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SubjectRe: [PATCH v9 4/4] rtc: ds1307: add frequency_test_enable sysfs attribute to check tick on m41txx
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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@micronovasrl.com> 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

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