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baf12ae2 EP |
1 | /** |
2 | * ds2482.c - provides i2c to w1-master bridge(s) | |
3 | * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com> | |
4 | * | |
5 | * The DS2482 is a sensor chip made by Dallas Semiconductor (Maxim). | |
6 | * It is a I2C to 1-wire bridge. | |
7 | * There are two variations: -100 and -800, which have 1 or 8 1-wire ports. | |
8 | * The complete datasheet can be obtained from MAXIM's website at: | |
9 | * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4382 | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License as published by | |
13 | * the Free Software Foundation; version 2 of the License. | |
14 | */ | |
15 | ||
16 | #include <linux/module.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/i2c.h> | |
20 | #include <linux/delay.h> | |
21 | #include <asm/delay.h> | |
22 | ||
23 | #include "../w1.h" | |
24 | #include "../w1_int.h" | |
25 | ||
baf12ae2 EP |
26 | /** |
27 | * The DS2482 registers - there are 3 registers that are addressed by a read | |
28 | * pointer. The read pointer is set by the last command executed. | |
29 | * | |
30 | * To read the data, issue a register read for any address | |
31 | */ | |
32 | #define DS2482_CMD_RESET 0xF0 /* No param */ | |
33 | #define DS2482_CMD_SET_READ_PTR 0xE1 /* Param: DS2482_PTR_CODE_xxx */ | |
34 | #define DS2482_CMD_CHANNEL_SELECT 0xC3 /* Param: Channel byte - DS2482-800 only */ | |
35 | #define DS2482_CMD_WRITE_CONFIG 0xD2 /* Param: Config byte */ | |
36 | #define DS2482_CMD_1WIRE_RESET 0xB4 /* Param: None */ | |
37 | #define DS2482_CMD_1WIRE_SINGLE_BIT 0x87 /* Param: Bit byte (bit7) */ | |
38 | #define DS2482_CMD_1WIRE_WRITE_BYTE 0xA5 /* Param: Data byte */ | |
39 | #define DS2482_CMD_1WIRE_READ_BYTE 0x96 /* Param: None */ | |
40 | /* Note to read the byte, Set the ReadPtr to Data then read (any addr) */ | |
41 | #define DS2482_CMD_1WIRE_TRIPLET 0x78 /* Param: Dir byte (bit7) */ | |
42 | ||
43 | /* Values for DS2482_CMD_SET_READ_PTR */ | |
44 | #define DS2482_PTR_CODE_STATUS 0xF0 | |
45 | #define DS2482_PTR_CODE_DATA 0xE1 | |
46 | #define DS2482_PTR_CODE_CHANNEL 0xD2 /* DS2482-800 only */ | |
47 | #define DS2482_PTR_CODE_CONFIG 0xC3 | |
48 | ||
49 | /** | |
50 | * Configure Register bit definitions | |
51 | * The top 4 bits always read 0. | |
52 | * To write, the top nibble must be the 1's compl. of the low nibble. | |
53 | */ | |
54 | #define DS2482_REG_CFG_1WS 0x08 | |
55 | #define DS2482_REG_CFG_SPU 0x04 | |
56 | #define DS2482_REG_CFG_PPM 0x02 | |
57 | #define DS2482_REG_CFG_APU 0x01 | |
58 | ||
59 | ||
60 | /** | |
61 | * Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only). | |
62 | * To set the channel, write the value at the index of the channel. | |
63 | * Read and compare against the corresponding value to verify the change. | |
64 | */ | |
65 | static const u8 ds2482_chan_wr[8] = | |
66 | { 0xF0, 0xE1, 0xD2, 0xC3, 0xB4, 0xA5, 0x96, 0x87 }; | |
67 | static const u8 ds2482_chan_rd[8] = | |
68 | { 0xB8, 0xB1, 0xAA, 0xA3, 0x9C, 0x95, 0x8E, 0x87 }; | |
