xref: /openbmc/linux/drivers/spi/spi-fsl-espi.c (revision 8684014d)
1 /*
2  * Freescale eSPI controller driver.
3  *
4  * Copyright 2010 Freescale Semiconductor, Inc.
5  *
6  * This program is free software; you can redistribute  it and/or modify it
7  * under  the terms of  the GNU General  Public License as published by the
8  * Free Software Foundation;  either version 2 of the  License, or (at your
9  * option) any later version.
10  */
11 #include <linux/delay.h>
12 #include <linux/err.h>
13 #include <linux/fsl_devices.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/module.h>
17 #include <linux/mm.h>
18 #include <linux/of.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_platform.h>
22 #include <linux/platform_device.h>
23 #include <linux/spi/spi.h>
24 #include <sysdev/fsl_soc.h>
25 
26 #include "spi-fsl-lib.h"
27 
28 /* eSPI Controller registers */
29 struct fsl_espi_reg {
30 	__be32 mode;		/* 0x000 - eSPI mode register */
31 	__be32 event;		/* 0x004 - eSPI event register */
32 	__be32 mask;		/* 0x008 - eSPI mask register */
33 	__be32 command;		/* 0x00c - eSPI command register */
34 	__be32 transmit;	/* 0x010 - eSPI transmit FIFO access register*/
35 	__be32 receive;		/* 0x014 - eSPI receive FIFO access register*/
36 	u8 res[8];		/* 0x018 - 0x01c reserved */
37 	__be32 csmode[4];	/* 0x020 - 0x02c eSPI cs mode register */
38 };
39 
40 struct fsl_espi_transfer {
41 	const void *tx_buf;
42 	void *rx_buf;
43 	unsigned len;
44 	unsigned n_tx;
45 	unsigned n_rx;
46 	unsigned actual_length;
47 	int status;
48 };
49 
50 /* eSPI Controller mode register definitions */
51 #define SPMODE_ENABLE		(1 << 31)
52 #define SPMODE_LOOP		(1 << 30)
53 #define SPMODE_TXTHR(x)		((x) << 8)
54 #define SPMODE_RXTHR(x)		((x) << 0)
55 
56 /* eSPI Controller CS mode register definitions */
57 #define CSMODE_CI_INACTIVEHIGH	(1 << 31)
58 #define CSMODE_CP_BEGIN_EDGECLK	(1 << 30)
59 #define CSMODE_REV		(1 << 29)
60 #define CSMODE_DIV16		(1 << 28)
61 #define CSMODE_PM(x)		((x) << 24)
62 #define CSMODE_POL_1		(1 << 20)
63 #define CSMODE_LEN(x)		((x) << 16)
64 #define CSMODE_BEF(x)		((x) << 12)
65 #define CSMODE_AFT(x)		((x) << 8)
66 #define CSMODE_CG(x)		((x) << 3)
67 
68 /* Default mode/csmode for eSPI controller */
69 #define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3))
70 #define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
71 		| CSMODE_AFT(0) | CSMODE_CG(1))
72 
73 /* SPIE register values */
74 #define	SPIE_NE		0x00000200	/* Not empty */
75 #define	SPIE_NF		0x00000100	/* Not full */
76 
77 /* SPIM register values */
78 #define	SPIM_NE		0x00000200	/* Not empty */
79 #define	SPIM_NF		0x00000100	/* Not full */
80 #define SPIE_RXCNT(reg)     ((reg >> 24) & 0x3F)
81 #define SPIE_TXCNT(reg)     ((reg >> 16) & 0x3F)
82 
83 /* SPCOM register values */
84 #define SPCOM_CS(x)		((x) << 30)
85 #define SPCOM_TRANLEN(x)	((x) << 0)
86 #define	SPCOM_TRANLEN_MAX	0xFFFF	/* Max transaction length */
87 
88 static void fsl_espi_change_mode(struct spi_device *spi)
89 {
90 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
