xref: /openbmc/linux/drivers/spi/spi-fsl-espi.c (revision e23feb16)
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/module.h>
12 #include <linux/delay.h>
13 #include <linux/irq.h>
14 #include <linux/spi/spi.h>
15 #include <linux/platform_device.h>
16 #include <linux/fsl_devices.h>
17 #include <linux/mm.h>
18 #include <linux/of.h>
19 #include <linux/of_platform.h>
20 #include <linux/interrupt.h>
21 #include <linux/err.h>
22 #include <sysdev/fsl_soc.h>
23 
24 #include "spi-fsl-lib.h"
25 
26 /* eSPI Controller registers */
27 struct fsl_espi_reg {
28 	__be32 mode;		/* 0x000 - eSPI mode register */
29 	__be32 event;		/* 0x004 - eSPI event register */
30 	__be32 mask;		/* 0x008 - eSPI mask register */
31 	__be32 command;		/* 0x00c - eSPI command register */
32 	__be32 transmit;	/* 0x010 - eSPI transmit FIFO access register*/
33 	__be32 receive;		/* 0x014 - eSPI receive FIFO access register*/
34 	u8 res[8];		/* 0x018 - 0x01c reserved */
35 	__be32 csmode[4];	/* 0x020 - 0x02c eSPI cs mode register */
36 };
37 
38 struct fsl_espi_transfer {
39 	const void *tx_buf;
40 	void *rx_buf;
41 	unsigned len;
42 	unsigned n_tx;
43 	unsigned n_rx;
44 	unsigned actual_length;
45 	int status;
46 };
47 
48 /* eSPI Controller mode register definitions */
49 #define SPMODE_ENABLE		(1 << 31)
50 #define SPMODE_LOOP		(1 << 30)
51 #define SPMODE_TXTHR(x)		((x) << 8)
52 #define SPMODE_RXTHR(x)		((x) << 0)
53 
54 /* eSPI Controller CS mode register definitions */
55 #define CSMODE_CI_INACTIVEHIGH	(1 << 31)
56 #define CSMODE_CP_BEGIN_EDGECLK	(1 << 30)
57 #define CSMODE_REV		(1 << 29)
58 #define CSMODE_DIV16		(1 << 28)
59 #define CSMODE_PM(x)		((x) << 24)
60 #define CSMODE_POL_1		(1 << 20)
61 #define CSMODE_LEN(x)		((x) << 16)
62 #define CSMODE_BEF(x)		((x) << 12)
63 #define CSMODE_AFT(x)		((x) << 8)
64 #define CSMODE_CG(x)		((x) << 3)
65 
66 /* Default mode/csmode for eSPI controller */
67 #define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3))
68 #define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
69 		| CSMODE_AFT(0) | CSMODE_CG(1))
70 
71 /* SPIE register values */
72 #define	SPIE_NE		0x00000200	/* Not empty */
73 #define	SPIE_NF		0x00000100	/* Not full */
74 
75 /* SPIM register values */
76 #define	SPIM_NE		0x00000200	/* Not empty */
77 #define	SPIM_NF		0x00000100	/* Not full */
78 #define SPIE_RXCNT(reg)     ((reg >> 24) & 0x3F)
79 #define SPIE_TXCNT(reg)     ((reg >> 16) & 0x3F)
80 
81 /* SPCOM register values */
82 #define SPCOM_CS(x)		((x) << 30)
83 #define SPCOM_TRANLEN(x)	((x) << 0)
84 #define	SPCOM_TRANLEN_MAX	0xFFFF	/* Max transaction length */
85 
86 static void fsl_espi_change_mode(struct spi_device *spi)
87 {
88 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
89 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
90 	struct fsl_espi_reg *reg_base = mspi->reg_base;
91 	__be32 __iomem *mode = &reg_base->csmode[spi->chip_select];
92 	__be32 __iomem *espi_mode = &reg_base->mode;
93 	u32 tmp;
94 	unsigned long flags;
95 
96 	/* Turn off IRQs locally to minimize time that SPI is disabled. */
97 	local_irq_save(flags);
98 
99 	/* Turn off SPI unit prior changing mode */
100 	tmp = mpc8xxx_spi_read_reg(espi_mode);
101 	mpc8xxx_spi_write_reg(espi_mode, tmp & ~SPMODE_ENABLE);
102 	mpc8xxx_spi_write_reg(mode, cs->hw_mode);
103 	mpc8xxx_spi_write_reg(espi_mode, tmp);
104 
105 	local_irq_restore(flags);
106 }
107 
108 static u32 fsl_espi_tx_buf_lsb(struct mpc8xxx_spi *mpc8xxx_spi)
