Merge branch 'vmwgfx-fixes-5.1' of git://people.freedesktop.org/~thomash/linux into...
[sfrench/cifs-2.6.git] / drivers / auxdisplay / ks0108.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    Filename: ks0108.c
4  *     Version: 0.1.0
5  * Description: ks0108 LCD Controller driver
6  *     Depends: parport
7  *
8  *      Author: Copyright (C) Miguel Ojeda Sandonis
9  *        Date: 2006-10-31
10  */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/delay.h>
18 #include <linux/fs.h>
19 #include <linux/io.h>
20 #include <linux/parport.h>
21 #include <linux/uaccess.h>
22 #include <linux/ks0108.h>
23
24 #define KS0108_NAME "ks0108"
25
26 /*
27  * Module Parameters
28  */
29
30 static unsigned int ks0108_port = CONFIG_KS0108_PORT;
31 module_param(ks0108_port, uint, S_IRUGO);
32 MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected");
33
34 static unsigned int ks0108_delay = CONFIG_KS0108_DELAY;
35 module_param(ks0108_delay, uint, S_IRUGO);
36 MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)");
37
38 /*
39  * Device
40  */
41
42 static struct parport *ks0108_parport;
43 static struct pardevice *ks0108_pardevice;
44
45 /*
46  * ks0108 Exported Commands (don't lock)
47  *
48  *   You _should_ lock in the top driver: This functions _should not_
49  *   get race conditions in any way. Locking for each byte here would be
50  *   so slow and useless.
51  *
52  *   There are not bit definitions because they are not flags,
53  *   just arbitrary combinations defined by the documentation for each
54  *   function in the ks0108 LCD controller. If you want to know what means
55  *   a specific combination, look at the function's name.
56  *
57  *   The ks0108_writecontrol bits need to be reverted ^(0,1,3) because
58  *   the parallel port also revert them using a "not" logic gate.
59  */
60
61 #define bit(n) (((unsigned char)1)<<(n))
62
63 void ks0108_writedata(unsigned char byte)
64 {
65         parport_write_data(ks0108_parport, byte);
66 }
67
68 void ks0108_writecontrol(unsigned char byte)
69 {
70         udelay(ks0108_delay);
71         parport_write_control(ks0108_parport, byte ^ (bit(0) | bit(1) | bit(3)));
72 }
73
74 void ks0108_displaystate(unsigned char state)
75 {
76         ks0108_writedata((state ? bit(0) : 0) | bit(1) | bit(2) | bit(3) | bit(4) | bit(5));
77 }
78
79 void ks0108_startline(unsigned char startline)
80 {
81         ks0108_writedata(min_t(unsigned char, startline, 63) | bit(6) |
82                          bit(7));
83 }
84
85 void ks0108_address(unsigned char address)
86 {
87         ks0108_writedata(min_t(unsigned char, address, 63) | bit(6));
88 }
89
90 void ks0108_page(unsigned char page)
91 {
92         ks0108_writedata(min_t(unsigned char, page, 7) | bit(3) | bit(4) |
93                          bit(5) | bit(7));
94 }
95
96 EXPORT_SYMBOL_GPL(ks0108_writedata);
97 EXPORT_SYMBOL_GPL(ks0108_writecontrol);
98 EXPORT_SYMBOL_GPL(ks0108_displaystate);
99 EXPORT_SYMBOL_GPL(ks0108_startline);
100 EXPORT_SYMBOL_GPL(ks0108_address);
101 EXPORT_SYMBOL_GPL(ks0108_page);
102
103 /*
104  * Is the module inited?
105  */
106
107 static unsigned char ks0108_inited;
108 unsigned char ks0108_isinited(void)
109 {
110         return ks0108_inited;
111 }
112 EXPORT_SYMBOL_GPL(ks0108_isinited);
113
114 static void ks0108_parport_attach(struct parport *port)
115 {
116         struct pardev_cb ks0108_cb;
117
118         if (port->base != ks0108_port)
119                 return;
120
121         memset(&ks0108_cb, 0, sizeof(ks0108_cb));
122         ks0108_cb.flags = PARPORT_DEV_EXCL;
123         ks0108_pardevice = parport_register_dev_model(port, KS0108_NAME,
124                                                       &ks0108_cb, 0);
125         if (!ks0108_pardevice) {
126                 pr_err("ERROR: parport didn't register new device\n");
127                 return;
128         }
129         if (parport_claim(ks0108_pardevice)) {
130                 pr_err("could not claim access to parport %i. Aborting.\n",
131                        ks0108_port);
132                 goto err_unreg_device;
133         }
134
135         ks0108_parport = port;
136         ks0108_inited = 1;
137         return;
138
139 err_unreg_device:
140         parport_unregister_device(ks0108_pardevice);
141         ks0108_pardevice = NULL;
142 }
143
144 static void ks0108_parport_detach(struct parport *port)
145 {
146         if (port->base != ks0108_port)
147                 return;
148
149         if (!ks0108_pardevice) {
150                 pr_err("%s: already unregistered.\n", KS0108_NAME);
151                 return;
152         }
153
154         parport_release(ks0108_pardevice);
155         parport_unregister_device(ks0108_pardevice);
156         ks0108_pardevice = NULL;
157         ks0108_parport = NULL;
158 }
159
160 /*
161  * Module Init & Exit
162  */
163
164 static struct parport_driver ks0108_parport_driver = {
165         .name = "ks0108",
166         .match_port = ks0108_parport_attach,
167         .detach = ks0108_parport_detach,
168         .devmodel = true,
169 };
170
171 static int __init ks0108_init(void)
172 {
173         return parport_register_driver(&ks0108_parport_driver);
174 }
175
176 static void __exit ks0108_exit(void)
177 {
178         parport_unregister_driver(&ks0108_parport_driver);
179 }
180
181 module_init(ks0108_init);
182 module_exit(ks0108_exit);
183
184 MODULE_LICENSE("GPL v2");
185 MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
186 MODULE_DESCRIPTION("ks0108 LCD Controller driver");
187