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From: Marek Vasut <marex@denx.de>
To: Mark Brown <broonie@kernel.org>
Cc: devicetree@vger.kernel.org, shawn.guo@linaro.org,
	b44548@freescale.com, dedekind1@gmail.com, b18965@freescale.com,
	linux-spi@vger.kernel.org, Huang Shijie <b32955@freescale.com>,
	linux-mtd@lists.infradead.org, kernel@pengutronix.de,
	Brian Norris <computersforpeace@gmail.com>,
	dwmw2@infradead.org, wangyuhang <wangyuhang2014@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V1 3/5] mtd: m25p80: add the quad-read support
Date: Thu, 22 Aug 2013 22:29:01 +0200	[thread overview]
Message-ID: <201308222229.01778.marex@denx.de> (raw)
In-Reply-To: <20130822195559.GU26118@sirena.org.uk>

Dear Mark Brown,

> On Thu, Aug 22, 2013 at 12:34:53PM -0700, Brian Norris wrote:
> > On Mon, Aug 19, 2013 at 12:10:01PM +0800, Huang Shijie wrote:
> > > +- m25p,quad-read : Use the "quad read" opcode to read data from the
> > > chip instead +                   of the usual "read" opcode. This
> > > opcode is not supported by +                   all chips and support
> > > for it can not be detected at runtime. +                   Refer to
> > > your chips' datasheet to check if this is supported +                 
> > >  by your chip.
> > 
> > Why can't this be detected at runtime? We added a "no fast read" flag to
> > the device table, so why not "dual/quad mode supported"? And believe it
> > or not, not all m25p80 users have device tree. So it isn't very logical
> > to tie this support to device-tree only.
> 
> There needs to be some way of saying if the additional data lines are
> actually wired up or not; it could be a negative property (flagging if
> the lines are not present) but that runs the risk of breaking systems
> if a driver acquires the ability to support extra data lines but a
> system doesn't have it.
> 
> This should be a generic property for all quad devices to use, though,
> since the same thing applies everywhere.

Full ACK, "m25p,dual-read" and "m25p,quad-read" sound like a good prop names?

Best regards,
Marek Vasut

WARNING: multiple messages have this Message-ID (diff)
From: marex@denx.de (Marek Vasut)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V1 3/5] mtd: m25p80: add the quad-read support
Date: Thu, 22 Aug 2013 22:29:01 +0200	[thread overview]
Message-ID: <201308222229.01778.marex@denx.de> (raw)
In-Reply-To: <20130822195559.GU26118@sirena.org.uk>

Dear Mark Brown,

> On Thu, Aug 22, 2013 at 12:34:53PM -0700, Brian Norris wrote:
> > On Mon, Aug 19, 2013 at 12:10:01PM +0800, Huang Shijie wrote:
> > > +- m25p,quad-read : Use the "quad read" opcode to read data from the
> > > chip instead +                   of the usual "read" opcode. This
> > > opcode is not supported by +                   all chips and support
> > > for it can not be detected at runtime. +                   Refer to
> > > your chips' datasheet to check if this is supported +                 
> > >  by your chip.
> > 
> > Why can't this be detected at runtime? We added a "no fast read" flag to
> > the device table, so why not "dual/quad mode supported"? And believe it
> > or not, not all m25p80 users have device tree. So it isn't very logical
> > to tie this support to device-tree only.
> 
> There needs to be some way of saying if the additional data lines are
> actually wired up or not; it could be a negative property (flagging if
> the lines are not present) but that runs the risk of breaking systems
> if a driver acquires the ability to support extra data lines but a
> system doesn't have it.
> 
> This should be a generic property for all quad devices to use, though,
> since the same thing applies everywhere.

Full ACK, "m25p,dual-read" and "m25p,quad-read" sound like a good prop names?

