1 /* ------------------------------------------------------------------------ *
2 * i2c-parport-light.c I2C bus over parallel port *
3 * ------------------------------------------------------------------------ *
4 Copyright (C) 2003-2010 Jean Delvare <jdelvare@suse.de>
5
6 Based on older i2c-velleman.c driver
7 Copyright (C) 1995-2000 Simon G. Vogl
8 With some changes from:
9 Frodo Looijaard <frodol@dds.nl>
10 Kyösti Mälkki <kmalkki@cc.hut.fi>
11
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 2 of the License, or
15 (at your option) any later version.
16
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
21 * ------------------------------------------------------------------------ */
22
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/delay.h>
27 #include <linux/platform_device.h>
28 #include <linux/ioport.h>
29 #include <linux/i2c.h>
30 #include <linux/i2c-algo-bit.h>
31 #include <linux/i2c-smbus.h>
32 #include <linux/io.h>
33 #include "i2c-parport.h"
34
35 #define DEFAULT_BASE 0x378
36 #define DRVNAME "i2c-parport-light"
37
38 static struct platform_device *pdev;
39
40 static u16 base;
41 module_param_hw(base, ushort, ioport, 0);
42 MODULE_PARM_DESC(base, "Base I/O address");
43
44 static int irq;
45 module_param_hw(irq, int, irq, 0);
46 MODULE_PARM_DESC(irq, "IRQ (optional)");
47
48 /* ----- Low-level parallel port access ----------------------------------- */
49
port_write(unsigned char p,unsigned char d)50 static inline void port_write(unsigned char p, unsigned char d)
51 {
52 outb(d, base+p);
53 }
54
port_read(unsigned char p)55 static inline unsigned char port_read(unsigned char p)
56 {
57 return inb(base+p);
58 }
59
60 /* ----- Unified line operation functions --------------------------------- */
61
line_set(int state,const struct lineop * op)62 static inline void line_set(int state, const struct lineop *op)
63 {
64 u8 oldval = port_read(op->port);
65
66 /* Touch only the bit(s) needed */
67 if ((op->inverted && !state) || (!op->inverted && state))
68 port_write(op->port, oldval | op->val);
69 else
70 port_write(op->port, oldval & ~op->val);
71 }
72
line_get(const struct lineop * op)73 static inline int line_get(const struct lineop *op)
74 {
75 u8 oldval = port_read(op->port);
76
77 return ((op->inverted && (oldval & op->val) != op->val)
78 || (!op->inverted && (oldval & op->val) == op->val));
79 }
80
81 /* ----- I2C algorithm call-back functions and structures ----------------- */
82
parport_setscl(void * data,int state)83 static void parport_setscl(void *data, int state)
84 {
85 line_set(state, &adapter_parm[type].setscl);
86 }
87
parport_setsda(void * data,int state)88 static void parport_setsda(void *data, int state)
89 {
90 line_set(state, &adapter_parm[type].setsda);
91 }
92
parport_getscl(void * data)93 static int parport_getscl(void *data)
94 {
95 return line_get(&adapter_parm[type].getscl);
96 }
97
parport_getsda(void * data)98 static int parport_getsda(void *data)
99 {
100 return line_get(&adapter_parm[type].getsda);
101 }
102
103 /* Encapsulate the functions above in the correct structure
104 Note that getscl will be set to NULL by the attaching code for adapters
105 that cannot read SCL back */
106 static struct i2c_algo_bit_data parport_algo_data = {
107 .setsda = parport_setsda,
108 .setscl = parport_setscl,
109 .getsda = parport_getsda,
110 .getscl = parport_getscl,
111 .udelay = 50,
112 .timeout = HZ,
113 };
114
115 /* ----- Driver registration ---------------------------------------------- */
116
117 static struct i2c_adapter parport_adapter = {
118 .owner = THIS_MODULE,
119 .class = I2C_CLASS_HWMON,
120 .algo_data = &parport_algo_data,
121 .name = "Parallel port adapter (light)",
122 };
123
124 /* SMBus alert support */
125 static struct i2c_smbus_alert_setup alert_data = {
126 };
127 static struct i2c_client *ara;
128 static struct lineop parport_ctrl_irq = {
129 .val = (1 << 4),
130 .port = PORT_CTRL,
131 };
132
i2c_parport_probe(struct platform_device * pdev)133 static int i2c_parport_probe(struct platform_device *pdev)
134 {
135 int err;
136
137 /* Reset hardware to a sane state (SCL and SDA high) */
138 parport_setsda(NULL, 1);
139 parport_setscl(NULL, 1);
140 /* Other init if needed (power on...) */
141 if (adapter_parm[type].init.val) {
142 line_set(1, &adapter_parm[type].init);
143 /* Give powered devices some time to settle */
144 msleep(100);
145 }
146
147 parport_adapter.dev.parent = &pdev->dev;
148 err = i2c_bit_add_bus(&parport_adapter);
149 if (err) {
150 dev_err(&pdev->dev, "Unable to register with I2C\n");
151 return err;
152 }
153
154 /* Setup SMBus alert if supported */
155 if (adapter_parm[type].smbus_alert && irq) {
156 alert_data.irq = irq;
157 ara = i2c_setup_smbus_alert(&parport_adapter, &alert_data);
158 if (ara)
159 line_set(1, &parport_ctrl_irq);
160 else
161 dev_warn(&pdev->dev, "Failed to register ARA client\n");
162 }
163
164 return 0;
165 }
166
i2c_parport_remove(struct platform_device * pdev)167 static int i2c_parport_remove(struct platform_device *pdev)
168 {
169 if (ara) {
170 line_set(0, &parport_ctrl_irq);
171 i2c_unregister_device(ara);
172 ara = NULL;
173 }
174 i2c_del_adapter(&parport_adapter);
175
176 /* Un-init if needed (power off...) */
177 if (adapter_parm[type].init.val)
178 line_set(0, &adapter_parm[type].init);
179
180 return 0;
181 }
182
183 static struct platform_driver i2c_parport_driver = {
184 .driver = {
185 .name = DRVNAME,
186 },
187 .probe = i2c_parport_probe,
188 .remove = i2c_parport_remove,
189 };
190
i2c_parport_device_add(u16 address)191 static int __init i2c_parport_device_add(u16 address)
192 {
193 int err;
194
195 pdev = platform_device_alloc(DRVNAME, -1);
196 if (!pdev) {
197 err = -ENOMEM;
198 printk(KERN_ERR DRVNAME ": Device allocation failed\n");
199 goto exit;
200 }
201
202 err = platform_device_add(pdev);
203 if (err) {
204 printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
205 err);
206 goto exit_device_put;
207 }
208
209 return 0;
210
211 exit_device_put:
212 platform_device_put(pdev);
213 exit:
214 return err;
215 }
216
i2c_parport_init(void)217 static int __init i2c_parport_init(void)
218 {
219 int err;
220
221 if (type < 0) {
222 printk(KERN_ERR DRVNAME ": adapter type unspecified\n");
223 return -ENODEV;
224 }
225
226 if (type >= ARRAY_SIZE(adapter_parm)) {
227 printk(KERN_ERR DRVNAME ": invalid type (%d)\n", type);
228 return -ENODEV;
229 }
230
231 if (base == 0) {
232 pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE);
233 base = DEFAULT_BASE;
234 }
235
236 if (!request_region(base, 3, DRVNAME))
237 return -EBUSY;
238
239 if (irq != 0)
240 pr_info(DRVNAME ": using irq %d\n", irq);
241
242 if (!adapter_parm[type].getscl.val)
243 parport_algo_data.getscl = NULL;
244
245 /* Sets global pdev as a side effect */
246 err = i2c_parport_device_add(base);
247 if (err)
248 goto exit_release;
249
250 err = platform_driver_register(&i2c_parport_driver);
251 if (err)
252 goto exit_device;
253
254 return 0;
255
256 exit_device:
257 platform_device_unregister(pdev);
258 exit_release:
259 release_region(base, 3);
260 return err;
261 }
262
i2c_parport_exit(void)263 static void __exit i2c_parport_exit(void)
264 {
265 platform_driver_unregister(&i2c_parport_driver);
266 platform_device_unregister(pdev);
267 release_region(base, 3);
268 }
269
270 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
271 MODULE_DESCRIPTION("I2C bus over parallel port (light)");
272 MODULE_LICENSE("GPL");
273
274 module_init(i2c_parport_init);
275 module_exit(i2c_parport_exit);
276
