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);
331
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