HI, On Thu, Oct 25, 2012 at 06:31:58PM +0530, Santosh Shilimkar wrote: > On Thursday 25 October 2012 05:55 PM, Felipe Balbi wrote: > >Later patches will come adding support for > >reporting amount of bytes transferred so that > >client drivers can count how many bytes are > >left to transfer. > > > >This is useful mostly in case of NACKs when > >client driver wants to know exactly which > >byte got NACKed so it doesn't have to resend > >all bytes again. > > > >In order to make that work with OMAP's I2C > >controller, we need to prevent sending STP > >bit until message is transferred. The reason > >behind that is because OMAP_I2C_CNT_REG gets > >reset to original value after STP bit is > >shifted through I2C_SDA line and that would > >prevent us from reading the correct number of > >bytes left to transfer. > > > >The full programming model suggested by IP > >owner was the following: > > > >- start I2C transfer (without STP bit) > >- upon completion or NACK, read I2C_CNT register > >- write STP bit to I2C_CON register > >- wait for ARDY bit > > > >With this patch we're implementing all steps > >except step #2 which will come in a later > >patch adding such support. > > > Will this not break the bisect since CNT and > NACK, completion is added in later patch not really. It keeps current behavior. -- balbi
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