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Date:   Wed, 19 Apr 2023 14:46:58 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Dinh Nguyen <dinh.nguyen@linux.intel.com>
Cc:     Guenter Roeck <linux@roeck-us.net>, linux-hwmon@vger.kernel.org,
        dinguyen@kernel.org, devicetree@vger.kernel.org,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        linux-kernel@vger.kernel.org, jdelvare@suse.com
Subject: Re: [PATCH 3/5] hwmon: (socfpga) Add hardware monitoring support on
 SoCFPGA platforms
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On Tue, Apr 18, 2023 at 12:29:40PM -0500, Dinh Nguyen wrote:
> On 4/17/2023 4:51 PM, Guenter Roeck wrote:
> > On 4/17/23 13:55, Dinh Nguyen wrote:

...

> > ... and this contradict each other. If bit 31 indicates an error,
> > this can not be a signed 32-bit value.
> > 
> You're right! I've re-read the spec and should have the the code look for
> the specific error values:
> 
> 0x80000000 - inactive
> 0x80000001 - old value
> 0x80000002 - invalid channel
> 0x80000003 -? corrupted.

No, they are not hex. Probably you need to define an error space with it, but
at least just use signed _decimal_ values.

Instead of BIT(31) this should go as

#define ..._ERR_BASE   INT_MIN // or equivalent if the type is not int
#define ..._ERR_MAX ... // or whatever name is better

Then in your code

	if (value >= _ERR_MAX)
		return 0;

	err = _ERR_MAX - value;
	switch (err) {
		...
	}

P.S. I asked during internal review if the values are bit fielded when errors.
AFAIU that time they are, now it seems different.

-- 
With Best Regards,
Andy Shevchenko