On Wed, May 04, 2016 at 02:38:23PM +0200, Niklas Söderlund wrote: > Make it possible to transfer i2c message buffers via DMA. > Start/Stop/Sending_Slave_Address and some data is still handled using > the old state machine, it is sending the bulk of the data that is done > via DMA. > > The first byte of a transmission and the last two bytes of reception are > sent/received using PIO. This is needed for the HW to have access to the > first byte before DMA transmit and to be able to set the STOP condition > for DMA reception. > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c-rcar.txt | 3 + > drivers/i2c/busses/i2c-rcar.c | 237 ++++++++++++++++++++- > 2 files changed, 236 insertions(+), 4 deletions(-) Is DMA actually faster or less cpu usage? I'm doubtful. Acked-by: Rob Herring <robh@xxxxxxxxxx>
