On Fri, 03 May 2019 08:47:29 +0200, Mark Brown wrote:

...

...

...

+#define cx2072x_plbk_eq_en_info snd_ctl_boolean_mono_info

...

...

Why not just use the function directly rather than hiding it?

...

Just a standard idiom. Can be replaced if preferred.

Please.

BTW, a good reason for the style above is that it makes code more undrestandable. For defining a ctl element, typically we define three callback functions, info, get and put, in that order:

static int foo_info() { .... }

static int foo_get() { .... }

static int foo_put() { ... };

and often the actual snd_kcontrol_new table containing these callbacks appears much later, where you'd need to scroll down a few screens to read that point.

In the above, especially defining the info callback at the beginning is important. By reading foo_init() at first, readers can know which type (int, boolean, enum, etc) and the number of elements to be used in get/put callbacks beforehand. It's a commonly seen mistake, for example, that a wrong type (e.g. integer) is passed to info callback while enum type is used in the get/put.

The #define above keeps this foo_info() definition while optimizing with the standard helper. If we drop this and set snd_ctl_boolean_mono_info directly in the snd_kcontrol_new entry, you'll have to go and back the screen just to take a look at the info callback.

That's why I called it a standard idiom. It's not strictly necessary, but often help reading / reviewing the code. Though, it's just another bikeshed theme, so I'm not sticking with this style.

thanks,

Takashi