i2c: Bus drivers return -Errno not -1

Tighten error paths used by various i2c adapters (mostly x86) so
they return real fault/errno codes instead of a "-1" (which is
most often interpreted as "-EPERM").  Build tested, with eyeball
review.

One minor initial goal is to have adapters consistently return
the code "-ENXIO" when addressing a device doesn't get an ACK
response, at least in the probe paths where they are already
good at stifling related logspam.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/i2c/busses/i2c-stub.c b/drivers/i2c/busses/i2c-stub.c
index d08eeec53913..e37ccd80f77a 100644
--- a/drivers/i2c/busses/i2c-stub.c
+++ b/drivers/i2c/busses/i2c-stub.c
@@ -43,7 +43,7 @@ struct stub_chip {
 
 static struct stub_chip *stub_chips;
 
-/* Return -1 on error. */
+/* Return negative errno on error. */
 static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
         char read_write, u8 command, int size, union i2c_smbus_data * data)
 {
@@ -120,7 +120,7 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
 
         default:
                 dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
-                ret = -1;
+                ret = -EOPNOTSUPP;
                 break;
         } /* switch (size) */