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1/*
2 * max3107.c - spi uart protocol driver for Maxim 3107
3 * Based on max3100.c
4 * by Christian Pellegrin <chripell@evolware.org>
5 * and max3110.c
6 * by Feng Tang <feng.tang@intel.com>
7 *
8 * Copyright (C) Aavamobile 2009
9 *
10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 *
26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27 *
28 */
29
30#include <linux/delay.h>
31#include <linux/device.h>
32#include <linux/serial_core.h>
33#include <linux/serial.h>
34#include <linux/gpio.h>
35#include <linux/spi/spi.h>
36#include <linux/freezer.h>
37#include "max3107.h"
38
39static const struct baud_table brg26_ext[] = {
40 { 300, MAX3107_BRG26_B300 },
41 { 600, MAX3107_BRG26_B600 },
42 { 1200, MAX3107_BRG26_B1200 },
43 { 2400, MAX3107_BRG26_B2400 },
44 { 4800, MAX3107_BRG26_B4800 },
45 { 9600, MAX3107_BRG26_B9600 },
46 { 19200, MAX3107_BRG26_B19200 },
47 { 57600, MAX3107_BRG26_B57600 },
48 { 115200, MAX3107_BRG26_B115200 },
49 { 230400, MAX3107_BRG26_B230400 },
50 { 460800, MAX3107_BRG26_B460800 },
51 { 921600, MAX3107_BRG26_B921600 },
52 { 0, 0 }
53};
54
55static const struct baud_table brg13_int[] = {
56 { 300, MAX3107_BRG13_IB300 },
57 { 600, MAX3107_BRG13_IB600 },
58 { 1200, MAX3107_BRG13_IB1200 },
59 { 2400, MAX3107_BRG13_IB2400 },
60 { 4800, MAX3107_BRG13_IB4800 },
61 { 9600, MAX3107_BRG13_IB9600 },
62 { 19200, MAX3107_BRG13_IB19200 },
63 { 57600, MAX3107_BRG13_IB57600 },
64 { 115200, MAX3107_BRG13_IB115200 },
65 { 230400, MAX3107_BRG13_IB230400 },
66 { 460800, MAX3107_BRG13_IB460800 },
67 { 921600, MAX3107_BRG13_IB921600 },
68 { 0, 0 }
69};
70
71static u32 get_new_brg(int baud, struct max3107_port *s)
72{
73 int i;
74 const struct baud_table *baud_tbl = s->baud_tbl;
75
76 for (i = 0; i < 13; i++) {
77 if (baud == baud_tbl[i].baud)
78 return baud_tbl[i].new_brg;
79 }
80
81 return 0;
82}
83
84/* Perform SPI transfer for write/read of device register(s) */
85int max3107_rw(struct max3107_port *s, u8 *tx, u8 *rx, int len)
86{
87 struct spi_message spi_msg;
88 struct spi_transfer spi_xfer;
89
90 /* Initialize SPI ,message */
91 spi_message_init(&spi_msg);
92
93 /* Initialize SPI transfer */
94 memset(&spi_xfer, 0, sizeof spi_xfer);
95 spi_xfer.len = len;
96 spi_xfer.tx_buf = tx;
97 spi_xfer.rx_buf = rx;
98 spi_xfer.speed_hz = MAX3107_SPI_SPEED;
99
100 /* Add SPI transfer to SPI message */
101 spi_message_add_tail(&spi_xfer, &spi_msg);
102
103#ifdef DBG_TRACE_SPI_DATA
104 {
105 int i;
106 pr_info("tx len %d:\n", spi_xfer.len);
107 for (i = 0 ; i < spi_xfer.len && i < 32 ; i++)
108 pr_info(" %x", ((u8 *)spi_xfer.tx_buf)[i]);
109 pr_info("\n");
110 }
111#endif
112
113 /* Perform synchronous SPI transfer */
114 if (spi_sync(s->spi, &spi_msg)) {
115 dev_err(&s->spi->dev, "spi_sync failure\n");
116 return -EIO;
117 }
118
119#ifdef DBG_TRACE_SPI_DATA
120 if (spi_xfer.rx_buf) {
121 int i;
122 pr_info("rx len %d:\n", spi_xfer.len);
123 for (i = 0 ; i < spi_xfer.len && i < 32 ; i++)
124 pr_info(" %x", ((u8 *)spi_xfer.rx_buf)[i]);
125 pr_info("\n");
126 }
127#endif
128 return 0;
129}
130EXPORT_SYMBOL_GPL(max3107_rw);
131
132/* Puts received data to circular buffer */
133static void put_data_to_circ_buf(struct max3107_port *s, unsigned char *data,
134 int len)
135{
136 struct uart_port *port = &s->port;
137 struct tty_struct *tty;
138
139 if (!port->state)
140 return;
141
142 tty = port->state->port.tty;
143 if (!tty)
144 return;
145
146 /* Insert received data */
147 tty_insert_flip_string(tty, data, len);
148 /* Update RX counter */
149 port->icount.rx += len;
150}
151
152/* Handle data receiving */
153static void max3107_handlerx(struct max3107_port *s, u16 rxlvl)
154{
155 int i;
156 int j;
157 int len; /* SPI transfer buffer length */
158 u16 *buf;
159 u8 *valid_str;
160
161 if (!s->rx_enabled)
162 /* RX is disabled */
163 return;
164
165 if (rxlvl == 0) {
166 /* RX fifo is empty */
167 return;
168 } else if (rxlvl >= MAX3107_RX_FIFO_SIZE) {
169 dev_warn(&s->spi->dev, "Possible RX FIFO overrun %d\n", rxlvl);
170 /* Ensure sanity of RX level */
171 rxlvl = MAX3107_RX_FIFO_SIZE;
172 }
173 if ((s->rxbuf == 0) || (s->rxstr == 0)) {
174 dev_warn(&s->spi->dev, "Rx buffer/str isn't ready\n");
