On Mon, Feb 12, 2024 at 03:31:50PM +0100, Duje Mihanović wrote:

On Monday, February 12, 2024 1:44:28 PM CET Daniel Thompson wrote:

quoted

On Mon, Feb 12, 2024 at 12:18:12PM +0100, Arnd Bergmann wrote:

quoted

From: Arnd Bergmann <arnd@arndb.de>

The new backlight driver unconditionally selects LEDS_EXPRESSWIRE, which
is in a different subsystem that may be disabled here:

WARNING: unmet direct dependencies detected for LEDS_EXPRESSWIRE

  Depends on [n]: NEW_LEDS [=n] && GPIOLIB [=y]
  Selected by [y]:
  - BACKLIGHT_KTD2801 [=y] && HAS_IOMEM [=y] && BACKLIGHT_CLASS_DEVICE

[=y]

quoted

quoted

Change the select to depends, to ensure the indirect dependency is
met as well even when LED support is disabled.

Fixes: 66c76c1cd984 ("backlight: Add Kinetic KTD2801 backlight support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---

 drivers/video/backlight/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/backlight/Kconfig

b/drivers/video/backlight/Kconfig index 230bca07b09d..f83f9ef037fc 100644

--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig

@@ -185,7 +185,7 @@ config BACKLIGHT_KTD253

 config BACKLIGHT_KTD2801

 	tristate "Backlight Driver for Kinetic KTD2801"

-	select LEDS_EXPRESSWIRE
+	depends on LEDS_EXPRESSWIRE

As far as I can tell this resolves the warning by making it impossible
to enable BACKLIGHT_KTD2801 unless a largely unrelated driver
(LEDS_KTD2692) is also enabled!

A better way to resolve this problem might be to eliminate the NEW_LEDS
dependency entirely:

I believe this would be the best thing to do here. Making LEDS_EXPRESSWIRE
user selectable doesn't make much sense to me as the library is rather low-
level (a quick grep turns up BTREE as an example of something similar) and IMO
the GPIOLIB dependency should be handled by LEDS_EXPRESSWIRE as it's the one
actually using the GPIO interface (except maybe for KTD2692 as it has some
extra GPIOs not present in the other one and thus handles them itself).

We can keep the GPIOLIB dependency in LEDS_EXPRESSWIRE but it also needs
to be included in the KTD2801 KConfig too... otherwise we'll get similar
problems to the ones Arnd addressed here:
https://lore.kernel.org/all/20240213165602.2230970-1-arnd@kernel.org/ (local)


Daniel.