1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (c) 2011-2016 Synaptics Incorporated |
4 | * Copyright (c) 2011 Unixphere |
5 | */ |
6 | |
7 | #include <linux/kernel.h> |
8 | #include <linux/module.h> |
9 | #include <linux/rmi.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/spi/spi.h> |
12 | #include <linux/of.h> |
13 | #include "rmi_driver.h" |
14 | |
15 | #define RMI_SPI_DEFAULT_XFER_BUF_SIZE 64 |
16 | |
17 | #define RMI_PAGE_SELECT_REGISTER 0x00FF |
18 | #define RMI_SPI_PAGE(addr) (((addr) >> 8) & 0x80) |
19 | #define RMI_SPI_XFER_SIZE_LIMIT 255 |
20 | |
21 | #define BUFFER_SIZE_INCREMENT 32 |
22 | |
23 | enum rmi_spi_op { |
24 | RMI_SPI_WRITE = 0, |
25 | RMI_SPI_READ, |
26 | RMI_SPI_V2_READ_UNIFIED, |
27 | RMI_SPI_V2_READ_SPLIT, |
28 | RMI_SPI_V2_WRITE, |
29 | }; |
30 | |
31 | struct rmi_spi_cmd { |
32 | enum rmi_spi_op op; |
33 | u16 addr; |
34 | }; |
35 | |
36 | struct rmi_spi_xport { |
37 | struct rmi_transport_dev xport; |
38 | struct spi_device *spi; |
39 | |
40 | struct mutex page_mutex; |
41 | int page; |
42 | |
43 | u8 *rx_buf; |
44 | u8 *tx_buf; |
45 | int xfer_buf_size; |
46 | |
47 | struct spi_transfer *rx_xfers; |
48 | struct spi_transfer *tx_xfers; |
49 | int rx_xfer_count; |
50 | int tx_xfer_count; |
51 | }; |
52 | |
53 | static int rmi_spi_manage_pools(struct rmi_spi_xport *rmi_spi, int len) |
54 | { |
55 | struct spi_device *spi = rmi_spi->spi; |
56 | int buf_size = rmi_spi->xfer_buf_size |
57 | ? rmi_spi->xfer_buf_size : RMI_SPI_DEFAULT_XFER_BUF_SIZE; |
58 | struct spi_transfer *xfer_buf; |
59 | void *buf; |
60 | void *tmp; |
61 | |
62 | while (buf_size < len) |
63 | buf_size *= 2; |
64 | |
65 | if (buf_size > RMI_SPI_XFER_SIZE_LIMIT) |
66 | buf_size = RMI_SPI_XFER_SIZE_LIMIT; |
67 | |
68 | tmp = rmi_spi->rx_buf; |
69 | buf = devm_kcalloc(dev: &spi->dev, n: buf_size, size: 2, |
70 | GFP_KERNEL | GFP_DMA); |
71 | if (!buf) |
72 | return -ENOMEM; |
73 | |
74 | rmi_spi->rx_buf = buf; |
75 | rmi_spi->tx_buf = &rmi_spi->rx_buf[buf_size]; |
76 | rmi_spi->xfer_buf_size = buf_size; |
77 | |
78 | if (tmp) |
79 | devm_kfree(dev: &spi->dev, p: tmp); |
80 | |
81 | if (rmi_spi->xport.pdata.spi_data.read_delay_us) |
82 | rmi_spi->rx_xfer_count = buf_size; |
83 | else |
84 | rmi_spi->rx_xfer_count = 1; |
85 | |
86 | if (rmi_spi->xport.pdata.spi_data.write_delay_us) |
87 | rmi_spi->tx_xfer_count = buf_size; |
88 | else |
89 | rmi_spi->tx_xfer_count = 1; |
90 | |
91 | /* |
92 | * Allocate a pool of spi_transfer buffers for devices which need |
93 | * per byte delays. |
94 | */ |
95 | tmp = rmi_spi->rx_xfers; |
96 | xfer_buf = devm_kcalloc(dev: &spi->dev, |
97 | n: rmi_spi->rx_xfer_count + rmi_spi->tx_xfer_count, |
98 | size: sizeof(struct spi_transfer), |
99 | GFP_KERNEL); |
100 | if (!xfer_buf) |
101 | return -ENOMEM; |
102 | |
103 | rmi_spi->rx_xfers = xfer_buf; |
104 | rmi_spi->tx_xfers = &xfer_buf[rmi_spi->rx_xfer_count]; |
105 | |
106 | if (tmp) |
107 | devm_kfree(dev: &spi->dev, p: tmp); |
108 | |
109 | return 0; |
110 | } |
111 | |
112 | static int rmi_spi_xfer(struct rmi_spi_xport *rmi_spi, |
113 | const struct rmi_spi_cmd *cmd, const u8 *tx_buf, |
114 | int tx_len, u8 *rx_buf, int rx_len) |
115 | { |
