1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /* linux/drivers/char/scx200_gpio.c
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun National Semiconductor SCx200 GPIO driver. Allows a user space
5*4882a593Smuzhiyun process to play with the GPIO pins.
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <linux/device.h>
10*4882a593Smuzhiyun #include <linux/fs.h>
11*4882a593Smuzhiyun #include <linux/module.h>
12*4882a593Smuzhiyun #include <linux/errno.h>
13*4882a593Smuzhiyun #include <linux/kernel.h>
14*4882a593Smuzhiyun #include <linux/init.h>
15*4882a593Smuzhiyun #include <linux/platform_device.h>
16*4882a593Smuzhiyun #include <linux/uaccess.h>
17*4882a593Smuzhiyun #include <asm/io.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #include <linux/types.h>
20*4882a593Smuzhiyun #include <linux/cdev.h>
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun #include <linux/scx200_gpio.h>
23*4882a593Smuzhiyun #include <linux/nsc_gpio.h>
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun #define DRVNAME "scx200_gpio"
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun static struct platform_device *pdev;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
30*4882a593Smuzhiyun MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver");
31*4882a593Smuzhiyun MODULE_LICENSE("GPL");
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun static int major = 0; /* default to dynamic major */
34*4882a593Smuzhiyun module_param(major, int, 0);
35*4882a593Smuzhiyun MODULE_PARM_DESC(major, "Major device number");
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun #define MAX_PINS 32 /* 64 later, when known ok */
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun struct nsc_gpio_ops scx200_gpio_ops = {
40*4882a593Smuzhiyun .owner = THIS_MODULE,
41*4882a593Smuzhiyun .gpio_config = scx200_gpio_configure,
42*4882a593Smuzhiyun .gpio_dump = nsc_gpio_dump,
43*4882a593Smuzhiyun .gpio_get = scx200_gpio_get,
44*4882a593Smuzhiyun .gpio_set = scx200_gpio_set,
45*4882a593Smuzhiyun .gpio_change = scx200_gpio_change,
46*4882a593Smuzhiyun .gpio_current = scx200_gpio_current
47*4882a593Smuzhiyun };
48*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(scx200_gpio_ops);
49*4882a593Smuzhiyun
scx200_gpio_open(struct inode * inode,struct file * file)50*4882a593Smuzhiyun static int scx200_gpio_open(struct inode *inode, struct file *file)
51*4882a593Smuzhiyun {
52*4882a593Smuzhiyun unsigned m = iminor(inode);
53*4882a593Smuzhiyun file->private_data = &scx200_gpio_ops;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun if (m >= MAX_PINS)
56*4882a593Smuzhiyun return -EINVAL;
57*4882a593Smuzhiyun return nonseekable_open(inode, file);
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun
scx200_gpio_release(struct inode * inode,struct file * file)60*4882a593Smuzhiyun static int scx200_gpio_release(struct inode *inode, struct file *file)
61*4882a593Smuzhiyun {
62*4882a593Smuzhiyun return 0;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun static const struct file_operations scx200_gpio_fileops = {
66*4882a593Smuzhiyun .owner = THIS_MODULE,
67*4882a593Smuzhiyun .write = nsc_gpio_write,
68*4882a593Smuzhiyun .read = nsc_gpio_read,
69*4882a593Smuzhiyun .open = scx200_gpio_open,
70*4882a593Smuzhiyun .release = scx200_gpio_release,
71*4882a593Smuzhiyun .llseek = no_llseek,
72*4882a593Smuzhiyun };
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */
75*4882a593Smuzhiyun
scx200_gpio_init(void)76*4882a593Smuzhiyun static int __init scx200_gpio_init(void)
77*4882a593Smuzhiyun {
78*4882a593Smuzhiyun int rc;
79*4882a593Smuzhiyun dev_t devid;
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun if (!scx200_gpio_present()) {
82*4882a593Smuzhiyun printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n");
83*4882a593Smuzhiyun return -ENODEV;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun /* support dev_dbg() with pdev->dev */
87*4882a593Smuzhiyun pdev = platform_device_alloc(DRVNAME, 0);
88*4882a593Smuzhiyun if (!pdev)
89*4882a593Smuzhiyun return -ENOMEM;
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun rc = platform_device_add(pdev);
92*4882a593Smuzhiyun if (rc)
93*4882a593Smuzhiyun goto undo_malloc;
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun /* nsc_gpio uses dev_dbg(), so needs this */
96*4882a593Smuzhiyun scx200_gpio_ops.dev = &pdev->dev;
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun if (major) {
99*4882a593Smuzhiyun devid = MKDEV(major, 0);
100*4882a593Smuzhiyun rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio");
101*4882a593Smuzhiyun } else {
102*4882a593Smuzhiyun rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio");
103*4882a593Smuzhiyun major = MAJOR(devid);
104*4882a593Smuzhiyun }
105*4882a593Smuzhiyun if (rc < 0) {
106*4882a593Smuzhiyun dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);
107*4882a593Smuzhiyun goto undo_platform_device_add;
108*4882a593Smuzhiyun }
109*4882a593Smuzhiyun
110*4882a593Smuzhiyun cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops);
111*4882a593Smuzhiyun cdev_add(&scx200_gpio_cdev, devid, MAX_PINS);
112*4882a593Smuzhiyun
113*4882a593Smuzhiyun return 0; /* succeed */
114*4882a593Smuzhiyun
115*4882a593Smuzhiyun undo_platform_device_add:
116*4882a593Smuzhiyun platform_device_del(pdev);
117*4882a593Smuzhiyun undo_malloc:
118*4882a593Smuzhiyun platform_device_put(pdev);
119*4882a593Smuzhiyun
120*4882a593Smuzhiyun return rc;
121*4882a593Smuzhiyun }
122*4882a593Smuzhiyun
scx200_gpio_cleanup(void)123*4882a593Smuzhiyun static void __exit scx200_gpio_cleanup(void)
124*4882a593Smuzhiyun {
125*4882a593Smuzhiyun cdev_del(&scx200_gpio_cdev);
126*4882a593Smuzhiyun /* cdev_put(&scx200_gpio_cdev); */
127*4882a593Smuzhiyun
128*4882a593Smuzhiyun unregister_chrdev_region(MKDEV(major, 0), MAX_PINS);
129*4882a593Smuzhiyun platform_device_unregister(pdev);
130*4882a593Smuzhiyun }
131*4882a593Smuzhiyun
132*4882a593Smuzhiyun module_init(scx200_gpio_init);
133*4882a593Smuzhiyun module_exit(scx200_gpio_cleanup);
134