[ patch -mm1 01/02 ] scx200_gpio: 1 cdev for N minors - cleanup,prep

[Jim Cromie]

this patch is mostly cleanup of scx200_gpio :
- drop #include <linux/config.h>
- s/DEVNAME/DRVNAME/    apparently a convention
- replace variable num_pins with  #define MAX_PINS
- s/dev/devid/   to clarify that its a dev_t, not a struct device dev.
- move devid = MKDEV(major,0)  into branch where its needed.

2 minor 'changes' :
- reduced MAX_PINS from 64 to 32.  Ive never tested other pins,
and theyre all multiplexed with other functions, some of which may be
in use on my soekris 4801, so I dont know what testing should yield.
If you (AKPM) think it should stay unchanged, please feel free to 
s/32/64/ the
patch directly, and consider this my Ack.  Otherwize I'll defer,
go read the datasheet, and see what I can do, when.

+EXPORT_SYMBOL(scx200_access);
This exposes the driver's vtable, which another driver can use
along with #include <linux/nsc_gpio.h>, to manipulate a gpio-pin.

Signed-off-by  Jim Cromie <jim.cromie@xxxxxxxxx>

---

$ diffstat diff.scx-normalize
scx200_gpio.c |   38 +++++++++++++++++++-------------------
1 files changed, 19 insertions(+), 19 deletions(-)


diff -ruNp -X dontdiff -X exclude-diffs x-0/drivers/char/scx200_gpio.c x-1/drivers/char/scx200_gpio.c
--- x-0/drivers/char/scx200_gpio.c	2006-07-06 13:19:16.000000000 -0600
+++ x-1/drivers/char/scx200_gpio.c	2006-07-10 20:19:17.000000000 -0600
@@ -5,7 +5,6 @@

   Copyright (c) 2001,2002 Christer Weinigel <wingel@xxxxxxxxxxxxxxx> */

-#include <linux/config.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/module.h>
@@ -22,19 +21,20 @@
#include <linux/scx200_gpio.h>
#include <linux/nsc_gpio.h>

-#define NAME "scx200_gpio"
-#define DEVNAME NAME
+#define DRVNAME "scx200_gpio"

static struct platform_device *pdev;

MODULE_AUTHOR("Christer Weinigel <wingel@xxxxxxxxxxxxxxx>");
-MODULE_DESCRIPTION("NatSemi SCx200 GPIO Pin Driver");
+MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver");
MODULE_LICENSE("GPL");

static int major = 0;		/* default to dynamic major */
module_param(major, int, 0);
MODULE_PARM_DESC(major, "Major device number");

+#define MAX_PINS 32		/* 64 later, when known ok */
+
struct nsc_gpio_ops scx200_access = {
	.owner		= THIS_MODULE,
	.gpio_config	= scx200_gpio_configure,
@@ -46,13 +46,14 @@ struct nsc_gpio_ops scx200_access = {
	.gpio_change	= scx200_gpio_change,
	.gpio_current	= scx200_gpio_current
};
+EXPORT_SYMBOL(scx200_access);

static int scx200_gpio_open(struct inode *inode, struct file *file)
{
	unsigned m = iminor(inode);
	file->private_data = &scx200_access;

-	if (m > 63)
+	if (m >= MAX_PINS)
		return -EINVAL;
	return nonseekable_open(inode, file);
}
@@ -72,20 +73,19 @@ static const struct file_operations scx2
};

struct cdev *scx200_devices;
-static int num_pins = 32;

static int __init scx200_gpio_init(void)
{
	int rc, i;
-	dev_t dev = MKDEV(major, 0);
+	dev_t devid;

	if (!scx200_gpio_present()) {
-		printk(KERN_ERR NAME ": no SCx200 gpio present\n");
+		printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n");
		return -ENODEV;
	}

	/* support dev_dbg() with pdev->dev */
-	pdev = platform_device_alloc(DEVNAME, 0);
+	pdev = platform_device_alloc(DRVNAME, 0);
	if (!pdev)
		return -ENOMEM;

@@ -96,22 +96,23 @@ static int __init scx200_gpio_init(void)
	/* nsc_gpio uses dev_dbg(), so needs this */
	scx200_access.dev = &pdev->dev;

-	if (major)
-		rc = register_chrdev_region(dev, num_pins, "scx200_gpio");
-	else {
-		rc = alloc_chrdev_region(&dev, 0, num_pins, "scx200_gpio");
-		major = MAJOR(dev);
+	if (major) {
+		devid = MKDEV(major, 0);
+		rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio");
+	} else {
+		rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio");
+		major = MAJOR(devid);
	}
	if (rc < 0) {
		dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);
		goto undo_platform_device_add;
	}
-	scx200_devices = kzalloc(num_pins * sizeof(struct cdev), GFP_KERNEL);
+	scx200_devices = kzalloc(MAX_PINS * sizeof(struct cdev), GFP_KERNEL);
	if (!scx200_devices) {
		rc = -ENOMEM;
		goto undo_chrdev_region;
	}
-	for (i = 0; i < num_pins; i++) {
+	for (i = 0; i < MAX_PINS; i++) {
		struct cdev *cdev = &scx200_devices[i];
		cdev_init(cdev, &scx200_gpio_fops);
		cdev->owner = THIS_MODULE;
@@ -124,7 +125,7 @@ static int __init scx200_gpio_init(void)
	return 0; /* succeed */

undo_chrdev_region:
-	unregister_chrdev_region(dev, num_pins);
+	unregister_chrdev_region(devid, MAX_PINS);
undo_platform_device_add:
	platform_device_del(pdev);
undo_malloc:
@@ -136,9 +137,8 @@ undo_malloc:
static void __exit scx200_gpio_cleanup(void)
{
	kfree(scx200_devices);
-	unregister_chrdev_region(MKDEV(major, 0), num_pins);
+	unregister_chrdev_region(MKDEV(major, 0), MAX_PINS);
	platform_device_unregister(pdev);
-	/* kfree(pdev); */
}

module_init(scx200_gpio_init);


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