116 | struct spi_device *spi = rmi_spi->spi; |
117 | struct rmi_device_platform_data_spi *spi_data = |
118 | &rmi_spi->xport.pdata.spi_data; |
119 | struct spi_message msg; |
120 | struct spi_transfer *xfer; |
121 | int ret = 0; |
122 | int len; |
123 | int cmd_len = 0; |
124 | int total_tx_len; |
125 | int i; |
126 | u16 addr = cmd->addr; |
127 | |
128 | spi_message_init(m: &msg); |
129 | |
130 | switch (cmd->op) { |
131 | case RMI_SPI_WRITE: |
132 | case RMI_SPI_READ: |
133 | cmd_len += 2; |
134 | break; |
135 | case RMI_SPI_V2_READ_UNIFIED: |
136 | case RMI_SPI_V2_READ_SPLIT: |
137 | case RMI_SPI_V2_WRITE: |
138 | cmd_len += 4; |
139 | break; |
140 | } |
141 | |
142 | total_tx_len = cmd_len + tx_len; |
143 | len = max(total_tx_len, rx_len); |
144 | |
145 | if (len > RMI_SPI_XFER_SIZE_LIMIT) |
146 | return -EINVAL; |
147 | |
148 | if (rmi_spi->xfer_buf_size < len) { |
149 | ret = rmi_spi_manage_pools(rmi_spi, len); |
150 | if (ret < 0) |
151 | return ret; |
152 | } |
153 | |
154 | if (addr == 0) |
155 | /* |
156 | * SPI needs an address. Use 0x7FF if we want to keep |
157 | * reading from the last position of the register pointer. |
158 | */ |
159 | addr = 0x7FF; |
160 | |
161 | switch (cmd->op) { |
162 | case RMI_SPI_WRITE: |
163 | rmi_spi->tx_buf[0] = (addr >> 8); |
164 | rmi_spi->tx_buf[1] = addr & 0xFF; |
165 | break; |
166 | case RMI_SPI_READ: |
167 | rmi_spi->tx_buf[0] = (addr >> 8) | 0x80; |
168 | rmi_spi->tx_buf[1] = addr & 0xFF; |
169 | break; |
170 | case RMI_SPI_V2_READ_UNIFIED: |
171 | break; |
172 | case RMI_SPI_V2_READ_SPLIT: |
173 | break; |
174 | case RMI_SPI_V2_WRITE: |
175 | rmi_spi->tx_buf[0] = 0x40; |
176 | rmi_spi->tx_buf[1] = (addr >> 8) & 0xFF; |
177 | rmi_spi->tx_buf[2] = addr & 0xFF; |
178 | rmi_spi->tx_buf[3] = tx_len; |
179 | break; |
180 | } |
181 | |
182 | if (tx_buf) |
183 | memcpy(&rmi_spi->tx_buf[cmd_len], tx_buf, tx_len); |
184 | |
185 | if (rmi_spi->tx_xfer_count > 1) { |
186 | for (i = 0; i < total_tx_len; i++) { |
187 | xfer = &rmi_spi->tx_xfers[i]; |
188 | memset(xfer, 0, sizeof(struct spi_transfer)); |
189 | xfer->tx_buf = &rmi_spi->tx_buf[i]; |
190 | xfer->len = 1; |
191 | xfer->delay.value = spi_data->write_delay_us; |
192 | xfer->delay.unit = SPI_DELAY_UNIT_USECS; |
193 | spi_message_add_tail(t: xfer, m: &msg); |
194 | } |
195 | } else { |
196 | xfer = rmi_spi->tx_xfers; |
197 | memset(xfer, 0, sizeof(struct spi_transfer)); |
198 | xfer->tx_buf = rmi_spi->tx_buf; |
199 | xfer->len = total_tx_len; |
200 | spi_message_add_tail(t: xfer, m: &msg); |
201 | } |
202 | |
203 | rmi_dbg(RMI_DEBUG_XPORT, dev: &spi->dev, fmt: "%s: cmd: %s tx_buf len: %d tx_buf: %*ph\n" , |
204 | __func__, cmd->op == RMI_SPI_WRITE ? "WRITE" : "READ" , |
205 | total_tx_len, total_tx_len, rmi_spi->tx_buf); |
206 | |
207 | if (rx_buf) { |
208 | if (rmi_spi->rx_xfer_count > 1) { |
209 | for (i = 0; i < rx_len; i++) { |
210 | xfer = &rmi_spi->rx_xfers[i]; |
211 | memset(xfer, 0, sizeof(struct spi_transfer)); |
212 | xfer->rx_buf = &rmi_spi->rx_buf[i]; |
213 | xfer->len = 1; |
214 | xfer->delay.value = spi_data->read_delay_us; |
215 | xfer->delay.unit = SPI_DELAY_UNIT_USECS; |
216 | spi_message_add_tail(t: xfer, m: &msg); |