91 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
92 	struct fsl_espi_reg *reg_base = mspi->reg_base;
93 	__be32 __iomem *mode = &reg_base->csmode[spi->chip_select];
94 	__be32 __iomem *espi_mode = &reg_base->mode;
95 	u32 tmp;
96 	unsigned long flags;
97 
98 	/* Turn off IRQs locally to minimize time that SPI is disabled. */
99 	local_irq_save(flags);
100 
101 	/* Turn off SPI unit prior changing mode */
102 	tmp = mpc8xxx_spi_read_reg(espi_mode);
103 	mpc8xxx_spi_write_reg(espi_mode, tmp & ~SPMODE_ENABLE);
104 	mpc8xxx_spi_write_reg(mode, cs->hw_mode);
105 	mpc8xxx_spi_write_reg(espi_mode, tmp);
106 
107 	local_irq_restore(flags);
108 }
109 
110 static u32 fsl_espi_tx_buf_lsb(struct mpc8xxx_spi *mpc8xxx_spi)
111 {
112 	u32 data;
113 	u16 data_h;
114 	u16 data_l;
115 	const u32 *tx = mpc8xxx_spi->tx;
116 
117 	if (!tx)
118 		return 0;
119 
120 	data = *tx++ << mpc8xxx_spi->tx_shift;
121 	data_l = data & 0xffff;
122 	data_h = (data >> 16) & 0xffff;
123 	swab16s(&data_l);
124 	swab16s(&data_h);
125 	data = data_h | data_l;
126 
127 	mpc8xxx_spi->tx = tx;
128 	return data;
129 }
130 
131 static int fsl_espi_setup_transfer(struct spi_device *spi,
132 					struct spi_transfer *t)
133 {
134 	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
135 	int bits_per_word = 0;
136 	u8 pm;
137 	u32 hz = 0;
138 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
139 
140 	if (t) {
141 		bits_per_word = t->bits_per_word;
142 		hz = t->speed_hz;
143 	}
144 
145 	/* spi_transfer level calls that work per-word */
146 	if (!bits_per_word)
147 		bits_per_word = spi->bits_per_word;
148 
149 	if (!hz)
150 		hz = spi->max_speed_hz;
151 
152 	cs->rx_shift = 0;
153 	cs->tx_shift = 0;
154 	cs->get_rx = mpc8xxx_spi_rx_buf_u32;
155 	cs->get_tx = mpc8xxx_spi_tx_buf_u32;
156 	if (bits_per_word <= 8) {
157 		cs->rx_shift = 8 - bits_per_word;
158 	} else {
159 		cs->rx_shift = 16 - bits_per_word;
160 		if (spi->mode & SPI_LSB_FIRST)
161 			cs->get_tx = fsl_espi_tx_buf_lsb;
162 	}
163 
164 	mpc8xxx_spi->rx_shift = cs->rx_shift;
165 	mpc8xxx_spi->tx_shift = cs->tx_shift;
166 	mpc8xxx_spi->get_rx = cs->get_rx;
167 	mpc8xxx_spi->get_tx = cs->get_tx;
168 
169 	bits_per_word = bits_per_word - 1;
170 
171 	/* mask out bits we are going to set */
172 	cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF));
173 
174 	cs->hw_mode |= CSMODE_LEN(bits_per_word);
175 
176 	if ((mpc8xxx_spi->spibrg / hz) > 64) {
177 		cs->hw_mode |= CSMODE_DIV16;
178 		pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 16 * 4);
179 
180 		WARN_ONCE(pm > 33, "%s: Requested speed is too low: %d Hz. "
181 			  "Will use %d Hz instead.\n", dev_name(&spi->dev),
182 				hz, mpc8xxx_spi->spibrg / (4 * 16 * (32 + 1)));
183 		if (pm > 33)
184 			pm = 33;
185 	} else {
186 		pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 4);
187 	}
188 	if (pm)
189 		pm--;
190 	if (pm < 2)
191 		pm = 2;
192 
193 	cs->hw_mode |= CSMODE_PM(pm);
194 
195 	fsl_espi_change_mode(spi);
196 	return 0;
197 }
198 
199 static int fsl_espi_cpu_bufs(struct mpc8xxx_spi *mspi, struct spi_transfer *t,
