Re: [PATCH v3 18/19] hwmon: (mr75203) add debugfs to read and write temperature coefficients

[Farber, Eliav]

On 8/31/2022 3:14 PM, Andy Shevchenko wrote:
> On Tue, Aug 30, 2022 at 07:22:11PM +0000, Eliav Farber wrote:
> > This change adds debugfs to read and write temperature sensor 
> > coefficients
> > - g, h, j and cal5.
> >
> > The coefficients can vary between product and product, so it can be very
> > useful to be able to modify them on the fly during the calibration
> > process.
> >
> > e.g.:
> >
> > cat /sys/kernel/debug/940f23d0000.pvt/ts_coeff_cal5
> > 4096
> >
> > echo 83000 > sys/kernel/debug/940f23d0000.pvt/ts_coeff_g
>
> ...
>
> > +     pvt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
>
> > +     if (!pvt->dbgfs_dir) {
> > +             dev_err(dev, "Failed to create dbgfs_dir\n");
> > +             return -EINVAL;
> > +     }
>
> No, just don't check the return value of debugfs API calls.
Do you mean that I should just do:
debugfs_create_dir(dev_name(dev), NULL);
Can you please explain why it's OK to ignore the return value?

> > +     debugfs_create_file("ts_coeff_h", 0644, pvt->dbgfs_dir, pvt,
> > +                         &pvt_ts_coeff_h_fops);
> > +     debugfs_create_file("ts_coeff_g", 0644, pvt->dbgfs_dir, pvt,
> > +                         &pvt_ts_coeff_g_fops);
> > +     debugfs_create_file("ts_coeff_j", 0644, pvt->dbgfs_dir, pvt,
> > +                         &pvt_ts_coeff_j_fops);
> > +     debugfs_create_file("ts_coeff_cal5", 0644, pvt->dbgfs_dir,  pvt,
> > +                         &pvt_ts_coeff_cal5_fops);
>
> debugfs has helpers for POD types, use them and shrink your code by ~80%.
Fixed for v4.
I used debugfs_create_u32() for ts_coeff_h, ts_coeff_g and ts_coeff_j.
For ts_coeff_cal5 I still use debugfs_create_file() because I must make
sure it is not set to 0.

> > +     ret = devm_add_action_or_reset(dev, devm_pvt_ts_dbgfs_remove, 
> > pvt);
> > +     if (ret) {
> > +             dev_err(dev, "failed to add action to remove pvt dbgfs 
> > (%d)\n",
> > +                     ret);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
>
> return devm_add_...
Fixed for v4.

--
Thanks, Eliav