Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
[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 };
55
56 /* Instantiate i2c devices based on the adapter name */
57 static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter)
58 {
59         if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) {
60                 dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n",
61                         tsl2550_info.type, tsl2550_info.addr);
62                 return i2c_new_device(adapter, &tsl2550_info);
63         }
64
65         return NULL;
66 }
67
68 static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
69                            unsigned short flags, char read_write, u8 command,
70                            int size, union i2c_smbus_data *data)
71 {
72         struct serio *serio = adapter->algo_data;
73         struct taos_data *taos = serio_get_drvdata(serio);
74         char *p;
75
76         /* Encode our transaction. "@" is for the device address, "$" for the
77            SMBus command and "#" for the data. */
78         p = taos->buffer;
79
80         /* The device remembers the last used address, no need to send it
81            again if it's the same */
82         if (addr != taos->addr)
83                 p += sprintf(p, "@%02X", addr);
84
85         switch (size) {
86         case I2C_SMBUS_BYTE:
87                 if (read_write == I2C_SMBUS_WRITE)
88                         sprintf(p, "$#%02X", command);
89                 else
90                         sprintf(p, "$");
91                 break;
92         case I2C_SMBUS_BYTE_DATA:
93                 if (read_write == I2C_SMBUS_WRITE)
94                         sprintf(p, "$%02X#%02X", command, data->byte);
95                 else
96                         sprintf(p, "$%02X", command);
97                 break;
98         default:
99                 dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
100                 return -EOPNOTSUPP;
101         }
102
103         /* Send the transaction to the TAOS EVM */
104         dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer);
105         taos->pos = 0;
106         taos->state = TAOS_STATE_SEND;
107         serio_write(serio, taos->buffer[0]);
108         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
109                                          msecs_to_jiffies(250));
110         if (taos->state != TAOS_STATE_IDLE) {
111                 dev_err(&adapter->dev, "Transaction failed "
112                         "(state=%d, pos=%d)\n", taos->state, taos->pos);
113                 taos->addr = 0;
114                 return -EIO;
115         }
116         taos->addr = addr;
117
118         /* Start the transaction and read the answer */
119         taos->pos = 0;
120         taos->state = TAOS_STATE_RECV;
121         serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<');
122         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
123                                          msecs_to_jiffies(150));
124         if (taos->state != TAOS_STATE_IDLE
125          || taos->pos != 6) {
126                 dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n",
127                         taos->pos);
128                 return -EIO;
129         }
130         dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer);
131
132         /* Interpret the returned string */
133         p = taos->buffer + 2;
134         p[3] = '\0';
135         if (!strcmp(p, "NAK"))
136                 return -ENODEV;
137
138         if (read_write == I2C_SMBUS_WRITE) {
139                 if (!strcmp(p, "ACK"))
140                         return 0;
141         } else {
142                 if (p[0] == 'x') {
143                         data->byte = simple_strtol(p + 1, NULL, 16);
144                         return 0;
145                 }
146         }
147
148         return -EIO;
149 }
150
151 static u32 taos_smbus_func(struct i2c_adapter *adapter)
152 {
153         return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA;
154 }
155
156 static const struct i2c_algorithm taos_algorithm = {
157         .smbus_xfer     = taos_smbus_xfer,
158         .functionality  = taos_smbus_func,
159 };
160
161 static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data,
162                                   unsigned int flags)
163 {
164         struct taos_data *taos = serio_get_drvdata(serio);
165
166         switch (taos->state) {
167         case TAOS_STATE_INIT:
168                 taos->buffer[taos->pos++] = data;
169                 if (data == ':'
170                  || taos->pos == TAOS_BUFFER_SIZE - 1) {
171                         taos->buffer[taos->pos] = '\0';
172                         taos->state = TAOS_STATE_IDLE;
173                         wake_up_interruptible(&wq);
174                 }
175                 break;
176         case TAOS_STATE_SEND:
177                 if (taos->buffer[++taos->pos])
178                         serio_write(serio, taos->buffer[taos->pos]);
179                 else {
180                         taos->state = TAOS_STATE_IDLE;
181                         wake_up_interruptible(&wq);
182                 }
183                 break;
184         case TAOS_STATE_RECV:
185                 taos->buffer[taos->pos++] = data;
186                 if (data == ']') {
187                         taos->buffer[taos->pos] = '\0';
188                         taos->state = TAOS_STATE_IDLE;
189                         wake_up_interruptible(&wq);
190                 }
191                 break;
192         }
193
194         return IRQ_HANDLED;
195 }
196
197 /* Extract the adapter name from the buffer received after reset.