109 {
110 	u32 data;
111 	u16 data_h;
112 	u16 data_l;
113 	const u32 *tx = mpc8xxx_spi->tx;
114 
115 	if (!tx)
116 		return 0;
117 
118 	data = *tx++ << mpc8xxx_spi->tx_shift;
119 	data_l = data & 0xffff;
120 	data_h = (data >> 16) & 0xffff;
121 	swab16s(&data_l);
122 	swab16s(&data_h);
123 	data = data_h | data_l;
124 
125 	mpc8xxx_spi->tx = tx;
126 	return data;
127 }
128 
129 static int fsl_espi_setup_transfer(struct spi_device *spi,
130 					struct spi_transfer *t)
131 {
132 	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
133 	int bits_per_word = 0;
134 	u8 pm;
135 	u32 hz = 0;
136 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
137 
138 	if (t) {
139 		bits_per_word = t->bits_per_word;
140 		hz = t->speed_hz;
141 	}
142 
143 	/* spi_transfer level calls that work per-word */
144 	if (!bits_per_word)
145 		bits_per_word = spi->bits_per_word;
146 
147 	if (!hz)
148 		hz = spi->max_speed_hz;
149 
150 	cs->rx_shift = 0;
151 	cs->tx_shift = 0;
152 	cs->get_rx = mpc8xxx_spi_rx_buf_u32;
153 	cs->get_tx = mpc8xxx_spi_tx_buf_u32;
154 	if (bits_per_word <= 8) {
155 		cs->rx_shift = 8 - bits_per_word;
156 	} else {
157 		cs->rx_shift = 16 - bits_per_word;
158 		if (spi->mode & SPI_LSB_FIRST)
159 			cs->get_tx = fsl_espi_tx_buf_lsb;
160 	}
161 
162 	mpc8xxx_spi->rx_shift = cs->rx_shift;
163 	mpc8xxx_spi->tx_shift = cs->tx_shift;
164 	mpc8xxx_spi->get_rx = cs->get_rx;
165 	mpc8xxx_spi->get_tx = cs->get_tx;
166 
167 	bits_per_word = bits_per_word - 1;
168 
169 	/* mask out bits we are going to set */
170 	cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF));
171 
172 	cs->hw_mode |= CSMODE_LEN(bits_per_word);
173 
174 	if ((mpc8xxx_spi->spibrg / hz) > 64) {
175 		cs->hw_mode |= CSMODE_DIV16;
176 		pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 16 * 4);
177 
178 		WARN_ONCE(pm > 33, "%s: Requested speed is too low: %d Hz. "
179 			  "Will use %d Hz instead.\n", dev_name(&spi->dev),
180 				hz, mpc8xxx_spi->spibrg / (4 * 16 * (32 + 1)));
181 		if (pm > 33)
182 			pm = 33;
183 	} else {
184 		pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 4);
185 	}
186 	if (pm)
187 		pm--;
188 	if (pm < 2)
189 		pm = 2;
190 
191 	cs->hw_mode |= CSMODE_PM(pm);
192 
193 	fsl_espi_change_mode(spi);
194 	return 0;
195 }
196 
197 static int fsl_espi_cpu_bufs(struct mpc8xxx_spi *mspi, struct spi_transfer *t,
198 		unsigned int len)
199 {
200 	u32 word;
201 	struct fsl_espi_reg *reg_base = mspi->reg_base;
202 
203 	mspi->count = len;
204 
205 	/* enable rx ints */
206 	mpc8xxx_spi_write_reg(&reg_base->mask, SPIM_NE);
207 
208 	/* transmit word */
209 	word = mspi->get_tx(mspi);
210 	mpc8xxx_spi_write_reg(&reg_base->transmit, word);
211 
212 	return 0;
213 }
214 
215 static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
216 {
217 	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
218 	struct fsl_espi_reg *reg_base = mpc8xxx_spi->reg_base;
219 	unsigned int len = t->len;
220 	u8 bits_per_word;
221 	int ret;
222 
223 	bits_per_word = spi->bits_per_word;
224 	if (t->bits_per_word)
225 		bits_per_word = t->bits_per_word;
226 
227 	mpc8xxx_spi->len = t->len;
228 	len = roundup(len, 4) / 4;
229 
230 	mpc8xxx_spi->tx = t->tx_buf;
231 	mpc8xxx_spi->rx = t->rx_buf;
232 
233 	INIT_COMPLETION(mpc8xxx_spi->done);
234 
235 	/* Set SPCOM[CS] and SPCOM[TRANLEN] field */
236 	if ((t->len - 1) > SPCOM_TRANLEN_MAX) {
237 		dev_err(mpc8xxx_spi->dev, "Transaction length (%d)"