175 return;
176 }
177 buf = s->rxbuf;
178 valid_str = s->rxstr;
179 while (rxlvl) {
180 pr_debug("rxlvl %d\n", rxlvl);
181 /* Clear buffer */
182 memset(buf, 0, sizeof(u16) * (MAX3107_RX_FIFO_SIZE + 2));
183 len = 0;
184 if (s->irqen_reg & MAX3107_IRQ_RXFIFO_BIT) {
185 /* First disable RX FIFO interrupt */
186 pr_debug("Disabling RX INT\n");
187 buf[0] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
188 s->irqen_reg &= ~MAX3107_IRQ_RXFIFO_BIT;
189 buf[0] |= s->irqen_reg;
190 len++;
191 }
192 /* Just increase the length by amount of words in FIFO since
193 * buffer was zeroed and SPI transfer of 0x0000 means reading
194 * from RX FIFO
195 */
196 len += rxlvl;
197 /* Append RX level query */
198 buf[len] = MAX3107_RXFIFOLVL_REG;
199 len++;
200
201 /* Perform the SPI transfer */
202 if (max3107_rw(s, (u8 *)buf, (u8 *)buf, len * 2)) {
203 dev_err(&s->spi->dev, "SPI transfer for RX h failed\n");
204 return;
205 }
206
207 /* Skip RX FIFO interrupt disabling word if it was added */
208 j = ((len - 1) - rxlvl);
209 /* Read received words */
210 for (i = 0; i < rxlvl; i++, j++)
211 valid_str[i] = (u8)buf[j];
212 put_data_to_circ_buf(s, valid_str, rxlvl);
213 /* Get new RX level */
214 rxlvl = (buf[len - 1] & MAX3107_SPI_RX_DATA_MASK);
215 }
216
217 if (s->rx_enabled) {
218 /* RX still enabled, re-enable RX FIFO interrupt */
219 pr_debug("Enabling RX INT\n");
220 buf[0] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
221 s->irqen_reg |= MAX3107_IRQ_RXFIFO_BIT;
222 buf[0] |= s->irqen_reg;
223 if (max3107_rw(s, (u8 *)buf, NULL, 2))
224 dev_err(&s->spi->dev, "RX FIFO INT enabling failed\n");
225 }
226
227 /* Push the received data to receivers */
228 if (s->port.state->port.tty)
229 tty_flip_buffer_push(s->port.state->port.tty);
230}
231
232
233/* Handle data sending */
234static void max3107_handletx(struct max3107_port *s)
235{
236 struct circ_buf *xmit = &s->port.state->xmit;
237 int i;
238 unsigned long flags;
239 int len; /* SPI transfer buffer length */
240 u16 *buf;
241
242 if (!s->tx_fifo_empty)
243 /* Don't send more data before previous data is sent */
244 return;
245
246 if (uart_circ_empty(xmit) || uart_tx_stopped(&s->port))
247 /* No data to send or TX is stopped */
248 return;
249
250 if (!s->txbuf) {
251 dev_warn(&s->spi->dev, "Txbuf isn't ready\n");
252 return;
253 }
254 buf = s->txbuf;
255 /* Get length of data pending in circular buffer */
256 len = uart_circ_chars_pending(xmit);
257 if (len) {
258 /* Limit to size of TX FIFO */
259 if (len > MAX3107_TX_FIFO_SIZE)
260 len = MAX3107_TX_FIFO_SIZE;
261
262 pr_debug("txlen %d\n", len);
263
264 /* Update TX counter */
265 s->port.icount.tx += len;
266
267 /* TX FIFO will no longer be empty */
268 s->tx_fifo_empty = 0;
269
270 i = 0;
271 if (s->irqen_reg & MAX3107_IRQ_TXEMPTY_BIT) {
272 /* First disable TX empty interrupt */
273 pr_debug("Disabling TE INT\n");
274 buf[i] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
275 s->irqen_reg &= ~MAX3107_IRQ_TXEMPTY_BIT;
276 buf[i] |= s->irqen_reg;
277 i++;
278 len++;
279 }
280 /* Add data to send */
281 spin_lock_irqsave(&s->port.lock, flags);
282 for ( ; i < len ; i++) {
283 buf[i] = (MAX3107_WRITE_BIT | MAX3107_THR_REG);
284 buf[i] |= ((u16)xmit->buf[xmit->tail] &
285 MAX3107_SPI_TX_DATA_MASK);
286 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
287 }
288 spin_unlock_irqrestore(&s->port.lock, flags);
289 if (!(s->irqen_reg & MAX3107_IRQ_TXEMPTY_BIT)) {
290 /* Enable TX empty interrupt */
291 pr_debug("Enabling TE INT\n");
292 buf[i] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
293 s->irqen_reg |= MAX3107_IRQ_TXEMPTY_BIT;
294 buf[i] |= s->irqen_reg;
295 i++;
296 len++;
297 }
298 if (!s->tx_enabled) {
299 /* Enable TX */
300 pr_debug("Enable TX\n");
301 buf[i] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
302 spin_lock_irqsave(&s->data_lock, flags);
303 s->mode1_reg &= ~MAX3107_MODE1_TXDIS_BIT;
304 buf[i] |= s->mode1_reg;
305 spin_unlock_irqrestore(&s->data_lock, flags);
306 s->tx_enabled = 1;
307 i++;
308 len++;
309 }
310
311 /* Perform the SPI transfer */
312 if (max3107_rw(s, (u8 *)buf, NULL, len*2)) {
313 dev_err(&s->spi->dev,
314 "SPI transfer TX handling failed\n");
315 return;
316 }
317 }
318
