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Date: Wed, 27 Nov 2013 16:14:15 +0000
From: Lee Jones <lee.jones@linaro.org>
To: Stefan Agner <stefan@agner.ch>
Cc: swarren@wwwdotorg.org, thierry.reding@gmail.com, sameo@linux.intel.com,
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Subject: Re: [PATCH 1/3] mfd: tps6586x: add version detection
Message-ID: <20131127161415.GT3296@lee--X1>
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On Wed, 27 Nov 2013, Stefan Agner wrote:

> Am 2013-11-27 16:30, schrieb Lee Jones:
> > On Wed, 27 Nov 2013, Stefan Agner wrote:
> > 
> >> Am 2013-11-27 15:36, schrieb Lee Jones:
> >> <snip>
> >> >> Perhaps I should suggest to make TPS6586X_ANY a positive number then,
> >> >> as a negative value to me indicates more of an error than a generic
> >> >> parameter.
> >> I see, its especially confusing since the version is filled using the
> >> i2c_smbus_read_byte_data functions return value. The version field is a
> >> 8-Bit value according to the data sheet, I could use 0x100 as
> >> TPS6586X_ANY identifier.
> > 
> > How far are we away from using 0xFF?
> > 
> > I'd be happy to use that and change it _if_ we ever get close.
> > 
> > If it's likely that it'll be used, then sure 0x100 sounds okay too.
> 
> Yes, I thought about 0xFF too. The latest device we support is TPS658643
> (according to data sheet release dates), which has the smallest version
> number (03). Since it seems to be a CRC (hence VERSIONCRC) the number is
> quite random. Also, 0xFF sounds like a bitmask which can mask all
> versions, but the versions can't be used bitwise... So I would prefer to
> go with 0x100.

Deal!

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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