| Message ID | 1358250716-21986-3-git-send-email-stigge@antcom.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 15 Jan 2013 12:51:52 +0100, Roland Stigge <stigge@antcom.de> wrote: > This patch adds sysfs support to the block GPIO API. > > Signed-off-by: Roland Stigge <stigge@antcom.de> Hi Roland. I'm going to ignore this patch for the time being because I think my comments on the first patch basically obsolete what is being done here. If the a gpio sequence parser is used instead of a global block gpio api is used, then a sysfs interface for blocks of GPIOs could be implemented merely as a separate device driver that consumes a bunch of standard GPIO references. I would also suggest that an API that accepts a stream of commands instead of a fixed u32 would be better for the userspace interface. When I originally suggested doing a char device interface, I was expecting the sysfs interface to be dropped entirely. g. > > --- > Documentation/ABI/testing/sysfs-gpio | 20 ++ > drivers/gpio/gpiolib.c | 252 ++++++++++++++++++++++++++++++++++- > include/asm-generic/gpio.h | 11 + > include/linux/gpio.h | 15 ++ > 4 files changed, 297 insertions(+), 1 deletion(-) > > --- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio > +++ linux-2.6/Documentation/ABI/testing/sysfs-gpio > @@ -25,3 +25,23 @@ Description: > /label ... (r/o) descriptive, not necessarily unique > /ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1) > > +What: /sys/class/gpioblock/ > +Date: October 2012 > +KernelVersion: 3.7 > +Contact: Roland Stigge <stigge@antcom.de> > +Description: > + > + Block GPIO devices are visible in sysfs as soon as they are registered > + (e.g. via devicetree definition). For actual I/O use, their "exported" > + boolean attribute must be set to "1". Then, the attribute "values" is > + created and at the same time, the GPIOs in the block are requested for > + exclusive use by sysfs. > + > + /sys/class/gpioblock > + /BLOCKNAME ... for each GPIO block name > + /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 hex > + (only available if /exported is 1) > + /mask ... current mask as 32 or 64 bit integer in hex > + (only available if /exported is 1) > --- linux-2.6.orig/drivers/gpio/gpiolib.c > +++ linux-2.6/drivers/gpio/gpiolib.c > @@ -224,7 +224,8 @@ static bool gpio_block_is_output(struct > int i; > > for (i = 0; i < block->ngpio; i++) > - if (!test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags)) > + if ((block->cur_mask & BIT(i)) && > + !test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags)) > return false; > return true; > } > @@ -1020,6 +1021,240 @@ 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 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, sizeof(unsigned long) == 4 ? "0x%08lx\n" : > + "0x%016lx\n", gpio_block_get(block, block->cur_mask)); > +} > + > +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; > + > + status = kstrtoul(buf, 0, &value); > + if (status == 0) { > + mutex_lock(&sysfs_lock); > + if (gpio_block_is_output(block)) { > + gpio_block_set(block, block->cur_mask, value); > + status = size; > + } else { > + status = -EPERM; > + } > + mutex_unlock(&sysfs_lock); > + } > + return status; > +} > + > +static struct device_attribute > +dev_attr_block_value = __ATTR(value, S_IWUSR | S_IRUGO, gpio_block_value_show, > + gpio_block_value_store); > + > +static ssize_t gpio_block_mask_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + const struct gpio_block *block = dev_get_drvdata(dev); > + > + return sprintf(buf, sizeof(unsigned long) == 4 ? "0x%08lx\n" : > + "0x%016lx\n", block->cur_mask); > +} > + > +static ssize_t gpio_block_mask_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 mask; > + > + status = kstrtoul(buf, 0, &mask); > + if (status == 0) { > + block->cur_mask = mask; > + status = size; > + } > + return status; > +} > + > +static struct device_attribute > +dev_attr_block_mask = __ATTR(mask, S_IWUSR | S_IRUGO, gpio_block_mask_show, > + gpio_block_mask_store); > + > +static struct class gpio_block_class; > + > +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_block_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; > +} > + > +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 out1; > + } > + > + dev = class_find_device(&gpio_block_class, NULL, block, match_export); > + if (!dev) { > + status = -ENODEV; > + goto out1; > + } > + > + status = device_create_file(dev, &dev_attr_block_value); > + if (status) > + goto out1; > + > + status = device_create_file(dev, &dev_attr_block_mask); > + if (status) > + goto out2; > + > + mutex_unlock(&sysfs_lock); > + return 0; > + > +out2: > + device_remove_file(dev, &dev_attr_block_value); > +out1: > + while (--i >= 0) > + 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_block_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); > + device_remove_file(dev, &dev_attr_block_mask); > + > + 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 struct device_attribute gpio_block_attrs[] = { > + __ATTR(exported, S_IWUSR | S_IRUGO, gpio_block_exported_show, > + gpio_block_exported_store), > + __ATTR(ngpio, S_IRUGO, gpio_block_ngpio_show, NULL), > + __ATTR_NULL, > +}; > + > +static struct class gpio_block_class = { > + .name = "gpioblock", > + .owner = THIS_MODULE, > + > + .dev_attrs = gpio_block_attrs, > +}; > + > +int gpio_block_export(struct gpio_block *block) > +{ > + int status = 0; > + struct device *dev; > + > + /* can't export until sysfs is available ... */ > + if (!gpio_block_class.p) { > + pr_debug("%s: called too early!