319 /* Indicate wake up if circular buffer is getting low on data */
320 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
321 uart_write_wakeup(&s->port);
322
323}
324
325/* Handle interrupts
326 * Also reads and returns current RX FIFO level
327 */
328static u16 handle_interrupt(struct max3107_port *s)
329{
330 u16 buf[4]; /* Buffer for SPI transfers */
331 u8 irq_status;
332 u16 rx_level;
333 unsigned long flags;
334
335 /* Read IRQ status register */
336 buf[0] = MAX3107_IRQSTS_REG;
337 /* Read status IRQ status register */
338 buf[1] = MAX3107_STS_IRQSTS_REG;
339 /* Read LSR IRQ status register */
340 buf[2] = MAX3107_LSR_IRQSTS_REG;
341 /* Query RX level */
342 buf[3] = MAX3107_RXFIFOLVL_REG;
343
344 if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 8)) {
345 dev_err(&s->spi->dev,
346 "SPI transfer for INTR handling failed\n");
347 return 0;
348 }
349
350 irq_status = (u8)buf[0];
351 pr_debug("IRQSTS %x\n", irq_status);
352 rx_level = (buf[3] & MAX3107_SPI_RX_DATA_MASK);
353
354 if (irq_status & MAX3107_IRQ_LSR_BIT) {
355 /* LSR interrupt */
356 if (buf[2] & MAX3107_LSR_RXTO_BIT)
357 /* RX timeout interrupt,
358 * handled by normal RX handling
359 */
360 pr_debug("RX TO INT\n");
361 }
362
363 if (irq_status & MAX3107_IRQ_TXEMPTY_BIT) {
364 /* Tx empty interrupt,
365 * disable TX and set tx_fifo_empty flag
366 */
367 pr_debug("TE INT, disabling TX\n");
368 buf[0] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
369 spin_lock_irqsave(&s->data_lock, flags);
370 s->mode1_reg |= MAX3107_MODE1_TXDIS_BIT;
371 buf[0] |= s->mode1_reg;
372 spin_unlock_irqrestore(&s->data_lock, flags);
373 if (max3107_rw(s, (u8 *)buf, NULL, 2))
374 dev_err(&s->spi->dev, "SPI transfer TX dis failed\n");
375 s->tx_enabled = 0;
376 s->tx_fifo_empty = 1;
377 }
378
379 if (irq_status & MAX3107_IRQ_RXFIFO_BIT)
380 /* RX FIFO interrupt,
381 * handled by normal RX handling
382 */
383 pr_debug("RFIFO INT\n");
384
385 /* Return RX level */
386 return rx_level;
387}
388
389/* Trigger work thread*/
390static void max3107_dowork(struct max3107_port *s)
391{
392 if (!work_pending(&s->work) && !freezing(current) && !s->suspended)
393 queue_work(s->workqueue, &s->work);
394 else
395 dev_warn(&s->spi->dev, "interrup isn't serviced normally!\n");
396}
397
398/* Work thread */
399static void max3107_work(struct work_struct *w)
400{
401 struct max3107_port *s = container_of(w, struct max3107_port, work);
402 u16 rxlvl = 0;
403 int len; /* SPI transfer buffer length */
404 u16 buf[5]; /* Buffer for SPI transfers */
405 unsigned long flags;
406
407 /* Start by reading current RX FIFO level */
408 buf[0] = MAX3107_RXFIFOLVL_REG;
409 if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 2)) {
410 dev_err(&s->spi->dev, "SPI transfer RX lev failed\n");
411 rxlvl = 0;
412 } else {
413 rxlvl = (buf[0] & MAX3107_SPI_RX_DATA_MASK);
414 }
415
416 do {
417 pr_debug("rxlvl %d\n", rxlvl);
418
419 /* Handle RX */
420 max3107_handlerx(s, rxlvl);
421 rxlvl = 0;
422
423 if (s->handle_irq) {
424 /* Handle pending interrupts
425 * We also get new RX FIFO level since new data may
426 * have been received while pushing received data to
427 * receivers
428 */
429 s->handle_irq = 0;
430 rxlvl = handle_interrupt(s);
431 }
432
433 /* Handle TX */
434 max3107_handletx(s);
435
436 /* Handle configuration changes */
437 len = 0;
438 spin_lock_irqsave(&s->data_lock, flags);
439 if (s->mode1_commit) {
440 pr_debug("mode1_commit\n");
441 buf[len] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
442 buf[len++] |= s->mode1_reg;
443 s->mode1_commit = 0;
444 }
445 if (s->lcr_commit) {
446 pr_debug("lcr_commit\n");
447 buf[len] = (MAX3107_WRITE_BIT | MAX3107_LCR_REG);
448 buf[len++] |= s->lcr_reg;
449 s->lcr_commit = 0;
450 }
451 if (s->brg_commit) {
452 pr_debug("brg_commit\n");
453 buf[len] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVMSB_REG);
454 buf[len++] |= ((s->brg_cfg >> 16) &
455 MAX3107_SPI_TX_DATA_MASK);
456 buf[len] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVLSB_REG);
457 buf[len++] |= ((s->brg_cfg >> 8) &
458 MAX3107_SPI_TX_DATA_MASK);
459 buf[len] = (MAX3107_WRITE_BIT | MAX3107_BRGCFG_REG);
460 buf[len++] |= ((s->brg_cfg) & 0xff);
461 s->brg_commit = 0;
462 }
