmsg->addr, i + 1, num);
+ if (i > 0 && ((pmsg - 1)->flags & I2C_M_RD))
+ restart = 0;
if (pmsg->flags & I2C_M_RD)
ret =
- mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+ mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len,
+ restart);
else
ret =
- mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+ mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len,
+ restart);
}
mpc_i2c_stop(i2c);
return (ret < 0) ? ret : num;
--
1.6.3.1
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
