linux-kernel - [PATCH v2 10/10] regulator: make the subsystem aware of shared GPIOs

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Message-Id: <20251022-gpio-shared-v2-10-d34aa1fbdf06@linaro.org>
Date: Wed, 22 Oct 2025 15:10:49 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Kees Cook <kees@...nel.org>, Mika Westerberg <westeri@...nel.org>, 
 Dmitry Torokhov <dmitry.torokhov@...il.com>, 
 Andrew Morton <akpm@...ux-foundation.org>, 
 Linus Walleij <linus.walleij@...aro.org>, 
 Manivannan Sadhasivam <mani@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Saravana Kannan <saravanak@...gle.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Andy Shevchenko <andy@...nel.org>, Bartosz Golaszewski <brgl@...ev.pl>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Srinivas Kandagatla <srini@...nel.org>, Liam Girdwood <lgirdwood@...il.com>, 
 Mark Brown <broonie@...nel.org>, Jaroslav Kysela <perex@...ex.cz>, 
 Takashi Iwai <tiwai@...e.com>
Cc: linux-hardening@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-gpio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-sound@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v2 10/10] regulator: make the subsystem aware of shared
 GPIOs

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

GPIOLIB is now aware of shared GPIOs and - for platforms where access to
such pins is managed internally - we don't need to keep track of the
enable count.

Once all users in the kernel switch to using the new mechanism, we'll be
able to drop the internal counting of users from the regulator code.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/regulator/core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index dd7b10e768c06c83d2a4fb5dfd0fce8d796c9185..f9690f0689fda85123d07967f3c87105829e330c 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2616,6 +2616,13 @@ static int regulator_ena_gpio_request(struct regulator_dev *rdev,
 
 	mutex_lock(&regulator_list_mutex);
 
+	if (gpiod_is_shared(gpiod))
+		/*
+		 * The sharing of this GPIO pin is managed internally by
+		 * GPIOLIB. We don't need to keep track of its enable count.
+		 */
+		goto skip_compare;
+
 	list_for_each_entry(pin, &regulator_ena_gpio_list, list) {
 		if (gpiod_is_equal(pin->gpiod, gpiod)) {
 			rdev_dbg(rdev, "GPIO is already used\n");
@@ -2628,6 +2635,7 @@ static int regulator_ena_gpio_request(struct regulator_dev *rdev,
 		return -ENOMEM;
 	}
 
+skip_compare:
 	pin = new_pin;
 	new_pin = NULL;
 

-- 
2.48.1