[patch -mm 03/20] chardev: GPIO for SCx200 & PC-8736x: add platforn_devicefor use w dev_dbg

[Jim Cromie]

3/20. patch.platform-dev-2

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@xxxxxxxxx>

---

diffstat gpio-scx/patch.platform-dev-2
scx200_gpio.c |   40 +++++++++++++++++++++++++++++-----------
1 files changed, 29 insertions(+), 11 deletions(-)

diff -ruNp -X dontdiff -X exclude-diffs ax-2/drivers/char/scx200_gpio.c ax-3/drivers/char/scx200_gpio.c
--- ax-2/drivers/char/scx200_gpio.c	2006-06-17 01:01:13.000000000 -0600
+++ ax-3/drivers/char/scx200_gpio.c	2006-06-17 01:04:20.000000000 -0600
@@ -6,11 +6,13 @@
   Copyright (c) 2001,2002 Christer Weinigel <wingel@xxxxxxxxxxxxxxx> */

#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@xxxxxxxxxxxxxxx>");
MODULE_DESCRIPTION("NatSemi SCx200 GPIO Pin Driver");
@@ -121,12 +126,20 @@ 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 -ENODEV;
+
+	rc = platform_device_add(pdev);
+	if (rc)
+		goto undo_platform_device_add;
+
	if (major)
		rc = register_chrdev_region(dev, num_devs, "scx200_gpio");
	else {
@@ -134,29 +147,31 @@ static int __init scx200_gpio_init(void)
		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);
	if (!scx200_devices) {
		rc = -ENOMEM;
-		goto fail_malloc;
+		goto undo_chrdev_region;
	}
	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 */
+		/* 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_devs);
+undo_platform_device_add:
+	platform_device_put(pdev);
+	kfree(pdev);		/* undo platform_device_alloc */
	return rc;
}

@@ -164,6 +179,9 @@ static void __exit scx200_gpio_cleanup(v
{
	kfree(scx200_devices);
	unregister_chrdev_region(MKDEV(major, 0), num_devs);
+	platform_device_put(pdev);
+	platform_device_unregister(pdev);
+	/* kfree(pdev); */
}

module_init(scx200_gpio_init);


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