Messages in this thread | | | Date | Wed, 19 Oct 2022 15:50:24 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH] hwmon: (jc42) Restore the min/max/critical temperatures on resume |
| |
On 10/19/22 15:03, Martin Blumenstingl wrote: > Hi Guenter, > > Thank you for the quick feedback! > > On Wed, Oct 19, 2022 at 11:51 PM Guenter Roeck <linux@roeck-us.net> wrote: > [...] >>> + if (data->valid || data->temp[t_min]) >> >> This contradicts "with applying the previous values by only configuring >> them if they are known valid". It explicitly applies the values if they >> are marked as not valid, and it also applies the values if they are 0 >> (I don't really see the value of doing that). >> >> Sorry, I don't understand the logic. Did you mean to use "&&" instead >> of "||" ? > My understanding is that that: > 1) data->valid = true is only set in jc42_update_device() (which is > only called when reading back the values from the registers) > 2) jc42_write() can write values without setting data->value = true > In other words: if jc42_read() is never called but jc42_write() is > then we still have some setting to apply while data->valid is false. > Whether that's possible in reality is something that I'm not sure > about. >
The above only means that the code is not optimized for the problem you are trying to solve.
- Calling jc42_update_device() would solve the valid problem. - Calling jc42_update_device() from the write function would solve it as well.
Relying on a previous call to the write function is most definitely wrong.
Also, for optimization, jc42_update_device() should really read the limit registers only once. The best solution would probably be to convert the driver to use regmap and let regmap handle the caching.
Guenter
> If your suggestion is to simplify this to use data->valid only then I > can do that. > It would be great if you could also comment on whether > jc42_update_device() should be called from jc42_suspend() to give the > driver the chance to at least read the data once (and set data->valid) > if this has not happened before. > > > Best regards, > Martin
| |