Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754114Ab2KQKBF (ORCPT ); Sat, 17 Nov 2012 05:01:05 -0500 Received: from antcom.de ([188.40.178.216]:34438 "EHLO chuck.antcom.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753590Ab2KQKBA (ORCPT ); Sat, 17 Nov 2012 05:01:00 -0500 From: Roland Stigge To: gregkh@linuxfoundation.org, grant.likely@secretlab.ca, linus.walleij@linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, w.sang@pengutronix.de, jbe@pengutronix.de, plagnioj@jcrosoft.com, highguy@gmail.com, broonie@opensource.wolfsonmicro.com, daniel-gl@gmx.net, rmallon@gmail.com Cc: Roland Stigge Subject: [PATCH 2/6 v7] gpio: Add sysfs support to block GPIO API Date: Sat, 17 Nov 2012 10:59:49 +0100 Message-Id: <1353146393-19312-3-git-send-email-stigge@antcom.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1353146393-19312-1-git-send-email-stigge@antcom.de> References: <1353146393-19312-1-git-send-email-stigge@antcom.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8762 Lines: 334 This patch adds sysfs support to the block GPIO API. Signed-off-by: Roland Stigge Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-gpio | 18 ++ drivers/gpio/gpiolib.c | 214 +++++++++++++++++++++++++++++++++++ include/asm-generic/gpio.h | 11 + include/linux/gpio.h | 13 ++ 4 files changed, 256 insertions(+) --- linux-2.6.orig/Documentation/ABI/testing/sysfs-gpio +++ linux-2.6/Documentation/ABI/testing/sysfs-gpio @@ -25,3 +25,21 @@ 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 +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) --- linux-2.6.orig/drivers/gpio/gpiolib.c +++ linux-2.6/drivers/gpio/gpiolib.c @@ -974,6 +974,214 @@ 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, ~0)); +} + +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; + + status = kstrtoul(buf, 0, &value); + if (status == 0) { + mutex_lock(&sysfs_lock); + if (gpio_block_is_output(block)) { + gpio_block_set(block, ~0, 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 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 out; + } + + dev = class_find_device(&gpio_block_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) + 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); + + 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; @@ -984,6 +1192,10 @@ 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). * @@ -1880,6 +2092,7 @@ int gpio_block_register(struct gpio_bloc return -EBUSY; list_add(&block->list, &gpio_block_list); + gpio_block_export(block); return 0; } @@ -1892,6 +2105,7 @@ 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 @@ -213,6 +213,8 @@ 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 */ @@ -272,6 +274,15 @@ 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 @@ -314,6 +314,19 @@ 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 */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/