238 				" beyond the SPCOM[TRANLEN] field\n", t->len);
239 		return -EINVAL;
240 	}
241 	mpc8xxx_spi_write_reg(&reg_base->command,
242 		(SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1)));
243 
244 	ret = fsl_espi_cpu_bufs(mpc8xxx_spi, t, len);
245 	if (ret)
246 		return ret;
247 
248 	wait_for_completion(&mpc8xxx_spi->done);
249 
250 	/* disable rx ints */
251 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
252 
253 	return mpc8xxx_spi->count;
254 }
255 
256 static inline void fsl_espi_addr2cmd(unsigned int addr, u8 *cmd)
257 {
258 	if (cmd) {
259 		cmd[1] = (u8)(addr >> 16);
260 		cmd[2] = (u8)(addr >> 8);
261 		cmd[3] = (u8)(addr >> 0);
262 	}
263 }
264 
265 static inline unsigned int fsl_espi_cmd2addr(u8 *cmd)
266 {
267 	if (cmd)
268 		return cmd[1] << 16 | cmd[2] << 8 | cmd[3] << 0;
269 
270 	return 0;
271 }
272 
273 static void fsl_espi_do_trans(struct spi_message *m,
274 				struct fsl_espi_transfer *tr)
275 {
276 	struct spi_device *spi = m->spi;
277 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
278 	struct fsl_espi_transfer *espi_trans = tr;
279 	struct spi_message message;
280 	struct spi_transfer *t, *first, trans;
281 	int status = 0;
282 
283 	spi_message_init(&message);
284 	memset(&trans, 0, sizeof(trans));
285 
286 	first = list_first_entry(&m->transfers, struct spi_transfer,
287 			transfer_list);
288 	list_for_each_entry(t, &m->transfers, transfer_list) {
289 		if ((first->bits_per_word != t->bits_per_word) ||
290 			(first->speed_hz != t->speed_hz)) {
291 			espi_trans->status = -EINVAL;
292 			dev_err(mspi->dev, "bits_per_word/speed_hz should be"
293 					" same for the same SPI transfer\n");
294 			return;
295 		}
296 
297 		trans.speed_hz = t->speed_hz;
298 		trans.bits_per_word = t->bits_per_word;
299 		trans.delay_usecs = max(first->delay_usecs, t->delay_usecs);
300 	}
301 
302 	trans.len = espi_trans->len;
303 	trans.tx_buf = espi_trans->tx_buf;
304 	trans.rx_buf = espi_trans->rx_buf;
305 	spi_message_add_tail(&trans, &message);
306 
307 	list_for_each_entry(t, &message.transfers, transfer_list) {
308 		if (t->bits_per_word || t->speed_hz) {
309 			status = -EINVAL;
310 
311 			status = fsl_espi_setup_transfer(spi, t);
312 			if (status < 0)
313 				break;
314 		}
315 
316 		if (t->len)
317 			status = fsl_espi_bufs(spi, t);
318 
319 		if (status) {
320 			status = -EMSGSIZE;
321 			break;
322 		}
323 
324 		if (t->delay_usecs)
325 			udelay(t->delay_usecs);
326 	}
327 
328 	espi_trans->status = status;
329 	fsl_espi_setup_transfer(spi, NULL);
330 }
331 
332 static void fsl_espi_cmd_trans(struct spi_message *m,
333 				struct fsl_espi_transfer *trans, u8 *rx_buff)
334 {
335 	struct spi_transfer *t;
336 	u8 *local_buf;
337 	int i = 0;
338 	struct fsl_espi_transfer *espi_trans = trans;
339 
340 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
341 	if (!local_buf) {
342 		espi_trans->status = -ENOMEM;
343 		return;
344 	}
345 
346 	list_for_each_entry(t, &m->transfers, transfer_list) {
347 		if (t->tx_buf) {
348 			memcpy(local_buf + i, t->tx_buf, t->len);
349 			i += t->len;
350 		}
351 	}
352 
353 	espi_trans->tx_buf = local_buf;
354 	espi_trans->rx_buf = local_buf + espi_trans->n_tx;
355 	fsl_espi_do_trans(m, espi_trans);
356 
357 	espi_trans->actual_length = espi_trans->len;
358 	kfree(local_buf);
359 }
360 
361 static void fsl_espi_rw_trans(struct spi_message *m,
362 				struct fsl_espi_transfer *trans, u8 *rx_buff)
363 {
