xref: /openbmc/linux/drivers/spi/spi-fsl-espi.c (revision 930beb5a)
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_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_platform.h>
22 #include <linux/interrupt.h>
23 #include <linux/err.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 	u8 bits_per_word;
223 	int ret;
224 
225 	bits_per_word = spi->bits_per_word;
226 	if (t->bits_per_word)
227 		bits_per_word = t->bits_per_word;
228 
229 	mpc8xxx_spi->len = t->len;
230 	len = roundup(len, 4) / 4;
231 
232 	mpc8xxx_spi->tx = t->tx_buf;
233 	mpc8xxx_spi->rx = t->rx_buf;
234 
235 	reinit_completion(&mpc8xxx_spi->done);
236 
237 	/* Set SPCOM[CS] and SPCOM[TRANLEN] field */
238 	if ((t->len - 1) > SPCOM_TRANLEN_MAX) {
239 		dev_err(mpc8xxx_spi->dev, "Transaction length (%d)"
240 				" beyond the SPCOM[TRANLEN] field\n", t->len);
241 		return -EINVAL;
242 	}
243 	mpc8xxx_spi_write_reg(&reg_base->command,
244 		(SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1)));
245 
246 	ret = fsl_espi_cpu_bufs(mpc8xxx_spi, t, len);
247 	if (ret)
248 		return ret;
249 
250 	wait_for_completion(&mpc8xxx_spi->done);
251 
252 	/* disable rx ints */
253 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
254 
255 	return mpc8xxx_spi->count;
256 }
257 
258 static inline void fsl_espi_addr2cmd(unsigned int addr, u8 *cmd)
259 {
260 	if (cmd) {
261 		cmd[1] = (u8)(addr >> 16);
262 		cmd[2] = (u8)(addr >> 8);
263 		cmd[3] = (u8)(addr >> 0);
264 	}
265 }
266 
267 static inline unsigned int fsl_espi_cmd2addr(u8 *cmd)
268 {
269 	if (cmd)
270 		return cmd[1] << 16 | cmd[2] << 8 | cmd[3] << 0;
271 
272 	return 0;
273 }
274 
275 static void fsl_espi_do_trans(struct spi_message *m,
276 				struct fsl_espi_transfer *tr)
277 {
278 	struct spi_device *spi = m->spi;
279 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
280 	struct fsl_espi_transfer *espi_trans = tr;
281 	struct spi_message message;
282 	struct spi_transfer *t, *first, trans;
283 	int status = 0;
284 
285 	spi_message_init(&message);
286 	memset(&trans, 0, sizeof(trans));
287 
288 	first = list_first_entry(&m->transfers, struct spi_transfer,
289 			transfer_list);
290 	list_for_each_entry(t, &m->transfers, transfer_list) {
291 		if ((first->bits_per_word != t->bits_per_word) ||
292 			(first->speed_hz != t->speed_hz)) {
293 			espi_trans->status = -EINVAL;
294 			dev_err(mspi->dev,
295 				"bits_per_word/speed_hz should be same for the same SPI transfer\n");
296 			return;
297 		}
298 
299 		trans.speed_hz = t->speed_hz;
300 		trans.bits_per_word = t->bits_per_word;
301 		trans.delay_usecs = max(first->delay_usecs, t->delay_usecs);
302 	}
303 
304 	trans.len = espi_trans->len;
305 	trans.tx_buf = espi_trans->tx_buf;
306 	trans.rx_buf = espi_trans->rx_buf;
307 	spi_message_add_tail(&trans, &message);
308 
309 	list_for_each_entry(t, &message.transfers, transfer_list) {
310 		if (t->bits_per_word || t->speed_hz) {
311 			status = -EINVAL;
312 
313 			status = fsl_espi_setup_transfer(spi, t);
314 			if (status < 0)
315 				break;
316 		}
317 
318 		if (t->len)
319 			status = fsl_espi_bufs(spi, t);
320 
321 		if (status) {
322 			status = -EMSGSIZE;
323 			break;
324 		}
325 
326 		if (t->delay_usecs)
327 			udelay(t->delay_usecs);
328 	}
329 
330 	espi_trans->status = status;
331 	fsl_espi_setup_transfer(spi, NULL);
332 }
333 
334 static void fsl_espi_cmd_trans(struct spi_message *m,
335 				struct fsl_espi_transfer *trans, u8 *rx_buff)
336 {
337 	struct spi_transfer *t;
338 	u8 *local_buf;
339 	int i = 0;
340 	struct fsl_espi_transfer *espi_trans = trans;
341 
342 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
