Messages in this thread | | | Date | Mon, 15 Oct 2012 20:07:02 +0200 | From | Jean-Christophe PLAGNIOL-VILLARD <> | Subject | Re: [PATCH RFC 2/6 v3] gpio: Add sysfs support to block GPIO API |
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On 21:11 Fri 12 Oct , Roland Stigge wrote: > This patch adds sysfs support to the block GPIO API. > > Signed-off-by: Roland Stigge <stigge@antcom.de> > > --- > Documentation/ABI/testing/sysfs-gpio | 6 > drivers/gpio/gpiolib.c | 226 ++++++++++++++++++++++++++++++++++- > include/asm-generic/gpio.h | 11 + > include/linux/gpio.h | 13 ++ > 4 files changed, 254 insertions(+), 2 deletions(-) I really don't like this sysfs we need to add a specific device with ioctl
I put Greg in Cc
Best Regards, J. > > --- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio > +++ linux-2.6/Documentation/ABI/testing/sysfs-gpio > @@ -24,4 +24,8 @@ Description: > /base ... (r/o) same as N > /label ... (r/o) descriptive, not necessarily unique > /ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1) > - > + /blockN ... for each GPIO block #N > + /ngpio ... (r/o) number of GPIOs in this group > + /exported ... sysfs export state of this group (0, 1) > + /value ... current value as 32 or 64 bit integer in decimal > + (only available if /exported is 1) > --- linux-2.6.orig/drivers/gpio/gpiolib.c > +++ linux-2.6/drivers/gpio/gpiolib.c > @@ -974,6 +974,218 @@ static void gpiochip_unexport(struct gpi > chip->label, status); > } > > +static ssize_t gpio_block_ngpio_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + const struct gpio_block *block = dev_get_drvdata(dev); > + > + return sprintf(buf, "%u\n", block->ngpio); > +} > +static struct device_attribute > +dev_attr_block_ngpio = __ATTR(ngpio, 0444, gpio_block_ngpio_show, NULL); > + > +static ssize_t gpio_block_value_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + const struct gpio_block *block = dev_get_drvdata(dev); > + > + return sprintf(buf, "%u\n", gpio_block_get(block)); > +} > + > +static bool gpio_block_is_output(struct gpio_block *block) > +{ > + int i; > + > + for (i = 0; i < block->ngpio; i++) > + if (!test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags)) > + return false; > + return true; > +} > + > +static ssize_t gpio_block_value_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + ssize_t status; > + struct gpio_block *block = dev_get_drvdata(dev); > + unsigned long value; > + > + mutex_lock(&sysfs_lock); > + > + status = kstrtoul(buf, 0, &value); > + if (status == 0) { > + if (gpio_block_is_output(block)) { > + gpio_block_set(block, value); > + status = size; > + } else { > + status = -EPERM; > + } > + } > + > + mutex_unlock(&sysfs_lock); > + return status; > +} > + > +static struct device_attribute > +dev_attr_block_value = __ATTR(value, 0644, gpio_block_value_show, > + gpio_block_value_store); > + > +static int gpio_block_value_is_exported(struct gpio_block *block) > +{ > + struct device *dev; > + struct sysfs_dirent *sd = NULL; > + > + mutex_lock(&sysfs_lock); > + dev = class_find_device(&gpio_class, NULL, block, match_export); > + if (!dev) > + goto out; > + > + sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value"); > + > +out: > + mutex_unlock(&sysfs_lock); > + return sd ? 1 : 0; > +} > + > +static ssize_t gpio_block_exported_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct gpio_block *block = dev_get_drvdata(dev); > + > + return sprintf(buf, "%u\n", gpio_block_value_is_exported(block)); > +} > + > +static int gpio_block_value_export(struct gpio_block *block) > +{ > + struct device *dev; > + int status; > + int i; > + > + mutex_lock(&sysfs_lock); > + > + for (i = 0; i < block->ngpio; i++) { > + status = gpio_request(block->gpio[i], "sysfs"); > + if (status) > + goto out; > + } > + > + dev = class_find_device(&gpio_class, NULL, block, match_export); > + if (!dev) { > + status = -ENODEV; > + goto out; > + } > + > + status = device_create_file(dev, &dev_attr_block_value); > + if (status) > + goto out; > + > + mutex_unlock(&sysfs_lock); > + return 0; > + > +out: > + while (i > 0) { > + i--; > + gpio_free(block->gpio[i]); > + } > + > + mutex_unlock(&sysfs_lock); > + return status; > +} > + > +static int gpio_block_value_unexport(struct