Messages in this thread | | | Date | Fri, 27 Oct 2023 08:51:27 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v5 2/4] hwmon: max31827: Add support for max31828 and max31829 |
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On 10/27/23 08:05, Matyas, Daniel wrote: > > >> -----Original Message----- >> From: Guenter Roeck <groeck7@gmail.com> On Behalf Of Guenter Roeck >> Sent: Friday, October 27, 2023 5:52 PM >> To: Matyas, Daniel <Daniel.Matyas@analog.com> >> Cc: 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 2/4] hwmon: max31827: Add support for >> max31828 and max31829 >> >> [External] >> >> On 10/27/23 06:00, Matyas, Daniel wrote: >> [ ... ] >> >>>> I also don't understand why that would be chip specific. I don't see >>>> anything along that line in the datasheet. >>>> >>>> Ah, wait ... I guess that is supposed to reflect the chip default. >>>> I don't see why the chip default makes a difference - a well defined >>>> default must be set either way. Again, there is no guarantee that the >>>> chip is in its default state when the driver is loaded. >>> >>> The well defined default was set in v4, but I deleted it, because the >> default value in hex for max31827 and max31828 alarm polarity, and >> max31827 fault queue is 0x0. I had 2 #defines for these values, but you >> said: >>> " Since MAX31827_ALRM_POL_LOW is 0, this code doesn't really do >> anything and just pollutes the code." >>> >>> So, I thought I should remove it altogether, since res is set to 0 in the >> beginning and the default value of these chips (i.e. 0) is implicitly set. >>> >>>> >>>> Also, why are the default values added in this patch and not in the >>>> previous patch ? >>>> >>> >>> In v4 these default values were set in the previous patch. >>> >> >> I asked you (or meant to ask you) to stop overwriting 0 with 0 in a >> variable. I didn't mean to ask you (if I did) to stop writing the default value >> into the chip. Sorry if I did; if so, that was a misunderstanding. >> >> Guenter > > Well, writing the default value into res, would just overwrite 0 with 0. Should I still do it? >
No, that is not correct. You don't know what is in the chip register. It may not be the chip default.
Guenter
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