343 	if (!local_buf) {
344 		espi_trans->status = -ENOMEM;
345 		return;
346 	}
347 
348 	list_for_each_entry(t, &m->transfers, transfer_list) {
349 		if (t->tx_buf) {
350 			memcpy(local_buf + i, t->tx_buf, t->len);
351 			i += t->len;
352 		}
353 	}
354 
355 	espi_trans->tx_buf = local_buf;
356 	espi_trans->rx_buf = local_buf + espi_trans->n_tx;
357 	fsl_espi_do_trans(m, espi_trans);
358 
359 	espi_trans->actual_length = espi_trans->len;
360 	kfree(local_buf);
361 }
362 
363 static void fsl_espi_rw_trans(struct spi_message *m,
364 				struct fsl_espi_transfer *trans, u8 *rx_buff)
365 {
366 	struct fsl_espi_transfer *espi_trans = trans;
367 	unsigned int n_tx = espi_trans->n_tx;
368 	unsigned int n_rx = espi_trans->n_rx;
369 	struct spi_transfer *t;
370 	u8 *local_buf;
371 	u8 *rx_buf = rx_buff;
372 	unsigned int trans_len;
373 	unsigned int addr;
374 	int i, pos, loop;
375 
376 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
377 	if (!local_buf) {
378 		espi_trans->status = -ENOMEM;
379 		return;
380 	}
381 
382 	for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
383 		trans_len = n_rx - pos;
384 		if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
385 			trans_len = SPCOM_TRANLEN_MAX - n_tx;
386 
387 		i = 0;
388 		list_for_each_entry(t, &m->transfers, transfer_list) {
389 			if (t->tx_buf) {
390 				memcpy(local_buf + i, t->tx_buf, t->len);
391 				i += t->len;
392 			}
393 		}
394 
395 		if (pos > 0) {
396 			addr = fsl_espi_cmd2addr(local_buf);
397 			addr += pos;
398 			fsl_espi_addr2cmd(addr, local_buf);
399 		}
400 
401 		espi_trans->n_tx = n_tx;
402 		espi_trans->n_rx = trans_len;
403 		espi_trans->len = trans_len + n_tx;
404 		espi_trans->tx_buf = local_buf;
405 		espi_trans->rx_buf = local_buf + n_tx;
406 		fsl_espi_do_trans(m, espi_trans);
407 
408 		memcpy(rx_buf + pos, espi_trans->rx_buf + n_tx, trans_len);
409 
410 		if (loop > 0)
411 			espi_trans->actual_length += espi_trans->len - n_tx;
412 		else
413 			espi_trans->actual_length += espi_trans->len;
414 	}
415 
416 	kfree(local_buf);
417 }
418 
419 static void fsl_espi_do_one_msg(struct spi_message *m)
420 {
421 	struct spi_transfer *t;
422 	u8 *rx_buf = NULL;
423 	unsigned int n_tx = 0;
424 	unsigned int n_rx = 0;
425 	struct fsl_espi_transfer espi_trans;
426 
427 	list_for_each_entry(t, &m->transfers, transfer_list) {
428 		if (t->tx_buf)
429 			n_tx += t->len;
430 		if (t->rx_buf) {
431 			n_rx += t->len;
432 			rx_buf = t->rx_buf;
433 		}
434 	}
435 
436 	espi_trans.n_tx = n_tx;
437 	espi_trans.n_rx = n_rx;
438 	espi_trans.len = n_tx + n_rx;
439 	espi_trans.actual_length = 0;
440 	espi_trans.status = 0;
441 
442 	if (!rx_buf)
443 		fsl_espi_cmd_trans(m, &espi_trans, NULL);
444 	else
445 		fsl_espi_rw_trans(m, &espi_trans, rx_buf);
446 
447 	m->actual_length = espi_trans.actual_length;
448 	m->status = espi_trans.status;
449 	m->complete(m->context);
450 }
451 
452 static int fsl_espi_setup(struct spi_device *spi)
453 {
454 	struct mpc8xxx_spi *mpc8xxx_spi;
455 	struct fsl_espi_reg *reg_base;
456 	int retval;
457 	u32 hw_mode;
458 	u32 loop_mode;
459 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
460 
461 	if (!spi->max_speed_hz)
462 		return -EINVAL;
463 
464 	if (!cs) {
465 		cs = kzalloc(sizeof *cs, GFP_KERNEL);
466 		if (!cs)
467 			return -ENOMEM;
468 		spi->controller_state = cs;
469 	}
470 
471 	mpc8xxx_spi = spi_master_get_devdata(spi->master);
472 	reg_base = mpc8xxx_spi->reg_base;
473 
474 	hw_mode = cs->hw_mode; /* Save original settings */
475 	cs->hw_mode = mpc8xxx_spi_read_reg(
476 			&reg_base->csmode[spi->chip_select]);
477 	/* mask out bits we are going to set */