463 spin_unlock_irqrestore(&s->data_lock, flags);
464
465 if (len > 0) {
466 if (max3107_rw(s, (u8 *)buf, NULL, len * 2))
467 dev_err(&s->spi->dev,
468 "SPI transfer config failed\n");
469 }
470
471 /* Reloop if interrupt handling indicated data in RX FIFO */
472 } while (rxlvl);
473
474}
475
476/* Set sleep mode */
477static void max3107_set_sleep(struct max3107_port *s, int mode)
478{
479 u16 buf[1]; /* Buffer for SPI transfer */
480 unsigned long flags;
481 pr_debug("enter, mode %d\n", mode);
482
483 buf[0] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
484 spin_lock_irqsave(&s->data_lock, flags);
485 switch (mode) {
486 case MAX3107_DISABLE_FORCED_SLEEP:
487 s->mode1_reg &= ~MAX3107_MODE1_FORCESLEEP_BIT;
488 break;
489 case MAX3107_ENABLE_FORCED_SLEEP:
490 s->mode1_reg |= MAX3107_MODE1_FORCESLEEP_BIT;
491 break;
492 case MAX3107_DISABLE_AUTOSLEEP:
493 s->mode1_reg &= ~MAX3107_MODE1_AUTOSLEEP_BIT;
494 break;
495 case MAX3107_ENABLE_AUTOSLEEP:
496 s->mode1_reg |= MAX3107_MODE1_AUTOSLEEP_BIT;
497 break;
498 default:
499 spin_unlock_irqrestore(&s->data_lock, flags);
500 dev_warn(&s->spi->dev, "invalid sleep mode\n");
501 return;
502 }
503 buf[0] |= s->mode1_reg;
504 spin_unlock_irqrestore(&s->data_lock, flags);
505
506 if (max3107_rw(s, (u8 *)buf, NULL, 2))
507 dev_err(&s->spi->dev, "SPI transfer sleep mode failed\n");
508
509 if (mode == MAX3107_DISABLE_AUTOSLEEP ||
510 mode == MAX3107_DISABLE_FORCED_SLEEP)
511 msleep(MAX3107_WAKEUP_DELAY);
512}
513
514/* Perform full register initialization */
515static void max3107_register_init(struct max3107_port *s)
516{
517 u16 buf[11]; /* Buffer for SPI transfers */
518
519 /* 1. Configure baud rate, 9600 as default */
520 s->baud = 9600;
521 /* the below is default*/
522 if (s->ext_clk) {
523 s->brg_cfg = MAX3107_BRG26_B9600;
524 s->baud_tbl = (struct baud_table *)brg26_ext;
525 } else {
526 s->brg_cfg = MAX3107_BRG13_IB9600;
527 s->baud_tbl = (struct baud_table *)brg13_int;
528 }
529
530 if (s->pdata->init)
531 s->pdata->init(s);
532
533 buf[0] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVMSB_REG)
534 | ((s->brg_cfg >> 16) & MAX3107_SPI_TX_DATA_MASK);
535 buf[1] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVLSB_REG)
536 | ((s->brg_cfg >> 8) & MAX3107_SPI_TX_DATA_MASK);
537 buf[2] = (MAX3107_WRITE_BIT | MAX3107_BRGCFG_REG)
538 | ((s->brg_cfg) & 0xff);
539
540 /* 2. Configure LCR register, 8N1 mode by default */
541 s->lcr_reg = MAX3107_LCR_WORD_LEN_8;
542 buf[3] = (MAX3107_WRITE_BIT | MAX3107_LCR_REG)
543 | s->lcr_reg;
544
545 /* 3. Configure MODE 1 register */
546 s->mode1_reg = 0;
547 /* Enable IRQ pin */
548 s->mode1_reg |= MAX3107_MODE1_IRQSEL_BIT;
549 /* Disable TX */
550 s->mode1_reg |= MAX3107_MODE1_TXDIS_BIT;
551 s->tx_enabled = 0;
552 /* RX is enabled */
553 s->rx_enabled = 1;
554 buf[4] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG)
555 | s->mode1_reg;
556
557 /* 4. Configure MODE 2 register */
558 buf[5] = (MAX3107_WRITE_BIT | MAX3107_MODE2_REG);
559 if (s->loopback) {
560 /* Enable loopback */
561 buf[5] |= MAX3107_MODE2_LOOPBACK_BIT;
562 }
563 /* Reset FIFOs */
564 buf[5] |= MAX3107_MODE2_FIFORST_BIT;
565 s->tx_fifo_empty = 1;
566
567 /* 5. Configure FIFO trigger level register */
568 buf[6] = (MAX3107_WRITE_BIT | MAX3107_FIFOTRIGLVL_REG);
569 /* RX FIFO trigger for 16 words, TX FIFO trigger not used */
570 buf[6] |= (MAX3107_FIFOTRIGLVL_RX(16) | MAX3107_FIFOTRIGLVL_TX(0));
571
572 /* 6. Configure flow control levels */
573 buf[7] = (MAX3107_WRITE_BIT | MAX3107_FLOWLVL_REG);
574 /* Flow control halt level 96, resume level 48 */
575 buf[7] |= (MAX3107_FLOWLVL_RES(48) | MAX3107_FLOWLVL_HALT(96));
576
577 /* 7. Configure flow control */
578 buf[8] = (MAX3107_WRITE_BIT | MAX3107_FLOWCTRL_REG);
579 /* Enable auto CTS and auto RTS flow control */
580 buf[8] |= (MAX3107_FLOWCTRL_AUTOCTS_BIT | MAX3107_FLOWCTRL_AUTORTS_BIT);
581
582 /* 8. Configure RX timeout register */
583 buf[9] = (MAX3107_WRITE_BIT | MAX3107_RXTO_REG);
584 /* Timeout after 48 character intervals */
585 buf[9] |= 0x0030;
586
587 /* 9. Configure LSR interrupt enable register */
588 buf[10] = (MAX3107_WRITE_BIT | MAX3107_LSR_IRQEN_REG);
589 /* Enable RX timeout interrupt */
590 buf[10] |= MAX3107_LSR_RXTO_BIT;
