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From: Bill Pringlemeir <bpringlemeir@nbsps.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 3/4] mtd: nand: add Freescale NFC driver
Date: Thu, 14 Aug 2014 10:26:12 -0400	[thread overview]
Message-ID: <871tsjkv0b.fsf@nbsps.com> (raw)
In-Reply-To: <1407970493.7427.192.camel@snotra.buserror.net> (Scott Wood's message of "Wed, 13 Aug 2014 17:54:53 -0500")

On 13 Aug 2014, scottwood at freescale.com wrote:

> On Wed, 2014-08-13 at 17:44 -0400, Bill Pringlemeir wrote:
>> Regarding "can't know in advance", I think that some of the register
>> values maybe set by the boot rom.  This might make more sense for
>> Linux than U-Boot.  However, after the initial configuration, many do
>> need the 'read/modify/write' as there are many bit fields with
>> different functionality.

> If the register is only modified by software, and not asynchronously
> by hardware, then you could read the value once when the driver
> starts, and cache its value to avoid a reportedly expensive I/O access
> every time you need to modify it.

Yes, that is a good point.  The regmap interface could be used in the
Linux kernel.  I don't see any infrastructure like that in U-Boot?  It
is fairly simple to re-invent as this driver only needs the flat
structure.

Regards,
Bill Pringlemeir.

  reply	other threads:[~2014-08-14 14:26 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-06  8:59 [U-Boot] [PATCH 0/4] arm: vf610: add NAND flash support Stefan Agner
2014-08-06  8:59 ` [U-Boot] [PATCH 1/4] arm: vf610: add NFC pin mux Stefan Agner
2014-08-30 15:14   ` [U-Boot] [U-Boot,1/4] " Tom Rini
2014-08-06  8:59 ` [U-Boot] [PATCH 2/4] arm: vf610: add NFC clock support Stefan Agner
2014-08-30 15:14   ` [U-Boot] [U-Boot,2/4] " Tom Rini
2014-08-06  8:59 ` [U-Boot] [PATCH 3/4] mtd: nand: add Freescale NFC driver Stefan Agner
2014-08-06 23:01   ` Bill Pringlemeir
2014-08-11 22:33   ` Scott Wood
2014-08-12 21:13     ` Stefan Agner
2014-08-12 22:17       ` Scott Wood
2014-08-12 22:58         ` Bill Pringlemeir
2014-08-13  8:13           ` Stefan Agner
2014-08-13 11:20           ` Stefan Agner
2014-08-13 15:14             ` Bill Pringlemeir
2014-08-13 16:27               ` Stefan Agner
2014-08-13 17:11                 ` Bill Pringlemeir
2014-08-13 20:32             ` Scott Wood
2014-08-13 20:41           ` Scott Wood
2014-08-13 21:44             ` Bill Pringlemeir
2014-08-13 22:54               ` Scott Wood
2014-08-14 14:26                 ` Bill Pringlemeir [this message]
2014-08-06  8:59 ` [U-Boot] [PATCH 4/4] arm: vf610: add NAND support for vf610twr Stefan Agner

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