From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baolin Wang Subject: Re: [PATCH 1/2] dt-bindings: spi: Add Spreadtrum SPI controller documentation Date: Wed, 8 Aug 2018 18:35:28 +0800 Message-ID: References: <64681bf903104c8a02f118294e616e2a12a5ebe4.1533638405.git.baolin.wang@linaro.org> <20180807134121.GA7958@sirena.org.uk> <20180808095025.GB9346@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Rob Herring , Mark Rutland , Orson Zhai , Chunyan Zhang , lanqing.liu@spreadtrum.com, linux-spi@vger.kernel.org, DTML , LKML To: Mark Brown Return-path: In-Reply-To: <20180808095025.GB9346@sirena.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org On 8 August 2018 at 17:50, Mark Brown 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