69 | ||
70 | ||
71 | /** | |
72 | * Status Register bit definitions (read only) | |
73 | */ | |
74 | #define DS2482_REG_STS_DIR 0x80 | |
75 | #define DS2482_REG_STS_TSB 0x40 | |
76 | #define DS2482_REG_STS_SBR 0x20 | |
77 | #define DS2482_REG_STS_RST 0x10 | |
78 | #define DS2482_REG_STS_LL 0x08 | |
79 | #define DS2482_REG_STS_SD 0x04 | |
80 | #define DS2482_REG_STS_PPD 0x02 | |
81 | #define DS2482_REG_STS_1WB 0x01 | |
82 | ||
83 | ||
61c91f7d JD |
84 | static int ds2482_probe(struct i2c_client *client, |
85 | const struct i2c_device_id *id); | |
61c91f7d | 86 | static int ds2482_remove(struct i2c_client *client); |
baf12ae2 EP |
87 | |
88 | ||
89 | /** | |
90 | * Driver data (common to all clients) | |
91 | */ | |
61c91f7d JD |
92 | static const struct i2c_device_id ds2482_id[] = { |
93 | { "ds2482", 0 }, | |
94 | { } | |
95 | }; | |
96 | ||
baf12ae2 EP |
97 | static struct i2c_driver ds2482_driver = { |
98 | .driver = { | |
99 | .owner = THIS_MODULE, | |
100 | .name = "ds2482", | |
101 | }, | |
61c91f7d JD |
102 | .probe = ds2482_probe, |
103 | .remove = ds2482_remove, | |
104 | .id_table = ds2482_id, | |
baf12ae2 EP |
105 | }; |
106 | ||
107 | /* | |
108 | * Client data (each client gets its own) | |
109 | */ | |
110 | ||
111 | struct ds2482_data; | |
112 | ||
113 | struct ds2482_w1_chan { | |
114 | struct ds2482_data *pdev; | |
115 | u8 channel; | |
116 | struct w1_bus_master w1_bm; | |
117 | }; | |
118 | ||
119 | struct ds2482_data { | |
61c91f7d | 120 | struct i2c_client *client; |
abd52a13 | 121 | struct mutex access_lock; |
baf12ae2 EP |
122 | |
123 | /* 1-wire interface(s) */ | |
124 | int w1_count; /* 1 or 8 */ | |
125 | struct ds2482_w1_chan w1_ch[8]; | |
126 | ||
127 | /* per-device values */ | |
128 | u8 channel; | |
129 | u8 read_prt; /* see DS2482_PTR_CODE_xxx */ | |
130 | u8 reg_config; | |
131 | }; | |
132 | ||
133 | ||
134 | /** | |
135 | * Sets the read pointer. | |
136 | * @param pdev The ds2482 client pointer | |
137 | * @param read_ptr see DS2482_PTR_CODE_xxx above | |
138 | * @return -1 on failure, 0 on success | |
139 | */ | |
140 | static inline int ds2482_select_register(struct ds2482_data *pdev, u8 read_ptr) | |
141 | { | |
142 | if (pdev->read_prt != read_ptr) { | |
61c91f7d | 143 | if (i2c_smbus_write_byte_data(pdev->client, |
baf12ae2 EP |
144 | DS2482_CMD_SET_READ_PTR, |
145 | read_ptr) < 0) | |
146 | return -1; | |
147 | ||
148 | pdev->read_prt = read_ptr; | |
149 | } | |
150 | return 0; | |
151 | } | |
152 | ||
153 | /** | |
154 | * Sends a command without a parameter | |
155 | * @param pdev The ds2482 client pointer | |
156 | * @param cmd DS2482_CMD_RESET, | |
157 | * DS2482_CMD_1WIRE_RESET, | |
158 | * DS2482_CMD_1WIRE_READ_BYTE | |
159 | * @return -1 on failure, 0 on success | |
160 | */ | |
161 | static inline int ds2482_send_cmd(struct ds2482_data *pdev, u8 cmd) | |
162 | { | |
61c91f7d | 163 | if (i2c_smbus_write_byte(pdev->client, cmd) < 0) |
baf12ae2 EP |
164 | return -1; |
165 | ||
166 | pdev->read_prt = DS2482_PTR_CODE_STATUS; | |