200 		unsigned int len)
201 {
202 	u32 word;
203 	struct fsl_espi_reg *reg_base = mspi->reg_base;
204 
205 	mspi->count = len;
206 
207 	/* enable rx ints */
208 	mpc8xxx_spi_write_reg(&reg_base->mask, SPIM_NE);
209 
210 	/* transmit word */
211 	word = mspi->get_tx(mspi);
212 	mpc8xxx_spi_write_reg(&reg_base->transmit, word);
213 
214 	return 0;
215 }
216 
217 static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
218 {
219 	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
220 	struct fsl_espi_reg *reg_base = mpc8xxx_spi->reg_base;
221 	unsigned int len = t->len;
222 	int ret;
223 
224 	mpc8xxx_spi->len = t->len;
225 	len = roundup(len, 4) / 4;
226 
227 	mpc8xxx_spi->tx = t->tx_buf;
228 	mpc8xxx_spi->rx = t->rx_buf;
229 
230 	reinit_completion(&mpc8xxx_spi->done);
231 
232 	/* Set SPCOM[CS] and SPCOM[TRANLEN] field */
233 	if ((t->len - 1) > SPCOM_TRANLEN_MAX) {
234 		dev_err(mpc8xxx_spi->dev, "Transaction length (%d)"
235 				" beyond the SPCOM[TRANLEN] field\n", t->len);
236 		return -EINVAL;
237 	}
238 	mpc8xxx_spi_write_reg(&reg_base->command,
239 		(SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1)));
240 
241 	ret = fsl_espi_cpu_bufs(mpc8xxx_spi, t, len);
242 	if (ret)
243 		return ret;
244 
245 	wait_for_completion(&mpc8xxx_spi->done);
246 
247 	/* disable rx ints */
248 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
249 
250 	return mpc8xxx_spi->count;
251 }
252 
253 static inline void fsl_espi_addr2cmd(unsigned int addr, u8 *cmd)
254 {
255 	if (cmd) {
256 		cmd[1] = (u8)(addr >> 16);
257 		cmd[2] = (u8)(addr >> 8);
258 		cmd[3] = (u8)(addr >> 0);
259 	}
260 }
261 
262 static inline unsigned int fsl_espi_cmd2addr(u8 *cmd)
263 {
264 	if (cmd)
265 		return cmd[1] << 16 | cmd[2] << 8 | cmd[3] << 0;
266 
267 	return 0;
268 }
269 
270 static void fsl_espi_do_trans(struct spi_message *m,
271 				struct fsl_espi_transfer *tr)
272 {
273 	struct spi_device *spi = m->spi;
274 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
275 	struct fsl_espi_transfer *espi_trans = tr;
276 	struct spi_message message;
277 	struct spi_transfer *t, *first, trans;
278 	int status = 0;
279 
280 	spi_message_init(&message);
281 	memset(&trans, 0, sizeof(trans));
282 
283 	first = list_first_entry(&m->transfers, struct spi_transfer,
284 			transfer_list);
285 	list_for_each_entry(t, &m->transfers, transfer_list) {
286 		if ((first->bits_per_word != t->bits_per_word) ||
287 			(first->speed_hz != t->speed_hz)) {
288 			espi_trans->status = -EINVAL;
289 			dev_err(mspi->dev,
290 				"bits_per_word/speed_hz should be same for the same SPI transfer\n");
291 			return;
292 		}
293 
294 		trans.speed_hz = t->speed_hz;
295 		trans.bits_per_word = t->bits_per_word;
296 		trans.delay_usecs = max(first->delay_usecs, t->delay_usecs);
297 	}
298 
299 	trans.len = espi_trans->len;
300 	trans.tx_buf = espi_trans->tx_buf;
301 	trans.rx_buf = espi_trans->rx_buf;
302 	spi_message_add_tail(&trans, &message);
303 
304 	list_for_each_entry(t, &message.transfers, transfer_list) {