364 	struct fsl_espi_transfer *espi_trans = trans;
365 	unsigned int n_tx = espi_trans->n_tx;
366 	unsigned int n_rx = espi_trans->n_rx;
367 	struct spi_transfer *t;
368 	u8 *local_buf;
369 	u8 *rx_buf = rx_buff;
370 	unsigned int trans_len;
371 	unsigned int addr;
372 	int i, pos, loop;
373 
374 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
375 	if (!local_buf) {
376 		espi_trans->status = -ENOMEM;
377 		return;
378 	}
379 
380 	for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
381 		trans_len = n_rx - pos;
382 		if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
383 			trans_len = SPCOM_TRANLEN_MAX - n_tx;
384 
385 		i = 0;
386 		list_for_each_entry(t, &m->transfers, transfer_list) {
387 			if (t->tx_buf) {
388 				memcpy(local_buf + i, t->tx_buf, t->len);
389 				i += t->len;
390 			}
391 		}
392 
393 		if (pos > 0) {
394 			addr = fsl_espi_cmd2addr(local_buf);
395 			addr += pos;
396 			fsl_espi_addr2cmd(addr, local_buf);
397 		}
398 
399 		espi_trans->n_tx = n_tx;
400 		espi_trans->n_rx = trans_len;
401 		espi_trans->len = trans_len + n_tx;
402 		espi_trans->tx_buf = local_buf;
403 		espi_trans->rx_buf = local_buf + n_tx;
404 		fsl_espi_do_trans(m, espi_trans);
405 
406 		memcpy(rx_buf + pos, espi_trans->rx_buf + n_tx, trans_len);
407 
408 		if (loop > 0)
409 			espi_trans->actual_length += espi_trans->len - n_tx;
410 		else
411 			espi_trans->actual_length += espi_trans->len;
412 	}
413 
414 	kfree(local_buf);
415 }
416 
417 static void fsl_espi_do_one_msg(struct spi_message *m)
418 {
419 	struct spi_transfer *t;
420 	u8 *rx_buf = NULL;
421 	unsigned int n_tx = 0;
422 	unsigned int n_rx = 0;
423 	struct fsl_espi_transfer espi_trans;
424 
425 	list_for_each_entry(t, &m->transfers, transfer_list) {
426 		if (t->tx_buf)
427 			n_tx += t->len;
428 		if (t->rx_buf) {
429 			n_rx += t->len;
430 			rx_buf = t->rx_buf;
431 		}
432 	}
433 
434 	espi_trans.n_tx = n_tx;
435 	espi_trans.n_rx = n_rx;
436 	espi_trans.len = n_tx + n_rx;
437 	espi_trans.actual_length = 0;
438 	espi_trans.status = 0;
439 
440 	if (!rx_buf)
441 		fsl_espi_cmd_trans(m, &espi_trans, NULL);
442 	else
443 		fsl_espi_rw_trans(m, &espi_trans, rx_buf);
444 
445 	m->actual_length = espi_trans.actual_length;
446 	m->status = espi_trans.status;
447 	m->complete(m->context);
448 }
449 
450 static int fsl_espi_setup(struct spi_device *spi)
451 {
452 	struct mpc8xxx_spi *mpc8xxx_spi;
453 	struct fsl_espi_reg *reg_base;
454 	int retval;
455 	u32 hw_mode;
456 	u32 loop_mode;
457 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
458 
459 	if (!spi->max_speed_hz)
460 		return -EINVAL;
461 
462 	if (!cs) {
463 		cs = kzalloc(sizeof *cs, GFP_KERNEL);
464 		if (!cs)
465 			return -ENOMEM;
466 		spi->controller_state = cs;
467 	}
468 
469 	mpc8xxx_spi = spi_master_get_devdata(spi->master);
470 	reg_base = mpc8xxx_spi->reg_base;
471 
472 	hw_mode = cs->hw_mode; /* Save original settings */
473 	cs->hw_mode = mpc8xxx_spi_read_reg(
474 			&reg_base->csmode[spi->chip_select]);
475 	/* mask out bits we are going to set */
476 	cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
477 			 | CSMODE_REV);
478 
479 	if (spi->mode & SPI_CPHA)
480 		cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
481 	if (spi->mode & SPI_CPOL)
482 		cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
483 	if (!(spi->mode & SPI_LSB_FIRST))
484 		cs->hw_mode |= CSMODE_REV;
485 
486 	/* Handle the loop mode */
