From: Guenter Roeck <linux@roeck-us.net>
To: Andreas Werner <andreas.werner@men.de>, linux-kernel@vger.kernel.org
Cc: jdelvare@suse.com, lm-sensors@lm-sensors.org, wni@nvidia.com
Subject: Re: LM90 driver and ti tmp461 detection
Date: Thu, 10 Dec 2015 08:41:57 -0800 [thread overview]
Message-ID: <5669AB55.5030309@roeck-us.net> (raw)
In-Reply-To: <20151210120856.GA27765@awelinux>
On 12/10/2015 04:08 AM, Andreas Werner wrote:
> Hi,
> i have a temperature sensor device named "TI TMP461" which is quite the
> same than the tmp451 which is already included in the lm90 driver.
>
> I just want to add the tmp461 to the driver but currently i have no way
> to differ between the tmp461 and tmp451.
>
> The main different is that the tmp461 address can be configured by to Pins
> whereas the tmp451 has a fixed address.
>
> The register layout is quite the same except that the tmp461 has one
> register more (0x16 Channel Enable Register).
>
> Every zero bit is the same for both bits, so we cannot use these bits for
> identification.
>
> Does anybody of you have a tmp451 to read out the register 0x16 (which is
> not implement but i expect a value). May be we can use this to
> identify the tmp461.
>
Here is a register dump.
00: 5d 69 00 04 08 bf 00 ff 53 00 00 00 00 00 00 00 ]i.???..S.......
10: a0 00 00 00 00 f0 00 00 00 a9 00 00 00 00 00 00 ?....?...?......
20: b8 0a 01 00 00 XX 00 00 00 00 0e 00 00 00 00 00 ???..X....?.....
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 00 ..............U.
there is nothing to distinguish the two chips as far as I can see.
Is your system a devicetree system ? If so, you can just
provide a compatible statement such as
compatible = "ti,tmp461", "ti,tmp451";
or simply instantiate the chip as tmp451.
Feel free to provide a patch adding '{ "tmp461", tmp451 },'
to lm90_id as well as the necessary documentation, but I don't
think there is anything we can do to detect the chip.
On the other side, I am a bit concerned that the chip detection doesn't
work well, since the chip ID register is really unsupported and just happens
to return 0 for both chips. I wonder if there are other TI chips which may
be mis-detected as TMP451.
Thanks,
Guenter
next prev parent reply other threads:[~2015-12-10 16:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-10 12:08 LM90 driver and ti tmp461 detection Andreas Werner
2015-12-10 16:41 ` Guenter Roeck [this message]
2015-12-10 17:12 ` Andreas Werner
2015-12-10 17:43 ` Guenter Roeck
2015-12-10 18:03 ` Andreas Werner
2015-12-10 17:49 ` Guenter Roeck
2015-12-10 18:09 ` Andreas Werner
2015-12-12 10:08 ` [lm-sensors] " Jean Delvare
2015-12-15 15:11 ` Andreas Werner
2015-12-17 11:48 ` Jean Delvare
2015-12-17 11:54 ` Andreas Werner
2015-12-17 14:57 ` Guenter Roeck
2015-12-18 8:18 ` Andreas Werner
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