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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 | * | |
7c81c60f | 6 | * Copyright (C) 2007 Jean Delvare <jdelvare@suse.de> |
b9cdad74 JD |
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. | |
b9cdad74 JD |
16 | */ |
17 | ||
18 | #include <linux/delay.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/input.h> | |
23 | #include <linux/serio.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/i2c.h> | |
26 | ||
27 | #define TAOS_BUFFER_SIZE 63 | |
28 | ||
29 | #define TAOS_STATE_INIT 0 | |
30 | #define TAOS_STATE_IDLE 1 | |
27693ce5 | 31 | #define TAOS_STATE_EOFF 2 |
b9cdad74 JD |
32 | #define TAOS_STATE_RECV 3 |
33 | ||
34 | #define TAOS_CMD_RESET 0x12 | |
27693ce5 JD |
35 | #define TAOS_CMD_ECHO_ON '+' |
36 | #define TAOS_CMD_ECHO_OFF '-' | |
b9cdad74 JD |
37 | |
38 | static DECLARE_WAIT_QUEUE_HEAD(wq); | |
39 | ||
40 | struct taos_data { | |
41 | struct i2c_adapter adapter; | |
42 | struct i2c_client *client; | |
43 | int state; | |
44 | u8 addr; /* last used address */ | |
45 | unsigned char buffer[TAOS_BUFFER_SIZE]; | |
46 | unsigned int pos; /* position inside the buffer */ | |
47 | }; | |
48 | ||
49 | /* TAOS TSL2550 EVM */ | |
50 | static struct i2c_board_info tsl2550_info = { | |
51 | I2C_BOARD_INFO("tsl2550", 0x39), | |
b9cdad74 JD |
52 | }; |
53 | ||
54 | /* Instantiate i2c devices based on the adapter name */ | |
55 | static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) | |
56 | { | |
57 | if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { | |
58 | dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", | |
3760f736 | 59 | tsl2550_info.type, tsl2550_info.addr); |
b9cdad74 JD |
60 | return i2c_new_device(adapter, &tsl2550_info); |
61 | } | |
62 | ||
63 | return NULL; | |
64 | } | |
65 | ||
66 | static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, | |
67 | unsigned short flags, char read_write, u8 command, | |
68 | int size, union i2c_smbus_data *data) | |
69 | { | |
70 | struct serio *serio = adapter->algo_data; | |
71 | struct taos_data *taos = serio_get_drvdata(serio); | |
72 | char *p; | |
73 | ||
74 | /* Encode our transaction. "@" is for the device address, "$" for the | |
75 | SMBus command and "#" for the data. */ | |
76 | p = taos->buffer; | |
77 | ||
78 | /* The device remembers the last used address, no need to send it | |
79 | again if it's the same */ | |
80 | if (addr != taos->addr) | |
81 | p += sprintf(p, "@%02X", addr); | |
82 | ||
83 | switch (size) { | |
84 | case I2C_SMBUS_BYTE: | |
85 | if (read_write == I2C_SMBUS_WRITE) | |
86 | sprintf(p, "$#%02X", command); | |
87 | else | |
88 | sprintf(p, "$"); | |
89 | break; | |
90 | case I2C_SMBUS_BYTE_DATA: | |
91 | if (read_write == I2C_SMBUS_WRITE) | |
92 | sprintf(p, "$%02X#%02X", command, data->byte); | |
93 | else | |
94 | sprintf(p, "$%02X", command); | |
95 | break; | |
96 | default: | |
ac7fc4fb JD |
97 | dev_warn(&adapter->dev, "Unsupported transaction %d\n", size); |
98 | return -EOPNOTSUPP; | |
b9cdad74 JD |
99 | } |
100 | ||
101 | /* Send the transaction to the TAOS EVM */ | |
102 | dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); | |
27693ce5 JD |
103 | for (p = taos->buffer; *p; p++) |
