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:

quoted

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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