Re: [PATCH v1 11/30] drm/tegra: dc: Support OPP and SoC core voltage scaling

[Dmitry Osipenko]

10.11.2020 23:29, Thierry Reding пишет:
>> +
>> +	dc->opp_table = dev_pm_opp_get_opp_table(dc->dev);
>> +	if (IS_ERR(dc->opp_table))
>> +		return dev_err_probe(dc->dev, PTR_ERR(dc->opp_table),
>> +				     "failed to prepare OPP table\n");
>> +
>> +	if (of_machine_is_compatible("nvidia,tegra20"))
>> +		hw_version = BIT(tegra_sku_info.soc_process_id);
>> +	else
>> +		hw_version = BIT(tegra_sku_info.soc_speedo_id);
>> +
>> +	hw_opp_table = dev_pm_opp_set_supported_hw(dc->dev, &hw_version, 1);
>> +	err = PTR_ERR_OR_ZERO(hw_opp_table);
> What's the point of this? A more canonical version would be:
> 
> 	if (IS_ERR(hw_opp_table)) {
> 		err = PTR_ERR(hw_opp_table);
> 		dev_err(dc->dev, ...);
> 		goto put_table;
> 	}
> 
> That uses the same number of lines but is much easier to read, in my
> opinion, because it is the canonical form.
> 

Your variant is much more difficult to read for me :/

I guess the only reason it could be "canonical" is because
PTR_ERR_OR_ZERO was added not so long time ago.

But don't worry, this code will be moved out in a v2 and it won't use
PTR_ERR_OR_ZERO.