From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: [PATCH] i2c-powermac: Reject unsupported I2C transactions Date: Wed, 30 Sep 2009 22:14:35 +0200 Message-ID: <20090930221435.58636363@hyperion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linux I2C , linuxppc-dev-mnsaURCQ41sdnm+yROfE0A@public.gmane.org Cc: Benjamin Herrenschmidt , Paul Mackerras List-Id: linux-i2c@vger.kernel.org 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 Cc: Benjamin Herrenschmidt Cc: Paul Mackerras --- drivers/i2c/busses/i2c-powermac.c | 6 ++++++ 1 file changed, 6 insertions(+) --- linux-2.6.32-rc1.orig/drivers/i2c/busses/i2c-powermac.c 2009-06-10 05:05:27.000000000 +0200 +++ linux-2.6.32-rc1/drivers/i2c/busses/i2c-powermac.c 2009-09-30 20:29:42.000000000 +0200 @@ -146,6 +146,12 @@ static int i2c_powermac_master_xfer( str 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; -- Jean Delvare