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Message-Id: <1354830456-17590-5-git-send-email-stigge@antcom.de> Date: Thu, 6 Dec 2012 22:47:34 +0100 From: Roland Stigge <stigge@...com.de> To: gregkh@...uxfoundation.org, grant.likely@...retlab.ca, linus.walleij@...aro.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, w.sang@...gutronix.de, jbe@...gutronix.de, plagnioj@...osoft.com, highguy@...il.com, broonie@...nsource.wolfsonmicro.com, daniel-gl@....net, rmallon@...il.com, tru@...k-microwave.de, sr@...x.de, wg@...ndegger.com Cc: Roland Stigge <stigge@...com.de> Subject: [PATCH 4/6 v10] gpiolib: Fix default attributes for class There is a race condition between creating a gpio or gpiochip device and adding default attributes. This patch fixes this by defining the default attributes as dev_attrs of the class. For this, it was necessary to create a separate gpiochip_class besides gpio_class. Signed-off-by: Roland Stigge <stigge@...com.de> --- Documentation/ABI/testing/sysfs-gpio | 11 ++++ drivers/gpio/gpiolib.c | 79 +++++++++++++++-------------------- 2 files changed, 45 insertions(+), 45 deletions(-) --- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio +++ linux-2.6/Documentation/ABI/testing/sysfs-gpio @@ -20,6 +20,17 @@ Description: /value ... always readable, writes fail for input GPIOs /direction ... r/w as: in, out (default low); write: high, low /edge ... r/w as: none, falling, rising, both + +What: /sys/class/gpiochip/ +Date: October 2012 +KernelVersion: 3.7 +Contact: Roland Stigge <stigge@...com.de> +Description: + + Each gpiochip is represented by a separate device having the following + attributes: + + /sys/class/gpiochip /gpiochipN ... for each gpiochip; #N is its first GPIO /base ... (r/o) same as N /label ... (r/o) descriptive, not necessarily unique --- linux-2.6.orig/drivers/gpio/gpiolib.c +++ linux-2.6/drivers/gpio/gpiolib.c @@ -334,9 +334,6 @@ static ssize_t gpio_value_store(struct d return status; } -static const DEVICE_ATTR(value, 0644, - gpio_value_show, gpio_value_store); - static irqreturn_t gpio_sysfs_irq(int irq, void *priv) { struct sysfs_dirent *value_sd = priv; @@ -557,19 +554,6 @@ static ssize_t gpio_active_low_store(str return status ? : size; } -static const DEVICE_ATTR(active_low, 0644, - gpio_active_low_show, gpio_active_low_store); - -static const struct attribute *gpio_attrs[] = { - &dev_attr_value.attr, - &dev_attr_active_low.attr, - NULL, -}; - -static const struct attribute_group gpio_attr_group = { - .attrs = (struct attribute **) gpio_attrs, -}; - /* * /sys/class/gpio/gpiochipN/ * /base ... matching gpio_chip.base (N) @@ -584,7 +568,6 @@ static ssize_t chip_base_show(struct dev return sprintf(buf, "%d\n", chip->base); } -static DEVICE_ATTR(base, 0444, chip_base_show, NULL); static ssize_t chip_label_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -593,7 +576,6 @@ static ssize_t chip_label_show(struct de return sprintf(buf, "%s\n", chip->label ? : ""); } -static DEVICE_ATTR(label, 0444, chip_label_show, NULL); static ssize_t chip_ngpio_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -602,18 +584,6 @@ static ssize_t chip_ngpio_show(struct de return sprintf(buf, "%u\n", chip->ngpio); } -static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); - -static const struct attribute *gpiochip_attrs[] = { - &dev_attr_base.attr, - &dev_attr_label.attr, - &dev_attr_ngpio.attr, - NULL, -}; - -static const struct attribute_group gpiochip_attr_group = { - .attrs = (struct attribute **) gpiochip_attrs, -}; /* * /sys/class/gpio/export ... write-only @@ -692,11 +662,32 @@ static struct class_attribute gpio_class __ATTR_NULL, }; +static struct device_attribute gpio_attrs[] = { + __ATTR(active_low, 0644, gpio_active_low_show, gpio_active_low_store), + __ATTR(value, 0644, gpio_value_show, gpio_value_store), + __ATTR_NULL, +}; + static struct class gpio_class = { .name = "gpio", .owner = THIS_MODULE, - .class_attrs = gpio_class_attrs, + .class_attrs = gpio_class_attrs, + .dev_attrs = gpio_attrs, +}; + +static struct device_attribute gpiochip_attrs[] = { + __ATTR(label, 0444, chip_label_show, NULL), + __ATTR(base, 0444, chip_base_show, NULL), + __ATTR(ngpio, 0444, chip_ngpio_show, NULL), + __ATTR_NULL, +}; + +static struct class gpiochip_class = { + .name = "gpiochip", + .owner = THIS_MODULE, + + .dev_attrs = gpiochip_attrs, }; @@ -753,10 +744,7 @@ int gpio_export(unsigned gpio, bool dire dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0), desc, ioname ? ioname : "gpio%u", gpio); if (!IS_ERR(dev)) { - status = sysfs_create_group(&dev->kobj, - &gpio_attr_group); - - if (!status && direction_may_change) + if (direction_may_change) status = device_create_file(dev, &dev_attr_direction); @@ -926,25 +914,22 @@ EXPORT_SYMBOL_GPL(gpio_unexport); static int gpiochip_export(struct gpio_chip *chip) { - int status; + int status = 0; struct device *dev; /* Many systems register gpio chips for SOC support very early, * before driver model support is available. In those cases we * export this later, in gpiolib_sysfs_init() ... here we just - * verify that _some_ field of gpio_class got initialized. + * verify that _some_ field of gpiochip_class got initialized. */ - if (!gpio_class.p) + if (!gpiochip_class.p) return 0; /* use chip->base for the ID; it's already known to be unique */ mutex_lock(&sysfs_lock); - dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, - "gpiochip%d", chip->base); - if (!IS_ERR(dev)) { - status = sysfs_create_group(&dev->kobj, - &gpiochip_attr_group); - } else + dev = device_create(&gpiochip_class, chip->dev, MKDEV(0, 0), chip, + "gpiochip%d", chip->base); + if (IS_ERR(dev)) status = PTR_ERR(dev); chip->exported = (status == 0); mutex_unlock(&sysfs_lock); @@ -972,7 +957,7 @@ static void gpiochip_unexport(struct gpi struct device *dev; mutex_lock(&sysfs_lock); - dev = class_find_device(&gpio_class, NULL, chip, match_export); + dev = class_find_device(&gpiochip_class, NULL, chip, match_export); if (dev) { put_device(dev); device_unregister(dev); @@ -1229,6 +1214,10 @@ static int __init gpiolib_sysfs_init(voi if (status < 0) return status; + status = class_register(&gpiochip_class); + if (status < 0) + return status; + status = class_register(&gpio_block_class); if (status < 0) return status; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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