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Tue, 10 Jun 2025 07:38:33 -0700 (PDT) Received: from [127.0.1.1] ([2a01:cb1d:dc:7e00:4d:e52b:812d:eb7c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4526e056138sm146001345e9.5.2025.06.10.07.38.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Jun 2025 07:38:33 -0700 (PDT) From: Bartosz Golaszewski Date: Tue, 10 Jun 2025 16:38:21 +0200 Subject: [PATCH RFC/RFT 06/15] gpio: sysfs: remove the mockdev pointer from struct gpio_device Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250610-gpio-sysfs-chip-export-v1-6-a8c7aa4478b1@linaro.org> References: <20250610-gpio-sysfs-chip-export-v1-0-a8c7aa4478b1@linaro.org> In-Reply-To: <20250610-gpio-sysfs-chip-export-v1-0-a8c7aa4478b1@linaro.org> To: Ahmad Fatoum , Kent Gibson , =?utf-8?q?Jan_L=C3=BCbbe?= , Marek Vasut , Geert Uytterhoeven , Linus Walleij , Bartosz Golaszewski Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; 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a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 From: Bartosz Golaszewski The usage of the mockdev pointer in struct gpio_device is limited to the GPIO sysfs code. There's no reason to keep it in this top-level structure. Create a separate structure containing the reference to the GPIO device and the dummy class device that will be passed to device_create_with_groups(). The !gdev->mockdev checks can be removed as long as we make sure that all operations on the GPIO class are protected with the sysfs lock. Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij --- drivers/gpio/gpiolib-sysfs.c | 81 +++++++++++++++++++++++++++++--------------- drivers/gpio/gpiolib.h | 3 -- 2 files changed, 53 insertions(+), 31 deletions(-) diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index f23b4efea5905a9eab51ed9e50b5159135a8e26c..956411fc467a26a9827c616d8dc067c70f9244bf 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -43,6 +43,11 @@ struct gpiod_data { bool direction_can_change; }; +struct gpiodev_data { + struct gpio_device *gdev; + struct device *cdev_base; /* Class device by GPIO base */ +}; + /* * Lock to serialise gpiod export and unexport, and prevent re-export of * gpiod whose chip is being unregistered. @@ -399,27 +404,27 @@ static const struct attribute_group *gpio_groups[] = { static ssize_t base_show(struct device *dev, struct device_attribute *attr, char *buf) { - const struct gpio_device *gdev = dev_get_drvdata(dev); + const struct gpiodev_data *data = dev_get_drvdata(dev); - return sysfs_emit(buf, "%u\n", gdev->base); + return sysfs_emit(buf, "%u\n", data->gdev->base); } static DEVICE_ATTR_RO(base); static ssize_t label_show(struct device *dev, struct device_attribute *attr, char *buf) { - const struct gpio_device *gdev = dev_get_drvdata(dev); + const struct gpiodev_data *data = dev_get_drvdata(dev); - return sysfs_emit(buf, "%s\n", gdev->label); + return sysfs_emit(buf, "%s\n", data->gdev->label); } static DEVICE_ATTR_RO(label); static ssize_t ngpio_show(struct device *dev, struct device_attribute *attr, char *buf) { - const struct gpio_device *gdev = dev_get_drvdata(dev); + const struct gpiodev_data *data = dev_get_drvdata(dev); - return sysfs_emit(buf, "%u\n", gdev->ngpio); + return sysfs_emit(buf, "%u\n", data->gdev->ngpio); } static DEVICE_ATTR_RO(ngpio); @@ -545,6 +550,26 @@ static const struct class gpio_class = { .class_groups = gpio_class_groups, }; +static int match_gdev(struct device *dev, const void *desc) +{ + struct gpiodev_data *data = dev_get_drvdata(dev); + const struct gpio_device *gdev = desc; + + return data && data->gdev == gdev; +} + +static struct gpiodev_data * +gdev_get_data(struct gpio_device *gdev) __must_hold(&sysfs_lock) +{ + struct device *cdev __free(put_device) = class_find_device(&gpio_class, + NULL, gdev, + match_gdev); + if (!cdev) + return NULL; + + return dev_get_drvdata(cdev); +}; + /** * gpiod_export - export a GPIO through sysfs * @desc: GPIO to make available, already requested @@ -590,12 +615,6 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) guard(mutex)(&sysfs_lock); - /* check if chip is being removed */ - if (!gdev->mockdev) { - status = -ENODEV; - goto err_clear_bit; - } - if (!test_bit(FLAG_REQUESTED, &desc->flags)) { gpiod_dbg(desc, "%s: unavailable (not requested)\n", __func__); status = -EPERM; @@ -719,9 +738,9 @@ EXPORT_SYMBOL_GPL(gpiod_unexport); int gpiochip_sysfs_register(struct gpio_device *gdev) { + struct gpiodev_data *data; struct gpio_chip *chip; struct device *parent; - struct device *dev; /* * Many systems add gpio chips for SOC support very early, @@ -747,32 +766,41 @@ int gpiochip_sysfs_register(struct gpio_device *gdev) else parent = &gdev->dev; - /* use chip->base for the ID; it's already known to be unique */ - dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), gdev, - gpiochip_groups, GPIOCHIP_NAME "%d", - chip->base); - if (IS_ERR(dev)) - return PTR_ERR(dev); + data = kmalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->gdev = gdev; guard(mutex)(&sysfs_lock); - gdev->mockdev = dev; + + /* use chip->base for the ID; it's already known to be unique */ + data->cdev_base = device_create_with_groups(&gpio_class, parent, + MKDEV(0, 0), data, + gpiochip_groups, + GPIOCHIP_NAME "%d", + chip->base); + if (IS_ERR(data->cdev_base)) { + kfree(data); + return PTR_ERR(data->cdev_base); + } return 0; } void gpiochip_sysfs_unregister(struct gpio_device *gdev) { + struct gpiodev_data *data; struct gpio_desc *desc; struct gpio_chip *chip; scoped_guard(mutex, &sysfs_lock) { - if (!gdev->mockdev) + data = gdev_get_data(gdev); + if (!data) return; - device_unregister(gdev->mockdev); - - /* prevent further gpiod exports */ - gdev->mockdev = NULL; + device_unregister(data->cdev_base); + kfree(data); } guard(srcu)(&gdev->srcu); @@ -798,9 +826,6 @@ static int gpiofind_sysfs_register(struct gpio_chip *gc, const void *data) struct gpio_device *gdev = gc->gpiodev; int ret; - if (gdev->mockdev) - return 0; - ret = gpiochip_sysfs_register(gdev); if (ret) chip_err(gc, "failed to register the sysfs entry: %d\n", ret); diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 58f64056de77b05e8cbcb2395a55da793b1a52fa..9b74738a9ca5b1a4826c8d56d871f8a7cf6ea1e7 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -27,8 +27,6 @@ * @dev: the GPIO device struct * @chrdev: character device for the GPIO device * @id: numerical ID number for the GPIO chip - * @mockdev: class device used by the deprecated sysfs interface (may be - * NULL) * @owner: helps prevent removal of modules exporting active GPIOs * @chip: pointer to the corresponding gpiochip, holding static * data for this device @@ -65,7 +63,6 @@ struct gpio_device { struct device dev; struct cdev chrdev; int id; - struct device *mockdev; struct module *owner; struct gpio_chip __rcu *chip; struct gpio_desc *descs;