305 		if (t->bits_per_word || t->speed_hz) {
306 			status = -EINVAL;
307 
308 			status = fsl_espi_setup_transfer(spi, t);
309 			if (status < 0)
310 				break;
311 		}
312 
313 		if (t->len)
314 			status = fsl_espi_bufs(spi, t);
315 
316 		if (status) {
317 			status = -EMSGSIZE;
318 			break;
319 		}
320 
321 		if (t->delay_usecs)
322 			udelay(t->delay_usecs);
323 	}
324 
325 	espi_trans->status = status;
326 	fsl_espi_setup_transfer(spi, NULL);
327 }
328 
329 static void fsl_espi_cmd_trans(struct spi_message *m,
330 				struct fsl_espi_transfer *trans, u8 *rx_buff)
331 {
332 	struct spi_transfer *t;
333 	u8 *local_buf;
334 	int i = 0;
335 	struct fsl_espi_transfer *espi_trans = trans;
336 
337 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
338 	if (!local_buf) {
339 		espi_trans->status = -ENOMEM;
340 		return;
341 	}
342 
343 	list_for_each_entry(t, &m->transfers, transfer_list) {
344 		if (t->tx_buf) {
345 			memcpy(local_buf + i, t->tx_buf, t->len);
346 			i += t->len;
347 		}
348 	}
349 
350 	espi_trans->tx_buf = local_buf;
351 	espi_trans->rx_buf = local_buf;
352 	fsl_espi_do_trans(m, espi_trans);
353 
354 	espi_trans->actual_length = espi_trans->len;
355 	kfree(local_buf);
356 }
357 
358 static void fsl_espi_rw_trans(struct spi_message *m,
359 				struct fsl_espi_transfer *trans, u8 *rx_buff)
360 {
361 	struct fsl_espi_transfer *espi_trans = trans;
362 	unsigned int n_tx = espi_trans->n_tx;
363 	unsigned int n_rx = espi_trans->n_rx;
364 	struct spi_transfer *t;
365 	u8 *local_buf;
366 	u8 *rx_buf = rx_buff;
367 	unsigned int trans_len;
368 	unsigned int addr;
369 	int i, pos, loop;
370 
371 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
372 	if (!local_buf) {
373 		espi_trans->status = -ENOMEM;
374 		return;
375 	}
376 
377 	for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
378 		trans_len = n_rx - pos;
379 		if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
380 			trans_len = SPCOM_TRANLEN_MAX - n_tx;
381 
382 		i = 0;
383 		list_for_each_entry(t, &m->transfers, transfer_list) {
384 			if (t->tx_buf) {
385 				memcpy(local_buf + i, t->tx_buf, t->len);
386 				i += t->len;
387 			}
388 		}
389 
390 		if (pos > 0) {
391 			addr = fsl_espi_cmd2addr(local_buf);
392 			addr += pos;
393 			fsl_espi_addr2cmd(addr, local_buf);
394 		}
395 
396 		espi_trans->n_tx = n_tx;
397 		espi_trans->n_rx = trans_len;
398 		espi_trans->len = trans_len + n_tx;
399 		espi_trans->tx_buf = local_buf;
400 		espi_trans->rx_buf = local_buf;
401 		fsl_espi_do_trans(m, espi_trans);
402 
403 		memcpy(rx_buf + pos, espi_trans->rx_buf + n_tx, trans_len);
404 
405 		if (loop > 0)
406 			espi_trans->actual_length += espi_trans->len - n_tx;
407 		else
408 			espi_trans->actual_length += espi_trans->len;
409 	}
410 
411 	kfree(local_buf);
412 }
413 
414 static int fsl_espi_do_one_msg(struct spi_master *master,
415 			       struct spi_message *m)
416 {
417 	struct spi_transfer *t;
418 	u8 *rx_buf = NULL;
419 	unsigned int n_tx = 0;
420 	unsigned int n_rx = 0;
421 	struct fsl_espi_transfer espi_trans;
