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b9cdad74 JD |
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 | |
27693ce5 | 35 | #define TAOS_STATE_EOFF 2 |
b9cdad74 JD |
36 | #define TAOS_STATE_RECV 3 |
37 | ||
38 | #define TAOS_CMD_RESET 0x12 | |
27693ce5 JD |
39 | #define TAOS_CMD_ECHO_ON '+' |
40 | #define TAOS_CMD_ECHO_OFF '-' | |
b9cdad74 JD |
41 | |
42 | static DECLARE_WAIT_QUEUE_HEAD(wq); | |
43 | ||
44 | struct taos_data { | |
45 | struct i2c_adapter adapter; | |
46 | struct i2c_client *client; | |
47 | int state; | |
48 | u8 addr; /* last used address */ | |
49 | unsigned char buffer[TAOS_BUFFER_SIZE]; | |
50 | unsigned int pos; /* position inside the buffer */ | |
51 | }; | |
52 | ||
53 | /* TAOS TSL2550 EVM */ | |
54 | static struct i2c_board_info tsl2550_info = { | |
55 | I2C_BOARD_INFO("tsl2550", 0x39), | |
b9cdad74 JD |
56 | }; |
57 | ||
58 | /* Instantiate i2c devices based on the adapter name */ | |
59 | static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) | |
60 | { | |
61 | if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { | |
62 | dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", | |
3760f736 | 63 | tsl2550_info.type, tsl2550_info.addr); |
b9cdad74 JD |
64 | return i2c_new_device(adapter, &tsl2550_info); |
65 | } | |
66 | ||
67 | return NULL; | |
68 | } | |
69 | ||
70 | static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, | |
71 | unsigned short flags, char read_write, u8 command, | |
72 | int size, union i2c_smbus_data *data) | |
73 | { | |
74 | struct serio *serio = adapter->algo_data; | |
75 | struct taos_data *taos = serio_get_drvdata(serio); | |
76 | char *p; | |
77 | ||
78 | /* Encode our transaction. "@" is for the device address, "$" for the | |
79 | SMBus command and "#" for the data. */ | |
80 | p = taos->buffer; | |
81 | ||
82 | /* The device remembers the last used address, no need to send it | |
83 | again if it's the same */ | |
84 | if (addr != taos->addr) | |
85 | p += sprintf(p, "@%02X", addr); | |
86 | ||
87 | switch (size) { | |
88 | case I2C_SMBUS_BYTE: | |
89 | if (read_write == I2C_SMBUS_WRITE) | |
90 | sprintf(p, "$#%02X", command); | |
91 | else | |
92 | sprintf(p, "$"); | |
93 | break; | |
94 | case I2C_SMBUS_BYTE_DATA: | |
95 | if (read_write == I2C_SMBUS_WRITE) | |
96 | sprintf(p, "$%02X#%02X", command, data->byte); | |
97 | else | |
98 | sprintf(p, "$%02X", command); | |
99 | break; | |
100 | default: | |
ac7fc4fb JD |
101 | dev_warn(&adapter->dev, "Unsupported transaction %d\n", size); |
102 | return -EOPNOTSUPP; | |
b9cdad74 JD |
103 | } |
104 | ||
105 | /* Send the transaction to the TAOS EVM */ | |
106 | dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); | |
27693ce5 JD |
107 | for (p = taos->buffer; *p; p++) |
108 | serio_write(serio, *p); | |
109 | ||
b9cdad74 JD |
110 | taos->addr = addr; |
111 | ||
112 | /* Start the transaction and read the answer */ | |
113 | taos->pos = 0; | |
114 | taos->state = TAOS_STATE_RECV; | |
115 | serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); | |
116 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
117 | msecs_to_jiffies(150)); | |
118 | if (taos->state != TAOS_STATE_IDLE | |
27693ce5 | 119 | || taos->pos != 5) { |
b9cdad74 JD |