198    The buffer is modified and a pointer inside the buffer is returned. */
199 static char *taos_adapter_name(char *buffer)
200 {
201         char *start, *end;
202
203         start = strstr(buffer, "TAOS ");
204         if (!start)
205                 return NULL;
206
207         end = strchr(start, '\r');
208         if (!end)
209                 return NULL;
210         *end = '\0';
211
212         return start;
213 }
214
215 static int taos_connect(struct serio *serio, struct serio_driver *drv)
216 {
217         struct taos_data *taos;
218         struct i2c_adapter *adapter;
219         char *name;
220         int err;
221
222         taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL);
223         if (!taos) {
224                 err = -ENOMEM;
225                 goto exit;
226         }
227         taos->state = TAOS_STATE_INIT;
228         serio_set_drvdata(serio, taos);
229
230         err = serio_open(serio, drv);
231         if (err)
232                 goto exit_kfree;
233
234         adapter = &taos->adapter;
235         adapter->owner = THIS_MODULE;
236         adapter->algo = &taos_algorithm;
237         adapter->algo_data = serio;
238         adapter->dev.parent = &serio->dev;
239
240         /* Reset the TAOS evaluation module to identify it */
241         serio_write(serio, TAOS_CMD_RESET);
242         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
243                                          msecs_to_jiffies(2000));
244
245         if (taos->state != TAOS_STATE_IDLE) {
246                 err = -ENODEV;
247                 dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, "
248                         "pos=%d)\n", taos->state, taos->pos);
249                 goto exit_close;
250         }
251
252         name = taos_adapter_name(taos->buffer);
253         if (!name) {
254                 err = -ENODEV;
255                 dev_err(&serio->dev, "TAOS EVM identification failed\n");
256                 goto exit_close;
257         }
258         strlcpy(adapter->name, name, sizeof(adapter->name));
259
260         err = i2c_add_adapter(adapter);
261         if (err)
262                 goto exit_close;
263         dev_dbg(&serio->dev, "Connected to TAOS EVM\n");
264
265         taos->client = taos_instantiate_device(adapter);
266         return 0;
267
268  exit_close:
269         serio_close(serio);
270  exit_kfree:
271         serio_set_drvdata(serio, NULL);
272         kfree(taos);
273  exit:
274         return err;
275 }
276
277 static void taos_disconnect(struct serio *serio)
278 {
279         struct taos_data *taos = serio_get_drvdata(serio);
280
281         if (taos->client)
282                 i2c_unregister_device(taos->client);
283         i2c_del_adapter(&taos->adapter);
284         serio_close(serio);
285         serio_set_drvdata(serio, NULL);
286         kfree(taos);
287
288         dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n");
289 }
290
291 static struct serio_device_id taos_serio_ids[] = {
292         {
293                 .type   = SERIO_RS232,
294                 .proto  = SERIO_TAOSEVM,
295                 .id     = SERIO_ANY,
296                 .extra  = SERIO_ANY,
297         },
298         { 0 }
299 };
300 MODULE_DEVICE_TABLE(serio, taos_serio_ids);
301
302 static struct serio_driver taos_drv = {
303         .driver         = {
304                 .name   = "taos-evm",
305         },
306         .description    = "TAOS evaluation module driver",
307         .id_table       = taos_serio_ids,
308         .connect        = taos_connect,
309         .disconnect     = taos_disconnect,
310         .interrupt      = taos_interrupt,
311 };
312
313 static int __init taos_init(void)
314 {
315         return serio_register_driver(&taos_drv);
316 }
317
318 static void __exit taos_exit(void)
319 {
320         serio_unregister_driver(&taos_drv);
321 }
322
323 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
324 MODULE_DESCRIPTION("TAOS evaluation module driver");
325 MODULE_LICENSE("GPL");
326
327 module_init(taos_init);
328 module_exit(taos_exit);