On Fri, Oct 21, 2011 at 05:14:45PM +0100, Jonathan Cameron wrote:
> On 10/21/11 17:09, Dmitry Torokhov wrote:
> > On Fri, Oct 21, 2011 at 12:57:16PM +0100, Jonathan Cameron wrote:
> >> This varient was introduced in
> >> i2c: boilerplate function for byte swapped smbus_write/read_word_data
> >>
> >> This also has the side effect of ensuring any errors from the i2c
> >> read and no longer mangled.
> >>
> >> Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxx>
> >> ---
> >> V2: include the write function as pointed out by Michael Hennerich.
> >>
> >> The patch introducing this swapped function is working its way through the i2c
> >> tree.
> >>
> >> drivers/input/touchscreen/ad7879-i2c.c | 4 ++--
> >> 1 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/input/touchscreen/ad7879-i2c.c b/drivers/input/touchscreen/ad7879-i2c.c
> >> index 4e4e58c..cc51392 100644
> >> --- a/drivers/input/touchscreen/ad7879-i2c.c
> >> +++ b/drivers/input/touchscreen/ad7879-i2c.c
> >> @@ -47,7 +47,7 @@ static int ad7879_i2c_read(struct device *dev, u8 reg)
> >> {
> >> struct i2c_client *client = to_i2c_client(dev);
> >>
> >> - return swab16(i2c_smbus_read_word_data(client, reg));
> >> + return i2c_smbus_read_word_swapped(client, reg);
> >
> > This is still not endian-safe. I wonder if introducing
> > i2c_smbus_read_word_swapped() just makes the metter worse by hiding
> > this...
> >
> > I'd prefer if we had i2c_smbus_read_be16() instead.
> smbus spec says that all transfers must be little endian.
> Hence it is type safe because the smbus controllers are guaranteed to have made
> that assumption and converted to cpu endianess. If not they are buggy.
> Hence, this is endian safe.
Ah, right... OK then.
--
Dmitry
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