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From: BhuvanChandra.DV <bhuvanchandra.dv@toradex.com>
To: Mark Brown <broonie@kernel.org>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
	"B44548@freescale.com" <B44548@freescale.com>,
	"pawel.moll@arm.com" <pawel.moll@arm.com>,
	"ijc+devicetree@hellion.org.uk" <ijc+devicetree@hellion.org.uk>,
	"Li.Xiubo@freescale.com" <Li.Xiubo@freescale.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"stefan@agner.ch" <stefan@agner.ch>,
	"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"galak@codeaurora.org" <galak@codeaurora.org>,
	"shawn.guo@linaro.org" <shawn.guo@linaro.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 7/7] spi: spi-fsl-dspi: Add support for TCFQ transfer mode
Date: Thu, 29 Jan 2015 12:53:57 +0000	[thread overview]
Message-ID: <1422536382672.21760@toradex.com> (raw)
In-Reply-To: <20150129121320.GI21293@sirena.org.uk>


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.

WARNING: multiple messages have this Message-ID (diff)
From: bhuvanchandra.dv@toradex.com (BhuvanChandra.DV)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 7/7] spi: spi-fsl-dspi: Add support for TCFQ transfer mode
Date: Thu, 29 Jan 2015 12:53:57 +0000	[thread overview]
Message-ID: <1422536382672.21760@toradex.com> (raw)
In-Reply-To: <20150129121320.GI21293@sirena.org.uk>


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.

  reply	other threads:[~2015-01-29 12:53 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-27 11:03 [PATCH 6/7] spi: spi-fsl-dspi: split the resuable code Bhuvanchandra DV
2015-01-27 11:03 ` Bhuvanchandra DV
2015-01-27 11:03 ` Bhuvanchandra DV
2015-01-27 11:03 ` Bhuvanchandra DV
2015-01-27 11:03 ` [PATCH 7/7] spi: spi-fsl-dspi: Add support for TCFQ transfer mode Bhuvanchandra DV
2015-01-27 11:03   ` Bhuvanchandra DV
2015-01-27 11:03   ` Bhuvanchandra DV
2015-01-27 11:03   ` Bhuvanchandra DV
2015-01-28 19:03   ` Mark Brown
2015-01-28 19:03     ` Mark Brown
2015-01-28 19:03     ` Mark Brown
2015-01-29 11:58     ` BhuvanChandra.DV
2015-01-29 11:58       ` BhuvanChandra.DV
2015-01-29 12:13       ` Mark Brown
2015-01-29 12:13         ` Mark Brown
2015-01-29 12:13         ` Mark Brown
2015-01-29 12:53         ` BhuvanChandra.DV [this message]
2015-01-29 12:53           ` BhuvanChandra.DV
2015-01-29 18:10           ` Stefan Agner
2015-01-29 18:10             ` Stefan Agner
2015-01-29 18:10             ` Stefan Agner
2015-01-29 18:10             ` Stefan Agner
2015-01-30 12:30             ` Mark Brown
2015-01-30 12:30               ` Mark Brown

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