xref: /openbmc/linux/drivers/spi/spi-fsl-espi.c (revision 63dc02bd)
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/of_spi.h>
21 #include <linux/interrupt.h>
22 #include <linux/err.h>
23 #include <sysdev/fsl_soc.h>
24 
25 #include "spi-fsl-lib.h"
26 
27 /* eSPI Controller registers */
28 struct fsl_espi_reg {
29 	__be32 mode;		/* 0x000 - eSPI mode register */
30 	__be32 event;		/* 0x004 - eSPI event register */
31 	__be32 mask;		/* 0x008 - eSPI mask register */
32 	__be32 command;		/* 0x00c - eSPI command register */
33 	__be32 transmit;	/* 0x010 - eSPI transmit FIFO access register*/
34 	__be32 receive;		/* 0x014 - eSPI receive FIFO access register*/
35 	u8 res[8];		/* 0x018 - 0x01c reserved */
36 	__be32 csmode[4];	/* 0x020 - 0x02c eSPI cs mode register */
37 };
38 
39 struct fsl_espi_transfer {
40 	const void *tx_buf;
41 	void *rx_buf;
42 	unsigned len;
43 	unsigned n_tx;
44 	unsigned n_rx;
45 	unsigned actual_length;
46 	int status;
47 };
48 
49 /* eSPI Controller mode register definitions */
50 #define SPMODE_ENABLE		(1 << 31)
51 #define SPMODE_LOOP		(1 << 30)
52 #define SPMODE_TXTHR(x)		((x) << 8)
53 #define SPMODE_RXTHR(x)		((x) << 0)
54 
55 /* eSPI Controller CS mode register definitions */
56 #define CSMODE_CI_INACTIVEHIGH	(1 << 31)
57 #define CSMODE_CP_BEGIN_EDGECLK	(1 << 30)
58 #define CSMODE_REV		(1 << 29)
59 #define CSMODE_DIV16		(1 << 28)
60 #define CSMODE_PM(x)		((x) << 24)
61 #define CSMODE_POL_1		(1 << 20)
62 #define CSMODE_LEN(x)		((x) << 16)
63 #define CSMODE_BEF(x)		((x) << 12)
64 #define CSMODE_AFT(x)		((x) << 8)
65 #define CSMODE_CG(x)		((x) << 3)
66 
67 /* Default mode/csmode for eSPI controller */
68 #define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3))
69 #define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
70 		| CSMODE_AFT(0) | CSMODE_CG(1))
71 
72 /* SPIE register values */
73 #define	SPIE_NE		0x00000200	/* Not empty */
74 #define	SPIE_NF		0x00000100	/* Not full */
75 
76 /* SPIM register values */
77 #define	SPIM_NE		0x00000200	/* Not empty */
78 #define	SPIM_NF		0x00000100	/* Not full */
79 #define SPIE_RXCNT(reg)     ((reg >> 24) & 0x3F)
80 #define SPIE_TXCNT(reg)     ((reg >> 16) & 0x3F)
81 
82 /* SPCOM register values */
83 #define SPCOM_CS(x)		((x) << 30)
84 #define SPCOM_TRANLEN(x)	((x) << 0)
85 #define	SPCOM_TRANLEN_MAX	0xFFFF	/* Max transaction length */
86 
87 static void fsl_espi_change_mode(struct spi_device *spi)
88 {
89 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
90 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
91 	struct fsl_espi_reg *reg_base = mspi->reg_base;
92 	__be32 __iomem *mode = &reg_base->csmode[spi->chip_select];
93 	__be32 __iomem *espi_mode = &reg_base->mode;
94 	u32 tmp;
95 	unsigned long flags;
96 
97 	/* Turn off IRQs locally to minimize time that SPI is disabled. */
98 	local_irq_save(flags);
99 
100 	/* Turn off SPI unit prior changing mode */
101 	tmp = mpc8xxx_spi_read_reg(espi_mode);
102 	mpc8xxx_spi_write_reg(espi_mode, tmp & ~SPMODE_ENABLE);
103 	mpc8xxx_spi_write_reg(mode, cs->hw_mode);
104 	mpc8xxx_spi_write_reg(espi_mode, tmp);
