Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1333019 > unrolled thread

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

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs  without a stop bit Wolfram Sang <wsa@the-dreams.de> - 2016-02-12 19:40 +0100

#1333019 — Re: [PATCH V7 3/6] i2c: qup: Transfer each i2c_msg in i2c_msgs without a stop bit

[Multipart message — attachments visible in raw view] — view raw

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 <sricharan@codeaurora.org>
> Reviewed-by: Andy Gross <andy.gross@linaro.org>
> Tested-by: Archit Taneja <architt@codeaurora.org>
> Tested-by: Telkar Nagender <ntelkar@codeaurora.org>

Shortened the commit message and applied to for-next, thanks!

[toc] | [standalone]

Back to top | Article view | linux.kernel

csiph-web