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From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] fsl: verify writes to the MAC address EEPROM
Date: Mon, 02 Aug 2010 23:11:21 +0200	[thread overview]
Message-ID: <20100802211121.2501FD3CE46@gemini.denx.de> (raw)
In-Reply-To: <4C57336E.7050704@freescale.com>

Dear Timur Tabi,

In message <4C57336E.7050704@freescale.com> you wrote:
> Wolfgang Denk wrote:
> > Why is this i2c_read() needed or actually useful? Should the error
> > return code from the i2c_write() above not be sufficient indication
> > that the writing failed?  If that was the case, then some other parts
> > of the code need fixing.
> 
> That's just the way the EEPROM chip works.  When it's set into write-protect
> mode, it cheerfully accepts all of the I2C write commands, and acknowledges
> them appropriately, but it doesn't actually store the data into the EEPROM.
>  The read-back is the only way I've found to verify that the write has
> actually occurred.

Is it correct to assume the the WP signal is connected to some GPIO
pin which can be set / unset in software?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Lots of folks confuse bad management with destiny.   -- Frank Hubbard

  reply	other threads:[~2010-08-02 21:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-02 18:03 [U-Boot] [PATCH] fsl: verify writes to the MAC address EEPROM Timur Tabi
2010-08-02 21:02 ` Wolfgang Denk
2010-08-02 21:06   ` Timur Tabi
2010-08-02 21:11     ` Wolfgang Denk [this message]
2010-08-02 21:14       ` Timur Tabi
2010-08-02 22:12         ` Wolfgang Denk
2010-08-02 22:44           ` Timur Tabi
2010-09-30 13:35 ` Kumar Gala

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