217 | } |
218 | } else { |
219 | xfer = rmi_spi->rx_xfers; |
220 | memset(xfer, 0, sizeof(struct spi_transfer)); |
221 | xfer->rx_buf = rmi_spi->rx_buf; |
222 | xfer->len = rx_len; |
223 | spi_message_add_tail(t: xfer, m: &msg); |
224 | } |
225 | } |
226 | |
227 | ret = spi_sync(spi, message: &msg); |
228 | if (ret < 0) { |
229 | dev_err(&spi->dev, "spi xfer failed: %d\n" , ret); |
230 | return ret; |
231 | } |
232 | |
233 | if (rx_buf) { |
234 | memcpy(rx_buf, rmi_spi->rx_buf, rx_len); |
235 | rmi_dbg(RMI_DEBUG_XPORT, dev: &spi->dev, fmt: "%s: (%d) %*ph\n" , |
236 | __func__, rx_len, rx_len, rx_buf); |
237 | } |
238 | |
239 | return 0; |
240 | } |
241 | |
242 | /* |
243 | * rmi_set_page - Set RMI page |
244 | * @xport: The pointer to the rmi_transport_dev struct |
245 | * @page: The new page address. |
246 | * |
247 | * RMI devices have 16-bit addressing, but some of the transport |
248 | * implementations (like SMBus) only have 8-bit addressing. So RMI implements |
249 | * a page address at 0xff of every page so we can reliable page addresses |
250 | * every 256 registers. |
251 | * |
252 | * The page_mutex lock must be held when this function is entered. |
253 | * |
254 | * Returns zero on success, non-zero on failure. |
255 | */ |
256 | static int rmi_set_page(struct rmi_spi_xport *rmi_spi, u8 page) |
257 | { |
258 | struct rmi_spi_cmd cmd; |
259 | int ret; |
260 | |
261 | cmd.op = RMI_SPI_WRITE; |
262 | cmd.addr = RMI_PAGE_SELECT_REGISTER; |
263 | |
264 | ret = rmi_spi_xfer(rmi_spi, cmd: &cmd, tx_buf: &page, tx_len: 1, NULL, rx_len: 0); |
265 | |
266 | if (ret) |
267 | rmi_spi->page = page; |
268 | |
269 | return ret; |
270 | } |
271 | |
272 | static int rmi_spi_write_block(struct rmi_transport_dev *xport, u16 addr, |
273 | const void *buf, size_t len) |
274 | { |
275 | struct rmi_spi_xport *rmi_spi = |
276 | container_of(xport, struct rmi_spi_xport, xport); |
277 | struct rmi_spi_cmd cmd; |
278 | int ret; |
279 | |
280 | mutex_lock(&rmi_spi->page_mutex); |
281 | |
282 | if (RMI_SPI_PAGE(addr) != rmi_spi->page) { |
283 | ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr)); |
284 | if (ret) |
285 | goto exit; |
286 | } |
287 | |
288 | cmd.op = RMI_SPI_WRITE; |
289 | cmd.addr = addr; |
290 | |
291 | ret = rmi_spi_xfer(rmi_spi, cmd: &cmd, tx_buf: buf, tx_len: len, NULL, rx_len: 0); |
292 | |
293 | exit: |
294 | mutex_unlock(lock: &rmi_spi->page_mutex); |
295 | return ret; |
296 | } |
297 | |
298 | static int rmi_spi_read_block(struct rmi_transport_dev *xport, u16 addr, |
299 | void *buf, size_t len) |
300 | { |
301 | struct rmi_spi_xport *rmi_spi = |
302 | container_of(xport, struct rmi_spi_xport, xport); |
303 | struct rmi_spi_cmd cmd; |
304 | int ret; |
305 | |
306 | mutex_lock(&rmi_spi->page_mutex); |
307 | |
308 | if (RMI_SPI_PAGE(addr) != rmi_spi->page) { |
309 | ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr)); |
310 | if (ret) |
311 | goto exit; |
312 | } |
313 | |
314 | cmd.op = RMI_SPI_READ; |
315 | cmd.addr = addr; |
316 | |
317 | ret = rmi_spi_xfer(rmi_spi, cmd: &cmd, NULL, tx_len: 0, rx_buf: buf, rx_len: len); |
318 | |
319 | exit: |
320 | mutex_unlock(lock: &rmi_spi->page_mutex); |
321 | return ret; |