\n", __func__); > + return -ENOENT; > + } > + > + mutex_lock(&sysfs_lock); > + dev = device_create(&gpio_block_class, NULL, MKDEV(0, 0), block, > + block->name); > + if (IS_ERR(dev)) > + 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_block_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; > @@ -1030,6 +1265,10 @@ static int __init gpiolib_sysfs_init(voi > if (status < 0) > return status; > > + status = class_register(&gpio_block_class); > + if (status < 0) > + return status; > + > /* Scan and register the gpio_chips which registered very > * early (e.g. before the class_register above was called). > * > @@ -1843,6 +2082,7 @@ struct gpio_block *gpio_block_create(uns > > block->name = name; > block->ngpio = size; > + block->cur_mask = ~0; > INIT_LIST_HEAD(&block->gbc_list); > block->gpio = kzalloc(sizeof(*block->gpio) * size, GFP_KERNEL); > if (!block->gpio) > @@ -2005,12 +2245,21 @@ EXPORT_SYMBOL_GPL(gpio_block_find_by_nam > > int gpio_block_register(struct gpio_block *block) > { > + int ret; > + > if (gpio_block_find_by_name(block->name)) > return -EBUSY; > > list_add(&block->list, &gpio_block_list); > > + ret = gpio_block_export(block); > + if (ret) > + goto err1; > + > return 0; > +err1: > + list_del(&block->list); > + return ret; > } > EXPORT_SYMBOL_GPL(gpio_block_register); > > @@ -2021,6 +2270,7 @@ void gpio_block_unregister(struct gpio_b > list_for_each_entry(i, &gpio_block_list, list) > if (i == block) { > list_del(&i->list); > + gpio_block_unexport(block); > break; > } > } > --- linux-2.6.orig/include/asm-generic/gpio.h > +++ linux-2.6/include/asm-generic/gpio.h > @@ -226,6 +226,8 @@ 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 */ > > @@ -285,6 +287,15 @@ 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 */ > > #ifdef CONFIG_PINCTRL > --- linux-2.6.orig/include/linux/gpio.h > +++ linux-2.6/include/linux/gpio.h > @@ -88,6 +88,7 @@ struct gpio_block_chip { > * @ngpio: number of gpios in this block > * @gpio: list of gpios in this block > * @list: global list of blocks, maintained by gpiolib > + * @cur_mask: currently used gpio mask used by userspace API > */ > struct gpio_block { > struct list_head gbc_list; > @@ -97,6 +98,7 @@ struct gpio_block { > unsigned *gpio; > > struct list_head list; > + unsigned long cur_mask; > }; > > #ifdef CONFIG_GENERIC_GPIO > @@ -314,6 +316,19 @@ 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 */
--- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio +++ linux-2.6/Documentation/ABI/testing/sysfs-gpio @@ -25,3 +25,23 @@ Description: /label ... (r/o) descriptive, not necessarily unique /ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1) +What: /sys/class/gpioblock/ +Date: October 2012 +KernelVersion: 3.7 +Contact: Roland Stigge <stigge@antcom.de> +Description: + + Block GPIO devices are visible in sysfs as soon as they are registered + (e.g. via devicetree definition). For actual I/O use, their "exported" + boolean attribute must be set to "1". Then, the attribute "values" is + created and at the same time, the GPIOs in the block are requested for + exclusive use by sysfs. + + /sys/class/gpioblock + /BLOCKNAME ... for each GPIO block name + /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 hex + (only available if /exported is 1) + /mask ... current mask as 32 or 64 bit integer in hex + (only available if /exported is 1) --- linux-2.6.orig/drivers/gpio/gpiolib.c +++ linux-2.6/drivers/gpio/gpiolib.c @@ -224,7 +224,8 @@ static bool gpio_block_is_output(struct int i; for (i = 0; i < block->ngpio; i++) - if (!test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags)) + if ((block->cur_mask & BIT(i)) && + !test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags)) return false; return true; } @@ -1020,6 +1021,240 @@ 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 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, sizeof(unsigned long) == 4 ? "0x%08lx\n" : + "0x%016lx\n", gpio_block_get(block, block->cur_mask)); +} + +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; + + status = kstrtoul(buf, 0, &value); + if (status == 0) { + mutex_lock(&sysfs_lock); + if (gpio_block_is_output(block)) { + gpio_block_set(block, block->cur_mask, value); + status = size; + } else { + status = -EPERM; + } + mutex_unlock(&sysfs_lock); + } + return status; +} + +static struct device_attribute +dev_attr_block_value = __ATTR(value, S_IWUSR | S_IRUGO, gpio_block_value_show, + gpio_block_value_store); + +static ssize_t gpio_block_mask_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct gpio_block *block = dev_get_drvdata(dev); + + return sprintf(buf, sizeof(unsigned long) == 4 ? "0x%08lx\n" : + "0x%016lx\n", block->cur_mask); +} + +static ssize_t gpio_block_mask_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 mask; + + status = kstrtoul(buf, 0, &mask); + if (status == 0) { + block->cur_mask = mask; + status = size; + } + return status; +} + +static struct device_attribute +dev_attr_block_mask = __ATTR(mask, S_IWUSR | S_IRUGO, gpio_block_mask_show, + gpio_block_mask_store); + +static struct class gpio_block_class; + +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_block_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; +} + +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 out1; + } + + dev = class_find_device(&gpio_block_class, NULL, block, match_export); + if (!dev) { + status = -ENODEV; + goto out1; + } + + status = device_create_file(dev, &dev_attr_block_value); + if (status) + goto out1; + + status = device_create_file(dev, &dev_attr_block_mask); + if (status) + goto out2; + + mutex_unlock(&sysfs_lock); + return 0; + +out2: + device_remove_file(dev, &dev_attr_block_value); +out1: + while (--i >= 0) + 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_block_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); + device_remove_file(dev, &dev_attr_block_mask); + + 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 struct device_attribute gpio_block_attrs[] = { + __ATTR(exported, S_IWUSR | S_IRUGO, gpio_block_exported_show, + gpio_block_exported_store), + __ATTR(ngpio, S_IRUGO, gpio_block_ngpio_show, NULL), + __ATTR_NULL, +}; + +static struct class gpio_block_class = { + .name = "gpioblock", + .owner = THIS_MODULE, + + .dev_attrs = gpio_block_attrs, +}; + +int gpio_block_export(struct gpio_block *block) +{ + int status = 0; + struct device *dev; + + /* can't export until sysfs is available ... */ + if (!gpio_block_class.p) { + pr_debug("%s: called too early!\n", __func__); + return -ENOENT; + } + + mutex_lock(&sysfs_lock); + dev = device_create(&gpio_block_class, NULL, MKDEV(0, 0), block, + block->name); + if (IS_ERR(dev)) + 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_block_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; @@ -1030,6 +1265,10 @@ static int __init gpiolib_sysfs_init(voi if (status < 0) return status; + status = class_register(&gpio_block_class); + if (status < 0) + return status; + /* Scan and register the gpio_chips which registered very * early (e.g. before the class_register above was called). * @@ -1843,6 +2082,7 @@ struct gpio_block *gpio_block_create(uns block->name = name; block->ngpio = size; + block->cur_mask = ~0; INIT_LIST_HEAD(&block->gbc_list); block->gpio = kzalloc(sizeof(*block->gpio) * size, GFP_KERNEL); if (!block->gpio) @@ -2005,12 +2245,21 @@ EXPORT_SYMBOL_GPL(gpio_block_find_by_nam int gpio_block_register(struct gpio_block *block) { + int ret; + if (gpio_block_find_by_name(block->name)) return -EBUSY; list_add(&block->list, &gpio_block_list); + ret = gpio_block_export(block); + if (ret) + goto err1; + return 0; +err1: + list_del(&block->list); + return ret; } EXPORT_SYMBOL_GPL(gpio_block_register); @@ -2021,6 +2270,7 @@ void gpio_block_unregister(struct gpio_b list_for_each_entry(i, &gpio_block_list, list) if (i == block) { list_del(&i->list); + gpio_block_unexport(block); break; } } --- linux-2.6.orig/include/asm-generic/gpio.h +++ linux-2.6/include/asm-generic/gpio.h @@ -226,6 +226,8 @@ 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 */ @@ -285,6 +287,15 @@ 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 */ #ifdef CONFIG_PINCTRL --- linux-2.6.orig/include/linux/gpio.h +++ linux-2.6/include/linux/gpio.h @@ -88,6 +88,7 @@ struct gpio_block_chip { * @ngpio: number of gpios in this block * @gpio: list of gpios in this block * @list: global list of blocks, maintained by gpiolib + * @cur_mask: currently used gpio mask used by userspace API */ struct gpio_block { struct list_head gbc_list; @@ -97,6 +98,7 @@ struct gpio_block { unsigned *gpio; struct list_head list; + unsigned long cur_mask; }; #ifdef CONFIG_GENERIC_GPIO @@ -314,6 +316,19 @@ 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 */
This patch adds sysfs support to the block GPIO API. Signed-off-by: Roland Stigge <stigge@antcom.de> --- Documentation/ABI/testing/sysfs-gpio | 20 ++ drivers/gpio/gpiolib.c | 252 ++++++++++++++++++++++++++++++++++- include/asm-generic/gpio.h | 11 + include/linux/gpio.h | 15 ++ 4 files changed, 297 insertions(+), 1 deletion(-)