[PATCH v2] spi: davinci: add support for adding delay between word's transmission

On 09/09/2014 01:20 PM, Mark Brown wrote:

On Tue, Sep 09, 2014 at 01:09:27PM -0400, Murali Karicheri wrote:

quoted

On 09/09/2014 12:55 PM, Mark Brown wrote:

quoted

On Tue, Sep 09, 2014 at 07:07:31PM +0300, Grygorii Strashko wrote:

quoted

quoted

quoted

- ti,spi-c2t-delay: Chip-select-active-to-transmit-start delay
	(SPIDELAY.C2TDELAY)

quoted

quoted

quoted

- ti,spi-t2c-delay: Transmit-end-to-chip-select-inactive delay
	(SPIDELAY.T2CDELAY)

quoted

quoted

Now I look at these they look very much like the standard delay feature
that the SPI subsystem has already - are they?

quoted

As Grygorii explained in previous postings (reproduced below), these delays
are handled by the SPI hardware on Keystone and affect the delay between
successive word tranmssion and has nothing to do with the delay you are
talking about. Isn't the standard delay you mention here is between
successive packets send down to the lower level driver (in this case
spi-davinci.c) ?

He talked about such delays between words (and there were some other
delays listed which seemed to meet that description) but the above don't
appear to refer to them, the above refer to delays around chip select
which most definitely are covered with the standard delays.

If these delays are not related to chip select then the documentation
needs to be fixed to not refer to chip select.

Ok. So what I understand is the issue is not having the right 
description to indicate that these parameters are delays associated with 
tranmission of successive words on the wire. Personally I like these 
description match with what is described in the device spec/ user guide 
and what is described above match with that. However we could add 
additional description as below to to make it more explicit.

spi-c2t-delay - delay after CS is asserted before output bits on wire
spi-t2c-delay - delay after tramission of bits and before deasserting CS
wdelay - delay between successive word transmission.

Do you think this will help?

Murali