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1da177e4 LT |
1 | /* $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> | |
17 | #include <linux/ioport.h> /* request_region, check_region */ | |
18 | #include <asm/atomic.h> | |
19 | #include <asm/ebus.h> /* EBus device */ | |
20 | #include <asm/oplib.h> /* OpenProm Library */ | |
21 | #include <asm/uaccess.h> /* put_/get_user */ | |
22 | ||
23 | #include <asm/display7seg.h> | |
24 | ||
25 | #define D7S_MINOR 193 | |
26 | #define D7S_OBPNAME "display7seg" | |
27 | #define D7S_DEVNAME "d7s" | |
28 | ||
29 | static int sol_compat = 0; /* Solaris compatibility mode */ | |
30 | ||
31 | #ifdef MODULE | |
32 | ||
33 | /* Solaris compatibility flag - | |
34 | * The Solaris implementation omits support for several | |
35 | * documented driver features (ref Sun doc 806-0180-03). | |
36 | * By default, this module supports the documented driver | |
37 | * abilities, rather than the Solaris implementation: | |
38 | * | |
39 | * 1) Device ALWAYS reverts to OBP-specified FLIPPED mode | |
40 | * upon closure of device or module unload. | |
41 | * 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of | |
42 | * FLIP bit | |
43 | * | |
44 | * If you wish the device to operate as under Solaris, | |
45 | * omitting above features, set this parameter to non-zero. | |
46 | */ | |
47 | module_param | |
48 | (sol_compat, int, 0); | |
49 | MODULE_PARM_DESC | |
50 | (sol_compat, | |
51 | "Disables documented functionality omitted from Solaris driver"); | |
52 | ||
53 | MODULE_AUTHOR | |
54 | ("Eric Brower <ebrower@usa.net>"); | |
55 | MODULE_DESCRIPTION | |
56 | ("7-Segment Display driver for Sun Microsystems CP1400/1500"); | |
57 | MODULE_LICENSE("GPL"); | |
58 | MODULE_SUPPORTED_DEVICE | |
59 | ("d7s"); | |
60 | #endif /* ifdef MODULE */ | |
61 | ||
62 | /* | |
63 | * Register block address- see header for details | |
64 | * ----------------------------------------- | |
65 | * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 | | |
66 | * ----------------------------------------- | |
67 | * | |
68 | * DP - Toggles decimal point on/off | |
69 | * ALARM - Toggles "Alarm" LED green/red | |
70 | * FLIP - Inverts display for upside-down mounted board | |
71 | * bits 0-4 - 7-segment display contents | |
72 | */ | |
73 | static void __iomem* d7s_regs; | |
74 | ||
75 | static inline void d7s_free(void) | |
76 | { | |
77 | iounmap(d7s_regs); | |
78 | } | |
79 | ||
80 | static inline int d7s_obpflipped(void) | |
81 | { | |
82 | int opt_node; | |
83 | ||
84 | opt_node = prom_getchild(prom_root_node); | |
85 | opt_node = prom_searchsiblings(opt_node, "options"); | |
86 | return ((-1 != prom_getintdefault(opt_node, "d7s-flipped?", -1)) ? 0 : 1); | |
87 | } | |
88 | ||
89 | static atomic_t d7s_users = ATOMIC_INIT(0); | |
90 | ||
91 | static int d7s_open(struct inode *inode, struct file *f) | |
92 | { | |
93 | if (D7S_MINOR != iminor(inode)) | |
94 | return -ENODEV; | |
95 | atomic_inc(&d7s_users); | |
96 | return 0; | |
97 | } | |
98 | ||
99 | static int d7s_release(struct inode *inode, struct file *f) | |
100 | { | |
101 | /* Reset flipped state to OBP default only if | |
102 | * no other users have the device open and we | |
103 | * are not operating in solaris-compat mode | |
104 | */ | |
105 | if (atomic_dec_and_test(&d7s_users) && !sol_compat) { | |
106 | int regval = 0; | |
107 | ||
108 | regval = readb(d7s_regs); | |
109 | (0 == d7s_obpflipped()) ? | |
110 | writeb(regval |= D7S_FLIP, d7s_regs): | |
111 | writeb(regval &= ~D7S_FLIP, d7s_regs); | |
112 | } | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static int d7s_ioctl(struct inode *inode, struct file *f, | |
