1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* ------------------------------------------------------------------------ *
3 * i2c-parport.c I2C bus over parallel port *
4 * ------------------------------------------------------------------------ *
5 Copyright (C) 2003-2011 Jean Delvare <jdelvare@suse.de>
6
7 Based on older i2c-philips-par.c driver
8 Copyright (C) 1995-2000 Simon G. Vogl
9 With some changes from:
10 Frodo Looijaard <frodol@dds.nl>
11 Kyösti Mälkki <kmalkki@cc.hut.fi>
12
13 * ------------------------------------------------------------------------ */
14
15 #define pr_fmt(fmt) "i2c-parport: " fmt
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/delay.h>
21 #include <linux/parport.h>
22 #include <linux/i2c.h>
23 #include <linux/i2c-algo-bit.h>
24 #include <linux/i2c-smbus.h>
25 #include <linux/slab.h>
26 #include <linux/list.h>
27 #include <linux/mutex.h>
28
29 #define PORT_DATA 0
30 #define PORT_STAT 1
31 #define PORT_CTRL 2
32
33 struct lineop {
34 u8 val;
35 u8 port;
36 u8 inverted;
37 };
38
39 struct adapter_parm {
40 struct lineop setsda;
41 struct lineop setscl;
42 struct lineop getsda;
43 struct lineop getscl;
44 struct lineop init;
45 unsigned int smbus_alert:1;
46 };
47
48 static const struct adapter_parm adapter_parm[] = {
49 /* type 0: Philips adapter */
50 {
51 .setsda = { 0x80, PORT_DATA, 1 },
52 .setscl = { 0x08, PORT_CTRL, 0 },
53 .getsda = { 0x80, PORT_STAT, 0 },
54 .getscl = { 0x08, PORT_STAT, 0 },
55 },
56 /* type 1: home brew teletext adapter */
57 {
58 .setsda = { 0x02, PORT_DATA, 0 },
59 .setscl = { 0x01, PORT_DATA, 0 },
60 .getsda = { 0x80, PORT_STAT, 1 },
61 },
62 /* type 2: Velleman K8000 adapter */
63 {
64 .setsda = { 0x02, PORT_CTRL, 1 },
65 .setscl = { 0x08, PORT_CTRL, 1 },
66 .getsda = { 0x10, PORT_STAT, 0 },
67 },
68 /* type 3: ELV adapter */
69 {
70 .setsda = { 0x02, PORT_DATA, 1 },
71 .setscl = { 0x01, PORT_DATA, 1 },
72 .getsda = { 0x40, PORT_STAT, 1 },
73 .getscl = { 0x08, PORT_STAT, 1 },
74 },
75 /* type 4: ADM1032 evaluation board */
76 {
77 .setsda = { 0x02, PORT_DATA, 1 },
78 .setscl = { 0x01, PORT_DATA, 1 },
79 .getsda = { 0x10, PORT_STAT, 1 },
80 .init = { 0xf0, PORT_DATA, 0 },
81 .smbus_alert = 1,
82 },
83 /* type 5: ADM1025, ADM1030 and ADM1031 evaluation boards */
84 {
85 .setsda = { 0x02, PORT_DATA, 1 },
86 .setscl = { 0x01, PORT_DATA, 1 },
87 .getsda = { 0x10, PORT_STAT, 1 },
88 },
89 /* type 6: Barco LPT->DVI (K5800236) adapter */
90 {
91 .setsda = { 0x02, PORT_DATA, 1 },
92 .setscl = { 0x01, PORT_DATA, 1 },
93 .getsda = { 0x20, PORT_STAT, 0 },
94 .getscl = { 0x40, PORT_STAT, 0 },
95 .init = { 0xfc, PORT_DATA, 0 },
96 },
97 /* type 7: One For All JP1 parallel port adapter */
98 {
99 .setsda = { 0x01, PORT_DATA, 0 },
100 .setscl = { 0x02, PORT_DATA, 0 },
101 .getsda = { 0x80, PORT_STAT, 1 },
102 .init = { 0x04, PORT_DATA, 1 },
103 },
104 /* type 8: VCT-jig */
105 {
106 .setsda = { 0x04, PORT_DATA, 1 },
107 .setscl = { 0x01, PORT_DATA, 1 },
108 .getsda = { 0x40, PORT_STAT, 0 },
109 .getscl = { 0x80, PORT_STAT, 1 },
110 },
111 };
112
113 /* ----- Device list ------------------------------------------------------ */
114
115 struct i2c_par {
116 struct pardevice *pdev;
117 struct i2c_adapter adapter;
118 struct i2c_algo_bit_data algo_data;
119 struct i2c_smbus_alert_setup alert_data;
120 struct i2c_client *ara;
121 struct list_head node;
122 };
123
124 static LIST_HEAD(adapter_list);
125 static DEFINE_MUTEX(adapter_list_lock);
126
127 #define MAX_DEVICE 4
128 static int parport[MAX_DEVICE] = {0, -1, -1, -1};
