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@xxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-mpc.c | 18 +++++++++++++++++-
1 files changed, 17 insertions(+), 1 deletions(-)
diff --git drivers/i2c/busses/i2c-mpc.c drivers/i2c/busses/i2c-mpc.c
index 3d31879..c08f287 100644
--- drivers/i2c/busses/i2c-mpc.c
+++ drivers/i2c/busses/i2c-mpc.c
@@ -574,7 +574,23 @@ 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;
}
--
1.7.8.6
--
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