104 | serio_write(serio, *p); | |
105 | ||
b9cdad74 JD |
106 | taos->addr = addr; |
107 | ||
108 | /* Start the transaction and read the answer */ | |
109 | taos->pos = 0; | |
110 | taos->state = TAOS_STATE_RECV; | |
111 | serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); | |
112 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
113 | msecs_to_jiffies(150)); | |
114 | if (taos->state != TAOS_STATE_IDLE | |
27693ce5 | 115 | || taos->pos != 5) { |
b9cdad74 JD |
116 | dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", |
117 | taos->pos); | |
118 | return -EIO; | |
119 | } | |
120 | dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); | |
121 | ||
122 | /* Interpret the returned string */ | |
27693ce5 | 123 | p = taos->buffer + 1; |
b9cdad74 JD |
124 | p[3] = '\0'; |
125 | if (!strcmp(p, "NAK")) | |
126 | return -ENODEV; | |
127 | ||
128 | if (read_write == I2C_SMBUS_WRITE) { | |
129 | if (!strcmp(p, "ACK")) | |
130 | return 0; | |
131 | } else { | |
132 | if (p[0] == 'x') { | |
c4c696fa LC |
133 | /* |
134 | * Voluntarily dropping error code of kstrtou8 since all | |
135 | * error code that it could return are invalid according | |
136 | * to Documentation/i2c/fault-codes. | |
137 | */ | |
138 | if (kstrtou8(p + 1, 16, &data->byte)) | |
139 | return -EPROTO; | |
b9cdad74 JD |
140 | return 0; |
141 | } | |
142 | } | |
143 | ||
144 | return -EIO; | |
145 | } | |
146 | ||
147 | static u32 taos_smbus_func(struct i2c_adapter *adapter) | |
148 | { | |
149 | return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; | |
150 | } | |
151 | ||
152 | static const struct i2c_algorithm taos_algorithm = { | |
153 | .smbus_xfer = taos_smbus_xfer, | |
154 | .functionality = taos_smbus_func, | |
155 | }; | |
156 | ||
157 | static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, | |
158 | unsigned int flags) | |
159 | { | |
160 | struct taos_data *taos = serio_get_drvdata(serio); | |
161 | ||
162 | switch (taos->state) { | |
163 | case TAOS_STATE_INIT: | |
164 | taos->buffer[taos->pos++] = data; | |
165 | if (data == ':' | |
166 | || taos->pos == TAOS_BUFFER_SIZE - 1) { | |
167 | taos->buffer[taos->pos] = '\0'; | |
168 | taos->state = TAOS_STATE_IDLE; | |
169 | wake_up_interruptible(&wq); | |
170 | } | |
171 | break; | |
27693ce5 JD |
172 | case TAOS_STATE_EOFF: |
173 | taos->state = TAOS_STATE_IDLE; | |
174 | wake_up_interruptible(&wq); | |
b9cdad74 JD |
175 | break; |
176 | case TAOS_STATE_RECV: | |
177 | taos->buffer[taos->pos++] = data; | |
178 | if (data == ']') { | |
179 | taos->buffer[taos->pos] = '\0'; | |
180 | taos->state = TAOS_STATE_IDLE; | |
181 | wake_up_interruptible(&wq); | |
182 | } | |
183 | break; | |
184 | } | |
185 | ||
186 | return IRQ_HANDLED; | |
187 | } | |
188 | ||
189 | /* Extract the adapter name from the buffer received after reset. | |
190 | The buffer is modified and a pointer inside the buffer is returned. */ | |
191 | static char *taos_adapter_name(char *buffer) | |
192 | { | |
193 | char *start, *end; | |
194 | ||
195 | start = strstr(buffer, "TAOS "); | |
196 | if (!start) | |
197 | return NULL; | |
198 | ||
199 | end = strchr(start, '\r'); | |
200 | if (!end) | |
201 | return NULL; | |
202 | *end = '\0'; | |
203 | ||