478 	cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
479 			 | CSMODE_REV);
480 
481 	if (spi->mode & SPI_CPHA)
482 		cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
483 	if (spi->mode & SPI_CPOL)
484 		cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
485 	if (!(spi->mode & SPI_LSB_FIRST))
486 		cs->hw_mode |= CSMODE_REV;
487 
488 	/* Handle the loop mode */
489 	loop_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
490 	loop_mode &= ~SPMODE_LOOP;
491 	if (spi->mode & SPI_LOOP)
492 		loop_mode |= SPMODE_LOOP;
493 	mpc8xxx_spi_write_reg(&reg_base->mode, loop_mode);
494 
495 	retval = fsl_espi_setup_transfer(spi, NULL);
496 	if (retval < 0) {
497 		cs->hw_mode = hw_mode; /* Restore settings */
498 		return retval;
499 	}
500 	return 0;
501 }
502 
503 void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
504 {
505 	struct fsl_espi_reg *reg_base = mspi->reg_base;
506 
507 	/* We need handle RX first */
508 	if (events & SPIE_NE) {
509 		u32 rx_data, tmp;
510 		u8 rx_data_8;
511 
512 		/* Spin until RX is done */
513 		while (SPIE_RXCNT(events) < min(4, mspi->len)) {
514 			cpu_relax();
515 			events = mpc8xxx_spi_read_reg(&reg_base->event);
516 		}
517 
518 		if (mspi->len >= 4) {
519 			rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
520 		} else {
521 			tmp = mspi->len;
522 			rx_data = 0;
523 			while (tmp--) {
524 				rx_data_8 = in_8((u8 *)&reg_base->receive);
525 				rx_data |= (rx_data_8 << (tmp * 8));
526 			}
527 
528 			rx_data <<= (4 - mspi->len) * 8;
529 		}
530 
531 		mspi->len -= 4;
532 
533 		if (mspi->rx)
534 			mspi->get_rx(rx_data, mspi);
535 	}
536 
537 	if (!(events & SPIE_NF)) {
538 		int ret;
539 
540 		/* spin until TX is done */
541 		ret = spin_event_timeout(((events = mpc8xxx_spi_read_reg(
542 				&reg_base->event)) & SPIE_NF) == 0, 1000, 0);
543 		if (!ret) {
544 			dev_err(mspi->dev, "tired waiting for SPIE_NF\n");
545 			return;
546 		}
547 	}
548 
549 	/* Clear the events */
550 	mpc8xxx_spi_write_reg(&reg_base->event, events);
551 
552 	mspi->count -= 1;
553 	if (mspi->count) {
554 		u32 word = mspi->get_tx(mspi);
555 
556 		mpc8xxx_spi_write_reg(&reg_base->transmit, word);
557 	} else {
558 		complete(&mspi->done);
559 	}
560 }
561 
562 static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
563 {
564 	struct mpc8xxx_spi *mspi = context_data;
565 	struct fsl_espi_reg *reg_base = mspi->reg_base;
566 	irqreturn_t ret = IRQ_NONE;
567 	u32 events;
568 
569 	/* Get interrupt events(tx/rx) */
570 	events = mpc8xxx_spi_read_reg(&reg_base->event);
571 	if (events)
572 		ret = IRQ_HANDLED;
573 
574 	dev_vdbg(mspi->dev, "%s: events %x\n", __func__, events);
575 
576 	fsl_espi_cpu_irq(mspi, events);
577 
578 	return ret;
579 }
580 
581 static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
582 {
583 	iounmap(mspi->reg_base);
584 }
585 
586 static struct spi_master * fsl_espi_probe(struct device *dev,
587 		struct resource *mem, unsigned int irq)
588 {
589 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
590 	struct spi_master *master;
591 	struct mpc8xxx_spi *mpc8xxx_spi;
592 	struct fsl_espi_reg *reg_base;
593 	u32 regval;
594 	int i, ret = 0;
595 
596 	master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
597 	if (!master) {
598 		ret = -ENOMEM;
599 		goto err;
600 	}
601 
602 	dev_set_drvdata(dev, master);
603 
604 	ret = mpc8xxx_spi_probe(dev, mem, irq);
605 	if (ret)
606 		goto err_probe;
607 
608 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
609 	master->setup = fsl_espi_setup;
610 
611 	mpc8xxx_spi = spi_master_get_devdata(master);
612 	mpc8xxx_spi->spi_do_one_msg = fsl_espi_do_one_msg;
