Thanks Andy. I'll incorporate patch version changelog and review findings for this patch in next version. Please let me know, if you have more findings for this patch. > -----Original Message----- > From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Sent: Tuesday, 14 December, 2021 5:33 PM > To: Saha, Tamal <tamal.saha@xxxxxxxxx> > Cc: wsa@xxxxxxxxxx; jarkko.nikula@xxxxxxxxxxxxxxx; linux- > i2c@xxxxxxxxxxxxxxx; Senthil, Bala <bala.senthil@xxxxxxxxx> > Subject: Re: [PATCH v2] i2c: designware: Do not complete i2c read without > RX_FULL interrupt > > 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 >