167 | return 0; | |
168 | } | |
169 | ||
170 | /** | |
171 | * Sends a command with a parameter | |
172 | * @param pdev The ds2482 client pointer | |
173 | * @param cmd DS2482_CMD_WRITE_CONFIG, | |
174 | * DS2482_CMD_1WIRE_SINGLE_BIT, | |
175 | * DS2482_CMD_1WIRE_WRITE_BYTE, | |
176 | * DS2482_CMD_1WIRE_TRIPLET | |
177 | * @param byte The data to send | |
178 | * @return -1 on failure, 0 on success | |
179 | */ | |
180 | static inline int ds2482_send_cmd_data(struct ds2482_data *pdev, | |
181 | u8 cmd, u8 byte) | |
182 | { | |
61c91f7d | 183 | if (i2c_smbus_write_byte_data(pdev->client, cmd, byte) < 0) |
baf12ae2 EP |
184 | return -1; |
185 | ||
186 | /* all cmds leave in STATUS, except CONFIG */ | |
187 | pdev->read_prt = (cmd != DS2482_CMD_WRITE_CONFIG) ? | |
188 | DS2482_PTR_CODE_STATUS : DS2482_PTR_CODE_CONFIG; | |
189 | return 0; | |
190 | } | |
191 | ||
192 | ||
193 | /* | |
194 | * 1-Wire interface code | |
195 | */ | |
196 | ||
197 | #define DS2482_WAIT_IDLE_TIMEOUT 100 | |
198 | ||
199 | /** | |
200 | * Waits until the 1-wire interface is idle (not busy) | |
201 | * | |
202 | * @param pdev Pointer to the device structure | |
203 | * @return the last value read from status or -1 (failure) | |
204 | */ | |
205 | static int ds2482_wait_1wire_idle(struct ds2482_data *pdev) | |
206 | { | |
207 | int temp = -1; | |
208 | int retries = 0; | |
209 | ||
210 | if (!ds2482_select_register(pdev, DS2482_PTR_CODE_STATUS)) { | |
211 | do { | |
61c91f7d | 212 | temp = i2c_smbus_read_byte(pdev->client); |
baf12ae2 | 213 | } while ((temp >= 0) && (temp & DS2482_REG_STS_1WB) && |
b4786f18 | 214 | (++retries < DS2482_WAIT_IDLE_TIMEOUT)); |
baf12ae2 EP |
215 | } |
216 | ||
67860739 | 217 | if (retries >= DS2482_WAIT_IDLE_TIMEOUT) |
baf12ae2 EP |
218 | printk(KERN_ERR "%s: timeout on channel %d\n", |
219 | __func__, pdev->channel); | |
220 | ||
221 | return temp; | |
222 | } | |
223 | ||
224 | /** | |
225 | * Selects a w1 channel. | |
226 | * The 1-wire interface must be idle before calling this function. | |
227 | * | |
228 | * @param pdev The ds2482 client pointer | |
229 | * @param channel 0-7 | |
230 | * @return -1 (failure) or 0 (success) | |
231 | */ | |
232 | static int ds2482_set_channel(struct ds2482_data *pdev, u8 channel) | |
233 | { | |
61c91f7d | 234 | if (i2c_smbus_write_byte_data(pdev->client, DS2482_CMD_CHANNEL_SELECT, |
baf12ae2 EP |
235 | ds2482_chan_wr[channel]) < 0) |
236 | return -1; | |
237 | ||
238 | pdev->read_prt = DS2482_PTR_CODE_CHANNEL; | |
239 | pdev->channel = -1; | |
61c91f7d | 240 | if (i2c_smbus_read_byte(pdev->client) == ds2482_chan_rd[channel]) { |
baf12ae2 EP |
241 | pdev->channel = channel; |
242 | return 0; | |
243 | } | |
244 | return -1; | |
245 | } | |
246 | ||
247 | ||
248 | /** | |
249 | * Performs the touch-bit function, which writes a 0 or 1 and reads the level. | |
250 | * | |
251 | * @param data The ds2482 channel pointer | |
252 | * @param bit The level to write: 0 or non-zero | |
253 | * @return The level read: 0 or 1 | |
254 | */ | |
