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| author | Joakim Tjernlund <Joakim.Tjernlund@transmode.se> | 2012-08-30 12:40:04 +0200 |
|---|---|---|
| committer | Wolfram Sang <w.sang@pengutronix.de> | 2012-09-14 16:01:04 +0200 |
| commit | 0c25aefa35c2fb5592895615f77d9f6fa36a849d (patch) | |
| tree | e9c05ae3468a10cb356b474ba0f661f750eda45f | |
| parent | 2bdbfa9c4a14f0015d1e189b17175a989d7c2a40 (diff) | |
| download | blackbird-op-linux-0c25aefa35c2fb5592895615f77d9f6fa36a849d.tar.gz blackbird-op-linux-0c25aefa35c2fb5592895615f77d9f6fa36a849d.zip | |
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>
| -rw-r--r-- | drivers/i2c/busses/i2c-mpc.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index b76731edbf10..64b0b4d265d5 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -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; } |
