linux-kernel - [PATCH v4 10/10] regulator: make the subsystem aware of shared GPIOs

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Message-Id: <20251112-gpio-shared-v4-10-b51f97b1abd8@linaro.org>
Date: Wed, 12 Nov 2025 14:55:39 +0100
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>, Alexey Klimov <alexey.klimov@...aro.org>, 
 Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>
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 v4 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.

Acked-by: Mark Brown <broonie@...nel.org>
Acked-by: Linus Walleij <linus.walleij@...aro.org>
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 2eab56df042e6b05abf0989f425dc161c7b0e66d..53b2b2d3746f9f2419234912d49bd8b4f21a893d 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2742,6 +2742,13 @@ 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");
@@ -2754,6 +2761,7 @@ static int regulator_ena_gpio_request(struct regulator_dev *rdev,
 		return -ENOMEM;
 	}
 
+skip_compare:
 	pin = new_pin;
 	new_pin = NULL;
 

-- 
2.51.0