Re: [PATCH RFC 3/7] hwmon: (da9052) Use devm_regulator_get_enable_get_voltage()

Guenter Roeck
2024-03-28T15:20:04Z

On 3/28/24 07:20, Jonathan Cameron wrote:
> On Wed, 27 Mar 2024 18:18:52 -0500
> David Lechner <dlechner@baylibre.com> wrote:
>
>> We can reduce boilerplate code by using
>> devm_regulator_get_enable_get_voltage().
>>
>> Signed-off-by: David Lechner <dlechner@baylibre.com>
>
> A few comments inline, but nothing substantial.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> ---
>> drivers/hwmon/da9052-hwmon.c | 33 +++++++--------------------------
>> 1 file changed, 7 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/hwmon/da9052-hwmon.c b/drivers/hwmon/da9052-hwmon.c
>> index 2bd7ae8100d7..70e7bc72e980 100644
>> --- a/drivers/hwmon/da9052-hwmon.c
>> +++ b/drivers/hwmon/da9052-hwmon.c
>> @@ -26,7 +26,6 @@ struct da9052_hwmon {
>> struct mutex hwmon_lock;
>> bool tsi_as_adc;
>> int tsiref_mv;
>> - struct regulator *tsiref;
>> struct completion tsidone;
>> };
>>
>> @@ -414,32 +413,19 @@ static int da9052_hwmon_probe(struct platform_device *pdev)
>> device_property_read_bool(pdev->dev.parent, "dlg,tsi-as-adc");
>>
>> if (hwmon->tsi_as_adc) {
>> - hwmon->tsiref = devm_regulator_get(pdev->dev.parent, "tsiref");
>> - if (IS_ERR(hwmon->tsiref)) {
>> - err = PTR_ERR(hwmon->tsiref);
>> - dev_err(&pdev->dev, "failed to get tsiref: %d", err);
>> + err = devm_regulator_get_enable_get_voltage(pdev->dev.parent,
>> + "tsiref");
>> + if (err < 0)
>> return err;
>> - }
>> -
>> - err = regulator_enable(hwmon->tsiref);
>> - if (err)
>> - return err;
>> -
>> - hwmon->tsiref_mv = regulator_get_voltage(hwmon->tsiref);
>> - if (hwmon->tsiref_mv < 0) {
>> - err = hwmon->tsiref_mv;
>> - goto exit_regulator;
>> - }
>>
>> /* convert from microvolt (DT) to millivolt (hwmon) */
>> - hwmon->tsiref_mv /= 1000;
>> + hwmon->tsiref_mv = err / 1000;
>>
>
> Using a variable called err for a good value is a bit ugly but fair enough if that
> is precedence in this driver.
>

It isn't. The existing code assigns the return value from regulator_get_voltage()
to hwmon->tsiref_mv and then evaluates it. I would not oppose introducing a variable
such as tsiref_uv, but not the misuse of 'err'. I am not going to accept the code
as suggested. It is bad style, and it would invite others to use it as precedent
when trying to introduce similar code.

>> }
>> @@ -483,10 +466,8 @@ static void da9052_hwmon_remove(struct platform_device *pdev)
>> {
>> struct da9052_hwmon *hwmon = platform_get_drvdata(pdev);
>>
>> - if (hwmon->tsi_as_adc) {
>> + if (hwmon->tsi_as_adc)
>> da9052_free_irq(hwmon->da9052, DA9052_IRQ_TSIREADY, hwmon);
> Superficially looks like devm_da9052_request_irq could be added that
> uses devm_request_threaded_irq() to allow dropping this remaining handling.
>

That should be a separate series of patches. A local solution might be
to use devm_add_action_or_reset(), but that should also be a separate patch.

Thanks,
Guenter