591
592 /* Perform SPI transfer */
593 if (max3107_rw(s, (u8 *)buf, NULL, 22))
594 dev_err(&s->spi->dev, "SPI transfer for init failed\n");
595
596 /* 10. Clear IRQ status register by reading it */
597 buf[0] = MAX3107_IRQSTS_REG;
598
599 /* 11. Configure interrupt enable register */
600 /* Enable LSR interrupt */
601 s->irqen_reg = MAX3107_IRQ_LSR_BIT;
602 /* Enable RX FIFO interrupt */
603 s->irqen_reg |= MAX3107_IRQ_RXFIFO_BIT;
604 buf[1] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG)
605 | s->irqen_reg;
606
607 /* 12. Clear FIFO reset that was set in step 6 */
608 buf[2] = (MAX3107_WRITE_BIT | MAX3107_MODE2_REG);
609 if (s->loopback) {
610 /* Keep loopback enabled */
611 buf[2] |= MAX3107_MODE2_LOOPBACK_BIT;
612 }
613
614 /* Perform SPI transfer */
615 if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 6))
616 dev_err(&s->spi->dev, "SPI transfer for init failed\n");
617
618}
619
620/* IRQ handler */
621static irqreturn_t max3107_irq(int irqno, void *dev_id)
622{
623 struct max3107_port *s = dev_id;
624
625 if (irqno != s->spi->irq) {
626 /* Unexpected IRQ */
627 return IRQ_NONE;
628 }
629
630 /* Indicate irq */
631 s->handle_irq = 1;
632
633 /* Trigger work thread */
634 max3107_dowork(s);
635
636 return IRQ_HANDLED;
637}
638
639/* HW suspension function
640 *
641 * Currently autosleep is used to decrease current consumption, alternative
642 * approach would be to set the chip to reset mode if UART is not being
643 * used but that would mess the GPIOs
644 *
645 */
646void max3107_hw_susp(struct max3107_port *s, int suspend)
647{
648 pr_debug("enter, suspend %d\n", suspend);
649
650 if (suspend) {
651 /* Suspend requested,
652 * enable autosleep to decrease current consumption
653 */
654 s->suspended = 1;
655 max3107_set_sleep(s, MAX3107_ENABLE_AUTOSLEEP);
656 } else {
657 /* Resume requested,
658 * disable autosleep
659 */
660 s->suspended = 0;
661 max3107_set_sleep(s, MAX3107_DISABLE_AUTOSLEEP);
662 }
663}
664EXPORT_SYMBOL_GPL(max3107_hw_susp);
665
666/* Modem status IRQ enabling */
667static void max3107_enable_ms(struct uart_port *port)
668{
669 /* Modem status not supported */
670}
671
672/* Data send function */
673static void max3107_start_tx(struct uart_port *port)
674{
675 struct max3107_port *s = container_of(port, struct max3107_port, port);
676
677 /* Trigger work thread for sending data */
678 max3107_dowork(s);
679}
680
681/* Function for checking that there is no pending transfers */
682static unsigned int max3107_tx_empty(struct uart_port *port)
683{
684 struct max3107_port *s = container_of(port, struct max3107_port, port);
685
686 pr_debug("returning %d\n",
687 (s->tx_fifo_empty && uart_circ_empty(&s->port.state->xmit)));
688 return s->tx_fifo_empty && uart_circ_empty(&s->port.state->xmit);
689}
690
691/* Function for stopping RX */
692static void max3107_stop_rx(struct uart_port *port)
693{
694 struct max3107_port *s = container_of(port, struct max3107_port, port);
695 unsigned long flags;
696
697 /* Set RX disabled in MODE 1 register */
698 spin_lock_irqsave(&s->data_lock, flags);
699 s->mode1_reg |= MAX3107_MODE1_RXDIS_BIT;
700 s->mode1_commit = 1;
701 spin_unlock_irqrestore(&s->data_lock, flags);
702 /* Set RX disabled */
703 s->rx_enabled = 0;
704 /* Trigger work thread for doing the actual configuration change */
705 max3107_dowork(s);
706}
707
708/* Function for returning control pin states */
709static unsigned int max3107_get_mctrl(struct uart_port *port)
710{
711 /* DCD and DSR are not wired and CTS/RTS is handled automatically
712 * so just indicate DSR and CAR asserted
713 */
714 return TIOCM_DSR | TIOCM_CAR;
715}
716
717/* Function for setting control pin states */
718static void max3107_set_mctrl(struct uart_port *port, unsigned int mctrl)
719{
720 /* DCD and DSR are not wired and CTS/RTS is hadnled automatically
721 * so do nothing
722 */
723}
724
725/* Function for configuring UART parameters */
726static void max3107_set_termios(struct uart_port *port,
727 struct ktermios *termios,
728 struct ktermios *old)
729{
730 struct max3107_port *s = container_of(port, struct max3107_port, port);
731 struct tty_struct *tty;
732 int baud;
733 u16 new_lcr = 0;
734 u32 new_brg = 0;