255 | static u8 ds2482_w1_touch_bit(void *data, u8 bit) | |
256 | { | |
257 | struct ds2482_w1_chan *pchan = data; | |
258 | struct ds2482_data *pdev = pchan->pdev; | |
259 | int status = -1; | |
260 | ||
abd52a13 | 261 | mutex_lock(&pdev->access_lock); |
baf12ae2 EP |
262 | |
263 | /* Select the channel */ | |
264 | ds2482_wait_1wire_idle(pdev); | |
265 | if (pdev->w1_count > 1) | |
266 | ds2482_set_channel(pdev, pchan->channel); | |
267 | ||
268 | /* Send the touch command, wait until 1WB == 0, return the status */ | |
269 | if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_SINGLE_BIT, | |
270 | bit ? 0xFF : 0)) | |
271 | status = ds2482_wait_1wire_idle(pdev); | |
272 | ||
abd52a13 | 273 | mutex_unlock(&pdev->access_lock); |
baf12ae2 EP |
274 | |
275 | return (status & DS2482_REG_STS_SBR) ? 1 : 0; | |
276 | } | |
277 | ||
278 | /** | |
279 | * Performs the triplet function, which reads two bits and writes a bit. | |
280 | * The bit written is determined by the two reads: | |
281 | * 00 => dbit, 01 => 0, 10 => 1 | |
282 | * | |
283 | * @param data The ds2482 channel pointer | |
284 | * @param dbit The direction to choose if both branches are valid | |
285 | * @return b0=read1 b1=read2 b3=bit written | |
286 | */ | |
287 | static u8 ds2482_w1_triplet(void *data, u8 dbit) | |
288 | { | |
289 | struct ds2482_w1_chan *pchan = data; | |
290 | struct ds2482_data *pdev = pchan->pdev; | |
291 | int status = (3 << 5); | |
292 | ||
abd52a13 | 293 | mutex_lock(&pdev->access_lock); |
baf12ae2 EP |
294 | |
295 | /* Select the channel */ | |
296 | ds2482_wait_1wire_idle(pdev); | |
297 | if (pdev->w1_count > 1) | |
298 | ds2482_set_channel(pdev, pchan->channel); | |
299 | ||
300 | /* Send the triplet command, wait until 1WB == 0, return the status */ | |
301 | if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_TRIPLET, | |
302 | dbit ? 0xFF : 0)) | |
303 | status = ds2482_wait_1wire_idle(pdev); | |
304 | ||
abd52a13 | 305 | mutex_unlock(&pdev->access_lock); |
baf12ae2 EP |
306 | |
307 | /* Decode the status */ | |
308 | return (status >> 5); | |
309 | } | |
310 | ||
311 | /** | |
312 | * Performs the write byte function. | |
313 | * | |
314 | * @param data The ds2482 channel pointer | |
315 | * @param byte The value to write | |
316 | */ | |
317 | static void ds2482_w1_write_byte(void *data, u8 byte) | |
318 | { | |
319 | struct ds2482_w1_chan *pchan = data; | |
320 | struct ds2482_data *pdev = pchan->pdev; | |
321 | ||
abd52a13 | 322 | mutex_lock(&pdev->access_lock); |
baf12ae2 EP |
323 | |
324 | /* Select the channel */ | |
325 | ds2482_wait_1wire_idle(pdev); | |
326 | if (pdev->w1_count > 1) | |
327 | ds2482_set_channel(pdev, pchan->channel); | |
328 | ||
329 | /* Send the write byte command */ | |
330 | ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_WRITE_BYTE, byte); | |
331 | ||
abd52a13 | 332 | mutex_unlock(&pdev->access_lock); |
baf12ae2 EP |
333 | } |
334 | ||
335 | /** | |
336 | * Performs the read byte function. | |
337 | * | |
338 | * @param data The ds2482 channel pointer | |
339 | * @return The value read | |