322 | } |
323 | |
324 | static const struct rmi_transport_ops rmi_spi_ops = { |
325 | .write_block = rmi_spi_write_block, |
326 | .read_block = rmi_spi_read_block, |
327 | }; |
328 | |
329 | #ifdef CONFIG_OF |
330 | static int rmi_spi_of_probe(struct spi_device *spi, |
331 | struct rmi_device_platform_data *pdata) |
332 | { |
333 | struct device *dev = &spi->dev; |
334 | int retval; |
335 | |
336 | retval = rmi_of_property_read_u32(dev, |
337 | result: &pdata->spi_data.read_delay_us, |
338 | prop: "spi-rx-delay-us" , optional: 1); |
339 | if (retval) |
340 | return retval; |
341 | |
342 | retval = rmi_of_property_read_u32(dev, |
343 | result: &pdata->spi_data.write_delay_us, |
344 | prop: "spi-tx-delay-us" , optional: 1); |
345 | if (retval) |
346 | return retval; |
347 | |
348 | return 0; |
349 | } |
350 | |
351 | static const struct of_device_id rmi_spi_of_match[] = { |
352 | { .compatible = "syna,rmi4-spi" }, |
353 | {}, |
354 | }; |
355 | MODULE_DEVICE_TABLE(of, rmi_spi_of_match); |
356 | #else |
357 | static inline int rmi_spi_of_probe(struct spi_device *spi, |
358 | struct rmi_device_platform_data *pdata) |
359 | { |
360 | return -ENODEV; |
361 | } |
362 | #endif |
363 | |
364 | static void rmi_spi_unregister_transport(void *data) |
365 | { |
366 | struct rmi_spi_xport *rmi_spi = data; |
367 | |
368 | rmi_unregister_transport_device(xport: &rmi_spi->xport); |
369 | } |
370 | |
371 | static int rmi_spi_probe(struct spi_device *spi) |
372 | { |
373 | struct rmi_spi_xport *rmi_spi; |
374 | struct rmi_device_platform_data *pdata; |
375 | struct rmi_device_platform_data *spi_pdata = spi->dev.platform_data; |
376 | int error; |
377 | |
378 | if (spi->master->flags & SPI_MASTER_HALF_DUPLEX) |
379 | return -EINVAL; |
380 | |
381 | rmi_spi = devm_kzalloc(dev: &spi->dev, size: sizeof(struct rmi_spi_xport), |
382 | GFP_KERNEL); |
383 | if (!rmi_spi) |
384 | return -ENOMEM; |
385 | |
386 | pdata = &rmi_spi->xport.pdata; |
387 | |
388 | if (spi->dev.of_node) { |
389 | error = rmi_spi_of_probe(spi, pdata); |
390 | if (error) |
391 | return error; |
392 | } else if (spi_pdata) { |
393 | *pdata = *spi_pdata; |
394 | } |
395 | |
396 | if (pdata->spi_data.bits_per_word) |
397 | spi->bits_per_word = pdata->spi_data.bits_per_word; |
398 | |
399 | if (pdata->spi_data.mode) |
400 | spi->mode = pdata->spi_data.mode; |
401 | |
402 | error = spi_setup(spi); |
403 | if (error < 0) { |
404 | dev_err(&spi->dev, "spi_setup failed!\n" ); |
405 | return error; |
406 | } |
407 | |
408 | pdata->irq = spi->irq; |
409 | |
410 | rmi_spi->spi = spi; |
411 | mutex_init(&rmi_spi->page_mutex); |
412 | |
413 | rmi_spi->xport.dev = &spi->dev; |
414 | rmi_spi->xport.proto_name = "spi" ; |
415 | rmi_spi->xport.ops = &rmi_spi_ops; |
416 | |
417 | spi_set_drvdata(spi, data: rmi_spi); |
418 | |
419 | error = rmi_spi_manage_pools(rmi_spi, RMI_SPI_DEFAULT_XFER_BUF_SIZE); |
420 | if (error) |
421 | return error; |
422 | |
423 | /* |
424 | * Setting the page to zero will (a) make sure the PSR is in a |
425 | * known state, and (b) make sure we can talk to the device. |
426 | */ |
427 | error = rmi_set_page(rmi_spi, page: 0); |
428 | if (error) { |
