1 /*
2  * Freescale STMP378X SPI master driver
3  *
4  * Author: dmitry pervushin <dimka@embeddedalley.com>
5  *
6  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
7  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
8  */
9 
10 /*
11  * The code contained herein is licensed under the GNU General Public
12  * License. You may obtain a copy of the GNU General Public License
13  * Version 2 or later at the following locations:
14  *
15  * http://www.opensource.org/licenses/gpl-license.html
16  * http://www.gnu.org/copyleft/gpl.html
17  */
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/platform_device.h>
22 #include <linux/spi/spi.h>
23 #include <linux/err.h>
24 #include <linux/clk.h>
25 #include <linux/io.h>
26 #include <linux/dma-mapping.h>
27 #include <linux/delay.h>
28 
29 #include <mach/platform.h>
30 #include <mach/stmp3xxx.h>
31 #include <mach/dma.h>
32 #include <mach/regs-ssp.h>
33 #include <mach/regs-apbh.h>
34 
35 
36 /* 0 means DMA mode(recommended, default), !0 - PIO mode */
37 static int pio;
38 static int clock;
39 
40 /* default timeout for busy waits is 2 seconds */
41 #define STMP_SPI_TIMEOUT	(2 * HZ)
42 
43 struct stmp_spi {
44 	int		id;
45 
46 	void *  __iomem regs;	/* vaddr of the control registers */
47 
48 	int		irq, err_irq;
49 	u32		dma;
50 	struct stmp3xxx_dma_descriptor d;
51 
52 	u32		speed_khz;
53 	u32		saved_timings;
54 	u32		divider;
55 
56 	struct clk	*clk;
57 	struct device	*master_dev;
58 
59 	struct work_struct work;
60 	struct workqueue_struct *workqueue;
61 
62 	/* lock protects queue access */
63 	spinlock_t lock;
64 	struct list_head queue;
65 
66 	struct completion done;
67 };
68 
69 #define busy_wait(cond)							\
70 	({								\
71 	unsigned long end_jiffies = jiffies + STMP_SPI_TIMEOUT;		\
72 	bool succeeded = false;						\
73 	do {								\
74 		if (cond) {						\
75 			succeeded = true;				\
76 			break;						\
77 		}							\
78 		cpu_relax();						\
79 	} while (time_before(jiffies, end_jiffies));			\
80 	succeeded;							\
81 	})
82 
83 /**
84  * stmp_spi_init_hw
85  * Initialize the SSP port
86  */
stmp_spi_init_hw(struct stmp_spi * ss)87 static int stmp_spi_init_hw(struct stmp_spi *ss)
88 {
89 	int err = 0;
90 	void *pins = ss->master_dev->platform_data;
91 
92 	err = stmp3xxx_request_pin_group(pins, dev_name(ss->master_dev));
93 	if (err)
94 		goto out;
95 
96 	ss->clk = clk_get(NULL, "ssp");
97 	if (IS_ERR(ss->clk)) {
98 		err = PTR_ERR(ss->clk);
99 		goto out_free_pins;
100 	}
101 	clk_enable(ss->clk);
102 
103 	stmp3xxx_reset_block(ss->regs, false);
104 	stmp3xxx_dma_reset_channel(ss->dma);
105 
106 	return 0;
107 
108 out_free_pins:
109 	stmp3xxx_release_pin_group(pins, dev_name(ss->master_dev));
110 out:
111 	return err;
112 }
113 
stmp_spi_release_hw(struct stmp_spi * ss)114 static void stmp_spi_release_hw(struct stmp_spi *ss)
115 {
116 	void *pins = ss->master_dev->platform_data;
117 
118 	if (ss->clk && !IS_ERR(ss->clk)) {
119 		clk_disable(ss->clk);
120 		clk_put(ss->clk);
121 	}
122 	stmp3xxx_release_pin_group(pins, dev_name(ss->master_dev));
123 }
124 
stmp_spi_setup_transfer(struct spi_device * spi,struct spi_transfer * t)125 static int stmp_spi_setup_transfer(struct spi_device *spi,
126 		struct spi_transfer *t)
127 {
128 	u8 bits_per_word;
129 	u32 hz;
130 	struct stmp_spi *ss = spi_master_get_devdata(spi->master);
131 	u16 rate;
132 
133 	bits_per_word = spi->bits_per_word;
