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From: Scott Wood <scottwood@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 3/4] mtd: nand: add Freescale NFC driver
Date: Wed, 13 Aug 2014 17:54:53 -0500	[thread overview]
Message-ID: <1407970493.7427.192.camel@snotra.buserror.net> (raw)
In-Reply-To: <8761hwkqtq.fsf@nbsps.com>

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.

-Scott

  reply	other threads:[~2014-08-13 22:54 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 [this message]
2014-08-14 14:26                 ` Bill Pringlemeir
2014-08-06  8:59 ` [U-Boot] [PATCH 4/4] arm: vf610: add NAND support for vf610twr Stefan Agner

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