429 | dev_err(&spi->dev, "Failed to set page select to 0.\n" ); |
430 | return error; |
431 | } |
432 | |
433 | dev_info(&spi->dev, "registering SPI-connected sensor\n" ); |
434 | |
435 | error = rmi_register_transport_device(xport: &rmi_spi->xport); |
436 | if (error) { |
437 | dev_err(&spi->dev, "failed to register sensor: %d\n" , error); |
438 | return error; |
439 | } |
440 | |
441 | error = devm_add_action_or_reset(&spi->dev, |
442 | rmi_spi_unregister_transport, |
443 | rmi_spi); |
444 | if (error) |
445 | return error; |
446 | |
447 | return 0; |
448 | } |
449 | |
450 | static int rmi_spi_suspend(struct device *dev) |
451 | { |
452 | struct spi_device *spi = to_spi_device(dev); |
453 | struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi); |
454 | int ret; |
455 | |
456 | ret = rmi_driver_suspend(rmi_dev: rmi_spi->xport.rmi_dev, enable_wake: true); |
457 | if (ret) |
458 | dev_warn(dev, "Failed to resume device: %d\n" , ret); |
459 | |
460 | return ret; |
461 | } |
462 | |
463 | static int rmi_spi_resume(struct device *dev) |
464 | { |
465 | struct spi_device *spi = to_spi_device(dev); |
466 | struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi); |
467 | int ret; |
468 | |
469 | ret = rmi_driver_resume(rmi_dev: rmi_spi->xport.rmi_dev, clear_wake: true); |
470 | if (ret) |
471 | dev_warn(dev, "Failed to resume device: %d\n" , ret); |
472 | |
473 | return ret; |
474 | } |
475 | |
476 | static int rmi_spi_runtime_suspend(struct device *dev) |
477 | { |
478 | struct spi_device *spi = to_spi_device(dev); |
479 | struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi); |
480 | int ret; |
481 | |
482 | ret = rmi_driver_suspend(rmi_dev: rmi_spi->xport.rmi_dev, enable_wake: false); |
483 | if (ret) |
484 | dev_warn(dev, "Failed to resume device: %d\n" , ret); |
485 | |
486 | return 0; |
487 | } |
488 | |
489 | static int rmi_spi_runtime_resume(struct device *dev) |
490 | { |
491 | struct spi_device *spi = to_spi_device(dev); |
492 | struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi); |
493 | int ret; |
494 | |
495 | ret = rmi_driver_resume(rmi_dev: rmi_spi->xport.rmi_dev, clear_wake: false); |
496 | if (ret) |
497 | dev_warn(dev, "Failed to resume device: %d\n" , ret); |
498 | |
499 | return 0; |
500 | } |
501 | |
502 | static const struct dev_pm_ops rmi_spi_pm = { |
503 | SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume) |
504 | RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume, NULL) |
505 | }; |
506 | |
507 | static const struct spi_device_id rmi_id[] = { |
508 | { "rmi4-spi" , 0 }, |
509 | { } |
510 | }; |
511 | MODULE_DEVICE_TABLE(spi, rmi_id); |
512 | |
513 | static struct spi_driver rmi_spi_driver = { |
514 | .driver = { |
515 | .name = "rmi4_spi" , |
516 | .pm = pm_ptr(&rmi_spi_pm), |
517 | .of_match_table = of_match_ptr(rmi_spi_of_match), |
518 | }, |
519 | .id_table = rmi_id, |
520 | .probe = rmi_spi_probe, |
521 | }; |
522 | |
523 | module_spi_driver(rmi_spi_driver); |
524 | |
525 | MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>" ); |
526 | MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>" ); |
527 | MODULE_DESCRIPTION("RMI SPI driver" ); |
528 | MODULE_LICENSE("GPL" ); |
529 | |