Thread (26 messages) 26 messages, 4 authors, 2016-03-28

[PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs without a stop bit

From: Wolfram Sang <hidden>
Date: 2016-02-12 18:38:23
Also in: linux-arm-msm, linux-devicetree, linux-i2c, lkml

On Tue, Jan 19, 2016 at 03:32:43PM +0530, Sricharan R wrote:
The definition of i2c_msg says that

"If this is the last message in a group, it is followed by a STOP.
Otherwise it is followed by the next @i2c_msg transaction segment,
beginning with a (repeated) START"

So the expectation is that there is no 'STOP' bit inbetween individual
i2c_msg segments with repeated 'START'. The QUP i2c hardware has no way
to inform that there should not be a 'STOP' at the end of transaction.
The only way to implement this is to coalesce all the i2c_msg in i2c_msgs
in to one transaction and transfer them. Adding the support for the same.

This is required for some clients like touchscreen which keeps
incrementing counts across individual transfers and 'STOP' bit inbetween
resets the counter, which is not required.

This patch adds the support in non-dma mode.

Signed-off-by: Sricharan R <redacted>
Reviewed-by: Andy Gross <redacted>
Tested-by: Archit Taneja <redacted>
Tested-by: Telkar Nagender <redacted>
Shortened the commit message and applied to for-next, thanks!

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