204 | return start; | |
205 | } | |
206 | ||
207 | static int taos_connect(struct serio *serio, struct serio_driver *drv) | |
208 | { | |
209 | struct taos_data *taos; | |
210 | struct i2c_adapter *adapter; | |
211 | char *name; | |
212 | int err; | |
213 | ||
214 | taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); | |
215 | if (!taos) { | |
216 | err = -ENOMEM; | |
217 | goto exit; | |
218 | } | |
219 | taos->state = TAOS_STATE_INIT; | |
220 | serio_set_drvdata(serio, taos); | |
221 | ||
222 | err = serio_open(serio, drv); | |
223 | if (err) | |
224 | goto exit_kfree; | |
225 | ||
226 | adapter = &taos->adapter; | |
227 | adapter->owner = THIS_MODULE; | |
228 | adapter->algo = &taos_algorithm; | |
229 | adapter->algo_data = serio; | |
230 | adapter->dev.parent = &serio->dev; | |
231 | ||
232 | /* Reset the TAOS evaluation module to identify it */ | |
233 | serio_write(serio, TAOS_CMD_RESET); | |
234 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
235 | msecs_to_jiffies(2000)); | |
236 | ||
237 | if (taos->state != TAOS_STATE_IDLE) { | |
238 | err = -ENODEV; | |
9b640f2e | 239 | dev_err(&serio->dev, "TAOS EVM reset failed (state=%d, " |
b9cdad74 JD |
240 | "pos=%d)\n", taos->state, taos->pos); |
241 | goto exit_close; | |
242 | } | |
243 | ||
244 | name = taos_adapter_name(taos->buffer); | |
245 | if (!name) { | |
246 | err = -ENODEV; | |
247 | dev_err(&serio->dev, "TAOS EVM identification failed\n"); | |
248 | goto exit_close; | |
249 | } | |
250 | strlcpy(adapter->name, name, sizeof(adapter->name)); | |
251 | ||
27693ce5 JD |
252 | /* Turn echo off for better performance */ |
253 | taos->state = TAOS_STATE_EOFF; | |
254 | serio_write(serio, TAOS_CMD_ECHO_OFF); | |
255 | ||
256 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
257 | msecs_to_jiffies(250)); | |
258 | if (taos->state != TAOS_STATE_IDLE) { | |
259 | err = -ENODEV; | |
9b640f2e | 260 | dev_err(&serio->dev, "TAOS EVM echo off failed " |
27693ce5 JD |
261 | "(state=%d)\n", taos->state); |
262 | goto exit_close; | |
263 | } | |
264 | ||
b9cdad74 JD |
265 | err = i2c_add_adapter(adapter); |
266 | if (err) | |
267 | goto exit_close; | |
9b640f2e | 268 | dev_info(&serio->dev, "Connected to TAOS EVM\n"); |
b9cdad74 JD |
269 | |
270 | taos->client = taos_instantiate_device(adapter); | |
271 | return 0; | |
272 | ||
273 | exit_close: | |
274 | serio_close(serio); | |
275 | exit_kfree: | |
b9cdad74 JD |
276 | kfree(taos); |
277 | exit: | |
278 | return err; | |
279 | } | |
280 | ||
281 | static void taos_disconnect(struct serio *serio) | |
282 | { | |
283 | struct taos_data *taos = serio_get_drvdata(serio); | |
284 | ||
285 | if (taos->client) | |
286 | i2c_unregister_device(taos->client); | |
287 | i2c_del_adapter(&taos->adapter); | |
288 | serio_close(serio); | |
b9cdad74 JD |
289 | kfree(taos); |
290 | ||
9b640f2e | 291 | dev_info(&serio->dev, "Disconnected from TAOS EVM\n"); |
b9cdad74 JD |
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 | ||
2fd6cf05 | 316 | module_serio_driver(taos_drv); |
b9cdad74 | 317 | |
7c81c60f | 318 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); |
b9cdad74 JD |
319 | MODULE_DESCRIPTION("TAOS evaluation module driver"); |
320 | MODULE_LICENSE("GPL"); |