From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B2E8DC43327 for ; Tue, 30 Jun 2026 10:16:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=wN+EcU0gGHH33bhyn/gHbeG7JZHnwpKvV3LKnR2eWeM=; b=eBtbZJD4uc1Ey91IoomAO8lyz2 a7PeonzDJX7o11T5nTqpenV8aUyKlNCkvH+175PqB6GDxASIM+CWs5AY8k5ZFl7MC0f4TQcezla86 cIA02Pt8RRpAlyF5reMlkUaAUvcBIzICT+sEgqSFtBtKFk9lSbPfygkvutu4Zo9zoiW04FEqDz1Os bF5NVDtaPXhPpgR1Bbu+bm0OxrPW/diUDp4iFtiFEyvFYAuLbCqPt2VWLUzb811Ic367p1zpZbOy0 +jpyNuf0FOHxMlIl64XXbiEdYCqM/wMsrJGAAaLTEb89UJzxpKYX3qy2F4PIgn5nc9BvKxW1nc4An YYZYBRYg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1weVW4-0000000GbI7-34Ie; Tue, 30 Jun 2026 10:16:32 +0000 Received: from mx.adeep.su ([185.250.0.168]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1weVW0-0000000GbHf-32Oh; Tue, 30 Jun 2026 10:16:31 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 2DC1D1CD0CC; Tue, 30 Jun 2026 13:16:13 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baodeep.com; s=dkim; t=1782814585; h=from:subject:date:message-id:to:cc:mime-version: content-transfer-encoding; bh=wN+EcU0gGHH33bhyn/gHbeG7JZHnwpKvV3LKnR2eWeM=; b=jC5ljsv/fRpC1AtIMayTHfeg0yZ0qKe3UHL+ssTZe5GiIleQX+Myb6i/5wARIpwukmdGOf QJFTuIGKV2MQA1M310phV3qVyA9mZj4j+mkUfT+Lk2N2zJFDQ33btXi9eLN9nKLrjsuI2h Vpp9lVjL/GB8xT7JYAQCPHwIC+p2HgwuMxU9fm51+i5RZ/59eWzCwm5pkFD7KpLYKIbVBB lDdzflPJ1asiQxq3co7fi2OEu6pYO6S4941wKqhNEVy3amf5Ugu7qy/33HiTr54wp3mTSC xtoSlGgBlLk6G/ebVuEnv+A4NnxvrXG6JL9zAQSkPYBPDwuDbU73oPWgzDHgVA== From: Viacheslav Bocharov To: Linus Walleij , Bartosz Golaszewski Cc: Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Marek Szyprowski , Robin Murphy , Diederik de Haas , linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 0/2] gpio: fix sleeping-in-atomic in shared-proxy; restore meson non-sleeping Date: Tue, 30 Jun 2026 13:15:43 +0300 Message-ID: <20260630101545.800625-1-v@baodeep.com> X-Mailer: git-send-email 2.54.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260630_031629_931738_555EC28E X-CRM114-Status: GOOD ( 10.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org gpio-shared-proxy chooses its descriptor lock (mutex vs spinlock) from the underlying chip's can_sleep, but under that lock it calls config and direction ops that reach sleeping pinctrl paths. On a controller with non-sleeping MMIO value ops the lock is a spinlock, so a sleeping call runs from atomic context: BUG: sleeping function called from invalid context ... pinctrl_gpio_set_config <- gpiochip_generic_config <- gpio_shared_proxy_set_config (voting spinlock held) <- ... <- mmc_pwrseq_simple_probe This was reported on Khadas VIM3 and worked around for Amlogic by commit 28f240683871 ("pinctrl: meson: mark the GPIO controller as sleeping"), which marked the whole meson controller sleeping. That workaround broke atomic value-path consumers: w1-gpio (1-Wire bitbang) no longer detects devices, because its IRQ-disabled read slot calls the non-cansleep gpiod_*_value() and now hits WARN_ON(can_sleep) per bit. Patch 1 fixes the proxy locking generically (always a sleeping mutex). Patch 2 then restores meson can_sleep=false, fixing 1-Wire. Patch 1 has a trade-off: a proxied GPIO becomes sleeping, so consumers gating on gpiod_cansleep() change behaviour. No current device needs atomic (non-cansleep) value access on a shared GPIO -- every report (Khadas VIM3, ODROID-M1, my test on JetHub D1+) is a shared reset line (eMMC/SDIO pwrseq or PCIe reset) driven through the cansleep accessors, which is what the proxy exists to vote on; bit-banging that needs atomic access cannot work through voting anyway. An alternative that keeps atomic value access (split locking) is possible but adds a second lock and new race windows, so this series takes the simpler mutex-only approach. The two are a unit: patch 2 must not be applied without patch 1, otherwise the original VIM3 splat returns on boards that share a meson GPIO -- please keep the order. I have not Cc'd stable; I will request stable backports separately once both patches have landed. Changes since v2: - gpio: shared-proxy: drop the set_func callback from gpio_shared_proxy_set_unlocked() and call gpiod_set_value_cansleep() directly. The shared direction_output path drives the already-output line through the value setter instead of re-issuing gpiod_direction_output() (equivalent, minus a redundant per-edge re-assert of drive config/bias). No change to the voting/value behaviour. Changes since v1: - gpio: shared-proxy: open-code the descriptor mutex; drop the gpio_shared_desc_lock guard and the gpio_shared_lockdep_assert() helper, move the mutex rationale to the can_sleep assignment. v1: https://lore.kernel.org/linux-gpio/20260610153329.937833-1-v@baodeep.com/ v2: https://lore.kernel.org/linux-gpio/20260625115718.1678991-1-v@baodeep.com/ Viacheslav Bocharov (2): gpio: shared-proxy: always serialize with a sleeping mutex pinctrl: meson: restore non-sleeping GPIO access drivers/gpio/gpio-shared-proxy.c | 76 ++++++++++----------------- drivers/gpio/gpiolib-shared.c | 9 +--- drivers/gpio/gpiolib-shared.h | 28 +--------- drivers/pinctrl/meson/pinctrl-meson.c | 2 +- 4 files changed, 33 insertions(+), 82 deletions(-) base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482 -- 2.54.0