735 unsigned long flags;
736
737 if (!port->state)
738 return;
739
740 tty = port->state->port.tty;
741 if (!tty)
742 return;
743
744 /* Get new LCR register values */
745 /* Word size */
746 if ((termios->c_cflag & CSIZE) == CS7)
747 new_lcr |= MAX3107_LCR_WORD_LEN_7;
748 else
749 new_lcr |= MAX3107_LCR_WORD_LEN_8;
750
751 /* Parity */
752 if (termios->c_cflag & PARENB) {
753 new_lcr |= MAX3107_LCR_PARITY_BIT;
754 if (!(termios->c_cflag & PARODD))
755 new_lcr |= MAX3107_LCR_EVENPARITY_BIT;
756 }
757
758 /* Stop bits */
759 if (termios->c_cflag & CSTOPB) {
760 /* 2 stop bits */
761 new_lcr |= MAX3107_LCR_STOPLEN_BIT;
762 }
763
764 /* Mask termios capabilities we don't support */
765 termios->c_cflag &= ~CMSPAR;
766
767 /* Set status ignore mask */
768 s->port.ignore_status_mask = 0;
769 if (termios->c_iflag & IGNPAR)
770 s->port.ignore_status_mask |= MAX3107_ALL_ERRORS;
771
772 /* Set low latency to immediately handle pushed data */
773 s->port.state->port.tty->low_latency = 1;
774
775 /* Get new baud rate generator configuration */
776 baud = tty_get_baud_rate(tty);
777
778 spin_lock_irqsave(&s->data_lock, flags);
779 new_brg = get_new_brg(baud, s);
780 /* if can't find the corrent config, use previous */
781 if (!new_brg) {
782 baud = s->baud;
783 new_brg = s->brg_cfg;
784 }
785 spin_unlock_irqrestore(&s->data_lock, flags);
786 tty_termios_encode_baud_rate(termios, baud, baud);
787 s->baud = baud;
788
789 /* Update timeout according to new baud rate */
790 uart_update_timeout(port, termios->c_cflag, baud);
791
792 spin_lock_irqsave(&s->data_lock, flags);
793 if (s->lcr_reg != new_lcr) {
794 s->lcr_reg = new_lcr;
795 s->lcr_commit = 1;
796 }
797 if (s->brg_cfg != new_brg) {
798 s->brg_cfg = new_brg;
799 s->brg_commit = 1;
800 }
801 spin_unlock_irqrestore(&s->data_lock, flags);
802
803 /* Trigger work thread for doing the actual configuration change */
804 max3107_dowork(s);
805}
806
807/* Port shutdown function */
808static void max3107_shutdown(struct uart_port *port)
809{
810 struct max3107_port *s = container_of(port, struct max3107_port, port);
811
812 if (s->suspended && s->pdata->hw_suspend)
813 s->pdata->hw_suspend(s, 0);
814
815 /* Free the interrupt */
816 free_irq(s->spi->irq, s);
817
818 if (s->workqueue) {
819 /* Flush and destroy work queue */
820 flush_workqueue(s->workqueue);
821 destroy_workqueue(s->workqueue);
822 s->workqueue = NULL;
823 }
824
825 /* Suspend HW */
826 if (s->pdata->hw_suspend)
827 s->pdata->hw_suspend(s, 1);
828}
829
830/* Port startup function */
831static int max3107_startup(struct uart_port *port)
832{
833 struct max3107_port *s = container_of(port, struct max3107_port, port);
834
835 /* Initialize work queue */
836 s->workqueue = create_freezable_workqueue("max3107");
837 if (!s->workqueue) {
838 dev_err(&s->spi->dev, "Workqueue creation failed\n");
839 return -EBUSY;
840 }
841 INIT_WORK(&s->work, max3107_work);
842
843 /* Setup IRQ */
844 if (request_irq(s->spi->irq, max3107_irq, IRQF_TRIGGER_FALLING,
845 "max3107", s)) {
846 dev_err(&s->spi->dev, "IRQ reguest failed\n");
847 destroy_workqueue(s->workqueue);
848 s->workqueue = NULL;
849 return -EBUSY;
850 }
851
852 /* Resume HW */
853 if (s->pdata->hw_suspend)
854 s->pdata->hw_suspend(s, 0);
855
856 /* Init registers */
857 max3107_register_init(s);
858
859 return 0;
860}
861
862/* Port type function */
863static const char *max3107_type(struct uart_port *port)
864{
865 struct max3107_port *s = container_of(port, struct max3107_port, port);
866 return s->spi->modalias;
867}
868
869/* Port release function */
870static void max3107_release_port(struct uart_port *port)
871{
872 /* Do nothing */
873}
874
875/* Port request function */
876static int max3107_request_port(struct uart_port *port)
877{
878 /* Do nothing */
879 return 0;
880}
881
882/* Port config function */
883static void max3107_config_port(struct uart_port *port, int flags)
884{
885 struct max3107_port *s = container_of(port, struct max3107_port, port);
886 s->port.type = PORT_MAX3107;
887}
888
889/* Port verify function */
890static int max3107_verify_port(struct uart_port *port,
891 struct serial_struct *ser)
892{
893 if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3107)
