When the au1550 i2c driver encounteres an error while addressing a slave
or has no data to send to a slave in the last i2c message, it returns to
the upper layers without issuing a i2c stop condition. This for example
resulted in the minute register of the RTC on my board to be overwritten
with a random value on a following transfer.
Fix the driver to send a stop over the i2c bus if one of the following
2 conditions are met:
* error when addressing a slave
* no data to send in the last i2c message
Signed-off-by: Manuel Lauss <mano@xxxxxxxxxxxxxxxxxxxxxxx>
--- a/drivers/i2c/busses/i2c-au1550.c 2007-04-26 05:08:32.000000000 +0200
+++ b/drivers/i2c/busses/i2c-au1550.c 2007-05-15 20:19:56.000000000 +0200
@@ -260,13 +260,20 @@ static int
au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
struct i2c_au1550_data *adap = i2c_adap->algo_data;
+ volatile psc_smb_t *sp = (volatile psc_smb_t *)(adap->psc_base);
struct i2c_msg *p;
int i, err = 0;
for (i = 0; !err && i < num; i++) {
p = &msgs[i];
err = do_address(adap, p->addr, p->flags & I2C_M_RD);
- if (err || !p->len)
+ if (err || ((!p->len) && (i == (num - 1)))) {
+ sp->psc_smbtxrx = PSC_SMBTXRX_STP;
+ au_sync();
+ wait_master_done(adap);
+ continue;
+ }
+ if (!p->len)
continue;
if (p->flags & I2C_M_RD)
err = i2c_read(adap, p->buf, p->len);
