modules/gpio_dev: move to drivers/char/ on older kernels as well, and create a package for it

SVN-Revision: 12133

1 files changed, 201 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/files/drivers/char/gpio_dev.c b/target/linux/generic-2.6/files/drivers/char/gpio_dev.c
new file mode 100644
index 0000000000..48ef76f8a9
--- /dev/null
+++ b/target/linux/generic-2.6/files/drivers/char/gpio_dev.c
@@ -0,0 +1,201 @@
+/*
+ * character device wrapper for generic gpio layer
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA02111-1307USA
+ *
+ * Feedback, Bugs...  blogic@openwrt.org
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <asm/atomic.h>
+#include <linux/init.h>
+#include <linux/genhd.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/gpio_dev.h>
+
+#define DRVNAME		"gpiodev"
+#define DEVNAME		"gpio"
+
+static int dev_major;
+static unsigned int gpio_access_mask;
+static struct class *gpio_class;
+
+/* Counter is 1, if the device is not opened and zero (or less) if opened. */
+static atomic_t gpio_open_cnt = ATOMIC_INIT(1);
+
+static int
+gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg)
+{
+	int retval = 0;
+
+	if (((1 << arg) & gpio_access_mask) != (1 << arg))
+	{
+		retval = -EINVAL;
+		goto out;
+	}
+
+	switch (cmd)
+	{
+	case GPIO_GET:
+		retval = gpio_get_value(arg);
+		break;
+
+	case GPIO_SET:
+		gpio_set_value(arg, 1);
+		break;
+
+	case GPIO_CLEAR:
+		gpio_set_value(arg, 0);
+		break;
+
+	case GPIO_DIR_IN:
+		gpio_direction_input(arg);
+		break;
+
+	case GPIO_DIR_OUT:
+		gpio_direction_output(arg, 0);
+		break;
+
+	default:
+		retval = -EINVAL;
+		break;
+	}
+
+out:
+	return retval;
+}
+
+static int
+gpio_open(struct inode *inode, struct file *file)
+{
+	int result = 0;
+	unsigned int dev_minor = MINOR(inode->i_rdev);
+
+	if (dev_minor != 0)
+	{
+		printk(KERN_ERR DRVNAME ": trying to access unknown minor device -> %d\n", dev_minor);
+		result = -ENODEV;
+		goto out;
+	}
+
+	/* FIXME: We should really allow multiple applications to open the device
+	 *        at the same time, as long as the apps access different IO pins.
+	 *        The generic gpio-registration functions can be used for that.
+	 *        Two new IOCTLs have to be introduced for that. Need to check userspace
+	 *        compatibility first. --mb */
+	if (!atomic_dec_and_test(&gpio_open_cnt)) {
+		atomic_inc(&gpio_open_cnt);
+		printk(KERN_ERR DRVNAME ": Device with minor ID %d already in use\n", dev_minor);
+		result = -EBUSY;
+		goto out;
+	}
+
+out:
+	return result;
+}
+
+static int
+gpio_close(struct inode * inode, struct file * file)
+{
+	smp_mb__before_atomic_inc();
+	atomic_inc(&gpio_open_cnt);
+
+	return 0;
+}
+
+struct file_operations gpio_fops = {
+	ioctl:		gpio_ioctl,
+	open:		gpio_open,
+	release:	gpio_close
+};
+
+static int
+gpio_probe(struct platform_device *dev)
+{
+	int result = 0;
+
+	dev_major = register_chrdev(0, DEVNAME, &gpio_fops);
+	if (!dev_major)
+	{
+		printk(KERN_ERR DRVNAME ": Error whilst opening %s \n", DEVNAME);
+		result = -ENODEV;
+		goto out;
+	}
+
+	gpio_class = class_create(THIS_MODULE, DEVNAME);
+	class_device_create(gpio_class, NULL, MKDEV(dev_major, 0), NULL, DEVNAME);
+
+	printk(KERN_INFO DRVNAME ": gpio device registered with major %d\n", dev_major);
+
+	if (dev->num_resources != 1)
+	{
+		printk(KERN_ERR DRVNAME ": device may only have 1 resource\n");
+		result = -ENODEV;
+		goto out;
+	}
+
+	gpio_access_mask = dev->resource[0].start;
+
+	printk(KERN_INFO DRVNAME ": gpio platform device registered with access mask %08X\n", gpio_access_mask);
+out:
+	return result;
+}
+
+static int
+gpio_remove(struct platform_device *dev)
+{
+	unregister_chrdev(dev_major, DEVNAME);
+	return 0;
+}
+
+static struct
+platform_driver gpio_driver = {
+	.probe = gpio_probe,
+	.remove = gpio_remove,
+	.driver = {
+		.name = "GPIODEV",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init
+gpio_mod_init(void)
+{
+	int ret = platform_driver_register(&gpio_driver);
+	if (ret)
+		printk(KERN_INFO DRVNAME ": Error registering platfom driver!");
+
+	return ret;
+}
+
+static void __exit
+gpio_mod_exit(void)
+{
+	platform_driver_unregister(&gpio_driver);
+}
+
+module_init (gpio_mod_init);
+module_exit (gpio_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("John Crispin / OpenWrt");
+MODULE_DESCRIPTION("Character device for for generic gpio api");