120 | dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", |
121 | taos->pos); | |
122 | return -EIO; | |
123 | } | |
124 | dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); | |
125 | ||
126 | /* Interpret the returned string */ | |
27693ce5 | 127 | p = taos->buffer + 1; |
b9cdad74 JD |
128 | p[3] = '\0'; |
129 | if (!strcmp(p, "NAK")) | |
130 | return -ENODEV; | |
131 | ||
132 | if (read_write == I2C_SMBUS_WRITE) { | |
133 | if (!strcmp(p, "ACK")) | |
134 | return 0; | |
135 | } else { | |
136 | if (p[0] == 'x') { | |
137 | data->byte = simple_strtol(p + 1, NULL, 16); | |
138 | return 0; | |
139 | } | |
140 | } | |
141 | ||
142 | return -EIO; | |
143 | } | |
144 | ||
145 | static u32 taos_smbus_func(struct i2c_adapter *adapter) | |
146 | { | |
147 | return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; | |
148 | } | |
149 | ||
150 | static const struct i2c_algorithm taos_algorithm = { | |
151 | .smbus_xfer = taos_smbus_xfer, | |
152 | .functionality = taos_smbus_func, | |
153 | }; | |
154 | ||
155 | static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, | |
156 | unsigned int flags) | |
157 | { | |
158 | struct taos_data *taos = serio_get_drvdata(serio); | |
159 | ||
160 | switch (taos->state) { | |
161 | case TAOS_STATE_INIT: | |
162 | taos->buffer[taos->pos++] = data; | |
163 | if (data == ':' | |
164 | || taos->pos == TAOS_BUFFER_SIZE - 1) { | |
165 | taos->buffer[taos->pos] = '\0'; | |
166 | taos->state = TAOS_STATE_IDLE; | |
167 | wake_up_interruptible(&wq); | |
168 | } | |
169 | break; | |
27693ce5 JD |
170 | case TAOS_STATE_EOFF: |
171 | taos->state = TAOS_STATE_IDLE; | |
172 | wake_up_interruptible(&wq); | |
b9cdad74 JD |
173 | break; |
174 | case TAOS_STATE_RECV: | |
175 | taos->buffer[taos->pos++] = data; | |
176 | if (data == ']') { | |
177 | taos->buffer[taos->pos] = '\0'; | |
178 | taos->state = TAOS_STATE_IDLE; | |
179 | wake_up_interruptible(&wq); | |
180 | } | |
181 | break; | |
182 | } | |
183 | ||
184 | return IRQ_HANDLED; | |
185 | } | |
186 | ||
187 | /* Extract the adapter name from the buffer received after reset. | |
188 | The buffer is modified and a pointer inside the buffer is returned. */ | |
189 | static char *taos_adapter_name(char *buffer) | |
190 | { | |
191 | char *start, *end; | |
192 | ||
193 | start = strstr(buffer, "TAOS "); | |
194 | if (!start) | |
195 | return NULL; | |
196 | ||
197 | end = strchr(start, '\r'); | |
198 | if (!end) | |
199 | return NULL; | |
200 | *end = '\0'; | |
201 | ||
202 | return start; | |
203 | } | |
204 | ||
205 | static int taos_connect(struct serio *serio, struct serio_driver *drv) | |
206 | { | |
207 | struct taos_data *taos; | |
208 | struct i2c_adapter *adapter; | |
209 | char *name; | |
210 | int err; | |
211 | ||
212 | taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); | |
213 | if (!taos) { | |
214 | err = -ENOMEM; | |
215 | goto exit; | |
216 | } | |
217 | taos->state = TAOS_STATE_INIT; | |
218 | serio_set_drvdata(serio, taos); | |
219 | ||
220 | err = serio_open(serio, drv); | |
221 | if (err) | |
222 | goto exit_kfree; | |
223 | ||
224 | adapter = &taos->adapter; | |
225 | adapter->owner = THIS_MODULE; | |
226 | adapter->algo = &taos_algorithm; | |
227 | adapter->algo_data = serio; | |
228 | adapter->dev.parent = &serio->dev; | |
