Re: [PATCH v9 4/4] rtc: ds1307: add frequency_test_enable sysfs attribute to check tick on m41txx

[Giulio Benetti]

Hi Andy,

Il 18/07/2018 14:47, Andy Shevchenko ha scritto:
> On Wed, Jul 18, 2018 at 12:40 PM, Giulio Benetti
> <giulio.benetti@xxxxxxxxxxxxxxxx> wrote:
> > On m41txx you can enable open-drain OUT pin to check if offset is ok.
> > Enabling OUT pin with frequency_test_enable attribute, OUT pin will tick
> > 512 times faster than 1s tick base.
> >
> > Enable or Disable FT bit on CONTROL register if freq_test is 1 or 0.
>
> > +static ssize_t frequency_test_enable_store(struct device *dev,
> > +                                          struct device_attribute *attr,
> > +                                          const char *buf, size_t count)
> > +{
> > +       struct ds1307 *ds1307 = dev_get_drvdata(dev);
>
>
> > +       bool freq_test_en = 0;
>
> First of all, initialization of boolean using int is not very best style.
> Second, this is not needed.

Ok I remove initialization.

> > +       int ret;
> > +
> > +       ret = kstrtobool(buf, &freq_test_en);
>
> > +       if (ret == -EINVAL) {
>
> What kind of other error code you may expect and why they are not
> considered as no error?

According to documentation, kstrtobool can only fail with -EINVAL.
See:
https://elixir.bootlin.com/linux/v4.18-rc5/source/lib/kstrtox.c#L332

> > +               dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
> > +               return ret;
> > +       }
> > +
> > +       regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
> > +                          freq_test_en ? M41TXX_BIT_FT : 0);
> > +
> > +       return count;
> > +}
> > +
> > +static ssize_t frequency_test_enable_show(struct device *dev,
> > +                                         struct device_attribute *attr,
> > +                                         char *buf)
> > +{
> > +       struct ds1307 *ds1307 = dev_get_drvdata(dev);
> > +       unsigned int ctrl_reg;
> > +
> > +       regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
> > +
>
> > +       if (ctrl_reg & M41TXX_BIT_FT)
> > +               return scnprintf(buf, PAGE_SIZE, "on\n");
> > +       else
> > +               return scnprintf(buf, PAGE_SIZE, "off\n");
>
> Entire condition might be one line.

Right, I change it.

> > +}
> > +
>
> > +static int ds1307_add_frequency_test(struct ds1307 *ds1307)
> > +{
>
> > +       int err = 0;
>
> Redundant assignment. See below.

Ok.

> > +
> > +       switch (ds1307->type) {
> > +       case m41t0:
> > +       case m41t00:
> > +       case m41t11:
> > +               /* Export sysfs entries */
> > +               err = sysfs_create_group(&(ds1307->dev)->kobj,
> > +                                        &rtc_freq_test_attr_group);
> > +               if (err) {
> > +                       dev_err(ds1307->dev,
> > +                               "Failed to create sysfs group: %d\n",
> > +                               err);
> > +                       return err;
> > +               }
> > +
> > +               err = devm_add_action_or_reset(ds1307->dev,
> > +                                              rtc_calib_remove_sysfs_group,
> > +                                              ds1307->dev);
> > +               if (err) {
> > +                       dev_err(ds1307->dev,
> > +                               "Failed to add sysfs cleanup action: %d\n",
> > +                               err);
> > +                       sysfs_remove_group(&(ds1307->dev)->kobj,
> > +                                          &rtc_freq_test_attr_group);
> > +                       return err;
> > +               }
> > +               break;
> > +       default:
> > +               break;
> > +       }
> > +
>
> > +       return err;
>
> return 0;

Ok.

Thanks

Giulio