118 | unsigned int cmd, unsigned long arg) | |
119 | { | |
120 | __u8 regs = readb(d7s_regs); | |
121 | __u8 ireg = 0; | |
122 | ||
123 | if (D7S_MINOR != iminor(inode)) | |
124 | return -ENODEV; | |
125 | ||
126 | switch (cmd) { | |
127 | case D7SIOCWR: | |
128 | /* assign device register values | |
129 | * we mask-out D7S_FLIP if in sol_compat mode | |
130 | */ | |
131 | if (get_user(ireg, (int __user *) arg)) | |
132 | return -EFAULT; | |
133 | if (0 != sol_compat) { | |
134 | (regs & D7S_FLIP) ? | |
135 | (ireg |= D7S_FLIP) : (ireg &= ~D7S_FLIP); | |
136 | } | |
137 | writeb(ireg, d7s_regs); | |
138 | break; | |
139 | ||
140 | case D7SIOCRD: | |
141 | /* retrieve device register values | |
142 | * NOTE: Solaris implementation returns D7S_FLIP bit | |
143 | * as toggled by user, even though it does not honor it. | |
144 | * This driver will not misinform you about the state | |
145 | * of your hardware while in sol_compat mode | |
146 | */ | |
147 | if (put_user(regs, (int __user *) arg)) | |
148 | return -EFAULT; | |
149 | break; | |
150 | ||
151 | case D7SIOCTM: | |
152 | /* toggle device mode-- flip display orientation */ | |
153 | (regs & D7S_FLIP) ? | |
154 | (regs &= ~D7S_FLIP) : (regs |= D7S_FLIP); | |
155 | writeb(regs, d7s_regs); | |
156 | break; | |
157 | }; | |
158 | ||
159 | return 0; | |
160 | } | |
161 | ||
162 | static struct file_operations d7s_fops = { | |
163 | .owner = THIS_MODULE, | |
164 | .ioctl = d7s_ioctl, | |
165 | .open = d7s_open, | |
166 | .release = d7s_release, | |
167 | }; | |
168 | ||
169 | static struct miscdevice d7s_miscdev = { D7S_MINOR, D7S_DEVNAME, &d7s_fops }; | |
170 | ||
171 | static int __init d7s_init(void) | |
172 | { | |
173 | struct linux_ebus *ebus = NULL; | |
174 | struct linux_ebus_device *edev = NULL; | |
175 | int iTmp = 0, regs = 0; | |
176 | ||
177 | for_each_ebus(ebus) { | |
178 | for_each_ebusdev(edev, ebus) { | |
179 | if (!strcmp(edev->prom_name, D7S_OBPNAME)) | |
180 | goto ebus_done; | |
181 | } | |
182 | } | |
183 | ||
184 | ebus_done: | |
185 | if(!edev) { | |
186 | printk("%s: unable to locate device\n", D7S_DEVNAME); | |
187 | return -ENODEV; | |
188 | } | |
189 | ||
190 | d7s_regs = ioremap(edev->resource[0].start, sizeof(__u8)); | |
191 | ||
192 | iTmp = misc_register(&d7s_miscdev); | |
193 | if (0 != iTmp) { | |
194 | printk("%s: unable to acquire miscdevice minor %i\n", | |
195 | D7S_DEVNAME, D7S_MINOR); | |
196 | iounmap(d7s_regs); | |
197 | return iTmp; | |
198 | } | |
199 | ||
200 | /* OBP option "d7s-flipped?" is honored as default | |
201 | * for the device, and reset default when detached | |
202 | */ | |
203 | regs = readb(d7s_regs); | |
204 | iTmp = d7s_obpflipped(); | |
205 | (0 == iTmp) ? | |
206 | writeb(regs |= D7S_FLIP, d7s_regs): | |
207 | writeb(regs &= ~D7S_FLIP, d7s_regs); | |
208 | ||
209 | printk("%s: 7-Segment Display%s at 0x%lx %s\n", | |
210 | D7S_DEVNAME, | |
211 | (0 == iTmp) ? (" (FLIPPED)") : (""), | |
212 | edev->resource[0].start, | |
213 | (0 != sol_compat) ? ("in sol_compat mode") : ("")); | |
214 | ||
215 | return 0; | |
216 | } | |
217 | ||
218 | static void __exit d7s_cleanup(void) | |
219 | { | |
220 | int regs = readb(d7s_regs); | |
221 | ||
222 | /* Honor OBP d7s-flipped? unless operating in solaris-compat mode */ | |
223 | if (0 == sol_compat) { | |
224 | (0 == d7s_obpflipped()) ? | |
225 | writeb(regs |= D7S_FLIP, d7s_regs): | |
226 | writeb(regs &= ~D7S_FLIP, d7s_regs); | |
227 | } | |
228 | ||
229 | misc_deregister(&d7s_miscdev); | |
230 | d7s_free(); | |
231 | } | |
232 | ||
233 | module_init(d7s_init); | |
234 | module_exit(d7s_cleanup); |