diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.c | 125 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/Kbuild | 1 | ||||
| -rw-r--r-- | include/uapi/linux/gpio.h | 28 |
5 files changed, 156 insertions, 1 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 30aca4aa5467..76986c3ab4ff 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4819,6 +4819,7 @@ F: drivers/gpio/ F: include/linux/gpio/ F: include/linux/gpio.h F: include/asm-generic/gpio.h +F: include/uapi/linux/gpio.h GRE DEMULTIPLEXER DRIVER M: Dmitry Kozlov <xeb@mail.ru> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 4b94e31a50af..70e0fff0a8a7 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -17,6 +17,10 @@ #include <linux/gpio/machine.h> #include <linux/pinctrl/consumer.h> #include <linux/idr.h> +#include <linux/cdev.h> +#include <linux/fs.h> +#include <linux/uaccess.h> +#include <uapi/linux/gpio.h> #include "gpiolib.h" @@ -45,6 +49,11 @@ /* Device and char device-related information */ static DEFINE_IDA(gpio_ida); +static dev_t gpio_devt; +#define GPIO_DEV_MAX 256 /* 256 GPIO chip devices supported */ +static struct bus_type gpio_bus_type = { + .name = "gpio", +}; /* gpio_lock prevents conflicts during gpio_desc[] table updates. * While any GPIO is requested, its gpio_chip is not removable; @@ -316,10 +325,84 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc) return 0; } +/** + * gpio_ioctl() - ioctl handler for the GPIO chardev + */ +static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct gpio_device *gdev = filp->private_data; + struct gpio_chip *chip = gdev->chip; + int __user *ip = (int __user *)arg; + struct gpiochip_info chipinfo; + + /* We fail any subsequent ioctl():s when the chip is gone */ + if (!chip) + return -ENODEV; + + if (cmd == GPIO_GET_CHIPINFO_IOCTL) { + /* Fill in the struct and pass to userspace */ + strncpy(chipinfo.name, dev_name(&gdev->dev), + sizeof(chipinfo.name)); + chipinfo.name[sizeof(chipinfo.name)-1] = '\0'; + chipinfo.lines = chip->ngpio; + if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) + return -EFAULT; + return 0; + } + return -EINVAL; +} + +/** + * gpio_chrdev_open() - open the chardev for ioctl operations + * @inode: inode for this chardev + * @filp: file struct for storing private data + * Returns 0 on success + */ +static int gpio_chrdev_open(struct inode *inode, struct file *filp) +{ + struct gpio_device *gdev = container_of(inode->i_cdev, + struct gpio_device, chrdev); + + /* Fail on open if the backing gpiochip is gone */ + if (!gdev || !gdev->chip) + return -ENODEV; + get_device(&gdev->dev); + filp->private_data = gdev; + return 0; +} + +/** + * gpio_chrdev_release() - close chardev after ioctl operations + * @inode: inode for this chardev + * @filp: file struct for storing private data + * Returns 0 on success + */ +static int gpio_chrdev_release(struct inode *inode, struct file *filp) +{ + struct gpio_device *gdev = container_of(inode->i_cdev, + struct gpio_device, chrdev); + + if (!gdev) + return -ENODEV; + put_device(&gdev->dev); + return 0; +} + + +static const struct file_operations gpio_fileops = { + .release = gpio_chrdev_release, + .open = gpio_chrdev_open, + .owner = THIS_MODULE, + .llseek = noop_llseek, + .unlocked_ioctl = gpio_ioctl, + .compat_ioctl = gpio_ioctl, +}; + static void gpiodevice_release(struct device *dev) { struct gpio_device *gdev = dev_get_drvdata(dev); + cdev_del(&gdev->chrdev); list_del(&gdev->list); ida_simple_remove(&gpio_ida, gdev->id); } @@ -357,6 +440,7 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) gdev = kmalloc(sizeof(*gdev), GFP_KERNEL); if (!gdev) return -ENOMEM; + gdev->dev.bus = &gpio_bus_type; gdev->chip = chip; chip->gpiodev = gdev; if (chip->parent) { @@ -452,9 +536,26 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) acpi_gpiochip_add(chip); + /* + * By first adding the chardev, and then adding the device, + * we get a device node entry in sysfs under + * /sys/bus/gpio/devices/gpiochipN/dev that can be used for + * coldplug of device nodes and other udev business. + */ + cdev_init(&gdev->chrdev, &gpio_fileops); + gdev->chrdev.owner = THIS_MODULE; + gdev->chrdev.kobj.parent = &gdev->dev.kobj; + gdev->dev.devt = MKDEV(MAJOR(gpio_devt), gdev->id); + status = cdev_add(&gdev->chrdev, gdev->dev.devt, 1); + if (status < 0) + chip_warn(chip, "failed to add char device %d:%d\n", + MAJOR(gpio_devt), gdev->id); + else + chip_dbg(chip, "added GPIO chardev (%d:%d)\n", + MAJOR(gpio_devt), gdev->id); status = device_add(&gdev->dev); if (status) - goto err_remove_chip; + goto err_remove_chardev; status = gpiochip_sysfs_register(chip); if (status) @@ -471,6 +572,8 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data) err_remove_device: device_del(&gdev->dev); +err_remove_chardev: + cdev_del(&gdev->chrdev); err_remove_chip: acpi_gpiochip_remove(chip); gpiochip_free_hogs(chip); @@ -2543,6 +2646,26 @@ void gpiod_put_array(struct gpio_descs *descs) } EXPORT_SYMBOL_GPL(gpiod_put_array); +static int __init gpiolib_dev_init(void) +{ + int ret; + + /* Register GPIO sysfs bus */ + ret = bus_register(&gpio_bus_type); + if (ret < 0) { + pr_err("gpiolib: could not register GPIO bus type\n"); + return ret; + } + + ret = alloc_chrdev_region(&gpio_devt, 0, GPIO_DEV_MAX, "gpiochip"); + if (ret < 0) { + pr_err("gpiolib: failed to allocate char dev region\n"); + bus_unregister(&gpio_bus_type); + } + return ret; +} +core_initcall(gpiolib_dev_init); + #ifdef CONFIG_DEBUG_FS static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 3f329c922f5b..1524ba0ca99d 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -26,6 +26,7 @@ struct acpi_device; * struct gpio_device - internal state container for GPIO devices * @id: numerical ID number for the GPIO chip * @dev: the GPIO device struct + * @chrdev: character device for the GPIO device * @owner: helps prevent removal of modules exporting active GPIOs * @chip: pointer to the corresponding gpiochip, holding static * data for this device @@ -39,6 +40,7 @@ struct acpi_device; struct gpio_device { int id; struct device dev; + struct cdev chrdev; struct module *owner; struct gpio_chip *chip; struct list_head list; diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild index ebd10e624598..5c9ae6a9b7f5 100644 --- a/include/uapi/linux/Kbuild +++ b/include/uapi/linux/Kbuild @@ -138,6 +138,7 @@ header-y += genetlink.h header-y += gen_stats.h header-y += gfs2_ondisk.h header-y += gigaset_dev.h +header-y += gpio.h header-y += gsmmux.h header-y += hdlcdrv.h header-y += hdlc.h diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h new file mode 100644 index 000000000000..3188a87bdaa0 --- /dev/null +++ b/include/uapi/linux/gpio.h @@ -0,0 +1,28 @@ +/* + * <linux/gpio.h> - userspace ABI for the GPIO character devices + * + * Copyright (C) 2015 Linus Walleij + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ +#ifndef _UAPI_GPIO_H_ +#define _UAPI_GPIO_H_ + +#include <linux/ioctl.h> +#include <linux/types.h> + +/** + * struct gpiochip_info - Information about a certain GPIO chip + * @name: the name of this GPIO chip + * @lines: number of GPIO lines on this chip + */ +struct gpiochip_info { + char name[32]; + __u32 lines; +}; + +#define GPIO_GET_CHIPINFO_IOCTL _IOR('o', 0x01, struct gpiochip_info) + +#endif /* _UAPI_GPIO_H_ */ |