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From: Thibaut Dambry <tdambry@atysmedical.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: redirect stdout
Date: Wed, 04 Jun 2014 18:11:00 +0200	[thread overview]
Message-ID: <538F4514.7050501@atysmedical.com> (raw)
In-Reply-To: <20140604101942.GF15686@pengutronix.de>

Thank you for your answer

I would use the eeprom to change linux bootargs parameters.
So the best way is to create a command isUsbDevice (where I read eeprom 
value and return 0 if OK )
and add this in a boot shell script:

#!/bin/sh
isUsbDevice
if [ $? -ne 0 ]; then
     bootargs="$bootargs pcm043_otg_mode=host"
else
     bootargs="$bootargs pcm043_otg_mode=device"
fi



Le 04/06/2014 12:19, Sascha Hauer a écrit :
> On Wed, Jun 04, 2014 at 11:25:38AM +0200, Thibaut Dambry wrote:
>> Hello
>>
>> I'm sorry if it is a dummy question, but I don't find a answer.
>> I would like do that in a barebox hush shell:
>>
>> value=`i2c_read -a 0x52 -b 0 -r 0x01 -c 1`
>>
>> But the shell don't interpret the ``.
>>
>> Is there a method to do that ?
> There is no redirection of any kind in barebox and this is not trivial
> to implement.
>
> You are trying to read a i2c register into a variable. This is not
> possible with the current implementation of the i2c command. Some
> commands work around this by adding a commandline parameter which lets
> you specify a variable in which the result is written, see for example
> the readline command. The i2c_read command could be extended similarly.
>
> OTOH most of the time this comes up it is better to implement a proper
> driver for the device. In case it's an EEPROM you're trying to access
> here you also better write C Code to interpret its content. This kind
> of shell parsing is often very fragile.
>
>> Thank you for this exciting software, I would contribute but I'm a
>> little intimidate by the great quality of hackers in this list.
> C'mon, we do not bite ;)
>
> Sascha
>


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Thibaut DAMBRY

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  reply	other threads:[~2014-06-04 16:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-04  9:25 Thibaut Dambry
2014-06-04 10:19 ` Sascha Hauer
2014-06-04 16:11   ` Thibaut Dambry [this message]
2014-06-05  5:47     ` Sascha Hauer

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