gpio_block *block) > +{ > + struct device *dev; > + int i; > + > + dev = class_find_device(&gpio_class, NULL, block, match_export); > + if (!dev) > + return -ENODEV; > + > + for (i = 0; i < block->ngpio; i++) > + gpio_free(block->gpio[i]); > + > + device_remove_file(dev, &dev_attr_block_value); > + > + return 0; > +} > + > +static ssize_t gpio_block_exported_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + long value; > + int status; > + struct gpio_block *block = dev_get_drvdata(dev); > + int exported = gpio_block_value_is_exported(block); > + > + status = kstrtoul(buf, 0, &value); > + if (status < 0) > + goto err; > + > + if (value != exported) { > + if (value) > + status = gpio_block_value_export(block); > + else > + status = gpio_block_value_unexport(block); > + if (!status) > + status = size; > + } else { > + status = size; > + } > +err: > + return status; > +} > + > +static DEVICE_ATTR(exported, 0644, gpio_block_exported_show, > + gpio_block_exported_store); > + > +static const struct attribute *gpio_block_attrs[] = { > + &dev_attr_block_ngpio.attr, > + &dev_attr_exported.attr, > + NULL, > +}; > + > +static const struct attribute_group gpio_block_attr_group = { > + .attrs = (struct attribute **) gpio_block_attrs, > +}; > + > +int gpio_block_export(struct gpio_block *block) > +{ > + int status; > + struct device *dev; > + > + /* can't export until sysfs is available ... */ > + if (!gpio_class.p) { > + pr_debug("%s: called too early!\n", __func__); > + return -ENOENT; > + } > + > + mutex_lock(&sysfs_lock); > + dev = device_create(&gpio_class, NULL, MKDEV(0, 0), block, > + block->name); > + if (!IS_ERR(dev)) > + status = sysfs_create_group(&dev->kobj, &gpio_block_attr_group); > + else > + status = PTR_ERR(dev); > + mutex_unlock(&sysfs_lock); > + > + return status; > +} > +EXPORT_SYMBOL_GPL(gpio_block_export); > + > +void gpio_block_unexport(struct gpio_block *block) > +{ > + struct device *dev; > + > + mutex_lock(&sysfs_lock); > + dev = class_find_device(&gpio_class, NULL, block, match_export); > + if (dev) > + device_unregister(dev); > + mutex_unlock(&sysfs_lock); > +} > +EXPORT_SYMBOL_GPL(gpio_block_unexport); > + > static int __init gpiolib_sysfs_init(void) > { > int status; > @@ -1882,7 +2094,14 @@ int gpio_block_register(struct gpio_bloc > break; > } > } > - return i == NR_GPIO_BLOCKS ? -EBUSY : 0; > + if (i == NR_GPIO_BLOCKS) > + goto err; > + > + gpio_block_export(block); > + > + return 0; > +err: > + return -EBUSY; > } > EXPORT_SYMBOL_GPL(gpio_block_register); > > @@ -1896,6 +2115,11 @@ void gpio_block_unregister(struct gpio_b > break; > } > } > + > + if (i == NR_GPIO_BLOCKS) > + return; > + > + gpio_block_unexport(block); > } > EXPORT_SYMBOL_GPL(gpio_block_unregister); > > --- linux-2.6.orig/include/asm-generic/gpio.h > +++ linux-2.6/include/asm-generic/gpio.h > @@ -210,6 +210,8 @@ extern int gpio_export_link(struct devic > unsigned gpio); > extern int gpio_sysfs_set_active_low(unsigned gpio, int value); > extern void gpio_unexport(unsigned gpio); > +extern int gpio_block_export(struct gpio_block *block); > +extern void gpio_block_unexport(struct gpio_block *block); > > #endif /* CONFIG_GPIO_SYSFS */ > > @@ -269,6 +271,15 @@ static inline int gpio_sysfs_set_active_ > static inline void gpio_unexport(unsigned gpio) > { > } > + > +static inline int gpio_block_export(struct gpio_block *block) > +{ > + return -ENOSYS; > +} > + > +static inline void gpio_block_unexport(struct gpio_block *block) > +{ > +} > #endif /* CONFIG_GPIO_SYSFS */ > > #endif /* _ASM_GENERIC_GPIO_H */ > --- linux-2.6.orig/include/linux/gpio.h > +++ linux-2.6/include/linux/gpio.h > @@ -278,6 +278,19 @@ static inline void gpio_unexport(unsigne > WARN_ON(1); > } > > +static inline int gpio_block_export(struct gpio_block *block) > +{ > + /* GPIO block can never have been requested or set as {in,out}put */ > + WARN_ON(1); > + return -EINVAL; > +} > + > +static inline void gpio_block_unexport(struct gpio_block *block) > +{ > + /* GPIO block can never have been exported */ > + WARN_ON(1); > +} > + > static inline int gpio_to_irq(unsigned gpio) > { > /* GPIO can never have been requested or set as input */
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