On Tue, Dec 14, 2021 at 02:00:59PM +0200, Andy Shevchenko wrote: > On Tue, Dec 14, 2021 at 08:25:18AM +0530, tamal.saha@xxxxxxxxx wrote: > > From: Tamal Saha <tamal.saha@xxxxxxxxx> > > > > Intel Keem Bay platform supports multimaster operations over same i2c Here you put multimaster... > > bus using Synopsys i2c DesignWare IP. When multi masters initiate i2c ...and here multi masters. Be consistent. I believe the best way is to use dash variant, i.e. multi-master(s), > > operation simultaneously in a loop, SCL line is stucked low forever > > after few i2c operations. Following interrupt sequences are observed > > in: > > working case: TX_EMPTY, RX_FULL and STOP_DET > > non working case: TX_EMPTY, STOP_DET, RX_FULL. > > > > DW_apb_i2c stretches the SCL line when the TX FIFO is empty or when > > RX FIFO is full. The DW_apb_i2c master will continue to hold the SCL > > line LOW until RX FIFO is read. > > > > Linux kernel i2c DesignWare driver does not handle above non working > > sequence. TX_EMPTY, RX_FULL and STOP_DET routine execution are required > > in sequence although RX_FULL interrupt is raised after STOP_DET by > > hardware. Clear STOP_DET for the following conditions: > > (STOP_DET ,RX_FULL, rx_outstanding) > > Write Operation: (1, 0, 0) > > Read Operation: > > RX_FULL followed by STOP_DET: (0, 1, 1) -> (1, 0, 0) > > STOP_DET followed by RX_FULL: (1, 0, 1) -> (1, 1, 0) > > RX_FULL and STOP_DET together: (1, 1, 1) > > > > Signed-off-by: Tamal Saha <tamal.saha@xxxxxxxxx> > > --- > > So, where is the changelog? -- With Best Regards, Andy Shevchenko
