1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* linux/drivers/char/nsc_gpio.c |
3 | |
4 | National Semiconductor common GPIO device-file/VFS methods. |
5 | Allows a user space process to control the GPIO pins. |
6 | |
7 | Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> |
8 | Copyright (c) 2005 Jim Cromie <jim.cromie@gmail.com> |
9 | */ |
10 | |
11 | #include <linux/fs.h> |
12 | #include <linux/module.h> |
13 | #include <linux/errno.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/init.h> |
16 | #include <linux/nsc_gpio.h> |
17 | #include <linux/platform_device.h> |
18 | #include <linux/uaccess.h> |
19 | #include <asm/io.h> |
20 | |
21 | #define NAME "nsc_gpio" |
22 | |
23 | void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index) |
24 | { |
25 | /* retrieve current config w/o changing it */ |
26 | u32 config = amp->gpio_config(index, ~0, 0); |
27 | |
28 | /* user requested via 'v' command, so its INFO */ |
29 | dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d\n" , |
30 | index, config, |
31 | (config & 1) ? "OE" : "TS" , /* output-enabled/tristate */ |
32 | (config & 2) ? "PP" : "OD" , /* push pull / open drain */ |
33 | (config & 4) ? "PUE" : "PUD" , /* pull up enabled/disabled */ |
34 | (config & 8) ? "LOCKED" : "" , /* locked / unlocked */ |
35 | (config & 16) ? "LEVEL" : "EDGE" ,/* level/edge input */ |
36 | (config & 32) ? "HI" : "LO" , /* trigger on rise/fall edge */ |
37 | (config & 64) ? "DEBOUNCE" : "" , /* debounce */ |
38 | |
39 | amp->gpio_get(index), amp->gpio_current(index)); |
40 | } |
41 | |
42 | ssize_t nsc_gpio_write(struct file *file, const char __user *data, |
43 | size_t len, loff_t *ppos) |
44 | { |
45 | unsigned m = iminor(inode: file_inode(f: file)); |
46 | struct nsc_gpio_ops *amp = file->private_data; |
47 | struct device *dev = amp->dev; |
48 | size_t i; |
49 | int err = 0; |
50 | |
51 | for (i = 0; i < len; ++i) { |
52 | char c; |
53 | if (get_user(c, data + i)) |
54 | return -EFAULT; |
55 | switch (c) { |
56 | case '0': |
57 | amp->gpio_set(m, 0); |
58 | break; |
59 | case '1': |
60 | amp->gpio_set(m, 1); |
61 | break; |
62 | case 'O': |
63 | dev_dbg(dev, "GPIO%d output enabled\n" , m); |
64 | amp->gpio_config(m, ~1, 1); |
65 | break; |
66 | case 'o': |
67 | dev_dbg(dev, "GPIO%d output disabled\n" , m); |
68 | amp->gpio_config(m, ~1, 0); |
69 | break; |
70 | case 'T': |
71 | dev_dbg(dev, "GPIO%d output is push pull\n" , m); |
72 | amp->gpio_config(m, ~2, 2); |
73 | break; |
74 | case 't': |
75 | dev_dbg(dev, "GPIO%d output is open drain\n" , m); |
76 | amp->gpio_config(m, ~2, 0); |
77 | break; |
78 | case 'P': |
79 | dev_dbg(dev, "GPIO%d pull up enabled\n" , m); |
80 | amp->gpio_config(m, ~4, 4); |
81 | break; |
82 | case 'p': |
83 | dev_dbg(dev, "GPIO%d pull up disabled\n" , m); |
84 | amp->gpio_config(m, ~4, 0); |
85 | break; |
86 | case 'v': |
87 | /* View Current pin settings */ |
88 | amp->gpio_dump(amp, m); |
89 | break; |
90 | case '\n': |
91 | /* end of settings string, do nothing */ |
92 | break; |
93 | default: |
94 | dev_err(dev, "io%2d bad setting: chr<0x%2x>\n" , |
95 | m, (int)c); |
96 | err++; |
97 | } |
98 | } |
99 | if (err) |
100 | return -EINVAL; /* full string handled, report error */ |
101 | |
102 | return len; |
103 | } |
104 | |
105 | ssize_t nsc_gpio_read(struct file *file, char __user * buf, |
106 | size_t len, loff_t * ppos) |
107 | { |
108 | unsigned m = iminor(inode: file_inode(f: file)); |
109 | int value; |
110 | struct nsc_gpio_ops *amp = file->private_data; |
111 | |
112 | value = amp->gpio_get(m); |
113 | if (put_user(value ? '1' : '0', buf)) |
114 | return -EFAULT; |
115 | |
116 | return 1; |
117 | } |
118 | |
119 | /* common file-ops routines for both scx200_gpio and pc87360_gpio */ |
120 | EXPORT_SYMBOL(nsc_gpio_write); |
121 | EXPORT_SYMBOL(nsc_gpio_read); |
122 | EXPORT_SYMBOL(nsc_gpio_dump); |
123 | |
124 | static int __init nsc_gpio_init(void) |
125 | { |
126 | printk(KERN_DEBUG NAME " initializing\n" ); |
127 | return 0; |
128 | } |
129 | |
130 | static void __exit nsc_gpio_cleanup(void) |
131 | { |
132 | printk(KERN_DEBUG NAME " cleanup\n" ); |
133 | } |
134 | |
135 | module_init(nsc_gpio_init); |
136 | module_exit(nsc_gpio_cleanup); |
137 | |
138 | MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>" ); |
139 | MODULE_DESCRIPTION("NatSemi GPIO Common Methods" ); |
140 | MODULE_LICENSE("GPL" ); |
141 | |