134 	if (t && t->bits_per_word)
135 		bits_per_word = t->bits_per_word;
136 
137 	/*
138 	 * Calculate speed:
139 	 *	- by default, use maximum speed from ssp clk
140 	 *	- if device overrides it, use it
141 	 *	- if transfer specifies other speed, use transfer's one
142 	 */
143 	hz = 1000 * ss->speed_khz / ss->divider;
144 	if (spi->max_speed_hz)
145 		hz = min(hz, spi->max_speed_hz);
146 	if (t && t->speed_hz)
147 		hz = min(hz, t->speed_hz);
148 
149 	if (hz == 0) {
150 		dev_err(&spi->dev, "Cannot continue with zero clock\n");
151 		return -EINVAL;
152 	}
153 
154 	if (bits_per_word != 8) {
155 		dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
156 			__func__, bits_per_word);
157 		return -EINVAL;
158 	}
159 
160 	dev_dbg(&spi->dev, "Requested clk rate = %uHz, max = %uHz/%d = %uHz\n",
161 		hz, ss->speed_khz, ss->divider,
162 		ss->speed_khz * 1000 / ss->divider);
163 
164 	if (ss->speed_khz * 1000 / ss->divider < hz) {
165 		dev_err(&spi->dev, "%s, unsupported clock rate %uHz\n",
166 			__func__, hz);
167 		return -EINVAL;
168 	}
169 
170 	rate = 1000 * ss->speed_khz/ss->divider/hz;
171 
172 	writel(BF(ss->divider, SSP_TIMING_CLOCK_DIVIDE)		|
173 	       BF(rate - 1, SSP_TIMING_CLOCK_RATE),
174 	       HW_SSP_TIMING + ss->regs);
175 
176 	writel(BF(1 /* mode SPI */, SSP_CTRL1_SSP_MODE)		|
177 	       BF(4 /* 8 bits   */, SSP_CTRL1_WORD_LENGTH)	|
178 	       ((spi->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) |
179 	       ((spi->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0) |
180 	       (pio ? 0 : BM_SSP_CTRL1_DMA_ENABLE),
181 	       ss->regs + HW_SSP_CTRL1);
182 
183 	return 0;
184 }
185 
stmp_spi_setup(struct spi_device * spi)186 static int stmp_spi_setup(struct spi_device *spi)
187 {
188 	/* spi_setup() does basic checks,
189 	 * stmp_spi_setup_transfer() does more later
190 	 */
191 	if (spi->bits_per_word != 8) {
192 		dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
193 			__func__, spi->bits_per_word);
194 		return -EINVAL;
195 	}
196 	return 0;
197 }
198 
stmp_spi_cs(unsigned cs)199 static inline u32 stmp_spi_cs(unsigned cs)
200 {
201 	return  ((cs & 1) ? BM_SSP_CTRL0_WAIT_FOR_CMD : 0) |
202 		((cs & 2) ? BM_SSP_CTRL0_WAIT_FOR_IRQ : 0);
203 }
204 
stmp_spi_txrx_dma(struct stmp_spi * ss,int cs,unsigned char * buf,dma_addr_t dma_buf,int len,int first,int last,bool write)205 static int stmp_spi_txrx_dma(struct stmp_spi *ss, int cs,
206 		unsigned char *buf, dma_addr_t dma_buf, int len,
207 		int first, int last, bool write)
208 {
209 	u32 c0 = 0;
210 	dma_addr_t spi_buf_dma = dma_buf;
211 	int status = 0;
212 	enum dma_data_direction dir = write ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
213 
214 	c0 |= (first ? BM_SSP_CTRL0_LOCK_CS : 0);
215 	c0 |= (last ? BM_SSP_CTRL0_IGNORE_CRC : 0);
216 	c0 |= (write ? 0 : BM_SSP_CTRL0_READ);
217 	c0 |= BM_SSP_CTRL0_DATA_XFER;
218 
219 	c0 |= stmp_spi_cs(cs);
220 
221 	c0 |= BF(len, SSP_CTRL0_XFER_COUNT);
222 
223 	if (!dma_buf)
224 		spi_buf_dma = dma_map_single(ss->master_dev, buf, len, dir);
225 
226 	ss->d.command->cmd =
227 		BF(len, APBH_CHn_CMD_XFER_COUNT)	|
228 		BF(1, APBH_CHn_CMD_CMDWORDS)		|
229 		BM_APBH_CHn_CMD_WAIT4ENDCMD		|
230 		BM_APBH_CHn_CMD_IRQONCMPLT		|
231 		BF(write ? BV_APBH_CHn_CMD_COMMAND__DMA_READ :
232 			   BV_APBH_CHn_CMD_COMMAND__DMA_WRITE,
233 		   APBH_CHn_CMD_COMMAND);
234 	ss->d.command->pio_words[0] = c0;
235 	ss->d.command->buf_ptr = spi_buf_dma;
