From: Timur Tabi <timur@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Odd value for I2C_TIMEOUT in fsl_i2c.c
Date: Fri, 04 Sep 2009 13:39:26 -0500 [thread overview]
Message-ID: <4AA15EDE.6080706@freescale.com> (raw)
In-Reply-To: <20090904183024.67AAA832E8DE@gemini.denx.de>
Wolfgang Denk wrote:
> Probably not. If you place a read request to a slow device it may
> take tens of milliseconds, or even longer - I have no idea. IIRC we
> had a box with a LCD display connected over I2C, which didn't ent
> into production as originally designed because writing the content
> took over 100 millisec.
Well, that's an extreme case that is board-specific. Perhaps I should do this:
#ifndef CONFIG_I2C_TIMEOUT
#define CONFIG_I2C_TIMEOUT 1000
#endif
Keep in mind that so far, the number 250 has been good enough for every board to date. Why my current board is happier with 500 is a mystery to me.
Also, should we be using the same value for the timeout in i2c_wait4bus() and i2c_wait()? It looks like i2c_wait() should have a much shorter timeout than i2c_wait4bus()?
--
Timur Tabi
Linux kernel developer at Freescale
next prev parent reply other threads:[~2009-09-04 18:39 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-03 15:22 [U-Boot] Odd value for I2C_TIMEOUT in fsl_i2c.c Timur Tabi
2009-09-04 7:16 ` Heiko Schocher
2009-09-04 9:25 ` Wolfgang Denk
2009-09-04 14:09 ` Timur Tabi
2009-09-04 15:01 ` Wolfgang Denk
2009-09-04 15:12 ` Timur Tabi
2009-09-04 15:28 ` Peter Tyser
2009-09-04 15:30 ` Timur Tabi
2009-09-04 16:04 ` Peter Tyser
2009-09-04 18:30 ` Wolfgang Denk
2009-09-04 18:39 ` Timur Tabi [this message]
2009-09-04 19:28 ` Wolfgang Denk
2009-09-04 18:28 ` Wolfgang Denk
2009-09-04 15:29 ` Wolfgang Denk
2009-09-04 18:34 ` Scott Wood
2009-09-04 19:23 ` Wolfgang Denk
2009-09-04 19:28 ` Scott Wood
2009-09-04 8:31 ` Wolfgang Denk
2009-09-04 18:36 ` Scott Wood
2009-09-04 19:27 ` Wolfgang Denk
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