regulator: Allow mtk-regulator-coupler to be built as a module

Justin Yeh <justin.yeh@mediatek.com> says:

MTK_REGULATOR_COUPLER can currently only be built into the kernel: it is
a bool, and its prompt is hidden unless COMPILE_TEST is set, so on real
MediaTek configurations the symbol has no prompt and is forced to its
"default ARCH_MEDIATEK" value.

Kernels that ship nearly everything as a module (Android GKI style
kernels, but distro kernels have the same shape) cannot use it that way.
Two things are in the way:

  - the four helpers the coupler calls are declared in
    include/linux/regulator/coupler.h for coupler implementations to
    use, but none of them is exported (patch 1);

  - the Kconfig symbol is a bool without a usable prompt (patch 2).

Link: https://patch.msgid.link/20260903062056.1024263-1-justin.yeh@mediatek.com

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 50fe91b6f267..14422cfe80e2 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -462,6 +462,7 @@ int regulator_check_voltage(struct regulator_dev *rdev,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(regulator_check_voltage);
 
 /* return 0 if the state is valid */
 static int regulator_check_states(suspend_state_t state)
@@ -502,6 +503,7 @@ int regulator_check_consumers(struct regulator_dev *rdev,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(regulator_check_consumers);
 
 /* current constraint check */
 static int regulator_check_current_limit(struct regulator_dev *rdev,
@@ -4469,6 +4471,7 @@ int regulator_do_balance_voltage(struct regulator_dev *rdev,
 out:
 	return ret;
 }
+EXPORT_SYMBOL_GPL(regulator_do_balance_voltage);
 
 static int regulator_balance_voltage(struct regulator_dev *rdev,
 				     suspend_state_t state)
@@ -5798,6 +5801,7 @@ int regulator_coupler_register(struct regulator_coupler *coupler)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(regulator_coupler_register);
 
 static struct regulator_coupler *
 regulator_find_coupler(struct regulator_dev *rdev)