[PATCH] chardev: GPIO for SCx200 & PC-8736x: add platforn_device for use w dev_dbg

Add a platform-device to scx200_gpio, and use its struct device dev member
(ie: devp) in dev_dbg() once.

There are 2 alternatives here (Im soliciting guidance/commentary):

- use isa_device, if/when its added to the kernel.

- alter scx200.c to EXPORT_GPL its private devp so that both scx200_gpio,
  and the (to be added) nsc_gpio module can use it.  Since the available devp
  is in 'grandparent', this seems like too much 'action at a distance'.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 36 insertions, 17 deletions

diff --git a/drivers/char/scx200_gpio.c b/drivers/char/scx200_gpio.c
index 507a5bf567cb..e6e52c48697b 100644
--- a/drivers/char/scx200_gpio.c
+++ b/drivers/char/scx200_gpio.c
@@ -6,11 +6,13 @@
    Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */
 
 #include <linux/config.h>
+#include <linux/device.h>
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/platform_device.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 
@@ -20,6 +22,9 @@
 #include <linux/scx200_gpio.h>
 
 #define NAME "scx200_gpio"
+#define DEVNAME NAME
+
+static struct platform_device *pdev;
 
 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
 MODULE_DESCRIPTION("NatSemi SCx200 GPIO Pin Driver");
@@ -114,56 +119,70 @@ static struct file_operations scx200_gpio_fops = {
 };
 
 struct cdev *scx200_devices;
-int num_devs = 32;
+static int num_pins = 32;
 
 static int __init scx200_gpio_init(void)
 {
         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 present\n");
                 return -ENODEV;
         }
+
+        /* support dev_dbg() with pdev->dev */
+        pdev = platform_device_alloc(DEVNAME, 0);
+        if (!pdev)
+                return -ENOMEM;
+
+        rc = platform_device_add(pdev);
+        if (rc)
+                goto undo_malloc;
+
         if (major)
-                rc = register_chrdev_region(dev, num_devs, "scx200_gpio");
+                rc = register_chrdev_region(dev, num_pins, "scx200_gpio");
         else {
-                rc = alloc_chrdev_region(&dev, 0, num_devs, "scx200_gpio");
+                rc = alloc_chrdev_region(&dev, 0, num_pins, "scx200_gpio");
                 major = MAJOR(dev);
         }
         if (rc < 0) {
-                printk(KERN_ERR NAME ": SCx200 chrdev_region: %d\n", rc);
-                return rc;
+                dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);
+                goto undo_platform_device_add;
         }
-        scx200_devices = kzalloc(num_devs * sizeof(struct cdev), GFP_KERNEL);
+        scx200_devices = kzalloc(num_pins * sizeof(struct cdev), GFP_KERNEL);
         if (!scx200_devices) {
                 rc = -ENOMEM;
-                goto fail_malloc;
+                goto undo_chrdev_region;
         }
-        for (i = 0; i < num_devs; i++) {
+        for (i = 0; i < num_pins; 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 */
+                /* tolerate 'minor' errors */
                 if (rc)
-                        printk(KERN_ERR NAME "Error %d on minor %d", rc, i);
+                        dev_err(&pdev->dev, "Error %d on minor %d", rc, i);
         }
 
-        return 0;               /* succeed */
+        return 0; /* succeed */
 
-fail_malloc:
-        unregister_chrdev_region(dev, num_devs);
+undo_chrdev_region:
+        unregister_chrdev_region(dev, num_pins);
+undo_platform_device_add:
+        platform_device_put(pdev);
+undo_malloc:
+        kfree(pdev);
         return rc;
 }
 
 static void __exit scx200_gpio_cleanup(void)
 {
         kfree(scx200_devices);
-        unregister_chrdev_region(MKDEV(major, 0), num_devs);
+        unregister_chrdev_region(MKDEV(major, 0), num_pins);
+        platform_device_put(pdev);
+        platform_device_unregister(pdev);
+        /* kfree(pdev); */
 }
 
 module_init(scx200_gpio_init);