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Commit 72fc2c7f authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Jean Delvare
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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: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent d47726c5

drivers/i2c/i2c-core.c

+10 −4
Original line number Diff line number Diff line
@@ -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);



		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);