[patch 03/19] chardev: pc8736x_gpio - upgrage scx200_gpio init per ldd3

GPIO SUPPORT FOR SCx200 & PC8736x

This patch-set reworks the 2.4 vintage scx200_gpio driver for modern
2.6, and refactors GPIO support to reuse it in a new driver for the
GPIO on PC-8736x chips.


03/19. patch.api26:

Adopt many modern 2.6 coding practices, ala LDD3.  Changes here
limited to newer (than 2.4) initialization calls from module init:
cdev_init, cdev_add, *_chrdev_region, mkdev

scx200_gpio.c |   55 
++++++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 42 insertions(+), 13 deletions(-)


diff -ruNp -X dontdiff -X exclude-diffs k16r-2/drivers/char/scx200_gpio.c 
k16r-3/drivers/char/scx200_gpio.c
--- k16r-2/drivers/char/scx200_gpio.c   2006-05-28 12:18:48.000000000 -0600
+++ k16r-3/drivers/char/scx200_gpio.c   2006-05-28 12:19:22.000000000 -0600
@@ -14,6 +14,9 @@
#include <asm/uaccess.h>
#include <asm/io.h>

+#include <linux/types.h>
+#include <linux/cdev.h>
+
#include <linux/scx200_gpio.h>

#define NAME "scx200_gpio"
@@ -26,6 +29,8 @@ static int major = 0;         /* default to dyn
module_param(major, int, 0);
MODULE_PARM_DESC(major, "Major device number");

+extern void scx200_gpio_dump(unsigned index);
+
static ssize_t scx200_gpio_write(struct file *file, const char __user * data,
                                 size_t len, loff_t * ppos)
{
@@ -109,33 +114,57 @@ static struct file_operations scx200_gpi
        .release = scx200_gpio_release,
};

+struct cdev *scx200_devices;
+int num_devs = 32;
+
static int __init scx200_gpio_init(void)
{
-       int r;
+       int rc, i;
+       dev_t dev = MKDEV(major, 0);

        printk(KERN_DEBUG NAME ": NatSemi SCx200 GPIO Driver\n");

        if (!scx200_gpio_present()) {
-               printk(KERN_ERR NAME ": no SCx200 gpio pins available\n");
+               printk(KERN_ERR NAME ": no SCx200 gpio present\n");
                return -ENODEV;
        }
-
-       r = register_chrdev(major, NAME, &scx200_gpio_fops);
-       if (r < 0) {
-               printk(KERN_ERR NAME ": unable to register character device\n");
-               return r;
-       }
-       if (!major) {
-               major = r;
-               printk(KERN_DEBUG NAME ": got dynamic major %d\n", major);
+       if (major)
+               rc = register_chrdev_region(dev, num_devs, "scx200_gpio");
+       else {
+               rc = alloc_chrdev_region(&dev, 0, num_devs, "scx200_gpio");
+               major = MAJOR(dev);
+       }
+       if (rc < 0) {
+               printk(KERN_ERR NAME ": SCx200 chrdev_region failure %d\n", rc);
+               return rc;
+       }
+       scx200_devices = kzalloc(num_devs * sizeof(struct cdev), GFP_KERNEL);
+       if (!scx200_devices) {
+               rc = -ENOMEM;
+               goto fail_malloc;
+       }
+       for (i = 0; i < num_devs; i++) {
+               struct cdev *cdev = &scx200_devices[i];
+               cdev_init(cdev, &scx200_gpio_fops);
+               cdev->owner = THIS_MODULE;
+               cdev->ops = &scx200_gpio_fops;
+               rc = cdev_add(cdev, MKDEV(major, i), 1);
+               /* Fail gracefully if need be */
+               if (rc)
+                       printk(KERN_ERR NAME "Error %d on minor %d", rc, i);
        }

-       return 0;
+       return 0;               /* succeed */
+
+      fail_malloc:
+       unregister_chrdev_region(dev, num_devs);
+       return rc;
}

static void __exit scx200_gpio_cleanup(void)
{
-       unregister_chrdev(major, NAME);
+       kfree(scx200_devices);
+       unregister_chrdev_region(MKDEV(major, 0), num_devs);
}

module_init(scx200_gpio_init);