236 
237 	stmp3xxx_dma_reset_channel(ss->dma);
238 	stmp3xxx_dma_clear_interrupt(ss->dma);
239 	stmp3xxx_dma_enable_interrupt(ss->dma);
240 	init_completion(&ss->done);
241 	stmp3xxx_dma_go(ss->dma, &ss->d, 1);
242 	wait_for_completion(&ss->done);
243 
244 	if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN))
245 		status = -ETIMEDOUT;
246 
247 	if (!dma_buf)
248 		dma_unmap_single(ss->master_dev, spi_buf_dma, len, dir);
249 
250 	return status;
251 }
252 
stmp_spi_enable(struct stmp_spi * ss)253 static inline void stmp_spi_enable(struct stmp_spi *ss)
254 {
255 	stmp3xxx_setl(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0);
256 	stmp3xxx_clearl(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0);
257 }
258 
stmp_spi_disable(struct stmp_spi * ss)259 static inline void stmp_spi_disable(struct stmp_spi *ss)
260 {
261 	stmp3xxx_clearl(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0);
262 	stmp3xxx_setl(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0);
263 }
264 
stmp_spi_txrx_pio(struct stmp_spi * ss,int cs,unsigned char * buf,int len,bool first,bool last,bool write)265 static int stmp_spi_txrx_pio(struct stmp_spi *ss, int cs,
266 		unsigned char *buf, int len,
267 		bool first, bool last, bool write)
268 {
269 	if (first)
270 		stmp_spi_enable(ss);
271 
272 	stmp3xxx_setl(stmp_spi_cs(cs), ss->regs + HW_SSP_CTRL0);
273 
274 	while (len--) {
275 		if (last && len <= 0)
276 			stmp_spi_disable(ss);
277 
278 		stmp3xxx_clearl(BM_SSP_CTRL0_XFER_COUNT,
279 				ss->regs + HW_SSP_CTRL0);
280 		stmp3xxx_setl(1, ss->regs + HW_SSP_CTRL0);
281 
282 		if (write)
283 			stmp3xxx_clearl(BM_SSP_CTRL0_READ,
284 					ss->regs + HW_SSP_CTRL0);
285 		else
286 			stmp3xxx_setl(BM_SSP_CTRL0_READ,
287 					ss->regs + HW_SSP_CTRL0);
288 
289 		/* Run! */
290 		stmp3xxx_setl(BM_SSP_CTRL0_RUN, ss->regs + HW_SSP_CTRL0);
291 
292 		if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) &
293 				BM_SSP_CTRL0_RUN))
294 			break;
295 
296 		if (write)
297 			writel(*buf, ss->regs + HW_SSP_DATA);
298 
299 		/* Set TRANSFER */
300 		stmp3xxx_setl(BM_SSP_CTRL0_DATA_XFER, ss->regs + HW_SSP_CTRL0);
301 
302 		if (!write) {
303 			if (busy_wait((readl(ss->regs + HW_SSP_STATUS) &
304 					BM_SSP_STATUS_FIFO_EMPTY)))
305 				break;
306 			*buf = readl(ss->regs + HW_SSP_DATA) & 0xFF;
307 		}
308 
309 		if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) &
310 					BM_SSP_CTRL0_RUN))
311 			break;
312 
313 		/* advance to the next byte */
314 		buf++;
315 	}
316 
317 	return len < 0 ? 0 : -ETIMEDOUT;
318 }
319 
stmp_spi_handle_message(struct stmp_spi * ss,struct spi_message * m)320 static int stmp_spi_handle_message(struct stmp_spi *ss, struct spi_message *m)
321 {
322 	bool first, last;
323 	struct spi_transfer *t, *tmp_t;
324 	int status = 0;
325 	int cs;
326 
327 	cs = m->spi->chip_select;
328 
329 	list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) {
330 
331 		first = (&t->transfer_list == m->transfers.next);
332 		last = (&t->transfer_list == m->transfers.prev);
333 
334 		if (first || t->speed_hz || t->bits_per_word)
335 			stmp_spi_setup_transfer(m->spi, t);
336 
337 		/* reject "not last" transfers which request to change cs */
338 		if (t->cs_change && !last) {
339 			dev_err(&m->spi->dev,
340 				"Message with t->cs_change has been skipped\n");
341 			continue;
342 		}
343 
344 		if (t->tx_buf) {
345 			status = pio ?