105 
106 	local_irq_restore(flags);
107 }
108 
109 static u32 fsl_espi_tx_buf_lsb(struct mpc8xxx_spi *mpc8xxx_spi)
110 {
111 	u32 data;
112 	u16 data_h;
113 	u16 data_l;
114 	const u32 *tx = mpc8xxx_spi->tx;
115 
116 	if (!tx)
117 		return 0;
118 
119 	data = *tx++ << mpc8xxx_spi->tx_shift;
120 	data_l = data & 0xffff;
121 	data_h = (data >> 16) & 0xffff;
122 	swab16s(&data_l);
123 	swab16s(&data_h);
124 	data = data_h | data_l;
125 
126 	mpc8xxx_spi->tx = tx;
127 	return data;
128 }
129 
130 static int fsl_espi_setup_transfer(struct spi_device *spi,
131 					struct spi_transfer *t)
132 {
133 	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
134 	int bits_per_word = 0;
135 	u8 pm;
136 	u32 hz = 0;
137 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
138 
139 	if (t) {
140 		bits_per_word = t->bits_per_word;
141 		hz = t->speed_hz;
142 	}
143 
144 	/* spi_transfer level calls that work per-word */
145 	if (!bits_per_word)
146 		bits_per_word = spi->bits_per_word;
147 
148 	/* Make sure its a bit width we support [4..16] */
149 	if ((bits_per_word < 4) || (bits_per_word > 16))
150 		return -EINVAL;
151 
152 	if (!hz)
153 		hz = spi->max_speed_hz;
154 
155 	cs->rx_shift = 0;
156 	cs->tx_shift = 0;
157 	cs->get_rx = mpc8xxx_spi_rx_buf_u32;
158 	cs->get_tx = mpc8xxx_spi_tx_buf_u32;
159 	if (bits_per_word <= 8) {
160 		cs->rx_shift = 8 - bits_per_word;
161 	} else if (bits_per_word <= 16) {
162 		cs->rx_shift = 16 - bits_per_word;
163 		if (spi->mode & SPI_LSB_FIRST)
164 			cs->get_tx = fsl_espi_tx_buf_lsb;
165 	} else {
166 		return -EINVAL;
167 	}
168 
169 	mpc8xxx_spi->rx_shift = cs->rx_shift;
170 	mpc8xxx_spi->tx_shift = cs->tx_shift;
171 	mpc8xxx_spi->get_rx = cs->get_rx;
172 	mpc8xxx_spi->get_tx = cs->get_tx;
173 
174 	bits_per_word = bits_per_word - 1;
175 
176 	/* mask out bits we are going to set */
177 	cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF));
178 
179 	cs->hw_mode |= CSMODE_LEN(bits_per_word);
180 
181 	if ((mpc8xxx_spi->spibrg / hz) > 64) {
182 		cs->hw_mode |= CSMODE_DIV16;
183 		pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 16 * 4);
184 
185 		WARN_ONCE(pm > 33, "%s: Requested speed is too low: %d Hz. "
186 			  "Will use %d Hz instead.\n", dev_name(&spi->dev),
187 				hz, mpc8xxx_spi->spibrg / (4 * 16 * (32 + 1)));
188 		if (pm > 33)
189 			pm = 33;
190 	} else {
191 		pm = DIV_ROUND_UP(mpc8xxx_spi->spibrg, hz * 4);
192 	}
193 	if (pm)
194 		pm--;
195 	if (pm < 2)
196 		pm = 2;
197 
198 	cs->hw_mode |= CSMODE_PM(pm);
199 
200 	fsl_espi_change_mode(spi);
201 	return 0;
202 }
203 
204 static int fsl_espi_cpu_bufs(struct mpc8xxx_spi *mspi, struct spi_transfer *t,
205 		unsigned int len)
206 {
207 	u32 word;
208 	struct fsl_espi_reg *reg_base = mspi->reg_base;
209 
210 	mspi->count = len;
211 
212 	/* enable rx ints */
213 	mpc8xxx_spi_write_reg(&reg_base->mask, SPIM_NE);
214 
215 	/* transmit word */
216 	word = mspi->get_tx(mspi);
217 	mpc8xxx_spi_write_reg(&reg_base->transmit, word);
218 
219 	return 0;
220 }
221 
222 static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
223 {