229 | ||
230 | /* Reset the TAOS evaluation module to identify it */ | |
231 | serio_write(serio, TAOS_CMD_RESET); | |
232 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
233 | msecs_to_jiffies(2000)); | |
234 | ||
235 | if (taos->state != TAOS_STATE_IDLE) { | |
236 | err = -ENODEV; | |
237 | dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, " | |
238 | "pos=%d)\n", taos->state, taos->pos); | |
239 | goto exit_close; | |
240 | } | |
241 | ||
242 | name = taos_adapter_name(taos->buffer); | |
243 | if (!name) { | |
244 | err = -ENODEV; | |
245 | dev_err(&serio->dev, "TAOS EVM identification failed\n"); | |
246 | goto exit_close; | |
247 | } | |
248 | strlcpy(adapter->name, name, sizeof(adapter->name)); | |
249 | ||
27693ce5 JD |
250 | /* Turn echo off for better performance */ |
251 | taos->state = TAOS_STATE_EOFF; | |
252 | serio_write(serio, TAOS_CMD_ECHO_OFF); | |
253 | ||
254 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
255 | msecs_to_jiffies(250)); | |
256 | if (taos->state != TAOS_STATE_IDLE) { | |
257 | err = -ENODEV; | |
258 | dev_err(&adapter->dev, "Echo off failed " | |
259 | "(state=%d)\n", taos->state); | |
260 | goto exit_close; | |
261 | } | |
262 | ||
b9cdad74 JD |
263 | err = i2c_add_adapter(adapter); |
264 | if (err) | |
265 | goto exit_close; | |
266 | dev_dbg(&serio->dev, "Connected to TAOS EVM\n"); | |
267 | ||
268 | taos->client = taos_instantiate_device(adapter); | |
269 | return 0; | |
270 | ||
271 | exit_close: | |
272 | serio_close(serio); | |
273 | exit_kfree: | |
274 | serio_set_drvdata(serio, NULL); | |
275 | kfree(taos); | |
276 | exit: | |
277 | return err; | |
278 | } | |
279 | ||
280 | static void taos_disconnect(struct serio *serio) | |
281 | { | |
282 | struct taos_data *taos = serio_get_drvdata(serio); | |
283 | ||
284 | if (taos->client) | |
285 | i2c_unregister_device(taos->client); | |
286 | i2c_del_adapter(&taos->adapter); | |
287 | serio_close(serio); | |
288 | serio_set_drvdata(serio, NULL); | |
289 | kfree(taos); | |
290 | ||
291 | dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n"); | |
292 | } | |
293 | ||
294 | static struct serio_device_id taos_serio_ids[] = { | |
295 | { | |
296 | .type = SERIO_RS232, | |
297 | .proto = SERIO_TAOSEVM, | |
298 | .id = SERIO_ANY, | |
299 | .extra = SERIO_ANY, | |
300 | }, | |
301 | { 0 } | |
302 | }; | |
303 | MODULE_DEVICE_TABLE(serio, taos_serio_ids); | |
304 | ||
305 | static struct serio_driver taos_drv = { | |
306 | .driver = { | |
307 | .name = "taos-evm", | |
308 | }, | |
309 | .description = "TAOS evaluation module driver", | |
310 | .id_table = taos_serio_ids, | |
311 | .connect = taos_connect, | |
312 | .disconnect = taos_disconnect, | |
313 | .interrupt = taos_interrupt, | |
314 | }; | |
315 | ||
316 | static int __init taos_init(void) | |
317 | { | |
318 | return serio_register_driver(&taos_drv); | |
319 | } | |
320 | ||
321 | static void __exit taos_exit(void) | |
322 | { | |
323 | serio_unregister_driver(&taos_drv); | |
324 | } | |
325 | ||
326 | MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); | |
327 | MODULE_DESCRIPTION("TAOS evaluation module driver"); | |
328 | MODULE_LICENSE("GPL"); | |
329 | ||
330 | module_init(taos_init); | |
331 | module_exit(taos_exit); |