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8e8e69d6 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
b9cdad74 JD |
2 | /* |
3 | * Driver for the TAOS evaluation modules | |
4 | * These devices include an I2C master which can be controlled over the | |
5 | * serial port. | |
6 | * | |
7c81c60f | 7 | * Copyright (C) 2007 Jean Delvare <jdelvare@suse.de> |
b9cdad74 JD |
8 | */ |
9 | ||
10 | #include <linux/delay.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/interrupt.h> | |
14 | #include <linux/input.h> | |
15 | #include <linux/serio.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/i2c.h> | |
18 | ||
19 | #define TAOS_BUFFER_SIZE 63 | |
20 | ||
21 | #define TAOS_STATE_INIT 0 | |
22 | #define TAOS_STATE_IDLE 1 | |
27693ce5 | 23 | #define TAOS_STATE_EOFF 2 |
b9cdad74 JD |
24 | #define TAOS_STATE_RECV 3 |
25 | ||
26 | #define TAOS_CMD_RESET 0x12 | |
27693ce5 JD |
27 | #define TAOS_CMD_ECHO_ON '+' |
28 | #define TAOS_CMD_ECHO_OFF '-' | |
b9cdad74 JD |
29 | |
30 | static DECLARE_WAIT_QUEUE_HEAD(wq); | |
31 | ||
32 | struct taos_data { | |
33 | struct i2c_adapter adapter; | |
34 | struct i2c_client *client; | |
35 | int state; | |
36 | u8 addr; /* last used address */ | |
37 | unsigned char buffer[TAOS_BUFFER_SIZE]; | |
38 | unsigned int pos; /* position inside the buffer */ | |
39 | }; | |
40 | ||
41 | /* TAOS TSL2550 EVM */ | |
42 | static struct i2c_board_info tsl2550_info = { | |
43 | I2C_BOARD_INFO("tsl2550", 0x39), | |
b9cdad74 JD |
44 | }; |
45 | ||
46 | /* Instantiate i2c devices based on the adapter name */ | |
47 | static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) | |
48 | { | |
49 | if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { | |
50 | dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", | |
3760f736 | 51 | tsl2550_info.type, tsl2550_info.addr); |
b9cdad74 JD |
52 | return i2c_new_device(adapter, &tsl2550_info); |
53 | } | |
54 | ||
55 | return NULL; | |
56 | } | |
57 | ||
58 | static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, | |
59 | unsigned short flags, char read_write, u8 command, | |
60 | int size, union i2c_smbus_data *data) | |
61 | { | |
62 | struct serio *serio = adapter->algo_data; | |
63 | struct taos_data *taos = serio_get_drvdata(serio); | |
64 | char *p; | |
65 | ||
66 | /* Encode our transaction. "@" is for the device address, "$" for the | |
67 | SMBus command and "#" for the data. */ | |
68 | p = taos->buffer; | |
69 | ||
70 | /* The device remembers the last used address, no need to send it | |
71 | again if it's the same */ | |
72 | if (addr != taos->addr) | |
73 | p += sprintf(p, "@%02X", addr); | |
74 | ||
75 | switch (size) { | |
76 | case I2C_SMBUS_BYTE: | |
77 | if (read_write == I2C_SMBUS_WRITE) | |
78 | sprintf(p, "$#%02X", command); | |
79 | else | |
80 | sprintf(p, "$"); | |
81 | break; | |
82 | case I2C_SMBUS_BYTE_DATA: | |
83 | if (read_write == I2C_SMBUS_WRITE) | |
84 | sprintf(p, "$%02X#%02X", command, data->byte); | |
85 | else | |
86 | sprintf(p, "$%02X", command); | |
87 | break; | |
88 | default: | |
ac7fc4fb JD |
89 | dev_warn(&adapter->dev, "Unsupported transaction %d\n", size); |
90 | return -EOPNOTSUPP; | |
b9cdad74 JD |
91 | } |
92 | ||
93 | /* Send the transaction to the TAOS EVM */ | |
94 | dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); | |
27693ce5 JD |
95 | for (p = taos->buffer; *p; p++) |
96 | serio_write(serio, *p); | |
97 | ||
b9cdad74 JD |
98 | taos->addr = addr; |
99 | ||
