diff options
| author | Clifford Wolf <clifford@clifford.at> | 2009-06-15 18:01:46 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@linux-fr.org> | 2009-06-15 18:01:46 +0200 |
| commit | 66b650f04576a6737579ec404446450026ff2e0b (patch) | |
| tree | 9653a442bfd01a97dd2a8c2e7930473d12623094 /drivers/i2c | |
| parent | 1cf92b453a405f6e452737962933a19ec1582029 (diff) | |
| download | linux-66b650f04576a6737579ec404446450026ff2e0b.tar.bz2 | |
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>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/i2c-core.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index dfd7bc8094bf..635c488262c0 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1022,7 +1022,8 @@ module_exit(i2c_exit); */ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { - int ret; + unsigned long orig_jiffies; + int ret, try; /* REVISIT the fault reporting model here is weak: * @@ -1060,7 +1061,15 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) mutex_lock_nested(&adap->bus_lock, adap->level); } - ret = adap->algo->master_xfer(adap,msgs,num); + /* Retry automatically on arbitration loss */ + orig_jiffies = jiffies; + for (ret = 0, try = 0; try <= adap->retries; try++) { + ret = adap->algo->master_xfer(adap, msgs, num); + if (ret != -EAGAIN) + break; + if (time_after(jiffies, orig_jiffies + adap->timeout)) + break; + } mutex_unlock(&adap->bus_lock); return ret; @@ -1995,14 +2004,27 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, char read_write, u8 command, int protocol, union i2c_smbus_data *data) { + unsigned long orig_jiffies; + int try; s32 res; flags &= I2C_M_TEN | I2C_CLIENT_PEC; if (adapter->algo->smbus_xfer) { mutex_lock(&adapter->bus_lock); - res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write, - command, protocol, data); + + /* Retry automatically on arbitration loss */ + orig_jiffies = jiffies; + for (res = 0, try = 0; try <= adapter->retries; try++) { + res = adapter->algo->smbus_xfer(adapter, addr, flags, + read_write, command, + protocol, data); + if (res != -EAGAIN) + break; + if (time_after(jiffies, + orig_jiffies + adapter->timeout)) + break; + } mutex_unlock(&adapter->bus_lock); } else res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write, |