346 			   stmp_spi_txrx_pio(ss, cs, (void *)t->tx_buf,
347 				   t->len, first, last, true) :
348 			   stmp_spi_txrx_dma(ss, cs, (void *)t->tx_buf,
349 				   t->tx_dma, t->len, first, last, true);
350 #ifdef DEBUG
351 			if (t->len < 0x10)
352 				print_hex_dump_bytes("Tx ",
353 					DUMP_PREFIX_OFFSET,
354 					t->tx_buf, t->len);
355 			else
356 				pr_debug("Tx: %d bytes\n", t->len);
357 #endif
358 		}
359 		if (t->rx_buf) {
360 			status = pio ?
361 			   stmp_spi_txrx_pio(ss, cs, t->rx_buf,
362 				   t->len, first, last, false) :
363 			   stmp_spi_txrx_dma(ss, cs, t->rx_buf,
364 				   t->rx_dma, t->len, first, last, false);
365 #ifdef DEBUG
366 			if (t->len < 0x10)
367 				print_hex_dump_bytes("Rx ",
368 					DUMP_PREFIX_OFFSET,
369 					t->rx_buf, t->len);
370 			else
371 				pr_debug("Rx: %d bytes\n", t->len);
372 #endif
373 		}
374 
375 		if (t->delay_usecs)
376 			udelay(t->delay_usecs);
377 
378 		if (status)
379 			break;
380 
381 	}
382 	return status;
383 }
384 
385 /**
386  * stmp_spi_handle - handle messages from the queue
387  */
stmp_spi_handle(struct work_struct * w)388 static void stmp_spi_handle(struct work_struct *w)
389 {
390 	struct stmp_spi *ss = container_of(w, struct stmp_spi, work);
391 	unsigned long flags;
392 	struct spi_message *m;
393 
394 	spin_lock_irqsave(&ss->lock, flags);
395 	while (!list_empty(&ss->queue)) {
396 		m = list_entry(ss->queue.next, struct spi_message, queue);
397 		list_del_init(&m->queue);
398 		spin_unlock_irqrestore(&ss->lock, flags);
399 
400 		m->status = stmp_spi_handle_message(ss, m);
401 		m->complete(m->context);
402 
403 		spin_lock_irqsave(&ss->lock, flags);
404 	}
405 	spin_unlock_irqrestore(&ss->lock, flags);
406 
407 	return;
408 }
409 
410 /**
411  * stmp_spi_transfer - perform message transfer.
412  * Called indirectly from spi_async, queues all the messages to
413  * spi_handle_message.
414  * @spi: spi device
415  * @m: message to be queued
416  */
stmp_spi_transfer(struct spi_device * spi,struct spi_message * m)417 static int stmp_spi_transfer(struct spi_device *spi, struct spi_message *m)
418 {
419 	struct stmp_spi *ss = spi_master_get_devdata(spi->master);
420 	unsigned long flags;
421 
422 	m->status = -EINPROGRESS;
423 	spin_lock_irqsave(&ss->lock, flags);
424 	list_add_tail(&m->queue, &ss->queue);
425 	queue_work(ss->workqueue, &ss->work);
426 	spin_unlock_irqrestore(&ss->lock, flags);
427 	return 0;
428 }
429 
stmp_spi_irq(int irq,void * dev_id)430 static irqreturn_t stmp_spi_irq(int irq, void *dev_id)
431 {
432 	struct stmp_spi *ss = dev_id;
433 
434 	stmp3xxx_dma_clear_interrupt(ss->dma);
435 	complete(&ss->done);
436 	return IRQ_HANDLED;
437 }
438 
stmp_spi_irq_err(int irq,void * dev_id)439 static irqreturn_t stmp_spi_irq_err(int irq, void *dev_id)
440 {
441 	struct stmp_spi *ss = dev_id;
442 	u32 c1, st;
443 
444 	c1 = readl(ss->regs + HW_SSP_CTRL1);
445 	st = readl(ss->regs + HW_SSP_STATUS);
446 	dev_err(ss->master_dev, "%s: status = 0x%08X, c1 = 0x%08X\n",
447 		__func__, st, c1);
448 	stmp3xxx_clearl(c1 & 0xCCCC0000, ss->regs + HW_SSP_CTRL1);
449 
