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Date:   Wed, 1 Nov 2023 09:39:12 -0500
From:   Patrick Williams <patrick@stwcx.xyz>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>,
        Jean Delvare <jdelvare@suse.com>, linux-hwmon@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] hwmon: emc1403: Add support for EMC1442
Message-ID: <ZUJjELqcTvxpWPTv@heinlein.vulture-banana.ts.net>
References: <20231031085807.618827-1-Delphine_CC_Chiu@wiwynn.com>
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On Tue, Oct 31, 2023 at 09:57:28PM -0700, Guenter Roeck wrote:
> On 10/31/23 19:27, Patrick Williams wrote:
> > On Tue, Oct 31, 2023 at 04:01:10PM -0700, Guenter Roeck wrote:
> >> On Tue, Oct 31, 2023 at 04:58:06PM +0800, Delphine CC Chiu wrote:
> >>> Add support for EMC1442 which is compatible with EMC1403.
> >>>
> >>
> >> Unfortunately, almost no information is available about this chip
> >> except that it ships in an 8-pin package. Are you sure the chip
> >> supports two external temperature sensors like EMC1403 ?
> >> The chip numbering and the number of pins would suggest that
> >> it only supports a single external temperature sensor,
> >> which would make it compatible to emc1402/emc1422.
> >>
> >> Guenter
> >=20
> > The datasheet I've seen says:
> >=20
> >>> The EMC1442 monitors two temperature channels (one
> >>> external and one internal).
> >=20
> > Based on this, I agree that emc1403 seems wrong.  The datasheet also
> > says:
> >=20
> >>> Pin compatible with EMC1412
> >=20
> >>
> >>> Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>
> >>> ---
> >>>   	{ "emc1422", emc1402 },
> >>>   	{ "emc1423", emc1403 },
> >>>   	{ "emc1424", emc1404 },
> >>> +	{ "emc1442", emc1403 },
> >=20
> > So, emc1402?
> >=20
>=20
> At the very least, if you are willing to confirm that formally
> if/when v2 is submitted.

Yes, I will confirm from the copy of the datasheet I have available
when v2 comes up.

> I previously rejected a similar patch adding emc1444 because it was
> impossible to get a datasheet to confirm that the chips are really
> register compatible. No idea why that has to be so secretive. It is a
> temperature sensor, for heaven's sake :-(

Delphine, could you reach out to the chip vendor and find out if they
are willing to publish a datasheet for this chip?  They might not have
updated their website yet because EMC1442 shows up on Microchip's site
but it has almost no information.

--=20
Patrick Williams

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