From patchwork Tue Sep 12 10:07:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 722355 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC0A3CA0EC3 for ; Tue, 12 Sep 2023 10:08:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234018AbjILKIH (ORCPT ); Tue, 12 Sep 2023 06:08:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233958AbjILKHp (ORCPT ); Tue, 12 Sep 2023 06:07:45 -0400 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [IPv6:2a00:1450:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F7841988 for ; Tue, 12 Sep 2023 03:07:41 -0700 (PDT) Received: by mail-wm1-x330.google.com with SMTP id 5b1f17b1804b1-402c46c49f4so58077795e9.1 for ; Tue, 12 Sep 2023 03:07:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20230601.gappssmtp.com; s=20230601; t=1694513260; x=1695118060; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=A6yCpRsJ9YDulO6YNUQQZrVJSWHh877hWXgywBs804o=; b=TpQxjVY+ICyqKwIHOyu+x0bHKtufJJxchZCIdaAx/ZI5LUYQE6fVKZJQojUOqIQsOz jB83+T/Bo0uv8S0/yRNnktVNbjtgHn6UpQycN4Yh6XyQR0sIWoGp1iUftf3u356UjWNS J2KJNUP76h6SHcIWOg7/cE6lf3A7WDSBoODGyRIvDGuxiOFKgGxMrYVYEYd80DYdykhm h+Bo/ItDxUOXtt3kiOjhBJaE4CC8EEenjZgroYoZBxCnJXZuG87MdtTScxU64xhF4+rh +cGObF+eiIt41IQjc9/syUcmMNYVdyLFZcUEJQTqetWKhru4PPNue5X7oEudDb68x1Mv htpA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694513260; x=1695118060; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=A6yCpRsJ9YDulO6YNUQQZrVJSWHh877hWXgywBs804o=; b=eP3k7VZpfJfyjj2J58ZOBu5W4n+mBVbR5M/Qu5OlO4et/uPdcsFpry8kKXxENxgRcK GC1J9thQHSPgEPvn/eAnEM3htXmJ+t3t0ktq+Oaste37/U6tVWXzuMDZ0JPPvQ0yF6Tb iYp5MYb4mdPa8N7uzfiNlVcIwInBqJZAUIImHWpW2GDWPXtsMwyJRz8pmI9CX09O3CfL lAFbzOdXWQD4j9RsCN955qQ0t5PLFRaBf5TNONpAJ4aDn4g0cPxeZ218UOdI0FXZbE7+ gkaYOgzAY3DpmL8Gk8DmjADFQ5d1XVMktXnddcj5cWyvTUJCMI2JR3pGRsFb4j0KdJB5 BFPQ== X-Gm-Message-State: AOJu0YxOJAzsz7tnQPIS8CXvkYjcPbOewyz7o7kQtiIbnAIpw+nQ44Nw HufbHPIKG9nn4oMl1cDwVJk7mg== X-Google-Smtp-Source: AGHT+IFcT7aRuxPokXUdCiwhobRYyRamsHE6NPEllDWPFOmdrpuZSdnUT0Q8AdVtMC65mNulQccRLA== X-Received: by 2002:a05:600c:204c:b0:401:23fc:1f92 with SMTP id p12-20020a05600c204c00b0040123fc1f92mr10852185wmg.25.1694513260155; Tue, 12 Sep 2023 03:07:40 -0700 (PDT) Received: from brgl-uxlite.home ([2a01:cb1d:334:ac00:907f:4cd7:f0ae:6b2a]) by smtp.gmail.com with ESMTPSA id h5-20020adfe985000000b0031ae8d86af4sm12351417wrm.103.2023.09.12.03.07.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Sep 2023 03:07:39 -0700 (PDT) From: Bartosz Golaszewski To: Linus Walleij , Andy Shevchenko , Mika Westerberg Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v2 05/11] gpiolib: provide gpio_device_get_desc() Date: Tue, 12 Sep 2023 12:07:21 +0200 Message-Id: <20230912100727.23197-6-brgl@bgdev.pl> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230912100727.23197-1-brgl@bgdev.pl> References: <20230912100727.23197-1-brgl@bgdev.pl> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Bartosz Golaszewski Getting the GPIO descriptor directly from the gpio_chip struct is dangerous as we don't take the reference to the underlying GPIO device. In order to start working towards removing gpiochip_get_desc(), let's provide a safer variant that works with an existing reference to struct gpio_device. Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij --- drivers/gpio/gpiolib.c | 45 +++++++++++++++++++++++++++---------- include/linux/gpio/driver.h | 2 ++ 2 files changed, 35 insertions(+), 12 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 9f20311e4c1a..e413136d1566 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -147,27 +147,48 @@ struct gpio_desc *gpio_to_desc(unsigned gpio) } EXPORT_SYMBOL_GPL(gpio_to_desc); -/** - * gpiochip_get_desc - get the GPIO descriptor corresponding to the given - * hardware number for this chip - * @gc: GPIO chip - * @hwnum: hardware number of the GPIO for this chip - * - * Returns: - * A pointer to the GPIO descriptor or ``ERR_PTR(-EINVAL)`` if no GPIO exists - * in the given chip for the specified hardware number. - */ +/* This function is deprecated and will be removed soon, don't use. */ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum) { - struct gpio_device *gdev = gc->gpiodev; + return gpio_device_get_desc(gc->gpiodev, hwnum); +} +EXPORT_SYMBOL_GPL(gpiochip_get_desc); + +/** + * gpio_device_get_desc() - get the GPIO descriptor corresponding to the given + * hardware number for this GPIO device + * @gdev: GPIO device to get the descriptor from + * @hwnum: hardware number of the GPIO for this chip + * + * Returns: + * A pointer to the GPIO descriptor or %EINVAL if no GPIO exists in the given + * chip for the specified hardware number or %ENODEV if the underlying chip + * already vanished. + * + * The reference count of struct gpio_device is *NOT* increased like when the + * GPIO is being requested for exclusive usage. It's up to the caller to make + * sure the GPIO device will stay alive together with the descriptor returned + * by this function. + */ +struct gpio_desc * +gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum) +{ + struct gpio_chip *gc = gdev->chip; + + /* + * FIXME: This will be locked once we protect gdev->chip everywhere + * with SRCU. + */ + if (!gc) + return ERR_PTR(-ENODEV); if (hwnum >= gdev->ngpio) return ERR_PTR(-EINVAL); return &gdev->descs[hwnum]; } -EXPORT_SYMBOL_GPL(gpiochip_get_desc); +EXPORT_SYMBOL_GPL(gpio_device_get_desc); /** * desc_to_gpio - convert a GPIO descriptor to the integer namespace diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index bcf418441ef2..5c0f2ccfd51b 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -767,6 +767,8 @@ struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *gc, void gpiochip_free_own_desc(struct gpio_desc *desc); struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum); +struct gpio_desc * +gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum); #ifdef CONFIG_GPIOLIB