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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2012-07-24 14:13:59 +0200
committerJean Delvare <khali@endymion.delvare>2012-07-24 14:13:59 +0200
commit72fc2c7f78b0c365454e60ad33b0e74aea43e3ab (patch)
treeb4416754f881f49b0e4cdb3585ed1f598c5a6c56 /drivers/i2c
parentd47726c52122d64253ae56e0fafdb7d0b954e97c (diff)
downloadlinux-linaro-stable-72fc2c7f78b0c365454e60ad33b0e74aea43e3ab.tar.gz
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 <laurent.pinchart@ideasonboard.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/i2c-core.c14
1 files 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);