[PATCH RESEND] soc: mediatek: mtk-regulator-coupler: Allow building as a module

[Justin Yeh]

MTK_REGULATOR_COUPLER is a bool whose prompt is only visible when
COMPILE_TEST is set, so on real MediaTek configurations the symbol has
no prompt at all and is forced to its default: it can only ever be
built in.

Turn it into a visible tristate so that the coupler can also be built
as a loadable module, which is what kernels shipping most of their
drivers as modules need. The "default ARCH_MEDIATEK" is kept, so
existing configurations keep building it in.

While at it, add the help text that the now user-visible prompt was
missing.

Signed-off-by: Justin Yeh <justin.yeh@xxxxxxxxxxxx>
---
Resend, now that the dependency is in mainline: this was patch 2/2 of

  https://lore.kernel.org/all/20260903062056.1024263-3-justin.yeh@xxxxxxxxxxxx/

and patch 1/2 ("regulator: core: Export helpers used by regulator
couplers") was merged as commit 59951bd9c6b6 ("regulator: core: Export
helpers used by regulator couplers") and is in v7.4-rc1. The diff is
unchanged; it is resent on top of v7.4-rc1 as a standalone patch, as
AngeloGioacchino asked.

 drivers/soc/mediatek/Kconfig | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
index d7293977f06e..4a2f2bccc213 100644
--- a/drivers/soc/mediatek/Kconfig
+++ b/drivers/soc/mediatek/Kconfig
@@ -56,9 +56,13 @@ config MTK_PMIC_WRAP
 	  hardware to connect the PMIC.
 
 config MTK_REGULATOR_COUPLER
-	bool "MediaTek SoC Regulator Coupler" if COMPILE_TEST
+	tristate "MediaTek SoC Regulator Coupler"
 	default ARCH_MEDIATEK
 	depends on REGULATOR
+	help
+	  Say yes here to add support for the MediaTek regulator coupler,
+	  which keeps the GPU supply and its coupled GPU SRAM supply
+	  voltage-balanced on the MediaTek SoCs that need it.
 
 config MTK_MMSYS
 	tristate "MediaTek MMSYS Support"
-- 
2.45.2