Hi Jean,
On Tuesday 17 July 2012 13:53:07 Jean Delvare wrote:
> On Tue, 26 Jun 2012 16:17:07 +0200, Laurent Pinchart wrote:
> > SCCB is a serial communication bus developed by Omnivision. Its 2-wire
> > mode is very similar to SMBus byte data transactions, but requires the
> > controller to ignore the ACK bit and to insert a stop condition after
> > each message.
> >
> > Add a device SCCB flag and a message stop flag to be passed to
> > controller drivers.
> >
> > Signed-off-by: Laurent Pinchart <[email protected]>
> > ---
> >
> > drivers/i2c/i2c-core.c | 13 ++++++++++++-
> > include/linux/i2c.h | 2 ++
> > 2 files changed, 14 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index feb7dc3..8cfa660 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -1939,6 +1939,12 @@ static s32 i2c_smbus_xfer_emulated(struct
> > i2c_adapter *adapter, u16 addr,>
> > u8 partial_pec = 0;
> > int status;
> >
> > + if (unlikely(flags & I2C_CLIENT_SCCB) && size != I2C_SMBUS_BYTE_DATA)
{
> > + dev_err(&adapter->dev,
> > + "SCCB devices only support I2C_SMBUS_BYTE_DATA\n");
> > + return -EINVAL;
> > + }
> > +
>
> I'm not sure if we really want this. If the SCCB protocol evolves,
> we'll have to loosen the check. If a devices follows SCCB for byte data
> transactions and I2C/SMBus for others, it won't work. Plus it slows
> down the function a bit, to catch a developer error which would not
> result in anything catastrophic anyway.
>
> I propose that we either drop the check completely (my preference) or
> make it depend on DEBUG.
I'm OK with dropping the check. Should I resubmit the patch or can you modify
it when applying ?
> > msgbuf0[0] = command;
> > switch (size) {
> >
> > case I2C_SMBUS_QUICK:
--
Regards,
Laurent Pinchart
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