340 | */ | |
341 | static u8 ds2482_w1_read_byte(void *data) | |
342 | { | |
343 | struct ds2482_w1_chan *pchan = data; | |
344 | struct ds2482_data *pdev = pchan->pdev; | |
345 | int result; | |
346 | ||
abd52a13 | 347 | mutex_lock(&pdev->access_lock); |
baf12ae2 EP |
348 | |
349 | /* Select the channel */ | |
350 | ds2482_wait_1wire_idle(pdev); | |
351 | if (pdev->w1_count > 1) | |
352 | ds2482_set_channel(pdev, pchan->channel); | |
353 | ||
354 | /* Send the read byte command */ | |
355 | ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_READ_BYTE); | |
356 | ||
357 | /* Wait until 1WB == 0 */ | |
358 | ds2482_wait_1wire_idle(pdev); | |
359 | ||
360 | /* Select the data register */ | |
361 | ds2482_select_register(pdev, DS2482_PTR_CODE_DATA); | |
362 | ||
363 | /* Read the data byte */ | |
61c91f7d | 364 | result = i2c_smbus_read_byte(pdev->client); |
baf12ae2 | 365 | |
abd52a13 | 366 | mutex_unlock(&pdev->access_lock); |
baf12ae2 EP |
367 | |
368 | return result; | |
369 | } | |
370 | ||
371 | ||
372 | /** | |
373 | * Sends a reset on the 1-wire interface | |
374 | * | |
375 | * @param data The ds2482 channel pointer | |
376 | * @return 0=Device present, 1=No device present or error | |
377 | */ | |
378 | static u8 ds2482_w1_reset_bus(void *data) | |
379 | { | |
380 | struct ds2482_w1_chan *pchan = data; | |
381 | struct ds2482_data *pdev = pchan->pdev; | |
382 | int err; | |
383 | u8 retval = 1; | |
384 | ||
abd52a13 | 385 | mutex_lock(&pdev->access_lock); |
baf12ae2 EP |
386 | |
387 | /* Select the channel */ | |
388 | ds2482_wait_1wire_idle(pdev); | |
389 | if (pdev->w1_count > 1) | |
390 | ds2482_set_channel(pdev, pchan->channel); | |
391 | ||
392 | /* Send the reset command */ | |
393 | err = ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_RESET); | |
394 | if (err >= 0) { | |
395 | /* Wait until the reset is complete */ | |
396 | err = ds2482_wait_1wire_idle(pdev); | |
397 | retval = !(err & DS2482_REG_STS_PPD); | |
398 | ||
399 | /* If the chip did reset since detect, re-config it */ | |
400 | if (err & DS2482_REG_STS_RST) | |
401 | ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG, | |
402 | 0xF0); | |
403 | } | |
404 | ||
abd52a13 | 405 | mutex_unlock(&pdev->access_lock); |
baf12ae2 EP |
406 | |
407 | return retval; | |
408 | } | |
409 | ||
410 | ||
61c91f7d JD |
411 | static int ds2482_probe(struct i2c_client *client, |
412 | const struct i2c_device_id *id) | |
baf12ae2 EP |
413 | { |
414 | struct ds2482_data *data; | |
61c91f7d | 415 | int err = -ENODEV; |
baf12ae2 EP |
416 | int temp1; |
417 | int idx; | |
418 | ||
0314b020 JD |
419 | if (!i2c_check_functionality(client->adapter, |
420 | I2C_FUNC_SMBUS_WRITE_BYTE_DATA | | |
421 | I2C_FUNC_SMBUS_BYTE)) | |
422 | return -ENODEV; | |
423 | ||
baf12ae2 EP |
424 | if (!(data = kzalloc(sizeof(struct ds2482_data), GFP_KERNEL))) { |
425 | err = -ENOMEM; | |
426 | goto exit; | |
427 | } | |
428 | ||
61c91f7d JD |
429 | data->client = client; |
430 | i2c_set_clientdata(client, data); | |
baf12ae2 EP |