894 return 0;
895
896 return -EINVAL;
897}
898
899/* Port stop TX function */
900static void max3107_stop_tx(struct uart_port *port)
901{
902 /* Do nothing */
903}
904
905/* Port break control function */
906static void max3107_break_ctl(struct uart_port *port, int break_state)
907{
908 /* We don't support break control, do nothing */
909}
910
911
912/* Port functions */
913static struct uart_ops max3107_ops = {
914 .tx_empty = max3107_tx_empty,
915 .set_mctrl = max3107_set_mctrl,
916 .get_mctrl = max3107_get_mctrl,
917 .stop_tx = max3107_stop_tx,
918 .start_tx = max3107_start_tx,
919 .stop_rx = max3107_stop_rx,
920 .enable_ms = max3107_enable_ms,
921 .break_ctl = max3107_break_ctl,
922 .startup = max3107_startup,
923 .shutdown = max3107_shutdown,
924 .set_termios = max3107_set_termios,
925 .type = max3107_type,
926 .release_port = max3107_release_port,
927 .request_port = max3107_request_port,
928 .config_port = max3107_config_port,
929 .verify_port = max3107_verify_port,
930};
931
932/* UART driver data */
933static struct uart_driver max3107_uart_driver = {
934 .owner = THIS_MODULE,
935 .driver_name = "ttyMAX",
936 .dev_name = "ttyMAX",
937 .nr = 1,
938};
939
940static int driver_registered = 0;
941
942
943
944/* 'Generic' platform data */
945static struct max3107_plat generic_plat_data = {
946 .loopback = 0,
947 .ext_clk = 1,
948 .hw_suspend = max3107_hw_susp,
949 .polled_mode = 0,
950 .poll_time = 0,
951};
952
953
954/*******************************************************************/
955
956/**
957 * max3107_probe - SPI bus probe entry point
958 * @spi: the spi device
959 *
960 * SPI wants us to probe this device and if appropriate claim it.
961 * Perform any platform specific requirements and then initialise
962 * the device.
963 */
964
965int max3107_probe(struct spi_device *spi, struct max3107_plat *pdata)
966{
967 struct max3107_port *s;
968 u16 buf[2]; /* Buffer for SPI transfers */
969 int retval;
970
971 pr_info("enter max3107 probe\n");
972
973 /* Allocate port structure */
974 s = kzalloc(sizeof(*s), GFP_KERNEL);
975 if (!s) {
976 pr_err("Allocating port structure failed\n");
977 return -ENOMEM;
978 }
979
980 s->pdata = pdata;
981
982 /* SPI Rx buffer
983 * +2 for RX FIFO interrupt
984 * disabling and RX level query
985 */
986 s->rxbuf = kzalloc(sizeof(u16) * (MAX3107_RX_FIFO_SIZE+2), GFP_KERNEL);
987 if (!s->rxbuf) {
988 pr_err("Allocating RX buffer failed\n");
989 retval = -ENOMEM;
990 goto err_free4;
991 }
992 s->rxstr = kzalloc(sizeof(u8) * MAX3107_RX_FIFO_SIZE, GFP_KERNEL);
993 if (!s->rxstr) {
994 pr_err("Allocating RX buffer failed\n");
995 retval = -ENOMEM;
996 goto err_free3;
997 }
998 /* SPI Tx buffer
999 * SPI transfer buffer
1000 * +3 for TX FIFO empty
1001 * interrupt disabling and
1002 * enabling and TX enabling
1003 */
1004 s->txbuf = kzalloc(sizeof(u16) * MAX3107_TX_FIFO_SIZE + 3, GFP_KERNEL);
1005 if (!s->txbuf) {
1006 pr_err("Allocating TX buffer failed\n");
1007 retval = -ENOMEM;
1008 goto err_free2;
1009 }
1010 /* Initialize shared data lock */
1011 spin_lock_init(&s->data_lock);
1012
1013 /* SPI intializations */
1014 dev_set_drvdata(&spi->dev, s);
1015 spi->mode = SPI_MODE_0;
1016 spi->dev.platform_data = pdata;
1017 spi->bits_per_word = 16;
1018 s->ext_clk = pdata->ext_clk;
1019 s->loopback = pdata->loopback;
1020 spi_setup(spi);
1021 s->spi = spi;
1022
1023 /* Check REV ID to ensure we are talking to what we expect */
1024 buf[0] = MAX3107_REVID_REG;
1025 if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 2)) {
1026 dev_err(&s->spi->dev, "SPI transfer for REVID read failed\n");
1027 retval = -EIO;
1028 goto err_free1;
1029 }
1030 if ((buf[0] & MAX3107_SPI_RX_DATA_MASK) != MAX3107_REVID1 &&
1031 (buf[0] & MAX3107_SPI_RX_DATA_MASK) != MAX3107_REVID2) {
1032 dev_err(&s->spi->dev, "REVID %x does not match\n",
1033 (buf[0] & MAX3107_SPI_RX_DATA_MASK));
1034 retval = -ENODEV;
1035 goto err_free1;
1036 }
1037
1038 /* Disable all interrupts */
1039 buf[0] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG | 0x0000);
1040 buf[0] |= 0x0000;
1041
1042 /* Configure clock source */
1043 buf[1] = (MAX3107_WRITE_BIT | MAX3107_CLKSRC_REG);
1044 if (s->ext_clk) {
1045 /* External clock */
1046 buf[1] |= MAX3107_CLKSRC_EXTCLK_BIT;