224 	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
225 	struct fsl_espi_reg *reg_base = mpc8xxx_spi->reg_base;
226 	unsigned int len = t->len;
227 	u8 bits_per_word;
228 	int ret;
229 
230 	bits_per_word = spi->bits_per_word;
231 	if (t->bits_per_word)
232 		bits_per_word = t->bits_per_word;
233 
234 	mpc8xxx_spi->len = t->len;
235 	len = roundup(len, 4) / 4;
236 
237 	mpc8xxx_spi->tx = t->tx_buf;
238 	mpc8xxx_spi->rx = t->rx_buf;
239 
240 	INIT_COMPLETION(mpc8xxx_spi->done);
241 
242 	/* Set SPCOM[CS] and SPCOM[TRANLEN] field */
243 	if ((t->len - 1) > SPCOM_TRANLEN_MAX) {
244 		dev_err(mpc8xxx_spi->dev, "Transaction length (%d)"
245 				" beyond the SPCOM[TRANLEN] field\n", t->len);
246 		return -EINVAL;
247 	}
248 	mpc8xxx_spi_write_reg(&reg_base->command,
249 		(SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1)));
250 
251 	ret = fsl_espi_cpu_bufs(mpc8xxx_spi, t, len);
252 	if (ret)
253 		return ret;
254 
255 	wait_for_completion(&mpc8xxx_spi->done);
256 
257 	/* disable rx ints */
258 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
259 
260 	return mpc8xxx_spi->count;
261 }
262 
263 static inline void fsl_espi_addr2cmd(unsigned int addr, u8 *cmd)
264 {
265 	if (cmd) {
266 		cmd[1] = (u8)(addr >> 16);
267 		cmd[2] = (u8)(addr >> 8);
268 		cmd[3] = (u8)(addr >> 0);
269 	}
270 }
271 
272 static inline unsigned int fsl_espi_cmd2addr(u8 *cmd)
273 {
274 	if (cmd)
275 		return cmd[1] << 16 | cmd[2] << 8 | cmd[3] << 0;
276 
277 	return 0;
278 }
279 
280 static void fsl_espi_do_trans(struct spi_message *m,
281 				struct fsl_espi_transfer *tr)
282 {
283 	struct spi_device *spi = m->spi;
284 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
285 	struct fsl_espi_transfer *espi_trans = tr;
286 	struct spi_message message;
287 	struct spi_transfer *t, *first, trans;
288 	int status = 0;
289 
290 	spi_message_init(&message);
291 	memset(&trans, 0, sizeof(trans));
292 
293 	first = list_first_entry(&m->transfers, struct spi_transfer,
294 			transfer_list);
295 	list_for_each_entry(t, &m->transfers, transfer_list) {
296 		if ((first->bits_per_word != t->bits_per_word) ||
297 			(first->speed_hz != t->speed_hz)) {
298 			espi_trans->status = -EINVAL;
299 			dev_err(mspi->dev, "bits_per_word/speed_hz should be"
300 					" same for the same SPI transfer\n");
301 			return;
302 		}
303 
304 		trans.speed_hz = t->speed_hz;
305 		trans.bits_per_word = t->bits_per_word;
306 		trans.delay_usecs = max(first->delay_usecs, t->delay_usecs);
307 	}
308 
309 	trans.len = espi_trans->len;
310 	trans.tx_buf = espi_trans->tx_buf;
311 	trans.rx_buf = espi_trans->rx_buf;
312 	spi_message_add_tail(&trans, &message);
313 
314 	list_for_each_entry(t, &message.transfers, transfer_list) {
315 		if (t->bits_per_word || t->speed_hz) {
316 			status = -EINVAL;
317 
318 			status = fsl_espi_setup_transfer(spi, t);
319 			if (status < 0)
320 				break;
321 		}
322 
323 		if (t->len)
324 			status = fsl_espi_bufs(spi, t);
325 
326 		if (status) {
327 			status = -EMSGSIZE;
328 			break;
329 		}
330 
331 		if (t->delay_usecs)
332 			udelay(t->delay_usecs);