431 | |
432 | /* Reset the device (sets the read_ptr to status) */ | |
433 | if (ds2482_send_cmd(data, DS2482_CMD_RESET) < 0) { | |
61c91f7d | 434 | dev_warn(&client->dev, "DS2482 reset failed.\n"); |
baf12ae2 EP |
435 | goto exit_free; |
436 | } | |
437 | ||
438 | /* Sleep at least 525ns to allow the reset to complete */ | |
439 | ndelay(525); | |
440 | ||
441 | /* Read the status byte - only reset bit and line should be set */ | |
61c91f7d | 442 | temp1 = i2c_smbus_read_byte(client); |
baf12ae2 | 443 | if (temp1 != (DS2482_REG_STS_LL | DS2482_REG_STS_RST)) { |
61c91f7d JD |
444 | dev_warn(&client->dev, "DS2482 reset status " |
445 | "0x%02X - not a DS2482\n", temp1); | |
baf12ae2 EP |
446 | goto exit_free; |
447 | } | |
448 | ||
449 | /* Detect the 8-port version */ | |
450 | data->w1_count = 1; | |
451 | if (ds2482_set_channel(data, 7) == 0) | |
452 | data->w1_count = 8; | |
453 | ||
454 | /* Set all config items to 0 (off) */ | |
455 | ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG, 0xF0); | |
456 | ||
abd52a13 | 457 | mutex_init(&data->access_lock); |
baf12ae2 | 458 | |
baf12ae2 EP |
459 | /* Register 1-wire interface(s) */ |
460 | for (idx = 0; idx < data->w1_count; idx++) { | |
461 | data->w1_ch[idx].pdev = data; | |
462 | data->w1_ch[idx].channel = idx; | |
463 | ||
464 | /* Populate all the w1 bus master stuff */ | |
465 | data->w1_ch[idx].w1_bm.data = &data->w1_ch[idx]; | |
466 | data->w1_ch[idx].w1_bm.read_byte = ds2482_w1_read_byte; | |
467 | data->w1_ch[idx].w1_bm.write_byte = ds2482_w1_write_byte; | |
468 | data->w1_ch[idx].w1_bm.touch_bit = ds2482_w1_touch_bit; | |
469 | data->w1_ch[idx].w1_bm.triplet = ds2482_w1_triplet; | |
470 | data->w1_ch[idx].w1_bm.reset_bus = ds2482_w1_reset_bus; | |
471 | ||
472 | err = w1_add_master_device(&data->w1_ch[idx].w1_bm); | |
473 | if (err) { | |
474 | data->w1_ch[idx].pdev = NULL; | |
475 | goto exit_w1_remove; | |
476 | } | |
477 | } | |
478 | ||
479 | return 0; | |
480 | ||
481 | exit_w1_remove: | |
baf12ae2 EP |
482 | for (idx = 0; idx < data->w1_count; idx++) { |
483 | if (data->w1_ch[idx].pdev != NULL) | |
484 | w1_remove_master_device(&data->w1_ch[idx].w1_bm); | |
485 | } | |
486 | exit_free: | |
487 | kfree(data); | |
488 | exit: | |
489 | return err; | |
490 | } | |
491 | ||
61c91f7d | 492 | static int ds2482_remove(struct i2c_client *client) |
baf12ae2 EP |
493 | { |
494 | struct ds2482_data *data = i2c_get_clientdata(client); | |
61c91f7d | 495 | int idx; |
baf12ae2 EP |
496 | |
497 | /* Unregister the 1-wire bridge(s) */ | |
498 | for (idx = 0; idx < data->w1_count; idx++) { | |
499 | if (data->w1_ch[idx].pdev != NULL) | |
500 | w1_remove_master_device(&data->w1_ch[idx].w1_bm); | |
501 | } | |
502 | ||
baf12ae2 EP |
503 | /* Free the memory */ |
504 | kfree(data); | |
505 | return 0; | |
506 | } | |
507 | ||
dbfd5ccc | 508 | module_i2c_driver(ds2482_driver); |
baf12ae2 EP |
509 | |
510 | MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); | |
511 | MODULE_DESCRIPTION("DS2482 driver"); | |
512 | MODULE_LICENSE("GPL"); |