1047 }
1048
1049 /* PLL bypass ON */
1050 buf[1] |= MAX3107_CLKSRC_PLLBYP_BIT;
1051
1052 /* Perform SPI transfer */
1053 if (max3107_rw(s, (u8 *)buf, NULL, 4)) {
1054 dev_err(&s->spi->dev, "SPI transfer for init failed\n");
1055 retval = -EIO;
1056 goto err_free1;
1057 }
1058
1059 /* Register UART driver */
1060 if (!driver_registered) {
1061 retval = uart_register_driver(&max3107_uart_driver);
1062 if (retval) {
1063 dev_err(&s->spi->dev, "Registering UART driver failed\n");
1064 goto err_free1;
1065 }
1066 driver_registered = 1;
1067 }
1068
1069 /* Initialize UART port data */
1070 s->port.fifosize = 128;
1071 s->port.ops = &max3107_ops;
1072 s->port.line = 0;
1073 s->port.dev = &spi->dev;
1074 s->port.uartclk = 9600;
1075 s->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
1076 s->port.irq = s->spi->irq;
1077 s->port.type = PORT_MAX3107;
1078
1079 /* Add UART port */
1080 retval = uart_add_one_port(&max3107_uart_driver, &s->port);
1081 if (retval < 0) {
1082 dev_err(&s->spi->dev, "Adding UART port failed\n");
1083 goto err_free1;
1084 }
1085
1086 if (pdata->configure) {
1087 retval = pdata->configure(s);
1088 if (retval < 0)
1089 goto err_free1;
1090 }
1091
1092 /* Go to suspend mode */
1093 if (pdata->hw_suspend)
1094 pdata->hw_suspend(s, 1);
1095
1096 return 0;
1097
1098err_free1:
1099 kfree(s->txbuf);
1100err_free2:
1101 kfree(s->rxstr);
1102err_free3:
1103 kfree(s->rxbuf);
1104err_free4:
1105 kfree(s);
1106 return retval;
1107}
1108EXPORT_SYMBOL_GPL(max3107_probe);
1109
1110/* Driver remove function */
1111int max3107_remove(struct spi_device *spi)
1112{
1113 struct max3107_port *s = dev_get_drvdata(&spi->dev);
1114
1115 pr_info("enter max3107 remove\n");
1116
1117 /* Remove port */
1118 if (uart_remove_one_port(&max3107_uart_driver, &s->port))
1119 dev_warn(&s->spi->dev, "Removing UART port failed\n");
1120
1121
1122 /* Free TxRx buffer */
1123 kfree(s->rxbuf);
1124 kfree(s->rxstr);
1125 kfree(s->txbuf);
1126
1127 /* Free port structure */
1128 kfree(s);
1129
1130 return 0;
1131}
1132EXPORT_SYMBOL_GPL(max3107_remove);
1133
1134/* Driver suspend function */
1135int max3107_suspend(struct spi_device *spi, pm_message_t state)
1136{
1137#ifdef CONFIG_PM
1138 struct max3107_port *s = dev_get_drvdata(&spi->dev);
1139
1140 pr_debug("enter suspend\n");
1141
1142 /* Suspend UART port */
1143 uart_suspend_port(&max3107_uart_driver, &s->port);
1144
1145 /* Go to suspend mode */
1146 if (s->pdata->hw_suspend)
1147 s->pdata->hw_suspend(s, 1);
1148#endif /* CONFIG_PM */
1149 return 0;
1150}
1151EXPORT_SYMBOL_GPL(max3107_suspend);
1152
1153/* Driver resume function */
1154int max3107_resume(struct spi_device *spi)
1155{
1156#ifdef CONFIG_PM
1157 struct max3107_port *s = dev_get_drvdata(&spi->dev);
1158
1159 pr_debug("enter resume\n");
1160
1161 /* Resume from suspend */
1162 if (s->pdata->hw_suspend)
1163 s->pdata->hw_suspend(s, 0);
1164
1165 /* Resume UART port */
1166 uart_resume_port(&max3107_uart_driver, &s->port);
1167#endif /* CONFIG_PM */
1168 return 0;
1169}
1170EXPORT_SYMBOL_GPL(max3107_resume);
1171
1172static int max3107_probe_generic(struct spi_device *spi)
1173{
1174 return max3107_probe(spi, &generic_plat_data);
1175}
1176
1177/* Spi driver data */
1178static struct spi_driver max3107_driver = {
1179 .driver = {
1180 .name = "max3107",
1181 .bus = &spi_bus_type,
1182 .owner = THIS_MODULE,
1183 },
1184 .probe = max3107_probe_generic,
1185 .remove = __devexit_p(max3107_remove),
1186 .suspend = max3107_suspend,
1187 .resume = max3107_resume,
1188};
1189
1190/* Driver init function */
1191static int __init max3107_init(void)
1192{
1193 pr_info("enter max3107 init\n");
1194 return spi_register_driver(&max3107_driver);
1195}
1196
1197/* Driver exit function */
1198static void __exit max3107_exit(void)
1199{
1200 pr_info("enter max3107 exit\n");
1201 /* Unregister UART driver */
1202 if (driver_registered)
1203 uart_unregister_driver(&max3107_uart_driver);
1204 spi_unregister_driver(&max3107_driver);
1205}
1206
1207module_init(max3107_init);
1208module_exit(max3107_exit);
1209
1210MODULE_DESCRIPTION("MAX3107 driver");
1211MODULE_AUTHOR("Aavamobile");
1212MODULE_ALIAS("spi:max3107");
1213MODULE_LICENSE("GPL v2");