Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6
[linux-2.6] / drivers / i2c / busses / i2c-taos-evm.c
1 /*
2  * Driver for the TAOS evaluation modules
3  * These devices include an I2C master which can be controlled over the
4  * serial port.
5  *
6  * Copyright (C) 2007 Jean Delvare <khali@linux-fr.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; version 2 of the License.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21
22 #include <linux/delay.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/interrupt.h>
26 #include <linux/input.h>
27 #include <linux/serio.h>
28 #include <linux/init.h>
29 #include <linux/i2c.h>
30
31 #define TAOS_BUFFER_SIZE        63
32
33 #define TAOS_STATE_INIT         0
34 #define TAOS_STATE_IDLE         1
35 #define TAOS_STATE_SEND         2
36 #define TAOS_STATE_RECV         3
37
38 #define TAOS_CMD_RESET          0x12
39
40 static DECLARE_WAIT_QUEUE_HEAD(wq);
41
42 struct taos_data {
43         struct i2c_adapter adapter;
44         struct i2c_client *client;
45         int state;
46         u8 addr;                /* last used address */
47         unsigned char buffer[TAOS_BUFFER_SIZE];
48         unsigned int pos;       /* position inside the buffer */
49 };
50
51 /* TAOS TSL2550 EVM */
52 static struct i2c_board_info tsl2550_info = {
53         I2C_BOARD_INFO("tsl2550", 0x39),
54         .type   = "tsl2550",
55 };
56
57 /* Instantiate i2c devices based on the adapter name */
58 static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter)
59 {
60         if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) {
61                 dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n",
62                         tsl2550_info.driver_name, tsl2550_info.addr);
63                 return i2c_new_device(adapter, &tsl2550_info);
64         }
65
66         return NULL;
67 }
68
69 static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
70                            unsigned short flags, char read_write, u8 command,
71                            int size, union i2c_smbus_data *data)
72 {
73         struct serio *serio = adapter->algo_data;
74         struct taos_data *taos = serio_get_drvdata(serio);
75         char *p;
76
77         /* Encode our transaction. "@" is for the device address, "$" for the
78            SMBus command and "#" for the data. */
79         p = taos->buffer;
80
81         /* The device remembers the last used address, no need to send it
82            again if it's the same */
83         if (addr != taos->addr)
84                 p += sprintf(p, "@%02X", addr);
85
86         switch (size) {
87         case I2C_SMBUS_BYTE:
88                 if (read_write == I2C_SMBUS_WRITE)
89                         sprintf(p, "$#%02X", command);
90                 else
91                         sprintf(p, "$");
92                 break;
93         case I2C_SMBUS_BYTE_DATA:
94                 if (read_write == I2C_SMBUS_WRITE)
95                         sprintf(p, "$%02X#%02X", command, data->byte);
96                 else
97                         sprintf(p, "$%02X", command);
98                 break;
99         default:
100                 dev_dbg(&adapter->dev, "Unsupported transaction size %d\n",
101                         size);
102                 return -EINVAL;
103         }
104
105         /* Send the transaction to the TAOS EVM */
106         dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer);
107         taos->pos = 0;
108         taos->state = TAOS_STATE_SEND;
109         serio_write(serio, taos->buffer[0]);
110         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
111                                          msecs_to_jiffies(250));
112         if (taos->state != TAOS_STATE_IDLE) {
113                 dev_err(&adapter->dev, "Transaction failed "
114                         "(state=%d, pos=%d)\n", taos->state, taos->pos);
115                 taos->addr = 0;
116                 return -EIO;
117         }
118         taos->addr = addr;
119
120         /* Start the transaction and read the answer */
121         taos->pos = 0;
122         taos->state = TAOS_STATE_RECV;
123         serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<');
124         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
125                                          msecs_to_jiffies(150));
126         if (taos->state != TAOS_STATE_IDLE
127          || taos->pos != 6) {
128                 dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n",
129                         taos->pos);
130                 return -EIO;
131         }
132         dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer);
133
134         /* Interpret the returned string */
135         p = taos->buffer + 2;
136         p[3] = '\0';
137         if (!strcmp(p, "NAK"))
138                 return -ENODEV;
139
140         if (read_write == I2C_SMBUS_WRITE) {
141                 if (!strcmp(p, "ACK"))
142                         return 0;
143         } else {
144                 if (p[0] == 'x') {
145                         data->byte = simple_strtol(p + 1, NULL, 16);
146                         return 0;
147                 }
148         }
149
150         return -EIO;
151 }
152
153 static u32 taos_smbus_func(struct i2c_adapter *adapter)
154 {
155         return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA;
156 }
157
158 static const struct i2c_algorithm taos_algorithm = {
159         .smbus_xfer     = taos_smbus_xfer,
160         .functionality  = taos_smbus_func,
161 };
162
163 static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data,
164                                   unsigned int flags)
165 {
166         struct taos_data *taos = serio_get_drvdata(serio);
167
168         switch (taos->state) {
169         case TAOS_STATE_INIT:
170                 taos->buffer[taos->pos++] = data;
171                 if (data == ':'
172                  || taos->pos == TAOS_BUFFER_SIZE - 1) {
173                         taos->buffer[taos->pos] = '\0';
174                         taos->state = TAOS_STATE_IDLE;
175                         wake_up_interruptible(&wq);
176                 }
177                 break;
178         case TAOS_STATE_SEND:
179                 if (taos->buffer[++taos->pos])
180                         serio_write(serio, taos->buffer[taos->pos]);
181                 else {
182                         taos->state = TAOS_STATE_IDLE;
183                         wake_up_interruptible(&wq);
184                 }
185                 break;
186         case TAOS_STATE_RECV:
187                 taos->buffer[taos->pos++] = data;
188                 if (data == ']') {
189                         taos->buffer[taos->pos] = '\0';
190                         taos->state = TAOS_STATE_IDLE;
191                         wake_up_interruptible(&wq);
192                 }
193                 break;
194         }
195
196         return IRQ_HANDLED;
197 }
198
199 /* Extract the adapter name from the buffer received after reset.
