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-rw-r--r--MAINTAINERS1
-rw-r--r--drivers/gpio/gpiolib.c125
-rw-r--r--drivers/gpio/gpiolib.h2
-rw-r--r--include/uapi/linux/Kbuild1
-rw-r--r--include/uapi/linux/gpio.h28
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_ */