Re: [PATCH v4 19/19] auxdisplay: ht16k33: Add LED support

From: Randy Dunlap
Date: Tue Jul 27 2021 - 17:05:11 EST


On 7/27/21 7:04 AM, Geert Uytterhoeven wrote:
> Instantiate a single LED based on the "led" subnode in DT.
> This allows the user to control display brightness and blinking (backed
> by hardware support) through the LED class API and triggers, and exposes
> the display color. The LED will be named
> "auxdisplay:<color>:<function>".
>
> When running in dot-matrix mode and if no "led" subnode is found, the
> driver falls back to the traditional backlight mode, to preserve
> backwards compatibility.
>
> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> ---
> v4:
> - Add missing select LEDS_CLASS,
>
> v3:
> - Remove unneeded C++ comment,
> - Use "err" instead of "error" to be consistent with existing driver
> naming style,
> - Make the creation of the LED device dependent on the presence of the
> "led" subnode in DT, so it can be used in dot-matrix mode too.
> - Use led_init_data() and devm_led_classdev_register_ext() to retrieve
> all LED properties from DT, instead of manual LED name construction
> based on just the "color" property,
>
> v2:
> - Use "auxdisplay" instead of DRIVER_NAME in LED name.

Hi Geert,

Since LEDS_CLASS depends on NEW_LEDS, does this also need to
select NEW_LEDS?

and similar for INPUT_MATRIXKMAP: it depends on INPUT.

However, selecting (enabling) an entire subsystem is not a
preferable thing to do.

> ---
> drivers/auxdisplay/Kconfig | 1 +
> drivers/auxdisplay/ht16k33.c | 124 ++++++++++++++++++++++++++++++-----
> 2 files changed, 108 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
> index 42fc7b155de09dbc..7436b9a4edbe5450 100644
> --- a/drivers/auxdisplay/Kconfig
> +++ b/drivers/auxdisplay/Kconfig
> @@ -176,6 +176,7 @@ config HT16K33
> select FB_SYS_IMAGEBLIT
> select INPUT_MATRIXKMAP
> select FB_BACKLIGHT
> + select LEDS_CLASS
> select LINEDISP
> help
> Say yes here to add support for Holtek HT16K33, RAM mapping 16*8

thanks.
--
~Randy