Re: [PATCH v2 18/18] auxdisplay: ht16k33: Add segment display LED support

Hi Marek,

On Fri, Jun 25, 2021 at 10:39 PM Marek Behun [off-list ref] wrote:

On Fri, 25 Jun 2021 14:59:02 +0200
Geert Uytterhoeven [off-list ref] wrote:

quoted

Instantiate a single LED for a segment display.  This allows the user to
control display brightness and blinking through the LED class API and
triggers, and exposes the display color.
The LED will be named "auxdisplay:<color>:backlight".

What if there are multiple "auxdisplay"s ?

I understand the LED core will just add a suffix on a name collision.

Doesn't this subsystem have IDs? So that you can use auxdisplayN for
device name, for example?

Auxdisplay does not have IDs, as there is no subsystem to register
with.  It's just a collection of drivers for auxiliary displays with
no common API.  Some drivers use fbdev, others use a chardev, or an
attribute file in sysfs.

BTW, I just followed Pavel's advice in naming.

quoted

+     of_property_read_u32(node, "color", &color);
+     seg->led.name = devm_kasprintf(dev, GFP_KERNEL,
+                     "auxdisplay:%s:" LED_FUNCTION_BACKLIGHT,
+                     color < LED_COLOR_ID_MAX ? led_colors[color] : "");

If you use devm_led_classdev_register_ext and pass struct
led_init_data, LED core will generate name of the LED itself.

Will that make any difference, except for adding more code?
Looking at the implementation, I still have to use devm_kasprintf()
to combine color and function for led_init_data.default_label?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds