1 /* ------------------------------------------------------------------------ *
2 * i2c-parport-light.c I2C bus over parallel port *
3 * ------------------------------------------------------------------------ *
4 Copyright (C) 2003-2010 Jean Delvare <khali@linux-fr.org>
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 You should have received a copy of the GNU General Public License
23 along with this program; if not, write to the Free Software
24 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 * ------------------------------------------------------------------------ */
26
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/delay.h>
31 #include <linux/platform_device.h>
32 #include <linux/ioport.h>
33 #include <linux/i2c.h>
34 #include <linux/i2c-algo-bit.h>
35 #include <linux/i2c-smbus.h>
36 #include <linux/io.h>
37 #include "i2c-parport.h"
38
39 #define DEFAULT_BASE 0x378
40 #define DRVNAME "i2c-parport-light"
41
42 static struct platform_device *pdev;
43
44 static u16 base;
45 module_param(base, ushort, 0);
46 MODULE_PARM_DESC(base, "Base I/O address");
47
48 static int irq;
49 module_param(irq, int, 0);
50 MODULE_PARM_DESC(irq, "IRQ (optional)");
51
52 /* ----- Low-level parallel port access ----------------------------------- */
53
port_write(unsigned char p,unsigned char d)54 static inline void port_write(unsigned char p, unsigned char d)
55 {
56 outb(d, base+p);
57 }
58
port_read(unsigned char p)59 static inline unsigned char port_read(unsigned char p)
60 {
61 return inb(base+p);
62 }
63
64 /* ----- Unified line operation functions --------------------------------- */
65
line_set(int state,const struct lineop * op)66 static inline void line_set(int state, const struct lineop *op)
67 {
68 u8 oldval = port_read(op->port);
69
70 /* Touch only the bit(s) needed */
71 if ((op->inverted && !state) || (!op->inverted && state))
72 port_write(op->port, oldval | op->val);
73 else
74 port_write(op->port, oldval & ~op->val);
75 }
76
line_get(const struct lineop * op)77 static inline int line_get(const struct lineop *op)
78 {
79 u8 oldval = port_read(op->port);
80
81 return ((op->inverted && (oldval & op->val) != op->val)
82 || (!op->inverted && (oldval & op->val) == op->val));
83 }
84
85 /* ----- I2C algorithm call-back functions and structures ----------------- */
86
parport_setscl(void * data,int state)87 static void parport_setscl(void *data, int state)
88 {
89 line_set(state, &adapter_parm[type].setscl);
90 }
91
parport_setsda(void * data,int state)92 static void parport_setsda(void *data, int state)
93 {
94 line_set(state, &adapter_parm[type].setsda);
95 }
96
parport_getscl(void * data)97 static int parport_getscl(void *data)
98 {
99 return line_get(&adapter_parm[type].getscl);
100 }
101
parport_getsda(void * data)102 static int parport_getsda(void *data)
103 {
104 return line_get(&adapter_parm[type].getsda);
105 }
106
107 /* Encapsulate the functions above in the correct structure
108 Note that getscl will be set to NULL by the attaching code for adapters
109 that cannot read SCL back */
110 static struct i2c_algo_bit_data parport_algo_data = {
111 .setsda = parport_setsda,
112 .setscl = parport_setscl,
113 .getsda = parport_getsda,
114 .getscl = parport_getscl,
115 .udelay = 50,
116 .timeout = HZ,
117 };
118
119 /* ----- Driver registration ---------------------------------------------- */
120
121 static struct i2c_adapter parport_adapter = {
122 .owner = THIS_MODULE,
123 .class = I2C_CLASS_HWMON,
124 .algo_data = &parport_algo_data,
125 .name = "Parallel port adapter (light)",
126 };
127
128 /* SMBus alert support */
129 static struct i2c_smbus_alert_setup alert_data = {
130 .alert_edge_triggered = 1,
131 };
132 static struct i2c_client *ara;