333 	}
334 
335 	espi_trans->status = status;
336 	fsl_espi_setup_transfer(spi, NULL);
337 }
338 
339 static void fsl_espi_cmd_trans(struct spi_message *m,
340 				struct fsl_espi_transfer *trans, u8 *rx_buff)
341 {
342 	struct spi_transfer *t;
343 	u8 *local_buf;
344 	int i = 0;
345 	struct fsl_espi_transfer *espi_trans = trans;
346 
347 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
348 	if (!local_buf) {
349 		espi_trans->status = -ENOMEM;
350 		return;
351 	}
352 
353 	list_for_each_entry(t, &m->transfers, transfer_list) {
354 		if (t->tx_buf) {
355 			memcpy(local_buf + i, t->tx_buf, t->len);
356 			i += t->len;
357 		}
358 	}
359 
360 	espi_trans->tx_buf = local_buf;
361 	espi_trans->rx_buf = local_buf + espi_trans->n_tx;
362 	fsl_espi_do_trans(m, espi_trans);
363 
364 	espi_trans->actual_length = espi_trans->len;
365 	kfree(local_buf);
366 }
367 
368 static void fsl_espi_rw_trans(struct spi_message *m,
369 				struct fsl_espi_transfer *trans, u8 *rx_buff)
370 {
371 	struct fsl_espi_transfer *espi_trans = trans;
372 	unsigned int n_tx = espi_trans->n_tx;
373 	unsigned int n_rx = espi_trans->n_rx;
374 	struct spi_transfer *t;
375 	u8 *local_buf;
376 	u8 *rx_buf = rx_buff;
377 	unsigned int trans_len;
378 	unsigned int addr;
379 	int i, pos, loop;
380 
381 	local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
382 	if (!local_buf) {
383 		espi_trans->status = -ENOMEM;
384 		return;
385 	}
386 
387 	for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
388 		trans_len = n_rx - pos;
389 		if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
390 			trans_len = SPCOM_TRANLEN_MAX - n_tx;
391 
392 		i = 0;
393 		list_for_each_entry(t, &m->transfers, transfer_list) {
394 			if (t->tx_buf) {
395 				memcpy(local_buf + i, t->tx_buf, t->len);
396 				i += t->len;
397 			}
398 		}
399 
400 		if (pos > 0) {
401 			addr = fsl_espi_cmd2addr(local_buf);
402 			addr += pos;
403 			fsl_espi_addr2cmd(addr, local_buf);
404 		}
405 
406 		espi_trans->n_tx = n_tx;
407 		espi_trans->n_rx = trans_len;
408 		espi_trans->len = trans_len + n_tx;
409 		espi_trans->tx_buf = local_buf;
410 		espi_trans->rx_buf = local_buf + n_tx;
411 		fsl_espi_do_trans(m, espi_trans);
412 
413 		memcpy(rx_buf + pos, espi_trans->rx_buf + n_tx, trans_len);
414 
415 		if (loop > 0)
416 			espi_trans->actual_length += espi_trans->len - n_tx;
417 		else
418 			espi_trans->actual_length += espi_trans->len;
419 	}
420 
421 	kfree(local_buf);
422 }
423 
424 static void fsl_espi_do_one_msg(struct spi_message *m)
425 {
426 	struct spi_transfer *t;
427 	u8 *rx_buf = NULL;
428 	unsigned int n_tx = 0;
429 	unsigned int n_rx = 0;
430 	struct fsl_espi_transfer espi_trans;
431 
432 	list_for_each_entry(t, &m->transfers, transfer_list) {
433 		if (t->tx_buf)
434 			n_tx += t->len;
435 		if (t->rx_buf) {
436 			n_rx += t->len;
437 			rx_buf = t->rx_buf;
438 		}
439 	}
440 
441 	espi_trans.n_tx = n_tx;
442 	espi_trans.n_rx = n_rx;
443 	espi_trans.len = n_tx + n_rx;
444 	espi_trans.actual_length = 0;
445 	espi_trans.status = 0;
446 
447 	if (!rx_buf)
