The tx function of the DDC I2C slave emulation was returning 1
on all writes resulting in NACK in the I2C bus. Changing it to
0 makes the DDC I2C work fine with bit-banged I2C such as the
versatile I2C.
I guess it was not affecting whatever I2C controller this was
used with until now, but with the Versatile I2C it surely
does not work.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Message-id: 20180227104903.21353-4-linus.walleij@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The point of writing a macro embedded in a 'do { ... } while (0)'
loop (particularly if the macro has multiple statements or would
otherwise end with an 'if' statement) is so that the macro can be
used as a drop-in statement with the caller supplying the
trailing ';'. Although our coding style frowns on brace-less 'if':
if (cond)
statement;
else
something else;
that is the classic case where failure to use do/while(0) wrapping
would cause the 'else' to pair with any embedded 'if' in the macro
rather than the intended outer 'if'. But conversely, if the macro
includes an embedded ';', then the same brace-less coding style
would now have two statements, making the 'else' a syntax error
rather than pairing with the outer 'if'. Thus, even though our
coding style with required braces is not impacted, ending a macro
with ';' makes our code harder to port to projects that use
brace-less styles.
The change should have no semantic impact. I was not able to
fully compile-test all of the changes (as some of them are
examples of the ugly bit-rotting debug print statements that are
completely elided by default, and I didn't want to recompile
with the necessary -D witnesses - cleaning those up is left as a
bite-sized task for another day); I did, however, audit that for
all files touched, all callers of the changed macros DID supply
a trailing ';' at the callsite, and did not appear to be used
as part of a brace-less conditional.
Found mechanically via: $ git grep -B1 'while (0);' | grep -A1 \\\\
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20171201232433.25193-7-eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Split the file into public and internal interfaces. I have to rename
the external one because we can't have two include files with the same
name in the same directory. Build system gets confused. The only
exported functions are the ones that handle basic types.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Add a return value to the event handler. Some I2C devices will
NAK if they have no data, so allow them to do this. This required
the following changes:
Go through all the event handlers and change them to return int
and return 0.
Modify i2c_start_transfer to terminate the transaction on a NAK.
Modify smbus handing to not assert if a NAK occurs on a second
operation, and terminate the transaction and return -1 instead.
Add some information on semantics to I2CSlaveClass.
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Implement an I2C slave which implements DDC and returns the
EDID data for an attached monitor.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Tested-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
Message-id: 1465833014-21982-7-git-send-email-fred.konrad@greensocs.com
- Rebased on the current master.
- Modified for QOM.
Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Tested-By: Hyun Kwon <hyun.kwon@xilinx.com>
[PMM: actually wire up the vmstate to dc->vmsd]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