422 
423 	list_for_each_entry(t, &m->transfers, transfer_list) {
424 		if (t->tx_buf)
425 			n_tx += t->len;
426 		if (t->rx_buf) {
427 			n_rx += t->len;
428 			rx_buf = t->rx_buf;
429 		}
430 	}
431 
432 	espi_trans.n_tx = n_tx;
433 	espi_trans.n_rx = n_rx;
434 	espi_trans.len = n_tx + n_rx;
435 	espi_trans.actual_length = 0;
436 	espi_trans.status = 0;
437 
438 	if (!rx_buf)
439 		fsl_espi_cmd_trans(m, &espi_trans, NULL);
440 	else
441 		fsl_espi_rw_trans(m, &espi_trans, rx_buf);
442 
443 	m->actual_length = espi_trans.actual_length;
444 	m->status = espi_trans.status;
445 	spi_finalize_current_message(master);
446 	return 0;
447 }
448 
449 static int fsl_espi_setup(struct spi_device *spi)
450 {
451 	struct mpc8xxx_spi *mpc8xxx_spi;
452 	struct fsl_espi_reg *reg_base;
453 	int retval;
454 	u32 hw_mode;
455 	u32 loop_mode;
456 	struct spi_mpc8xxx_cs *cs = spi_get_ctldata(spi);
457 
458 	if (!spi->max_speed_hz)
459 		return -EINVAL;
460 
461 	if (!cs) {
462 		cs = kzalloc(sizeof(*cs), GFP_KERNEL);
463 		if (!cs)
464 			return -ENOMEM;
465 		spi_set_ctldata(spi, cs);
466 	}
467 
468 	mpc8xxx_spi = spi_master_get_devdata(spi->master);
469 	reg_base = mpc8xxx_spi->reg_base;
470 
471 	hw_mode = cs->hw_mode; /* Save original settings */
472 	cs->hw_mode = mpc8xxx_spi_read_reg(
473 			&reg_base->csmode[spi->chip_select]);
474 	/* mask out bits we are going to set */
475 	cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
476 			 | CSMODE_REV);
477 
478 	if (spi->mode & SPI_CPHA)
479 		cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
480 	if (spi->mode & SPI_CPOL)
481 		cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
482 	if (!(spi->mode & SPI_LSB_FIRST))
483 		cs->hw_mode |= CSMODE_REV;
484 
485 	/* Handle the loop mode */
486 	loop_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
487 	loop_mode &= ~SPMODE_LOOP;
488 	if (spi->mode & SPI_LOOP)
489 		loop_mode |= SPMODE_LOOP;
490 	mpc8xxx_spi_write_reg(&reg_base->mode, loop_mode);
491 
492 	retval = fsl_espi_setup_transfer(spi, NULL);
493 	if (retval < 0) {
494 		cs->hw_mode = hw_mode; /* Restore settings */
495 		return retval;
496 	}
497 	return 0;
498 }
499 
500 static void fsl_espi_cleanup(struct spi_device *spi)
501 {
502 	struct spi_mpc8xxx_cs *cs = spi_get_ctldata(spi);
503 
504 	kfree(cs);
505 	spi_set_ctldata(spi, NULL);
506 }
507 
508 void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
509 {
510 	struct fsl_espi_reg *reg_base = mspi->reg_base;
511 
512 	/* We need handle RX first */
513 	if (events & SPIE_NE) {
514 		u32 rx_data, tmp;
515 		u8 rx_data_8;
516 
517 		/* Spin until RX is done */
518 		while (SPIE_RXCNT(events) < min(4, mspi->len)) {
519 			cpu_relax();
520 			events = mpc8xxx_spi_read_reg(&reg_base->event);
521 		}
522 
523 		if (mspi->len >= 4) {
524 			rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
525 		} else {
526 			tmp = mspi->len;
527 			rx_data = 0;
528 			while (tmp--) {
529 				rx_data_8 = in_8((u8 *)&reg_base->receive);
530 				rx_data |= (rx_data_8 << (tmp * 8));
531 			}