133 static struct lineop parport_ctrl_irq = {
134 .val = (1 << 4),
135 .port = PORT_CTRL,
136 };
137
i2c_parport_probe(struct platform_device * pdev)138 static int __devinit i2c_parport_probe(struct platform_device *pdev)
139 {
140 int err;
141
142 /* Reset hardware to a sane state (SCL and SDA high) */
143 parport_setsda(NULL, 1);
144 parport_setscl(NULL, 1);
145 /* Other init if needed (power on...) */
146 if (adapter_parm[type].init.val) {
147 line_set(1, &adapter_parm[type].init);
148 /* Give powered devices some time to settle */
149 msleep(100);
150 }
151
152 parport_adapter.dev.parent = &pdev->dev;
153 err = i2c_bit_add_bus(&parport_adapter);
154 if (err) {
155 dev_err(&pdev->dev, "Unable to register with I2C\n");
156 return err;
157 }
158
159 /* Setup SMBus alert if supported */
160 if (adapter_parm[type].smbus_alert && irq) {
161 alert_data.irq = irq;
162 ara = i2c_setup_smbus_alert(&parport_adapter, &alert_data);
163 if (ara)
164 line_set(1, &parport_ctrl_irq);
165 else
166 dev_warn(&pdev->dev, "Failed to register ARA client\n");
167 }
168
169 return 0;
170 }
171
i2c_parport_remove(struct platform_device * pdev)172 static int __devexit i2c_parport_remove(struct platform_device *pdev)
173 {
174 if (ara) {
175 line_set(0, &parport_ctrl_irq);
176 i2c_unregister_device(ara);
177 ara = NULL;
178 }
179 i2c_del_adapter(&parport_adapter);
180
181 /* Un-init if needed (power off...) */
182 if (adapter_parm[type].init.val)
183 line_set(0, &adapter_parm[type].init);
184
185 return 0;
186 }
187
188 static struct platform_driver i2c_parport_driver = {
189 .driver = {
190 .owner = THIS_MODULE,
191 .name = DRVNAME,
192 },
193 .probe = i2c_parport_probe,
194 .remove = __devexit_p(i2c_parport_remove),
195 };
196
i2c_parport_device_add(u16 address)197 static int __init i2c_parport_device_add(u16 address)
198 {
199 int err;
200
201 pdev = platform_device_alloc(DRVNAME, -1);
202 if (!pdev) {
203 err = -ENOMEM;
204 printk(KERN_ERR DRVNAME ": Device allocation failed\n");
205 goto exit;
206 }
207
208 err = platform_device_add(pdev);
209 if (err) {
210 printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
211 err);
212 goto exit_device_put;
213 }
214
215 return 0;
216
217 exit_device_put:
218 platform_device_put(pdev);
219 exit:
220 return err;
221 }
222
i2c_parport_init(void)223 static int __init i2c_parport_init(void)
224 {
225 int err;
226
227 if (type < 0) {
228 printk(KERN_ERR DRVNAME ": adapter type unspecified\n");
229 return -ENODEV;
230 }
231
232 if (type >= ARRAY_SIZE(adapter_parm)) {
233 printk(KERN_ERR DRVNAME ": invalid type (%d)\n", type);
234 return -ENODEV;
235 }
236
237 if (base == 0) {
238 pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE);
239 base = DEFAULT_BASE;
240 }
241
242 if (!request_region(base, 3, DRVNAME))
243 return -EBUSY;
244
245 if (irq != 0)
246 pr_info(DRVNAME ": using irq %d\n", irq);
247
248 if (!adapter_parm[type].getscl.val)
249 parport_algo_data.getscl = NULL;
250
251 /* Sets global pdev as a side effect */
252 err = i2c_parport_device_add(base);
253 if (err)
254 goto exit_release;
255
256 err = platform_driver_register(&i2c_parport_driver);
257 if (err)
258 goto exit_device;
259
260 return 0;
261
262 exit_device:
263 platform_device_unregister(pdev);
264 exit_release:
265 release_region(base, 3);
266 return err;
267 }
268
i2c_parport_exit(void)269 static void __exit i2c_parport_exit(void)
270 {
271 platform_driver_unregister(&i2c_parport_driver);
272 platform_device_unregister(pdev);
273 release_region(base, 3);
274 }
275
276 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
277 MODULE_DESCRIPTION("I2C bus over parallel port (light)");
278 MODULE_LICENSE("GPL");
279
280 module_init(i2c_parport_init);
281 module_exit(i2c_parport_exit);
282