613 	mpc8xxx_spi->spi_remove = fsl_espi_remove;
614 
615 	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
616 	if (!mpc8xxx_spi->reg_base) {
617 		ret = -ENOMEM;
618 		goto err_probe;
619 	}
620 
621 	reg_base = mpc8xxx_spi->reg_base;
622 
623 	/* Register for SPI Interrupt */
624 	ret = request_irq(mpc8xxx_spi->irq, fsl_espi_irq,
625 			  0, "fsl_espi", mpc8xxx_spi);
626 	if (ret)
627 		goto free_irq;
628 
629 	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
630 		mpc8xxx_spi->rx_shift = 16;
631 		mpc8xxx_spi->tx_shift = 24;
632 	}
633 
634 	/* SPI controller initializations */
635 	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
636 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
637 	mpc8xxx_spi_write_reg(&reg_base->command, 0);
638 	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);
639 
640 	/* Init eSPI CS mode register */
641 	for (i = 0; i < pdata->max_chipselect; i++)
642 		mpc8xxx_spi_write_reg(&reg_base->csmode[i], CSMODE_INIT_VAL);
643 
644 	/* Enable SPI interface */
645 	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
646 
647 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
648 
649 	ret = spi_register_master(master);
650 	if (ret < 0)
651 		goto unreg_master;
652 
653 	dev_info(dev, "at 0x%p (irq = %d)\n", reg_base, mpc8xxx_spi->irq);
654 
655 	return master;
656 
657 unreg_master:
658 	free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
659 free_irq:
660 	iounmap(mpc8xxx_spi->reg_base);
661 err_probe:
662 	spi_master_put(master);
663 err:
664 	return ERR_PTR(ret);
665 }
666 
667 static int of_fsl_espi_get_chipselects(struct device *dev)
668 {
669 	struct device_node *np = dev->of_node;
670 	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
671 	const u32 *prop;
672 	int len;
673 
674 	prop = of_get_property(np, "fsl,espi-num-chipselects", &len);
675 	if (!prop || len < sizeof(*prop)) {
676 		dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
677 		return -EINVAL;
678 	}
679 
680 	pdata->max_chipselect = *prop;
681 	pdata->cs_control = NULL;
682 
683 	return 0;
684 }
685 
686 static int of_fsl_espi_probe(struct platform_device *ofdev)
687 {
688 	struct device *dev = &ofdev->dev;
689 	struct device_node *np = ofdev->dev.of_node;
690 	struct spi_master *master;
691 	struct resource mem;
692 	unsigned int irq;
693 	int ret = -ENOMEM;
694 
695 	ret = of_mpc8xxx_spi_probe(ofdev);
696 	if (ret)
697 		return ret;
698 
699 	ret = of_fsl_espi_get_chipselects(dev);
700 	if (ret)
701 		goto err;
702 
703 	ret = of_address_to_resource(np, 0, &mem);
704 	if (ret)
705 		goto err;
706 
707 	irq = irq_of_parse_and_map(np, 0);
708 	if (!ret) {
709 		ret = -EINVAL;
710 		goto err;
711 	}
712 
713 	master = fsl_espi_probe(dev, &mem, irq);
714 	if (IS_ERR(master)) {
715 		ret = PTR_ERR(master);
716 		goto err;
717 	}
718 
719 	return 0;
720 
721 err:
722 	return ret;
723 }
724 
725 static int of_fsl_espi_remove(struct platform_device *dev)
726 {
727 	return mpc8xxx_spi_remove(&dev->dev);
728 }
729 
730 static const struct of_device_id of_fsl_espi_match[] = {
731 	{ .compatible = "fsl,mpc8536-espi" },
732 	{}
733 };
734 MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
735 
736 static struct platform_driver fsl_espi_driver = {
737 	.driver = {
738 		.name = "fsl_espi",
739 		.owner = THIS_MODULE,
740 		.of_match_table = of_fsl_espi_match,
741 	},
742 	.probe		= of_fsl_espi_probe,
743 	.remove		= of_fsl_espi_remove,
744 };
745 module_platform_driver(fsl_espi_driver);
746 
747 MODULE_AUTHOR("Mingkai Hu");
748 MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
749 MODULE_LICENSE("GPL");
750