Best regards,
Marek Vasut

  reply	other threads:[~2013-08-22 20:29 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-19  4:09 [PATCH V1 0/5] Add the Quadspi driver for vf610-twr Huang Shijie
2013-08-19  4:09 ` Huang Shijie
2013-08-19  4:09 ` [PATCH V1 1/5] mtd: m25p80: move the spi-nor commands to a header Huang Shijie
2013-08-19  4:09   ` Huang Shijie
2013-08-19  4:10 ` [PATCH V1 2/5] mtd: m25p80: add support for Spansion s25fl128s chip Huang Shijie
2013-08-19  4:10   ` Huang Shijie
2013-08-19  4:10 ` [PATCH V1 3/5] mtd: m25p80: add the quad-read support Huang Shijie
2013-08-19  4:10   ` Huang Shijie
2013-08-22 19:34   ` Brian Norris
2013-08-22 19:34     ` Brian Norris
2013-08-22 19:55     ` Mark Brown
2013-08-22 19:55       ` Mark Brown
2013-08-22 20:29       ` Marek Vasut [this message]
2013-08-22 20:29         ` Marek Vasut
2013-08-22 23:36         ` Mark Brown
2013-08-22 23:36           ` Mark Brown
2013-08-22 23:58           ` Marek Vasut
2013-08-22 23:58             ` Marek Vasut
2013-08-23  9:41             ` Mark Brown
2013-08-23  9:41               ` Mark Brown
2013-08-23 10:42               ` Marek Vasut
2013-08-23 10:42                 ` Marek Vasut
2013-08-23 11:46               ` Brian Norris
2013-08-23 11:46                 ` Brian Norris
2013-08-23 11:53                 ` Brian Norris
2013-08-23 11:53                   ` Brian Norris
2013-08-23 12:01                   ` Mark Brown
2013-08-23 12:01                     ` Mark Brown
2013-08-23 13:20                   ` yuhang wang
2013-08-23 13:20                     ` yuhang wang
2013-08-23  6:26       ` Huang Shijie
2013-08-23  6:26         ` Huang Shijie
2013-08-23 11:23       ` Brian Norris
2013-08-23 11:23         ` Brian Norris
2013-08-23 11:27         ` Sourav Poddar
2013-08-23 11:27           ` Sourav Poddar
2013-08-23 11:30         ` Mark Brown
2013-08-23 11:30           ` Mark Brown
2013-08-23  9:05   ` yuhang wang
2013-08-23  9:05     ` yuhang wang
2013-08-23  9:25     ` Huang Shijie
2013-08-23  9:25       ` Huang Shijie
2013-08-23  9:57       ` Sourav Poddar
2013-08-23  9:57         ` Sourav Poddar
2013-08-24  2:45         ` Huang Shijie
2013-08-24  2:45           ` Huang Shijie
2013-08-23 15:59           ` Sourav Poddar
2013-08-23 15:59             ` Sourav Poddar
2013-08-23 13:59       ` yuhang wang
2013-08-23 13:59         ` yuhang wang
2013-08-24  3:01         ` Huang Shijie
2013-08-24  3:01           ` Huang Shijie
2013-08-19  4:10 ` [PATCH V1 4/5] spi: Add Freescale QuadSpi driver Huang Shijie
2013-08-19  4:10   ` Huang Shijie
2013-08-22 19:21   ` Brian Norris
2013-08-22 19:21     ` Brian Norris
2013-08-23  2:14     ` Huang Shijie
2013-08-23  2:14       ` Huang Shijie
2013-08-23  6:59     ` Huang Shijie
2013-08-23  6:59       ` Huang Shijie
2013-08-23 16:44   ` Mark Brown
2013-08-23 16:44     ` Mark Brown
2013-08-24  7:11     ` Brian Norris
2013-08-24  7:11       ` Brian Norris
2013-08-24 13:42     ` Huang Shijie
2013-08-24 13:42       ` Huang Shijie
2013-08-19  4:10 ` [PATCH V1 5/5] ARM: dts: vf610-twr: Add SPI NOR support Huang Shijie
2013-08-19  4:10   ` Huang Shijie

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