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i2c: mpc: Wait for STOP to hit the bus 

mpc_i2c_stop() only initiates STOP but does not wait for it to
hit the I2C bus. This is a problem when using I2C devices which
uses fairly long clock stretching just before STOP if you also
have an i2c-mux which may switch to another bus before STOP has
been processed.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Joakim Tjernlund 2012-08-30 12:40:04 +02:00 committed by Wolfram Sang
parent 2bdbfa9c4a
commit 0c25aefa35
1 changed files with 17 additions and 1 deletions
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18
drivers/i2c/busses/i2c-mpc.c
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@ -576,7 +576,23 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
}
}
mpc_i2c_stop(i2c);
mpc_i2c_stop(i2c); /* Initiate STOP */
orig_jiffies = jiffies;
/* Wait until STOP is seen, allow up to 1 s */
while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
if (time_after(jiffies, orig_jiffies + HZ)) {
u8 status = readb(i2c->base + MPC_I2C_SR);
dev_dbg(i2c->dev, "timeout\n");
if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) {
writeb(status & ~CSR_MAL,
i2c->base + MPC_I2C_SR);
mpc_i2c_fixup(i2c);
}
return -EIO;
}
cond_resched();
}
return (ret < 0) ? ret : num;
}