532 
533 			rx_data <<= (4 - mspi->len) * 8;
534 		}
535 
536 		mspi->len -= 4;
537 
538 		if (mspi->rx)
539 			mspi->get_rx(rx_data, mspi);
540 	}
541 
542 	if (!(events & SPIE_NF)) {
543 		int ret;
544 
545 		/* spin until TX is done */
546 		ret = spin_event_timeout(((events = mpc8xxx_spi_read_reg(
547 				&reg_base->event)) & SPIE_NF) == 0, 1000, 0);
548 		if (!ret) {
549 			dev_err(mspi->dev, "tired waiting for SPIE_NF\n");
550 			return;
551 		}
552 	}
553 
554 	/* Clear the events */
555 	mpc8xxx_spi_write_reg(&reg_base->event, events);
556 
557 	mspi->count -= 1;
558 	if (mspi->count) {
559 		u32 word = mspi->get_tx(mspi);
560 
561 		mpc8xxx_spi_write_reg(&reg_base->transmit, word);
562 	} else {
563 		complete(&mspi->done);
564 	}
565 }
566 
567 static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
568 {
569 	struct mpc8xxx_spi *mspi = context_data;
570 	struct fsl_espi_reg *reg_base = mspi->reg_base;
571 	irqreturn_t ret = IRQ_NONE;
572 	u32 events;
573 
574 	/* Get interrupt events(tx/rx) */
575 	events = mpc8xxx_spi_read_reg(&reg_base->event);
576 	if (events)
577 		ret = IRQ_HANDLED;
578 
579 	dev_vdbg(mspi->dev, "%s: events %x\n", __func__, events);
580 
581 	fsl_espi_cpu_irq(mspi, events);
582 
583 	return ret;
584 }
585 
586 static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
587 {
588 	iounmap(mspi->reg_base);
589 }
590 
591 static int fsl_espi_suspend(struct spi_master *master)
592 {
593 	struct mpc8xxx_spi *mpc8xxx_spi;
594 	struct fsl_espi_reg *reg_base;
595 	u32 regval;
596 
597 	mpc8xxx_spi = spi_master_get_devdata(master);
598 	reg_base = mpc8xxx_spi->reg_base;
599 
600 	regval = mpc8xxx_spi_read_reg(&reg_base->mode);
601 	regval &= ~SPMODE_ENABLE;
602 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
603 
604 	return 0;
605 }
606 
607 static int fsl_espi_resume(struct spi_master *master)
608 {
609 	struct mpc8xxx_spi *mpc8xxx_spi;
610 	struct fsl_espi_reg *reg_base;
611 	u32 regval;
612 
613 	mpc8xxx_spi = spi_master_get_devdata(master);
614 	reg_base = mpc8xxx_spi->reg_base;
615 
616 	regval = mpc8xxx_spi_read_reg(&reg_base->mode);
617 	regval |= SPMODE_ENABLE;
618 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
619 
620 	return 0;
621 }
622 
623 static struct spi_master * fsl_espi_probe(struct device *dev,
624 		struct resource *mem, unsigned int irq)
625 {
626 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
627 	struct spi_master *master;
628 	struct mpc8xxx_spi *mpc8xxx_spi;
629 	struct fsl_espi_reg *reg_base;
630 	struct device_node *nc;
631 	const __be32 *prop;
632 	u32 regval, csmode;
633 	int i, len, ret = 0;
634 
635 	master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
636 	if (!master) {
637 		ret = -ENOMEM;
638 		goto err;
639 	}
640 
641 	dev_set_drvdata(dev, master);
642 
643 	mpc8xxx_spi_probe(dev, mem, irq);
644 
645 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
646 	master->setup = fsl_espi_setup;
647 	master->cleanup = fsl_espi_cleanup;
648 	master->transfer_one_message = fsl_espi_do_one_msg;
