From mboxrd@z Thu Jan 1 00:00:00 1970 From: BhuvanChandra.DV Subject: Re: [PATCH 7/7] spi: spi-fsl-dspi: Add support for TCFQ transfer mode Date: Thu, 29 Jan 2015 12:53:57 +0000 Message-ID: <1422536382672.21760@toradex.com> References: <1422356608-15961-1-git-send-email-bhuvanchandra.dv@toradex.com> <1422356608-15961-2-git-send-email-bhuvanchandra.dv@toradex.com> <20150128190342.GE21293@sirena.org.uk> <1422533049999.91114@toradex.com> <20150129121320.GI21293@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150129121320.GI21293@sirena.org.uk> Content-Language: en-IN Content-ID: <2EB79AB5DBC01549B4F66E2879FBDED3@toradex.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Mark Brown Cc: "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "linux@arm.linux.org.uk" , "B44548@freescale.com" , "pawel.moll@arm.com" , "ijc+devicetree@hellion.org.uk" , "Li.Xiubo@freescale.com" , "linux-kernel@vger.kernel.org" , "stefan@agner.ch" , "linux-spi@vger.kernel.org" , "robh+dt@kernel.org" , "galak@codeaurora.org" , "shawn.guo@linaro.org" , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On 01/29/2015 05:43 PM, Mark Brown wrote: > On Thu, Jan 29, 2015 at 11:58:25AM +0000, BhuvanChandra.DV wrote: > >> As far as i understood the major difference between the two modes are when >> the interrupt to trigger, as EOQ mode will trigger the interrupt at end of >> queue and TCF will trigger the interrupt at every frame transfer. Probably >> mode selection shouldn't be a device tree property, but i don't see any >> automatic way to choose between the modes. >> Maybe a config would be more appropriate? > Or if there's either no particular reason to choose one over the other > or one is always better then just pick one in the driver and don't worry > about implementing both. Among the two, EOQ would be better since with TCF, interrupts are generated at every frame transfer, which could be a problem at higher frequencies. I think we can omit this patch then. From mboxrd@z Thu Jan 1 00:00:00 1970 From: bhuvanchandra.dv@toradex.com (BhuvanChandra.DV) Date: Thu, 29 Jan 2015 12:53:57 +0000 Subject: [PATCH 7/7] spi: spi-fsl-dspi: Add support for TCFQ transfer mode In-Reply-To: <20150129121320.GI21293@sirena.org.uk> References: <1422356608-15961-1-git-send-email-bhuvanchandra.dv@toradex.com> <1422356608-15961-2-git-send-email-bhuvanchandra.dv@toradex.com> <20150128190342.GE21293@sirena.org.uk> <1422533049999.91114@toradex.com> <20150129121320.GI21293@sirena.org.uk> Message-ID: <1422536382672.21760@toradex.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/29/2015 05:43 PM, Mark Brown wrote: > On Thu, Jan 29, 2015 at 11:58:25AM +0000, BhuvanChandra.DV wrote: > >> As far as i understood the major difference between the two modes are when >> the interrupt to trigger, as EOQ mode will trigger the interrupt at end of >> queue and TCF will trigger the interrupt at every frame transfer. Probably >> mode selection shouldn't be a device tree property, but i don't see any >> automatic way to choose between the modes. >> Maybe a config would be more appropriate? > Or if there's either no particular reason to choose one over the other > or one is always better then just pick one in the driver and don't worry > about implementing both. Among the two, EOQ would be better since with TCF, interrupts are generated at every frame transfer, which could be a problem at higher frequencies. I think we can omit this patch then.