450 	return IRQ_HANDLED;
451 }
452 
stmp_spi_probe(struct platform_device * dev)453 static int __devinit stmp_spi_probe(struct platform_device *dev)
454 {
455 	int err = 0;
456 	struct spi_master *master;
457 	struct stmp_spi *ss;
458 	struct resource *r;
459 
460 	master = spi_alloc_master(&dev->dev, sizeof(struct stmp_spi));
461 	if (master == NULL) {
462 		err = -ENOMEM;
463 		goto out0;
464 	}
465 	master->flags = SPI_MASTER_HALF_DUPLEX;
466 
467 	ss = spi_master_get_devdata(master);
468 	platform_set_drvdata(dev, master);
469 
470 	/* Get resources(memory, IRQ) associated with the device */
471 	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
472 	if (r == NULL) {
473 		err = -ENODEV;
474 		goto out_put_master;
475 	}
476 	ss->regs = ioremap(r->start, resource_size(r));
477 	if (!ss->regs) {
478 		err = -EINVAL;
479 		goto out_put_master;
480 	}
481 
482 	ss->master_dev = &dev->dev;
483 	ss->id = dev->id;
484 
485 	INIT_WORK(&ss->work, stmp_spi_handle);
486 	INIT_LIST_HEAD(&ss->queue);
487 	spin_lock_init(&ss->lock);
488 
489 	ss->workqueue = create_singlethread_workqueue(dev_name(&dev->dev));
490 	if (!ss->workqueue) {
491 		err = -ENXIO;
492 		goto out_put_master;
493 	}
494 	master->transfer = stmp_spi_transfer;
495 	master->setup = stmp_spi_setup;
496 
497 	/* the spi->mode bits understood by this driver: */
498 	master->mode_bits = SPI_CPOL | SPI_CPHA;
499 
500 	ss->irq = platform_get_irq(dev, 0);
501 	if (ss->irq < 0) {
502 		err = ss->irq;
503 		goto out_put_master;
504 	}
505 	ss->err_irq = platform_get_irq(dev, 1);
506 	if (ss->err_irq < 0) {
507 		err = ss->err_irq;
508 		goto out_put_master;
509 	}
510 
511 	r = platform_get_resource(dev, IORESOURCE_DMA, 0);
512 	if (r == NULL) {
513 		err = -ENODEV;
514 		goto out_put_master;
515 	}
516 
517 	ss->dma = r->start;
518 	err = stmp3xxx_dma_request(ss->dma, &dev->dev, dev_name(&dev->dev));
519 	if (err)
520 		goto out_put_master;
521 
522 	err = stmp3xxx_dma_allocate_command(ss->dma, &ss->d);
523 	if (err)
524 		goto out_free_dma;
525 
526 	master->bus_num = dev->id;
527 	master->num_chipselect = 1;
528 
529 	/* SPI controller initializations */
530 	err = stmp_spi_init_hw(ss);
531 	if (err) {
532 		dev_dbg(&dev->dev, "cannot initialize hardware\n");
533 		goto out_free_dma_desc;
534 	}
535 
536 	if (clock) {
537 		dev_info(&dev->dev, "clock rate forced to %d\n", clock);
538 		clk_set_rate(ss->clk, clock);
539 	}
540 	ss->speed_khz = clk_get_rate(ss->clk);
541 	ss->divider = 2;
542 	dev_info(&dev->dev, "max possible speed %d = %ld/%d kHz\n",
543 		ss->speed_khz, clk_get_rate(ss->clk), ss->divider);
544 
545 	/* Register for SPI interrupt */
546 	err = request_irq(ss->irq, stmp_spi_irq, 0,
547 			  dev_name(&dev->dev), ss);
548 	if (err) {
549 		dev_dbg(&dev->dev, "request_irq failed, %d\n", err);
550 		goto out_release_hw;
551 	}
552 
553 	/* ..and shared interrupt for all SSP controllers */
554 	err = request_irq(ss->err_irq, stmp_spi_irq_err, IRQF_SHARED,
555 			  dev_name(&dev->dev), ss);
556 	if (err) {
557 		dev_dbg(&dev->dev, "request_irq(error) failed, %d\n", err);