649 	master->prepare_transfer_hardware = fsl_espi_resume;
650 	master->unprepare_transfer_hardware = fsl_espi_suspend;
651 
652 	mpc8xxx_spi = spi_master_get_devdata(master);
653 	mpc8xxx_spi->spi_remove = fsl_espi_remove;
654 
655 	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
656 	if (!mpc8xxx_spi->reg_base) {
657 		ret = -ENOMEM;
658 		goto err_probe;
659 	}
660 
661 	reg_base = mpc8xxx_spi->reg_base;
662 
663 	/* Register for SPI Interrupt */
664 	ret = request_irq(mpc8xxx_spi->irq, fsl_espi_irq,
665 			  0, "fsl_espi", mpc8xxx_spi);
666 	if (ret)
667 		goto free_irq;
668 
669 	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
670 		mpc8xxx_spi->rx_shift = 16;
671 		mpc8xxx_spi->tx_shift = 24;
672 	}
673 
674 	/* SPI controller initializations */
675 	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
676 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
677 	mpc8xxx_spi_write_reg(&reg_base->command, 0);
678 	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);
679 
680 	/* Init eSPI CS mode register */
681 	for_each_available_child_of_node(master->dev.of_node, nc) {
682 		/* get chip select */
683 		prop = of_get_property(nc, "reg", &len);
684 		if (!prop || len < sizeof(*prop))
685 			continue;
686 		i = be32_to_cpup(prop);
687 		if (i < 0 || i >= pdata->max_chipselect)
688 			continue;
689 
690 		csmode = CSMODE_INIT_VAL;
691 		/* check if CSBEF is set in device tree */
692 		prop = of_get_property(nc, "fsl,csbef", &len);
693 		if (prop && len >= sizeof(*prop)) {
694 			csmode &= ~(CSMODE_BEF(0xf));
695 			csmode |= CSMODE_BEF(be32_to_cpup(prop));
696 		}
697 		/* check if CSAFT is set in device tree */
698 		prop = of_get_property(nc, "fsl,csaft", &len);
699 		if (prop && len >= sizeof(*prop)) {
700 			csmode &= ~(CSMODE_AFT(0xf));
701 			csmode |= CSMODE_AFT(be32_to_cpup(prop));
702 		}
703 		mpc8xxx_spi_write_reg(&reg_base->csmode[i], csmode);
704 
705 		dev_info(dev, "cs=%d, init_csmode=0x%x\n", i, csmode);
706 	}
707 
708 	/* Enable SPI interface */
709 	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
710 
711 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
712 
713 	ret = spi_register_master(master);
714 	if (ret < 0)
715 		goto unreg_master;
716 
717 	dev_info(dev, "at 0x%p (irq = %d)\n", reg_base, mpc8xxx_spi->irq);
718 
719 	return master;
720 
721 unreg_master:
722 	free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
723 free_irq:
724 	iounmap(mpc8xxx_spi->reg_base);
725 err_probe:
726 	spi_master_put(master);
727 err:
728 	return ERR_PTR(ret);
729 }
730 
731 static int of_fsl_espi_get_chipselects(struct device *dev)
732 {
733 	struct device_node *np = dev->of_node;
734 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
735 	const u32 *prop;
736 	int len;
737 
738 	prop = of_get_property(np, "fsl,espi-num-chipselects", &len);
739 	if (!prop || len < sizeof(*prop)) {
740 		dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
741 		return -EINVAL;
742 	}
743 
744 	pdata->max_chipselect = *prop;
745 	pdata->cs_control = NULL;
746 
747 	return 0;
748 }
749 
