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>
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index b76731e..64b0b4d 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -576,7 +576,23 @@
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;
}