100 | /* Start the transaction and read the answer */ | |
101 | taos->pos = 0; | |
102 | taos->state = TAOS_STATE_RECV; | |
103 | serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); | |
104 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
105 | msecs_to_jiffies(150)); | |
106 | if (taos->state != TAOS_STATE_IDLE | |
27693ce5 | 107 | || taos->pos != 5) { |
b9cdad74 JD |
108 | dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", |
109 | taos->pos); | |
110 | return -EIO; | |
111 | } | |
112 | dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); | |
113 | ||
114 | /* Interpret the returned string */ | |
27693ce5 | 115 | p = taos->buffer + 1; |
b9cdad74 JD |
116 | p[3] = '\0'; |
117 | if (!strcmp(p, "NAK")) | |
118 | return -ENODEV; | |
119 | ||
120 | if (read_write == I2C_SMBUS_WRITE) { | |
121 | if (!strcmp(p, "ACK")) | |
122 | return 0; | |
123 | } else { | |
124 | if (p[0] == 'x') { | |
c4c696fa LC |
125 | /* |
126 | * Voluntarily dropping error code of kstrtou8 since all | |
127 | * error code that it could return are invalid according | |
128 | * to Documentation/i2c/fault-codes. | |
129 | */ | |
130 | if (kstrtou8(p + 1, 16, &data->byte)) | |
131 | return -EPROTO; | |
b9cdad74 JD |
132 | return 0; |
133 | } | |
134 | } | |
135 | ||
136 | return -EIO; | |
137 | } | |
138 | ||
139 | static u32 taos_smbus_func(struct i2c_adapter *adapter) | |
140 | { | |
141 | return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; | |
142 | } | |
143 | ||
144 | static const struct i2c_algorithm taos_algorithm = { | |
145 | .smbus_xfer = taos_smbus_xfer, | |
146 | .functionality = taos_smbus_func, | |
147 | }; | |
148 | ||
149 | static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, | |
150 | unsigned int flags) | |
151 | { | |
152 | struct taos_data *taos = serio_get_drvdata(serio); | |
153 | ||
154 | switch (taos->state) { | |
155 | case TAOS_STATE_INIT: | |
156 | taos->buffer[taos->pos++] = data; | |
157 | if (data == ':' | |
158 | || taos->pos == TAOS_BUFFER_SIZE - 1) { | |
159 | taos->buffer[taos->pos] = '\0'; | |
160 | taos->state = TAOS_STATE_IDLE; | |
161 | wake_up_interruptible(&wq); | |
162 | } | |
163 | break; | |
27693ce5 JD |
164 | case TAOS_STATE_EOFF: |
165 | taos->state = TAOS_STATE_IDLE; | |
166 | wake_up_interruptible(&wq); | |
b9cdad74 JD |
167 | break; |
168 | case TAOS_STATE_RECV: | |
169 | taos->buffer[taos->pos++] = data; | |
170 | if (data == ']') { | |
171 | taos->buffer[taos->pos] = '\0'; | |
172 | taos->state = TAOS_STATE_IDLE; | |
173 | wake_up_interruptible(&wq); | |
174 | } | |
175 | break; | |
176 | } | |
177 | ||
178 | return IRQ_HANDLED; | |
179 | } | |
180 | ||
181 | /* Extract the adapter name from the buffer received after reset. | |
182 | The buffer is modified and a pointer inside the buffer is returned. */ | |
183 | static char *taos_adapter_name(char *buffer) | |
184 | { | |
185 | char *start, *end; | |
186 | ||
187 | start = strstr(buffer, "TAOS "); | |
188 | if (!start) | |
189 | return NULL; | |
190 | ||
191 | end = strchr(start, '\r'); | |
192 | if (!end) | |
193 | return NULL; | |
194 | *end = '\0'; | |
195 | ||
196 | return start; | |
197 | } | |
198 | ||
199 | static int taos_connect(struct serio *serio, struct serio_driver *drv) | |
200 | { | |
201 | struct taos_data *taos; | |
202 | struct i2c_adapter *adapter; | |
203 | char *name; | |
204 | int err; | |
205 | ||
206 | taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); | |
207 | if (!taos) { | |
208 | err = -ENOMEM; | |