129 module_param_array(parport, int, NULL, 0);
130 MODULE_PARM_DESC(parport,
131 "List of parallel ports to bind to, by index.\n"
132 " At most " __stringify(MAX_DEVICE) " devices are supported.\n"
133 " Default is one device connected to parport0.\n"
134 );
135
136 static int type = -1;
137 module_param(type, int, 0);
138 MODULE_PARM_DESC(type,
139 "Type of adapter:\n"
140 " 0 = Philips adapter\n"
141 " 1 = home brew teletext adapter\n"
142 " 2 = Velleman K8000 adapter\n"
143 " 3 = ELV adapter\n"
144 " 4 = ADM1032 evaluation board\n"
145 " 5 = ADM1025, ADM1030 and ADM1031 evaluation boards\n"
146 " 6 = Barco LPT->DVI (K5800236) adapter\n"
147 " 7 = One For All JP1 parallel port adapter\n"
148 " 8 = VCT-jig\n"
149 );
150
151 /* ----- Low-level parallel port access ----------------------------------- */
152
port_write_data(struct parport * p,unsigned char d)153 static void port_write_data(struct parport *p, unsigned char d)
154 {
155 parport_write_data(p, d);
156 }
157
port_write_control(struct parport * p,unsigned char d)158 static void port_write_control(struct parport *p, unsigned char d)
159 {
160 parport_write_control(p, d);
161 }
162
port_read_data(struct parport * p)163 static unsigned char port_read_data(struct parport *p)
164 {
165 return parport_read_data(p);
166 }
167
port_read_status(struct parport * p)168 static unsigned char port_read_status(struct parport *p)
169 {
170 return parport_read_status(p);
171 }
172
port_read_control(struct parport * p)173 static unsigned char port_read_control(struct parport *p)
174 {
175 return parport_read_control(p);
176 }
177
178 static void (* const port_write[])(struct parport *, unsigned char) = {
179 port_write_data,
180 NULL,
181 port_write_control,
182 };
183
184 static unsigned char (* const port_read[])(struct parport *) = {
185 port_read_data,
186 port_read_status,
187 port_read_control,
188 };
189
190 /* ----- Unified line operation functions --------------------------------- */
191
line_set(struct parport * data,int state,const struct lineop * op)192 static inline void line_set(struct parport *data, int state,
193 const struct lineop *op)
194 {
195 u8 oldval = port_read[op->port](data);
196
197 /* Touch only the bit(s) needed */
198 if ((op->inverted && !state) || (!op->inverted && state))
199 port_write[op->port](data, oldval | op->val);
200 else
201 port_write[op->port](data, oldval & ~op->val);
202 }
203
line_get(struct parport * data,const struct lineop * op)204 static inline int line_get(struct parport *data,
205 const struct lineop *op)
206 {
207 u8 oldval = port_read[op->port](data);
208
209 return ((op->inverted && (oldval & op->val) != op->val)
210 || (!op->inverted && (oldval & op->val) == op->val));
211 }
212
213 /* ----- I2C algorithm call-back functions and structures ----------------- */
214
parport_setscl(void * data,int state)215 static void parport_setscl(void *data, int state)
216 {
217 line_set((struct parport *) data, state, &adapter_parm[type].setscl);
218 }
219
parport_setsda(void * data,int state)220 static void parport_setsda(void *data, int state)
221 {
222 line_set((struct parport *) data, state, &adapter_parm[type].setsda);
223 }
224
parport_getscl(void * data)225 static int parport_getscl(void *data)
226 {
227 return line_get((struct parport *) data, &adapter_parm[type].getscl);
228 }
229
parport_getsda(void * data)230 static int parport_getsda(void *data)
231 {
232 return line_get((struct parport *) data, &adapter_parm[type].getsda);
233 }
234
235 /* Encapsulate the functions above in the correct structure.