448 		fsl_espi_cmd_trans(m, &espi_trans, NULL);
449 	else
450 		fsl_espi_rw_trans(m, &espi_trans, rx_buf);
451 
452 	m->actual_length = espi_trans.actual_length;
453 	m->status = espi_trans.status;
454 	m->complete(m->context);
455 }
456 
457 static int fsl_espi_setup(struct spi_device *spi)
458 {
459 	struct mpc8xxx_spi *mpc8xxx_spi;
460 	struct fsl_espi_reg *reg_base;
461 	int retval;
462 	u32 hw_mode;
463 	u32 loop_mode;
464 	struct spi_mpc8xxx_cs *cs = spi->controller_state;
465 
466 	if (!spi->max_speed_hz)
467 		return -EINVAL;
468 
469 	if (!cs) {
470 		cs = kzalloc(sizeof *cs, GFP_KERNEL);
471 		if (!cs)
472 			return -ENOMEM;
473 		spi->controller_state = cs;
474 	}
475 
476 	mpc8xxx_spi = spi_master_get_devdata(spi->master);
477 	reg_base = mpc8xxx_spi->reg_base;
478 
479 	hw_mode = cs->hw_mode; /* Save original settings */
480 	cs->hw_mode = mpc8xxx_spi_read_reg(
481 			&reg_base->csmode[spi->chip_select]);
482 	/* mask out bits we are going to set */
483 	cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
484 			 | CSMODE_REV);
485 
486 	if (spi->mode & SPI_CPHA)
487 		cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
488 	if (spi->mode & SPI_CPOL)
489 		cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
490 	if (!(spi->mode & SPI_LSB_FIRST))
491 		cs->hw_mode |= CSMODE_REV;
492 
493 	/* Handle the loop mode */
494 	loop_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
495 	loop_mode &= ~SPMODE_LOOP;
496 	if (spi->mode & SPI_LOOP)
497 		loop_mode |= SPMODE_LOOP;
498 	mpc8xxx_spi_write_reg(&reg_base->mode, loop_mode);
499 
500 	retval = fsl_espi_setup_transfer(spi, NULL);
501 	if (retval < 0) {
502 		cs->hw_mode = hw_mode; /* Restore settings */
503 		return retval;
504 	}
505 	return 0;
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 struct spi_master * __devinit fsl_espi_probe(struct device *dev,
592 		struct resource *mem, unsigned int irq)
593 {
594 	struct fsl_spi_platform_data *pdata = dev->platform_data;
595 	struct spi_master *master;
596 	struct mpc8xxx_spi *mpc8xxx_spi;
597 	struct fsl_espi_reg *reg_base;
598 	u32 regval;
599 	int i, ret = 0;
600 
601 	master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
602 	if (!master) {
603 		ret = -ENOMEM;
604 		goto err;
605 	}
606 
607 	dev_set_drvdata(dev, master);
608 
609 	ret = mpc8xxx_spi_probe(dev, mem, irq);
610 	if (ret)
611 		goto err_probe;
612 
613 	master->setup = fsl_espi_setup;
614 
615 	mpc8xxx_spi = spi_master_get_devdata(master);
616 	mpc8xxx_spi->spi_do_one_msg = fsl_espi_do_one_msg;
617 	mpc8xxx_spi->spi_remove = fsl_espi_remove;
618 
619 	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
620 	if (!mpc8xxx_spi->reg_base) {
621 		ret = -ENOMEM;
622 		goto err_probe;
623 	}
624 
625 	reg_base = mpc8xxx_spi->reg_base;
626 
627 	/* Register for SPI Interrupt */
628 	ret = request_irq(mpc8xxx_spi->irq, fsl_espi_irq,
629 			  0, "fsl_espi", mpc8xxx_spi);
630 	if (ret)
631 		goto free_irq;
632 
633 	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
634 		mpc8xxx_spi->rx_shift = 16;
635 		mpc8xxx_spi->tx_shift = 24;
636 	}
637 
