i2c: Retry automatically on arbitration loss
Some small changes in i2c core to retry i2c xfers until either the maximum number of retries or the timeout is hit. Signed-off-by: Clifford Wolf <clifford@clifford.at> Signed-off-by: Jean Delvare <khali@linux-fr.org>
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@ -1022,7 +1022,8 @@ module_exit(i2c_exit);
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*/
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int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
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{
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int ret;
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unsigned long orig_jiffies;
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int ret, try;
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/* REVISIT the fault reporting model here is weak:
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*
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@ -1060,7 +1061,15 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
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mutex_lock_nested(&adap->bus_lock, adap->level);
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}
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ret = adap->algo->master_xfer(adap,msgs,num);
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/* Retry automatically on arbitration loss */
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orig_jiffies = jiffies;
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for (ret = 0, try = 0; try <= adap->retries; try++) {
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ret = adap->algo->master_xfer(adap, msgs, num);
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if (ret != -EAGAIN)
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break;
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if (time_after(jiffies, orig_jiffies + adap->timeout))
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break;
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}
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mutex_unlock(&adap->bus_lock);
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return ret;
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@ -1995,14 +2004,27 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
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char read_write, u8 command, int protocol,
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union i2c_smbus_data *data)
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{
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unsigned long orig_jiffies;
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int try;
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s32 res;
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flags &= I2C_M_TEN | I2C_CLIENT_PEC;
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if (adapter->algo->smbus_xfer) {
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mutex_lock(&adapter->bus_lock);
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res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
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command, protocol, data);
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/* Retry automatically on arbitration loss */
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orig_jiffies = jiffies;
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for (res = 0, try = 0; try <= adapter->retries; try++) {
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res = adapter->algo->smbus_xfer(adapter, addr, flags,
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read_write, command,
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protocol, data);
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if (res != -EAGAIN)
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break;
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if (time_after(jiffies,
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orig_jiffies + adapter->timeout))
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break;
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}
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mutex_unlock(&adapter->bus_lock);
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} else
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res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
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