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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
42static struct platform_device *pdev;
43
44static u16 base;
45module_param(base, ushort, 0);
46MODULE_PARM_DESC(base, "Base I/O address");
47
48static int irq;
49module_param(irq, int, 0);
50MODULE_PARM_DESC(irq, "IRQ (optional)");
51
52
53
54static inline void port_write(unsigned char p, unsigned char d)
55{
56 outb(d, base+p);
57}
58
59static inline unsigned char port_read(unsigned char p)
60{
61 return inb(base+p);
62}
63
64
65
66static inline void line_set(int state, const struct lineop *op)
67{
68 u8 oldval = port_read(op->port);
69
70
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
77static 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
86
87static void parport_setscl(void *data, int state)
88{
89 line_set(state, &adapter_parm[type].setscl);
90}
91
92static void parport_setsda(void *data, int state)
93{
94 line_set(state, &adapter_parm[type].setsda);
95}
96
97static int parport_getscl(void *data)
98{
99 return line_get(&adapter_parm[type].getscl);
100}
101
102static int parport_getsda(void *data)
103{
104 return line_get(&adapter_parm[type].getsda);
105}
106
107
108
109
110static 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
120
121static 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
129static struct i2c_smbus_alert_setup alert_data = {
130 .alert_edge_triggered = 1,
131};
132static struct i2c_client *ara;
133static struct lineop parport_ctrl_irq = {
134 .val = (1 << 4),
135 .port = CTRL,
136};
137
138static int __devinit i2c_parport_probe(struct platform_device *pdev)
139{
140 int err;
141
142
143 parport_setsda(NULL, 1);
144 parport_setscl(NULL, 1);
145
146 if (adapter_parm[type].init.val) {
147 line_set(1, &adapter_parm[type].init);
148
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
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
172static 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
182 if (adapter_parm[type].init.val)
183 line_set(0, &adapter_parm[type].init);
184
185 return 0;
186}
187
188static 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
197static 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
217exit_device_put:
218 platform_device_put(pdev);
219exit:
220 return err;
221}
222
223static 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
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
262exit_device:
263 platform_device_unregister(pdev);
264exit_release:
265 release_region(base, 3);
266 return err;
267}
268
269static 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
276MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
277MODULE_DESCRIPTION("I2C bus over parallel port (light)");
278MODULE_LICENSE("GPL");
279
280module_init(i2c_parport_init);
281module_exit(i2c_parport_exit);
282