487 	loop_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
488 	loop_mode &= ~SPMODE_LOOP;
489 	if (spi->mode & SPI_LOOP)
490 		loop_mode |= SPMODE_LOOP;
491 	mpc8xxx_spi_write_reg(&reg_base->mode, loop_mode);
492 
493 	retval = fsl_espi_setup_transfer(spi, NULL);
494 	if (retval < 0) {
495 		cs->hw_mode = hw_mode; /* Restore settings */
496 		return retval;
497 	}
498 	return 0;
499 }
500 
501 void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
502 {
503 	struct fsl_espi_reg *reg_base = mspi->reg_base;
504 
505 	/* We need handle RX first */
506 	if (events & SPIE_NE) {
507 		u32 rx_data, tmp;
508 		u8 rx_data_8;
509 
510 		/* Spin until RX is done */
511 		while (SPIE_RXCNT(events) < min(4, mspi->len)) {
512 			cpu_relax();
513 			events = mpc8xxx_spi_read_reg(&reg_base->event);
514 		}
515 
516 		if (mspi->len >= 4) {
517 			rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
518 		} else {
519 			tmp = mspi->len;
520 			rx_data = 0;
521 			while (tmp--) {
522 				rx_data_8 = in_8((u8 *)&reg_base->receive);
523 				rx_data |= (rx_data_8 << (tmp * 8));
524 			}
525 
526 			rx_data <<= (4 - mspi->len) * 8;
527 		}
528 
529 		mspi->len -= 4;
530 
531 		if (mspi->rx)
532 			mspi->get_rx(rx_data, mspi);
533 	}
534 
535 	if (!(events & SPIE_NF)) {
536 		int ret;
537 
538 		/* spin until TX is done */
539 		ret = spin_event_timeout(((events = mpc8xxx_spi_read_reg(
540 				&reg_base->event)) & SPIE_NF) == 0, 1000, 0);
541 		if (!ret) {
542 			dev_err(mspi->dev, "tired waiting for SPIE_NF\n");
543 			return;
544 		}
545 	}
546 
547 	/* Clear the events */
548 	mpc8xxx_spi_write_reg(&reg_base->event, events);
549 
550 	mspi->count -= 1;
551 	if (mspi->count) {
552 		u32 word = mspi->get_tx(mspi);
553 
554 		mpc8xxx_spi_write_reg(&reg_base->transmit, word);
555 	} else {
556 		complete(&mspi->done);
557 	}
558 }
559 
560 static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
561 {
562 	struct mpc8xxx_spi *mspi = context_data;
563 	struct fsl_espi_reg *reg_base = mspi->reg_base;
564 	irqreturn_t ret = IRQ_NONE;
565 	u32 events;
566 
567 	/* Get interrupt events(tx/rx) */
568 	events = mpc8xxx_spi_read_reg(&reg_base->event);
569 	if (events)
570 		ret = IRQ_HANDLED;
571 
572 	dev_vdbg(mspi->dev, "%s: events %x\n", __func__, events);
573 
574 	fsl_espi_cpu_irq(mspi, events);
575 
576 	return ret;
577 }
578 
579 static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
580 {
581 	iounmap(mspi->reg_base);
582 }
583 
584 static struct spi_master * fsl_espi_probe(struct device *dev,
585 		struct resource *mem, unsigned int irq)
586 {
587 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
588 	struct spi_master *master;
589 	struct mpc8xxx_spi *mpc8xxx_spi;
590 	struct fsl_espi_reg *reg_base;
591 	u32 regval;
592 	int i, ret = 0;
593 
594 	master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
595 	if (!master) {
596 		ret = -ENOMEM;
597 		goto err;
598 	}
599 
600 	dev_set_drvdata(dev, master);
601 
602 	ret = mpc8xxx_spi_probe(dev, mem, irq);
603 	if (ret)
604 		goto err_probe;
605 
606 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
607 	master->setup = fsl_espi_setup;
608 
609 	mpc8xxx_spi = spi_master_get_devdata(master);
610 	mpc8xxx_spi->spi_do_one_msg = fsl_espi_do_one_msg;
611 	mpc8xxx_spi->spi_remove = fsl_espi_remove;
612 
613 	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
614 	if (!mpc8xxx_spi->reg_base) {
615 		ret = -ENOMEM;
616 		goto err_probe;
