Commit 6f7e549f authored Dec 06, 2009 by Jean Delvare

i2c-powermac: Reject unsupported I2C transactions



The i2c-powermac driver doesn't support arbitrary multi-message I2C
transactions, only SMBus ones. Make it clear by returning an error if
a multi-message I2C transaction is attempted. This is better than only
processing the first message, because most callers won't recover from
the short transaction. Anyone wishing to issue multi-message
transactions should use the SMBus API instead of the raw I2C API.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Michel Daenzer <michel@daenzer.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>

parent dddc66ff

drivers/i2c/busses/i2c-powermac.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -146,6 +146,12 @@ static int i2c_powermac_master_xfer( struct i2c_adapter *adap,
		int read;
		int addrdir;

		if (num != 1) {
		dev_err(&adap->dev,
		"Multi-message I2C transactions not supported\n");
		return -EOPNOTSUPP;
		}

		if (msgs->flags & I2C_M_TEN)
		return -EINVAL;
		read = (msgs->flags & I2C_M_RD) != 0;