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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: display7seg.c,v 1.6 2002/01/08 16:00:16 davem Exp $
2 *
3 * display7seg - Driver implementation for the 7-segment display
4 * present on Sun Microsystems CP1400 and CP1500
5 *
6 * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
7 *
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/fs.h>
13#include <linux/errno.h>
14#include <linux/major.h>
15#include <linux/init.h>
16#include <linux/miscdevice.h>
Peter Osterlundfb911ee2005-09-13 01:25:15 -070017#include <linux/ioport.h> /* request_region */
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -080018#include <linux/smp_lock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <asm/atomic.h>
20#include <asm/ebus.h> /* EBus device */
21#include <asm/oplib.h> /* OpenProm Library */
22#include <asm/uaccess.h> /* put_/get_user */
23
24#include <asm/display7seg.h>
25
26#define D7S_MINOR 193
27#define D7S_OBPNAME "display7seg"
28#define D7S_DEVNAME "d7s"
29
30static int sol_compat = 0; /* Solaris compatibility mode */
31
32#ifdef MODULE
33
34/* Solaris compatibility flag -
35 * The Solaris implementation omits support for several
36 * documented driver features (ref Sun doc 806-0180-03).
37 * By default, this module supports the documented driver
38 * abilities, rather than the Solaris implementation:
39 *
40 * 1) Device ALWAYS reverts to OBP-specified FLIPPED mode
41 * upon closure of device or module unload.
42 * 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of
43 * FLIP bit
44 *
45 * If you wish the device to operate as under Solaris,
46 * omitting above features, set this parameter to non-zero.
47 */
48module_param
49 (sol_compat, int, 0);
50MODULE_PARM_DESC
51 (sol_compat,
52 "Disables documented functionality omitted from Solaris driver");
53
54MODULE_AUTHOR
55 ("Eric Brower <ebrower@usa.net>");
56MODULE_DESCRIPTION
57 ("7-Segment Display driver for Sun Microsystems CP1400/1500");
58MODULE_LICENSE("GPL");
59MODULE_SUPPORTED_DEVICE
60 ("d7s");
61#endif /* ifdef MODULE */
62
63/*
64 * Register block address- see header for details
65 * -----------------------------------------
66 * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |
67 * -----------------------------------------
68 *
69 * DP - Toggles decimal point on/off
70 * ALARM - Toggles "Alarm" LED green/red
71 * FLIP - Inverts display for upside-down mounted board
72 * bits 0-4 - 7-segment display contents
73 */
74static void __iomem* d7s_regs;
75
76static inline void d7s_free(void)
77{
78 iounmap(d7s_regs);
79}
80
81static inline int d7s_obpflipped(void)
82{
83 int opt_node;
84
85 opt_node = prom_getchild(prom_root_node);
86 opt_node = prom_searchsiblings(opt_node, "options");
87 return ((-1 != prom_getintdefault(opt_node, "d7s-flipped?", -1)) ? 0 : 1);
88}
89
90static atomic_t d7s_users = ATOMIC_INIT(0);
91
92static int d7s_open(struct inode *inode, struct file *f)
93{
94 if (D7S_MINOR != iminor(inode))
95 return -ENODEV;
96 atomic_inc(&d7s_users);
97 return 0;
98}
99
100static int d7s_release(struct inode *inode, struct file *f)
101{
102 /* Reset flipped state to OBP default only if
103 * no other users have the device open and we
104 * are not operating in solaris-compat mode
105 */
106 if (atomic_dec_and_test(&d7s_users) && !sol_compat) {
107 int regval = 0;
108
109 regval = readb(d7s_regs);
110 (0 == d7s_obpflipped()) ?
111 writeb(regval |= D7S_FLIP, d7s_regs):
112 writeb(regval &= ~D7S_FLIP, d7s_regs);
113 }
114
115 return 0;
116}
117
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800118static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
120 __u8 regs = readb(d7s_regs);
121 __u8 ireg = 0;
Andrew Mortona5aac372005-11-10 21:14:16 -0800122 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800124 if (D7S_MINOR != iminor(file->f_dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 return -ENODEV;
126
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800127 lock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 switch (cmd) {
129 case D7SIOCWR:
130 /* assign device register values
131 * we mask-out D7S_FLIP if in sol_compat mode
132 */
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800133 if (get_user(ireg, (int __user *) arg)) {
134 error = -EFAULT;
135 break;
136 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 if (0 != sol_compat) {
138 (regs & D7S_FLIP) ?