750 static int of_fsl_espi_probe(struct platform_device *ofdev)
751 {
752 	struct device *dev = &ofdev->dev;
753 	struct device_node *np = ofdev->dev.of_node;
754 	struct spi_master *master;
755 	struct resource mem;
756 	unsigned int irq;
757 	int ret = -ENOMEM;
758 
759 	ret = of_mpc8xxx_spi_probe(ofdev);
760 	if (ret)
761 		return ret;
762 
763 	ret = of_fsl_espi_get_chipselects(dev);
764 	if (ret)
765 		goto err;
766 
767 	ret = of_address_to_resource(np, 0, &mem);
768 	if (ret)
769 		goto err;
770 
771 	irq = irq_of_parse_and_map(np, 0);
772 	if (!irq) {
773 		ret = -EINVAL;
774 		goto err;
775 	}
776 
777 	master = fsl_espi_probe(dev, &mem, irq);
778 	if (IS_ERR(master)) {
779 		ret = PTR_ERR(master);
780 		goto err;
781 	}
782 
783 	return 0;
784 
785 err:
786 	return ret;
787 }
788 
789 static int of_fsl_espi_remove(struct platform_device *dev)
790 {
791 	return mpc8xxx_spi_remove(&dev->dev);
792 }
793 
794 #ifdef CONFIG_PM_SLEEP
795 static int of_fsl_espi_suspend(struct device *dev)
796 {
797 	struct spi_master *master = dev_get_drvdata(dev);
798 	int ret;
799 
800 	ret = spi_master_suspend(master);
801 	if (ret) {
802 		dev_warn(dev, "cannot suspend master\n");
803 		return ret;
804 	}
805 
806 	return fsl_espi_suspend(master);
807 }
808 
809 static int of_fsl_espi_resume(struct device *dev)
810 {
811 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
812 	struct spi_master *master = dev_get_drvdata(dev);
813 	struct mpc8xxx_spi *mpc8xxx_spi;
814 	struct fsl_espi_reg *reg_base;
815 	u32 regval;
816 	int i;
817 
818 	mpc8xxx_spi = spi_master_get_devdata(master);
819 	reg_base = mpc8xxx_spi->reg_base;
820 
821 	/* SPI controller initializations */
822 	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
823 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
824 	mpc8xxx_spi_write_reg(&reg_base->command, 0);
825 	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);
826 
827 	/* Init eSPI CS mode register */
828 	for (i = 0; i < pdata->max_chipselect; i++)
829 		mpc8xxx_spi_write_reg(&reg_base->csmode[i], CSMODE_INIT_VAL);
830 
831 	/* Enable SPI interface */
832 	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
833 
834 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
835 
836 	return spi_master_resume(master);
837 }
838 #endif /* CONFIG_PM_SLEEP */
839 
840 static const struct dev_pm_ops espi_pm = {
841 	SET_SYSTEM_SLEEP_PM_OPS(of_fsl_espi_suspend, of_fsl_espi_resume)
842 };
843 
844 static const struct of_device_id of_fsl_espi_match[] = {
845 	{ .compatible = "fsl,mpc8536-espi" },
846 	{}
847 };
848 MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
849 
850 static struct platform_driver fsl_espi_driver = {
851 	.driver = {
852 		.name = "fsl_espi",
853 		.of_match_table = of_fsl_espi_match,
854 		.pm = &espi_pm,
855 	},
856 	.probe		= of_fsl_espi_probe,
857 	.remove		= of_fsl_espi_remove,
858 };
859 module_platform_driver(fsl_espi_driver);
860 
861 MODULE_AUTHOR("Mingkai Hu");
862 MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
863 MODULE_LICENSE("GPL");
864