236 Note that this is only a template, from which the real structures are
237 copied. The attaching code will set getscl to NULL for adapters that
238 cannot read SCL back, and will also make the data field point to
239 the parallel port structure. */
240 static const struct i2c_algo_bit_data parport_algo_data = {
241 .setsda = parport_setsda,
242 .setscl = parport_setscl,
243 .getsda = parport_getsda,
244 .getscl = parport_getscl,
245 .udelay = 10, /* ~50 kbps */
246 .timeout = HZ,
247 };
248
249 /* ----- I2c and parallel port call-back functions and structures --------- */
250
i2c_parport_irq(void * data)251 static void i2c_parport_irq(void *data)
252 {
253 struct i2c_par *adapter = data;
254 struct i2c_client *ara = adapter->ara;
255
256 if (ara) {
257 dev_dbg(&ara->dev, "SMBus alert received\n");
258 i2c_handle_smbus_alert(ara);
259 } else
260 dev_dbg(&adapter->adapter.dev,
261 "SMBus alert received but no ARA client!\n");
262 }
263
i2c_parport_attach(struct parport * port)264 static void i2c_parport_attach(struct parport *port)
265 {
266 struct i2c_par *adapter;
267 int i;
268 struct pardev_cb i2c_parport_cb;
269
270 if (type < 0) {
271 pr_warn("adapter type unspecified\n");
272 return;
273 }
274
275 if (type >= ARRAY_SIZE(adapter_parm)) {
276 pr_warn("invalid type (%d)\n", type);
277 return;
278 }
279
280 for (i = 0; i < MAX_DEVICE; i++) {
281 if (parport[i] == -1)
282 continue;
283 if (port->number == parport[i])
284 break;
285 }
286 if (i == MAX_DEVICE) {
287 pr_debug("Not using parport%d.\n", port->number);
288 return;
289 }
290
291 adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
292 if (!adapter)
293 return;
294 memset(&i2c_parport_cb, 0, sizeof(i2c_parport_cb));
295 i2c_parport_cb.flags = PARPORT_FLAG_EXCL;
296 i2c_parport_cb.irq_func = i2c_parport_irq;
297 i2c_parport_cb.private = adapter;
298
299 pr_debug("attaching to %s\n", port->name);
300 parport_disable_irq(port);
301 adapter->pdev = parport_register_dev_model(port, "i2c-parport",
302 &i2c_parport_cb, i);
303 if (!adapter->pdev) {
304 pr_err("Unable to register with parport\n");
305 goto err_free;
306 }
307
308 /* Fill the rest of the structure */
309 adapter->adapter.owner = THIS_MODULE;
310 adapter->adapter.class = I2C_CLASS_HWMON;
311 strscpy(adapter->adapter.name, "Parallel port adapter",
312 sizeof(adapter->adapter.name));
313 adapter->algo_data = parport_algo_data;
314 /* Slow down if we can't sense SCL */
315 if (!adapter_parm[type].getscl.val) {
316 adapter->algo_data.getscl = NULL;
317 adapter->algo_data.udelay = 50; /* ~10 kbps */
318 }
319 adapter->algo_data.data = port;
320 adapter->adapter.algo_data = &adapter->algo_data;
321 adapter->adapter.dev.parent = port->physport->dev;
322
323 if (parport_claim_or_block(adapter->pdev) < 0) {
324 dev_err(&adapter->pdev->dev,
325 "Could not claim parallel port\n");
326 goto err_unregister;
327 }
328
329 /* Reset hardware to a sane state (SCL and SDA high) */
330 parport_setsda(port, 1);
331 parport_setscl(port, 1);
332 /* Other init if needed (power on...) */
333 if (adapter_parm[type].init.val) {
334 line_set(port, 1, &adapter_parm[type].init);
335 /* Give powered devices some time to settle */
336 msleep(100);
337 }
338
339 if (i2c_bit_add_bus(&adapter->adapter) < 0) {
340 dev_err(&adapter->pdev->dev, "Unable to register with I2C\n");
341 goto err_unregister;
342 }
343
344 /* Setup SMBus alert if supported */
345 if (adapter_parm[type].smbus_alert) {
346 struct i2c_client *ara;
347
348 ara = i2c_new_smbus_alert_device(&adapter->adapter,
349 &adapter->alert_data);
350 if (!IS_ERR(ara)) {
351 adapter->ara = ara;
352 parport_enable_irq(port);
353 } else {
354 dev_warn(&adapter->pdev->dev,
355 "Failed to register ARA client\n");
356 }
357 }
358
359 /* Add the new adapter to the list */
360 mutex_lock(&adapter_list_lock);
361 list_add_tail(&adapter->node, &adapter_list);
362 mutex_unlock(&adapter_list_lock);
363 return;
364
365 err_unregister:
366 parport_release(adapter->pdev);
367 parport_unregister_device(adapter->pdev);
368 err_free:
369 kfree(adapter);
370 }
371
i2c_parport_detach(struct parport * port)372 static void i2c_parport_detach(struct parport *port)
373 {
374 struct i2c_par *adapter, *_n;
375
376 /* Walk the list */
377 mutex_lock(&adapter_list_lock);
378 list_for_each_entry_safe(adapter, _n, &adapter_list, node) {
379 if (adapter->pdev->port == port) {
380 if (adapter->ara) {
381 parport_disable_irq(port);
382 i2c_unregister_device(adapter->ara);
383 }
384 i2c_del_adapter(&adapter->adapter);
385
386 /* Un-init if needed (power off...) */
387 if (adapter_parm[type].init.val)
388 line_set(port, 0, &adapter_parm[type].init);
389
390 parport_release(adapter->pdev);
391 parport_unregister_device(adapter->pdev);
392 list_del(&adapter->node);
393 kfree(adapter);
394 }
395 }
396 mutex_unlock(&adapter_list_lock);
397 }
398
399 static struct parport_driver i2c_parport_driver = {
400 .name = "i2c-parport",
401 .match_port = i2c_parport_attach,
402 .detach = i2c_parport_detach,
403 .devmodel = true,
404 };
405 module_parport_driver(i2c_parport_driver);
406
407 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
408 MODULE_DESCRIPTION("I2C bus over parallel port");
409 MODULE_LICENSE("GPL");
410