139 (ireg |= D7S_FLIP) : (ireg &= ~D7S_FLIP);
140 }
141 writeb(ireg, d7s_regs);
142 break;
143
144 case D7SIOCRD:
145 /* retrieve device register values
146 * NOTE: Solaris implementation returns D7S_FLIP bit
147 * as toggled by user, even though it does not honor it.
148 * This driver will not misinform you about the state
149 * of your hardware while in sol_compat mode
150 */
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800151 if (put_user(regs, (int __user *) arg)) {
152 error = -EFAULT;
153 break;
154 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 break;
156
157 case D7SIOCTM:
158 /* toggle device mode-- flip display orientation */
159 (regs & D7S_FLIP) ?
160 (regs &= ~D7S_FLIP) : (regs |= D7S_FLIP);
161 writeb(regs, d7s_regs);
162 break;
163 };
David S. Millerfeee2072005-11-09 12:05:37 -0800164 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800166 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167}
168
169static struct file_operations d7s_fops = {
Christoph Hellwig1d5d00b2005-11-07 14:13:01 -0800170 .owner = THIS_MODULE,
171 .unlocked_ioctl = d7s_ioctl,
172 .compat_ioctl = d7s_ioctl,
173 .open = d7s_open,
174 .release = d7s_release,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175};
176
177static struct miscdevice d7s_miscdev = { D7S_MINOR, D7S_DEVNAME, &d7s_fops };
178
179static int __init d7s_init(void)
180{
181 struct linux_ebus *ebus = NULL;
182 struct linux_ebus_device *edev = NULL;
183 int iTmp = 0, regs = 0;
184
185 for_each_ebus(ebus) {
186 for_each_ebusdev(edev, ebus) {
187 if (!strcmp(edev->prom_name, D7S_OBPNAME))
188 goto ebus_done;
189 }
190 }
191
192ebus_done:
193 if(!edev) {
194 printk("%s: unable to locate device\n", D7S_DEVNAME);
195 return -ENODEV;
196 }
197
198 d7s_regs = ioremap(edev->resource[0].start, sizeof(__u8));
199
200 iTmp = misc_register(&d7s_miscdev);
201 if (0 != iTmp) {
202 printk("%s: unable to acquire miscdevice minor %i\n",
203 D7S_DEVNAME, D7S_MINOR);
204 iounmap(d7s_regs);
205 return iTmp;
206 }
207
208 /* OBP option "d7s-flipped?" is honored as default
209 * for the device, and reset default when detached
210 */
211 regs = readb(d7s_regs);
212 iTmp = d7s_obpflipped();
213 (0 == iTmp) ?
214 writeb(regs |= D7S_FLIP, d7s_regs):
215 writeb(regs &= ~D7S_FLIP, d7s_regs);
216
217 printk("%s: 7-Segment Display%s at 0x%lx %s\n",
218 D7S_DEVNAME,
219 (0 == iTmp) ? (" (FLIPPED)") : (""),
220 edev->resource[0].start,
221 (0 != sol_compat) ? ("in sol_compat mode") : (""));
222
223 return 0;
224}
225
226static void __exit d7s_cleanup(void)
227{
228 int regs = readb(d7s_regs);
229
230 /* Honor OBP d7s-flipped? unless operating in solaris-compat mode */
231 if (0 == sol_compat) {
232 (0 == d7s_obpflipped()) ?
233 writeb(regs |= D7S_FLIP, d7s_regs):
234 writeb(regs &= ~D7S_FLIP, d7s_regs);
235 }
236
237 misc_deregister(&d7s_miscdev);
238 d7s_free();
239}
240
241module_init(d7s_init);
242module_exit(d7s_cleanup);