Re: [PATCH] i2c: imx: fix the i2c bus hang issue when do repeat restart

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

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On Wed, Apr 30, 2014 at 02:24:58PM +0800, Fugang Duan wrote:
> Test i2c device Maxim max44009, datasheet is located at:
> http://www.maximintegrated.com/datasheet/index.mvp/id/7175
> 
> The max44009 support repeat operation like:
> read -> repeat restart -> read/write
> 
> The current i2c imx host controller driver don't support this
> operation that causes i2c bus hang due to "MTX" is cleared in
> .i2c_imx_read(). If "read" is the last message there have no problem,
> so the current driver supports all SMbus operation like:
> write -> repeat restart -> read/write
> 
> IMX i2c controller for master receiver has some limitation:
> - If it is the last byte for one operation, it must generate STOP
>   signal before read I2DR to prevent controller from generating another
>   clock cycle.
> - If it is the last byte in the read, and then do repeat restart, it must
>   set "MTX" before read I2DR to prevent controller from generating another
>   extra clock cycle.
> 
> The patch is to fix the issue.
> 
> Signed-off-by: Fugang Duan <B38611-KZfg59tc24xl57MIdRCFDg@public.gmane.org>

Applied to for-next, thanks!


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