209 | goto exit; | |
210 | } | |
211 | taos->state = TAOS_STATE_INIT; | |
212 | serio_set_drvdata(serio, taos); | |
213 | ||
214 | err = serio_open(serio, drv); | |
215 | if (err) | |
216 | goto exit_kfree; | |
217 | ||
218 | adapter = &taos->adapter; | |
219 | adapter->owner = THIS_MODULE; | |
220 | adapter->algo = &taos_algorithm; | |
221 | adapter->algo_data = serio; | |
222 | adapter->dev.parent = &serio->dev; | |
223 | ||
224 | /* Reset the TAOS evaluation module to identify it */ | |
225 | serio_write(serio, TAOS_CMD_RESET); | |
226 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
227 | msecs_to_jiffies(2000)); | |
228 | ||
229 | if (taos->state != TAOS_STATE_IDLE) { | |
230 | err = -ENODEV; | |
9b640f2e | 231 | dev_err(&serio->dev, "TAOS EVM reset failed (state=%d, " |
b9cdad74 JD |
232 | "pos=%d)\n", taos->state, taos->pos); |
233 | goto exit_close; | |
234 | } | |
235 | ||
236 | name = taos_adapter_name(taos->buffer); | |
237 | if (!name) { | |
238 | err = -ENODEV; | |
239 | dev_err(&serio->dev, "TAOS EVM identification failed\n"); | |
240 | goto exit_close; | |
241 | } | |
242 | strlcpy(adapter->name, name, sizeof(adapter->name)); | |
243 | ||
27693ce5 JD |
244 | /* Turn echo off for better performance */ |
245 | taos->state = TAOS_STATE_EOFF; | |
246 | serio_write(serio, TAOS_CMD_ECHO_OFF); | |
247 | ||
248 | wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, | |
249 | msecs_to_jiffies(250)); | |
250 | if (taos->state != TAOS_STATE_IDLE) { | |
251 | err = -ENODEV; | |
9b640f2e | 252 | dev_err(&serio->dev, "TAOS EVM echo off failed " |
27693ce5 JD |
253 | "(state=%d)\n", taos->state); |
254 | goto exit_close; | |
255 | } | |
256 | ||
b9cdad74 JD |
257 | err = i2c_add_adapter(adapter); |
258 | if (err) | |
259 | goto exit_close; | |
9b640f2e | 260 | dev_info(&serio->dev, "Connected to TAOS EVM\n"); |
b9cdad74 JD |
261 | |
262 | taos->client = taos_instantiate_device(adapter); | |
263 | return 0; | |
264 | ||
265 | exit_close: | |
266 | serio_close(serio); | |
267 | exit_kfree: | |
b9cdad74 JD |
268 | kfree(taos); |
269 | exit: | |
270 | return err; | |
271 | } | |
272 | ||
273 | static void taos_disconnect(struct serio *serio) | |
274 | { | |
275 | struct taos_data *taos = serio_get_drvdata(serio); | |
276 | ||
bfd96212 | 277 | i2c_unregister_device(taos->client); |
b9cdad74 JD |
278 | i2c_del_adapter(&taos->adapter); |
279 | serio_close(serio); | |
b9cdad74 JD |
280 | kfree(taos); |
281 | ||
9b640f2e | 282 | dev_info(&serio->dev, "Disconnected from TAOS EVM\n"); |
b9cdad74 JD |
283 | } |
284 | ||
c6a6bdbd | 285 | static const struct serio_device_id taos_serio_ids[] = { |
b9cdad74 JD |
286 | { |
287 | .type = SERIO_RS232, | |
288 | .proto = SERIO_TAOSEVM, | |
289 | .id = SERIO_ANY, | |
290 | .extra = SERIO_ANY, | |
291 | }, | |
292 | { 0 } | |
293 | }; | |
294 | MODULE_DEVICE_TABLE(serio, taos_serio_ids); | |
295 | ||
296 | static struct serio_driver taos_drv = { | |
297 | .driver = { | |
298 | .name = "taos-evm", | |
299 | }, | |
300 | .description = "TAOS evaluation module driver", | |
301 | .id_table = taos_serio_ids, | |
302 | .connect = taos_connect, | |
303 | .disconnect = taos_disconnect, | |
304 | .interrupt = taos_interrupt, | |
305 | }; | |
306 | ||
2fd6cf05 | 307 | module_serio_driver(taos_drv); |
b9cdad74 | 308 | |
7c81c60f | 309 | MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); |
b9cdad74 JD |
310 | MODULE_DESCRIPTION("TAOS evaluation module driver"); |
311 | MODULE_LICENSE("GPL"); |