558 		goto out_free_irq;
559 	}
560 
561 	err = spi_register_master(master);
562 	if (err) {
563 		dev_dbg(&dev->dev, "cannot register spi master, %d\n", err);
564 		goto out_free_irq_2;
565 	}
566 	dev_info(&dev->dev, "at (mapped) 0x%08X, irq=%d, bus %d, %s mode\n",
567 			(u32)ss->regs, ss->irq, master->bus_num,
568 			pio ? "PIO" : "DMA");
569 	return 0;
570 
571 out_free_irq_2:
572 	free_irq(ss->err_irq, ss);
573 out_free_irq:
574 	free_irq(ss->irq, ss);
575 out_free_dma_desc:
576 	stmp3xxx_dma_free_command(ss->dma, &ss->d);
577 out_free_dma:
578 	stmp3xxx_dma_release(ss->dma);
579 out_release_hw:
580 	stmp_spi_release_hw(ss);
581 out_put_master:
582 	if (ss->workqueue)
583 		destroy_workqueue(ss->workqueue);
584 	if (ss->regs)
585 		iounmap(ss->regs);
586 	platform_set_drvdata(dev, NULL);
587 	spi_master_put(master);
588 out0:
589 	return err;
590 }
591 
stmp_spi_remove(struct platform_device * dev)592 static int __devexit stmp_spi_remove(struct platform_device *dev)
593 {
594 	struct stmp_spi *ss;
595 	struct spi_master *master;
596 
597 	master = platform_get_drvdata(dev);
598 	if (master == NULL)
599 		goto out0;
600 	ss = spi_master_get_devdata(master);
601 
602 	spi_unregister_master(master);
603 
604 	free_irq(ss->err_irq, ss);
605 	free_irq(ss->irq, ss);
606 	stmp3xxx_dma_free_command(ss->dma, &ss->d);
607 	stmp3xxx_dma_release(ss->dma);
608 	stmp_spi_release_hw(ss);
609 	destroy_workqueue(ss->workqueue);
610 	iounmap(ss->regs);
611 	spi_master_put(master);
612 	platform_set_drvdata(dev, NULL);
613 out0:
614 	return 0;
615 }
616 
617 #ifdef CONFIG_PM
stmp_spi_suspend(struct platform_device * pdev,pm_message_t pmsg)618 static int stmp_spi_suspend(struct platform_device *pdev, pm_message_t pmsg)
619 {
620 	struct stmp_spi *ss;
621 	struct spi_master *master;
622 
623 	master = platform_get_drvdata(pdev);
624 	ss = spi_master_get_devdata(master);
625 
626 	ss->saved_timings = readl(HW_SSP_TIMING + ss->regs);
627 	clk_disable(ss->clk);
628 
629 	return 0;
630 }
631 
stmp_spi_resume(struct platform_device * pdev)632 static int stmp_spi_resume(struct platform_device *pdev)
633 {
634 	struct stmp_spi *ss;
635 	struct spi_master *master;
636 
637 	master = platform_get_drvdata(pdev);
638 	ss = spi_master_get_devdata(master);
639 
640 	clk_enable(ss->clk);
641 	stmp3xxx_reset_block(ss->regs, false);
642 	writel(ss->saved_timings, ss->regs + HW_SSP_TIMING);
643 
644 	return 0;
645 }
646 
647 #else
648 #define stmp_spi_suspend NULL
649 #define stmp_spi_resume  NULL
650 #endif
651 
652 static struct platform_driver stmp_spi_driver = {
653 	.probe	= stmp_spi_probe,
654 	.remove	= __devexit_p(stmp_spi_remove),
655 	.driver = {
656 		.name = "stmp3xxx_ssp",
657 		.owner = THIS_MODULE,
658 	},
659 	.suspend = stmp_spi_suspend,
660 	.resume  = stmp_spi_resume,
661 };
662 module_platform_driver(stmp_spi_driver);
663 
664 module_param(pio, int, S_IRUGO);
665 module_param(clock, int, S_IRUGO);
666 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com>");
667 MODULE_DESCRIPTION("STMP3xxx SPI/SSP driver");
668 MODULE_LICENSE("GPL");
669