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From:   =?iso-8859-1?Q?Jan_Kundr=E1t?= <jan.kundrat@cesnet.cz>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     =?iso-8859-1?Q?V=E1clav_Kubern=E1t?= <kubernat@cesnet.cz>,
        Jean Delvare <jdelvare@suse.com>,
        Jonathan Corbet <corbet@lwn.net>,
        <linux-hwmon@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 2/5] hwmon: (max31790) Fix and split =?iso-8859-1?Q?pwm*=5Fenable?=
Date:   Wed, 19 May 2021 11:10:10 +0200
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> As it turns out, even the current code doesn't really work for fans 7..12.
> =09=09sr =3D get_tach_period(data->fan_dynamics[channel]);
> However, the data->fan_dynamics array has only 6 entries, not 12, so
> reading fan[7-12]_input will result in bad/random values.

Hi Guenter, I'm Vaclav's colleague. The chip can indeed reconfigure each=20
PWMOUT pin either as a PWM output or as a TACH input, but that's not=20
something that's correctly implemented in the current code, and we have no=20=

use for that either (and we cannot test that on our PCBs easily, we do not=20=

have the manufacturer's eval kit).

It looks to me that the original bug is that the current docs mention 12=20
fan inputs. Would you be OK with a patch series which fixes the docs so=20
that the chip always exports 6 TACH inputs and 6 PWMOUT channels?

Cheers,
Jan