From 72fc2c7f78b0c365454e60ad33b0e74aea43e3ab Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Tue, 24 Jul 2012 14:13:59 +0200 Subject: [PATCH] i2c: Fall back to emulated SMBus if the operation isn't supported natively Adapter drivers might support only a subset of the SMBus operations natively. Those drivers currently have to manually emulate unsupported operations using I2C. Make the i2c_smbus_xfer() function fall back to i2c_smbus_xfer_emulated() when the adapter's .smbus_xfer() operation returns -EOPNOTSUPP, like it already does when the .smbus_xfer() operation isn't available at all. [JD: Minor optimization.] Signed-off-by: Laurent Pinchart Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 361978a8485a..26488aa893d5 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -2140,11 +2140,17 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, break; } i2c_unlock_adapter(adapter); - } else - res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, - command, protocol, data); - return res; + if (res != -EOPNOTSUPP || !adapter->algo->master_xfer) + return res; + /* + * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't + * implement native support for the SMBus operation. + */ + } + + return i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, + command, protocol, data); } EXPORT_SYMBOL(i2c_smbus_xfer); -- 2.20.1