Messages in this thread | | | Subject | Re: [PATCH v2 3/3] hwmon: ltc2990: support all measurement modes | From | Mike Looijmans <> | Date | Thu, 29 Jun 2017 09:45:32 +0200 |
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On 28-06-17 19:02, Tom Levens wrote: > > On Wed, 28 Jun 2017, Guenter Roeck wrote: > >> On Wed, Jun 28, 2017 at 05:29:38PM +0200, Tom Levens wrote: >>> >> [ ... ] >> >>>> >>>>> Whatever happened to this patch though? It didn't make it to mainline, >>>>> otherwise I'd have found it sooner... >>>>> >>>> I'll have to look it up, but I guess I didn't get an updated version. >>> >>> As far as I remember I had a working V3 of this patch, but it is entirely >>> possible that it was never submitted as I have been busy with other projects >>> recently. I'll dig it out and check that it is complete. >>> >> FWIW, I don't see it at >> https://patchwork.kernel.org/project/linux-hwmon/list/?submitter=171225&state=* >> >> Maybe you were waiting for a reply from Rob. Either case, it might make >> sense to only provide valid modes, ie to abstract the mode bits from the >> hardware, such as >> >> 0 - internal temp only >> 1 - Tr1 >> 2 - V1 >> 3 - V1-V2 >> 4 - Tr2 >> 5 - V3 >> 6 - V3-V4 >> 7 to 14 - per bit 0..2 >> >> Guenter >> > > You are right, there was still an open question about how best to handle the > mode selection in DT. > > In the latest version of my patch I have it implemented as an array for > setting the two values, for example: > > lltc,meas-mode = <7 3>; > > This sets bits [2..0] = 7 and [4..3] = 3. Of course these could be split into > two DT properties, but I was unsure what to name them as both fields are > called "mode" in the datasheet and "mode-43"/"mode-20" (or similar) is ugly. > > With regards to your proposal, it is not clear to me whether the modes which > have the same result are exactly equivalent. Does disabling a measurement with > the mode[4..3] bits really leaves the part in a safe state for all possible HW > connections? With this doubt in my head, I would prefer to keep the option > available to the user to select any specific mode. But I am open to suggestions. > > Mike, if you would like to test it, the latest version of my code is here: > > https://github.com/levens/ltc2990/blob/dev/drivers/hwmon/ltc2990.c >
I pulled your patches, added two lines to the devicetree and it works fine, I'm seeing plausible results: root@topic-miami:/sys/class/hwmon# grep . */* hwmon0/name:battery-gauge hwmon0/temp1_input:291700 hwmon1/in0_input:3258 hwmon1/in1_input:1824 hwmon1/in2_input:1916 hwmon1/in3_input:1512 hwmon1/in4_input:2066 hwmon1/name:ltc2990 hwmon1/temp1_input:28062 hwmon1/uevent:OF_NAME=ltc2990 hwmon1/uevent:OF_FULLNAME=/gpios-i2c@50/ltc2990@4c hwmon1/uevent:OF_COMPATIBLE_0=lltc,ltc2990 hwmon1/uevent:OF_COMPATIBLE_N=1 hwmon2/curr1_input:1825 hwmon2/curr2_input:349 hwmon2/in0_input:3244 hwmon2/name:ltc2990 hwmon2/temp1_input:31500 hwmon2/uevent:OF_NAME=ltc2990 hwmon2/uevent:OF_FULLNAME=/gpios-i2c@52/ltc2990@4C hwmon2/uevent:OF_COMPATIBLE_0=ltc2990 hwmon2/uevent:OF_COMPATIBLE_N=1
As you can see, two ltc2990 on two busses, one measuring current and one measuring 4 independent voltages.
I also like your implementation of the mode setting better, it's much simpler than mine. And you've solved a bug in the temperature reading as well.
Kind regards,
Mike Looijmans System Expert
TOPIC Products Materiaalweg 4, NL-5681 RJ Best Postbus 440, NL-5680 AK Best Telefoon: +31 (0) 499 33 69 79 E-mail: mike.looijmans@topicproducts.com Website: www.topicproducts.com
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