638 	/* SPI controller initializations */
639 	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
640 	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
641 	mpc8xxx_spi_write_reg(&reg_base->command, 0);
642 	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);
643 
644 	/* Init eSPI CS mode register */
645 	for (i = 0; i < pdata->max_chipselect; i++)
646 		mpc8xxx_spi_write_reg(&reg_base->csmode[i], CSMODE_INIT_VAL);
647 
648 	/* Enable SPI interface */
649 	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
650 
651 	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
652 
653 	ret = spi_register_master(master);
654 	if (ret < 0)
655 		goto unreg_master;
656 
657 	dev_info(dev, "at 0x%p (irq = %d)\n", reg_base, mpc8xxx_spi->irq);
658 
659 	return master;
660 
661 unreg_master:
662 	free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
663 free_irq:
664 	iounmap(mpc8xxx_spi->reg_base);
665 err_probe:
666 	spi_master_put(master);
667 err:
668 	return ERR_PTR(ret);
669 }
670 
671 static int of_fsl_espi_get_chipselects(struct device *dev)
672 {
673 	struct device_node *np = dev->of_node;
674 	struct fsl_spi_platform_data *pdata = dev->platform_data;
675 	const u32 *prop;
676 	int len;
677 
678 	prop = of_get_property(np, "fsl,espi-num-chipselects", &len);
679 	if (!prop || len < sizeof(*prop)) {
680 		dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
681 		return -EINVAL;
682 	}
683 
684 	pdata->max_chipselect = *prop;
685 	pdata->cs_control = NULL;
686 
687 	return 0;
688 }
689 
690 static int __devinit of_fsl_espi_probe(struct platform_device *ofdev)
691 {
692 	struct device *dev = &ofdev->dev;
693 	struct device_node *np = ofdev->dev.of_node;
694 	struct spi_master *master;
695 	struct resource mem;
696 	struct resource irq;
697 	int ret = -ENOMEM;
698 
699 	ret = of_mpc8xxx_spi_probe(ofdev);
700 	if (ret)
701 		return ret;
702 
703 	ret = of_fsl_espi_get_chipselects(dev);
704 	if (ret)
705 		goto err;
706 
707 	ret = of_address_to_resource(np, 0, &mem);
708 	if (ret)
709 		goto err;
710 
711 	ret = of_irq_to_resource(np, 0, &irq);
712 	if (!ret) {
713 		ret = -EINVAL;
714 		goto err;
715 	}
716 
717 	master = fsl_espi_probe(dev, &mem, irq.start);
718 	if (IS_ERR(master)) {
719 		ret = PTR_ERR(master);
720 		goto err;
721 	}
722 
723 	return 0;
724 
725 err:
726 	return ret;
727 }
728 
729 static int __devexit of_fsl_espi_remove(struct platform_device *dev)
730 {
731 	return mpc8xxx_spi_remove(&dev->dev);
732 }
733 
734 static const struct of_device_id of_fsl_espi_match[] = {
735 	{ .compatible = "fsl,mpc8536-espi" },
736 	{}
737 };
738 MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
739 
740 static struct platform_driver fsl_espi_driver = {
741 	.driver = {
742 		.name = "fsl_espi",
743 		.owner = THIS_MODULE,
744 		.of_match_table = of_fsl_espi_match,
745 	},
746 	.probe		= of_fsl_espi_probe,
747 	.remove		= __devexit_p(of_fsl_espi_remove),
748 };
749 module_platform_driver(fsl_espi_driver);
750 
751 MODULE_AUTHOR("Mingkai Hu");
752 MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
753 MODULE_LICENSE("GPL");
754