Re: [PATCH 1/2] dt-bindings: spi: Add Spreadtrum SPI controller documentation

From: Baolin Wang
Date: Wed Aug 08 2018 - 06:35:33 EST

On 8 August 2018 at 17:50, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Wed, Aug 08, 2018 at 10:26:42AM +0800, Baolin Wang wrote:
>> Sorry for confusing. Let me try to explain it explicitly.
>> We can set the word size (bits_per_word) for each transmission, for
>> our SPI controller, after every word size transmission, we need one
>> interval time (hardware automatically) to make sure the slave has
>> enough time to receive the whole data.
> OK, so it's an inter word delay. Some other controllers definitely have
> the same feature.
>> Yes, I agree we should configure it at runtime by the device, but we
>> did not find one member to use in 'struct spi_transfer', we just find
>> one similar 'delay_usecs' member in 'struct spi_transfer' but not
>> same. We can use 'delay_usecs' to set our hardware interval value,
>> but we should clean it when transfer is done, since we do not need to
>> delay after the transfer in spi_transfer_one _message(). Or can we add
>> one new member maybe named 'word_interval' to indicate the interval
>> time between word size transmission?
> Right, I don't think we added this yet (if we did I can't see it). I'd
> add a new field to spi_transfer for this, then other controllers with
> the same support can implement it as well and drivers can start using
> it too.

OK. So I will name the new filed as 'word_delay', is it OK for you?

Baolin Wang
Best Regards