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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') { | |
133 | data->byte = simple_strtol(p + 1, NULL, 16); | |
134 | return 0; | |
135 | } | |
136 | } | |
137 | ||
138 | return -EIO; | |
139 | } | |
140 | ||
141 | static u32 taos_smbus_func(struct i2c_adapter *adapter) | |
142 | { | |
143 | return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; | |
144 | } | |
145 | ||
146 | static const struct i2c_algorithm taos_algorithm = { | |
147 | .smbus_xfer = taos_smbus_xfer, | |
148 | .functionality = taos_smbus_func, | |
149 | }; | |
150 | ||
151 | static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, | |
152 | unsigned int flags) | |
153 | { | |
154 | struct taos_data *taos = serio_get_drvdata(serio); | |
155 | ||
156 | switch (taos->state) { | |
157 | case TAOS_STATE_INIT: | |
158 | taos->buffer[taos->pos++] = data; | |
159 | if (data == ':' | |
160 | || taos->pos == TAOS_BUFFER_SIZE - 1) { | |
161 | taos->buffer[taos->pos] = '\0'; | |
162 | taos->state = TAOS_STATE_IDLE; | |
163 | wake_up_interruptible(&wq); | |
164 | } | |
165 | break; | |
27693ce5 JD |
166 | case TAOS_STATE_EOFF: |
167 | taos->state = TAOS_STATE_IDLE; | |
168 | wake_up_interruptible(&wq); | |
b9cdad74 JD |
169 | break; |
170 | case TAOS_STATE_RECV: | |
171 | taos->buffer[taos->pos++] = data; | |
172 | if (data == ']') { | |
173 | taos->buffer[taos->pos] = '\0'; | |
174 | taos->state = TAOS_STATE_IDLE; | |
175 | wake_up_interruptible(&wq); | |
176 | } | |
177 | break; | |
178 | } | |
179 | ||
180 | return IRQ_HANDLED; | |
181 | } | |
182 | ||
183 | /* Extract the adapter name from the buffer received after reset. | |
184 | The buffer is modified and a pointer inside the buffer is returned. */ | |
185 | static char *taos_adapter_name(char *buffer) | |
186 | { | |
187 | char *start, *end; | |
188 | ||
189 | start = strstr(buffer, "TAOS "); | |
190 | if (!start) | |
191 | return NULL; | |
192 | ||
193 | end = strchr(start, '\r'); | |
194 | if (!end) | |
195 | return NULL; | |
196 | *end = '\0'; | |
197 | ||
198 | return start; | |
199 | } | |
200 | ||
201 | static int taos_connect(struct serio *serio, struct serio_driver *drv) | |
202 | { | |
203 | struct taos_data *taos; | |
204 | struct i2c_adapter *adapter; | |
205 | char *name; | |
206 | int err; | |
207 | ||
208 | taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); | |
209 | if (!taos) { | |
210 | err = -ENOMEM; | |
211 | goto exit; | |
212 | } | |
213 | taos->state = TAOS_STATE_INIT; | |
214 | serio_set_drvdata(serio, taos); | |
215 | ||
216 | err = serio_open(serio, drv); | |
217 | if (err) | |
218 | goto exit_kfree; | |
219 | ||
220 | adapter = &taos->adapter; | |
221 | adapter->owner = THIS_MODULE; | |
222 | adapter->algo = &taos_algorithm; | |
223 | adapter->algo_data = serio; | |
224 | adapter->dev.parent = &serio->dev; | |
225 | ||
226 | /* Reset the TAOS evaluation module to identify it */ | |
227 | serio_write(serio, TAOS_CMD_RESET); | |
228 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
229 | msecs_to_jiffies(2000)); | |
230 | ||
231 | if (taos->state != TAOS_STATE_IDLE) { | |
232 | err = -ENODEV; | |
9b640f2e | 233 | dev_err(&serio->dev, "TAOS EVM reset failed (state=%d, " |
b9cdad74 JD |
234 | "pos=%d)\n", taos->state, taos->pos); |
235 | goto exit_close; | |
236 | } | |
237 | ||
238 | name = taos_adapter_name(taos->buffer); | |
239 | if (!name) { | |
240 | err = -ENODEV; | |
241 | dev_err(&serio->dev, "TAOS EVM identification failed\n"); | |
242 | goto exit_close; | |
243 | } | |
244 | strlcpy(adapter->name, name, sizeof(adapter->name)); | |
245 | ||
27693ce5 JD |
246 | /* Turn echo off for better performance */ |
247 | taos->state = TAOS_STATE_EOFF; | |
248 | serio_write(serio, TAOS_CMD_ECHO_OFF); | |
249 | ||
250 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
251 | msecs_to_jiffies(250)); | |
252 | if (taos->state != TAOS_STATE_IDLE) { | |
253 | err = -ENODEV; | |
9b640f2e | 254 | dev_err(&serio->dev, "TAOS EVM echo off failed " |
27693ce5 JD |
255 | "(state=%d)\n", taos->state); |
256 | goto exit_close; | |
257 | } | |
258 | ||
b9cdad74 JD |
259 | err = i2c_add_adapter(adapter); |
260 | if (err) | |
261 | goto exit_close; | |
9b640f2e | 262 | dev_info(&serio->dev, "Connected to TAOS EVM\n"); |
b9cdad74 JD |
263 | |
264 | taos->client = taos_instantiate_device(adapter); | |
265 | return 0; | |
266 | ||
267 | exit_close: | |
268 | serio_close(serio); | |
269 | exit_kfree: | |
b9cdad74 JD |
270 | kfree(taos); |
271 | exit: | |
272 | return err; | |
273 | } | |
274 | ||
275 | static void taos_disconnect(struct serio *serio) | |
276 | { | |
277 | struct taos_data *taos = serio_get_drvdata(serio); | |
278 | ||
279 | if (taos->client) | |
280 | i2c_unregister_device(taos->client); | |
281 | i2c_del_adapter(&taos->adapter); | |
282 | serio_close(serio); | |
b9cdad74 JD |
283 | kfree(taos); |
284 | ||
9b640f2e | 285 | dev_info(&serio->dev, "Disconnected from TAOS EVM\n"); |
b9cdad74 JD |
286 | } |
287 | ||
288 | static struct serio_device_id taos_serio_ids[] = { | |
289 | { | |
290 | .type = SERIO_RS232, | |
291 | .proto = SERIO_TAOSEVM, | |
292 | .id = SERIO_ANY, | |
293 | .extra = SERIO_ANY, | |
294 | }, | |
295 | { 0 } | |
296 | }; | |
297 | MODULE_DEVICE_TABLE(serio, taos_serio_ids); | |
298 | ||
299 | static struct serio_driver taos_drv = { | |
300 | .driver = { | |
301 | .name = "taos-evm", | |
302 | }, | |
303 | .description = "TAOS evaluation module driver", | |
304 | .id_table = taos_serio_ids, | |
305 | .connect = taos_connect, | |
306 | .disconnect = taos_disconnect, | |
307 | .interrupt = taos_interrupt, | |
308 | }; | |
309 | ||
2fd6cf05 | 310 | module_serio_driver(taos_drv); |
b9cdad74 | 311 | |
7c81c60f | 312 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); |
b9cdad74 JD |
313 | MODULE_DESCRIPTION("TAOS evaluation module driver"); |
314 | MODULE_LICENSE("GPL"); |