Re: [PATCH 0/3] ASoC: cs35l41/cs35l45/cs4265: sort the reg_defaults tables

On 05/08/2026 10:25 am, Charles Keepax wrote:
> On Wed, Aug 05, 2026 at 12:10:10PM +0300, Péter Ujfalusi wrote:
>> On 05/08/2026 12:00, Richard Fitzgerald wrote:
>>>>> Found by an audit of all reg_defaults tables under sound/, the SoundWire
>>>>> codec drivers are fixed by a separate series.
>>>>
>>>> Wow. Would it make sense to have a regmap helper to double-check the
>>>> addresses are indeed in-order in those reg_default tables?
>>>> I am not sure how this requirement can be enforced by just inspection, a
>>>> warning would help detect this sort of issues on more platforms.
>>>>
>>> It does seem probable that anything that relies on people just
>>> remembering to keep a large table sorted is prone to breaking,
>>> especially if the addresses are provided by named constant instead of
>>> a list of hardcoded numbers.
>>>
>>> Should regmap check the table when the regmap is first created?
>>> As it has to search the table during normal use anyway, one extra walk
>>> when the regmap is created probably isn't a serious overhead.
>>
>> But it will be done for _all_ devices which uses regmap on boot, small
>> things do add up, see my reply to Pierre-Louis.
> 
> Indeed, if we were to add some sort of auto-checker it should
> be guarded behind something like perhaps a Kconfig option or the
> DEBUG define.
> 
> Thanks,
> Charles

regcache_init() already walks the defaults table checking the stride

	for (i = 0; i < config->num_reg_defaults; i++)
		if (config->reg_defaults[i].reg % map->reg_stride)
			return -EINVAL;

so checking that each entry is larger than previous is trivial extra
overhead. I think most regmaps are cached.