200    The buffer is modified and a pointer inside the buffer is returned. */
201 static char *taos_adapter_name(char *buffer)
202 {
203         char *start, *end;
204
205         start = strstr(buffer, "TAOS ");
206         if (!start)
207                 return NULL;
208
209         end = strchr(start, '\r');
210         if (!end)
211                 return NULL;
212         *end = '\0';
213
214         return start;
215 }
216
217 static int taos_connect(struct serio *serio, struct serio_driver *drv)
218 {
219         struct taos_data *taos;
220         struct i2c_adapter *adapter;
221         char *name;
222         int err;
223
224         taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL);
225         if (!taos) {
226                 err = -ENOMEM;
227                 goto exit;
228         }
229         taos->state = TAOS_STATE_INIT;
230         serio_set_drvdata(serio, taos);
231
232         err = serio_open(serio, drv);
233         if (err)
234                 goto exit_kfree;
235
236         adapter = &taos->adapter;
237         adapter->owner = THIS_MODULE;
238         adapter->algo = &taos_algorithm;
239         adapter->algo_data = serio;
240         adapter->dev.parent = &serio->dev;
241
242         /* Reset the TAOS evaluation module to identify it */
243         serio_write(serio, TAOS_CMD_RESET);
244         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
245                                          msecs_to_jiffies(2000));
246
247         if (taos->state != TAOS_STATE_IDLE) {
248                 err = -ENODEV;
249                 dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, "
250                         "pos=%d)\n", taos->state, taos->pos);
251                 goto exit_close;
252         }
253
254         name = taos_adapter_name(taos->buffer);
255         if (!name) {
256                 err = -ENODEV;
257                 dev_err(&serio->dev, "TAOS EVM identification failed\n");
258                 goto exit_close;
259         }
260         strlcpy(adapter->name, name, sizeof(adapter->name));
261
262         err = i2c_add_adapter(adapter);
263         if (err)
264                 goto exit_close;
265         dev_dbg(&serio->dev, "Connected to TAOS EVM\n");
266
267         taos->client = taos_instantiate_device(adapter);
268         return 0;
269
270  exit_close:
271         serio_close(serio);
272  exit_kfree:
273         serio_set_drvdata(serio, NULL);
274         kfree(taos);
275  exit:
276         return err;
277 }
278
279 static void taos_disconnect(struct serio *serio)
280 {
281         struct taos_data *taos = serio_get_drvdata(serio);
282
283         if (taos->client)
284                 i2c_unregister_device(taos->client);
285         i2c_del_adapter(&taos->adapter);
286         serio_close(serio);
287         serio_set_drvdata(serio, NULL);
288         kfree(taos);
289
290         dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n");
291 }
292
293 static struct serio_device_id taos_serio_ids[] = {
294         {
295                 .type   = SERIO_RS232,
296                 .proto  = SERIO_TAOSEVM,
297                 .id     = SERIO_ANY,
298                 .extra  = SERIO_ANY,
299         },
300         { 0 }
301 };
302 MODULE_DEVICE_TABLE(serio, taos_serio_ids);
303
304 static struct serio_driver taos_drv = {
305         .driver         = {
306                 .name   = "taos-evm",
307         },
308         .description    = "TAOS evaluation module driver",
309         .id_table       = taos_serio_ids,
310         .connect        = taos_connect,
311         .disconnect     = taos_disconnect,
312         .interrupt      = taos_interrupt,
313 };
314
315 static int __init taos_init(void)
316 {
317         return serio_register_driver(&taos_drv);
318 }
319
320 static void __exit taos_exit(void)
321 {
322         serio_unregister_driver(&taos_drv);
323 }
324
325 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
326 MODULE_DESCRIPTION("TAOS evaluation module driver");
327 MODULE_LICENSE("GPL");
328
329 module_init(taos_init);
330 module_exit(taos_exit);