617 	}
618 
619 	reg_base = mpc8xxx_spi->reg_base;
620 
621 	/* Register for SPI Interrupt */
622 	ret = request_irq(mpc8xxx_spi->irq, fsl_espi_irq,
623 			  0, "fsl_espi", mpc8xxx_spi);
624 	if (ret)
625 		goto free_irq;
626 
627 	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
628 		mpc8xxx_spi->rx_shift = 16;
629 		mpc8xxx_spi->tx_shift = 24;
630 	}
631 
632 	/* SPI controller initializations */
633 	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
634 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
635 	mpc8xxx_spi_write_reg(&reg_base->command, 0);
636 	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);
637 
638 	/* Init eSPI CS mode register */
639 	for (i = 0; i < pdata->max_chipselect; i++)
640 		mpc8xxx_spi_write_reg(&reg_base->csmode[i], CSMODE_INIT_VAL);
641 
642 	/* Enable SPI interface */
643 	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
644 
645 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
646 
647 	ret = spi_register_master(master);
648 	if (ret < 0)
649 		goto unreg_master;
650 
651 	dev_info(dev, "at 0x%p (irq = %d)\n", reg_base, mpc8xxx_spi->irq);
652 
653 	return master;
654 
655 unreg_master:
656 	free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
657 free_irq:
658 	iounmap(mpc8xxx_spi->reg_base);
659 err_probe:
660 	spi_master_put(master);
661 err:
662 	return ERR_PTR(ret);
663 }
664 
665 static int of_fsl_espi_get_chipselects(struct device *dev)
666 {
667 	struct device_node *np = dev->of_node;
668 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
669 	const u32 *prop;
670 	int len;
671 
672 	prop = of_get_property(np, "fsl,espi-num-chipselects", &len);
673 	if (!prop || len < sizeof(*prop)) {
674 		dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
675 		return -EINVAL;
676 	}
677 
678 	pdata->max_chipselect = *prop;
679 	pdata->cs_control = NULL;
680 
681 	return 0;
682 }
683 
684 static int of_fsl_espi_probe(struct platform_device *ofdev)
685 {
686 	struct device *dev = &ofdev->dev;
687 	struct device_node *np = ofdev->dev.of_node;
688 	struct spi_master *master;
689 	struct resource mem;
690 	struct resource irq;
691 	int ret = -ENOMEM;
692 
693 	ret = of_mpc8xxx_spi_probe(ofdev);
694 	if (ret)
695 		return ret;
696 
697 	ret = of_fsl_espi_get_chipselects(dev);
698 	if (ret)
699 		goto err;
700 
701 	ret = of_address_to_resource(np, 0, &mem);
702 	if (ret)
703 		goto err;
704 
705 	ret = of_irq_to_resource(np, 0, &irq);
706 	if (!ret) {
707 		ret = -EINVAL;
708 		goto err;
709 	}
710 
711 	master = fsl_espi_probe(dev, &mem, irq.start);
712 	if (IS_ERR(master)) {
713 		ret = PTR_ERR(master);
714 		goto err;
715 	}
716 
717 	return 0;
718 
719 err:
720 	return ret;
721 }
722 
723 static int of_fsl_espi_remove(struct platform_device *dev)
724 {
725 	return mpc8xxx_spi_remove(&dev->dev);
726 }
727 
728 static const struct of_device_id of_fsl_espi_match[] = {
729 	{ .compatible = "fsl,mpc8536-espi" },
730 	{}
731 };
732 MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
733 
734 static struct platform_driver fsl_espi_driver = {
735 	.driver = {
736 		.name = "fsl_espi",
737 		.owner = THIS_MODULE,
738 		.of_match_table = of_fsl_espi_match,
739 	},
740 	.probe		= of_fsl_espi_probe,
741 	.remove		= of_fsl_espi_remove,
742 };
743 module_platform_driver(fsl_espi_driver);
744 
745 MODULE_AUTHOR("Mingkai Hu");
746 MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
747 MODULE_LICENSE("GPL");
748