summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi-omap-100k.c
blob: 78d29a18dcc4e8de8f3b329fd899baed160c9060 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
/*
 * OMAP7xx SPI 100k controller driver
 * Author: Fabrice Crohas <fcrohas@gmail.com>
 * from original omap1_mcspi driver
 *
 * Copyright (C) 2005, 2006 Nokia Corporation
 * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
 *              Juha Yrj�l� <juha.yrjola@nokia.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/slab.h>

#include <linux/spi/spi.h>

#define OMAP1_SPI100K_MAX_FREQ          48000000

#define ICR_SPITAS      (OMAP7XX_ICR_BASE + 0x12)

#define SPI_SETUP1      0x00
#define SPI_SETUP2      0x02
#define SPI_CTRL        0x04
#define SPI_STATUS      0x06
#define SPI_TX_LSB      0x08
#define SPI_TX_MSB      0x0a
#define SPI_RX_LSB      0x0c
#define SPI_RX_MSB      0x0e

#define SPI_SETUP1_INT_READ_ENABLE      (1UL << 5)
#define SPI_SETUP1_INT_WRITE_ENABLE     (1UL << 4)
#define SPI_SETUP1_CLOCK_DIVISOR(x)     ((x) << 1)
#define SPI_SETUP1_CLOCK_ENABLE         (1UL << 0)

#define SPI_SETUP2_ACTIVE_EDGE_FALLING  (0UL << 0)
#define SPI_SETUP2_ACTIVE_EDGE_RISING   (1UL << 0)
#define SPI_SETUP2_NEGATIVE_LEVEL       (0UL << 5)
#define SPI_SETUP2_POSITIVE_LEVEL       (1UL << 5)
#define SPI_SETUP2_LEVEL_TRIGGER        (0UL << 10)
#define SPI_SETUP2_EDGE_TRIGGER         (1UL << 10)

#define SPI_CTRL_SEN(x)                 ((x) << 7)
#define SPI_CTRL_WORD_SIZE(x)           (((x) - 1) << 2)
#define SPI_CTRL_WR                     (1UL << 1)
#define SPI_CTRL_RD                     (1UL << 0)

#define SPI_STATUS_WE                   (1UL << 1)
#define SPI_STATUS_RD                   (1UL << 0)

#define WRITE 0
#define READ  1


/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
 * cache operations; better heuristics consider wordsize and bitrate.
 */
#define DMA_MIN_BYTES                   8

#define SPI_RUNNING	0
#define SPI_SHUTDOWN	1

struct omap1_spi100k {
	struct work_struct      work;

	/* lock protects queue and registers */
	spinlock_t              lock;
	struct list_head        msg_queue;
	struct spi_master       *master;
	struct clk              *ick;
	struct clk              *fck;

	/* Virtual base address of the controller */
	void __iomem            *base;

	/* State of the SPI */
	unsigned int		state;
};

struct omap1_spi100k_cs {
	void __iomem            *base;
	int                     word_len;
};

static struct workqueue_struct *omap1_spi100k_wq;

#define MOD_REG_BIT(val, mask, set) do { \
	if (set) \
		val |= mask; \
	else \
		val &= ~mask; \
} while (0)

static void spi100k_enable_clock(struct spi_master *master)
{
	unsigned int val;
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* enable SPI */
	val = readw(spi100k->base + SPI_SETUP1);
	val |= SPI_SETUP1_CLOCK_ENABLE;
	writew(val, spi100k->base + SPI_SETUP1);
}

static void spi100k_disable_clock(struct spi_master *master)
{
	unsigned int val;
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* disable SPI */
	val = readw(spi100k->base + SPI_SETUP1);
	val &= ~SPI_SETUP1_CLOCK_ENABLE;
	writew(val, spi100k->base + SPI_SETUP1);
}

static void spi100k_write_data(struct spi_master *master, int len, int data)
{
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* write 16-bit word, shifting 8-bit data if necessary */
	if (len <= 8) {
		data <<= 8;
		len = 16;
	}

	spi100k_enable_clock(master);
	writew( data , spi100k->base + SPI_TX_MSB);

	writew(SPI_CTRL_SEN(0) |
	       SPI_CTRL_WORD_SIZE(len) |
	       SPI_CTRL_WR,
	       spi100k->base + SPI_CTRL);

	/* Wait for bit ack send change */
	while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE);
	udelay(1000);

	spi100k_disable_clock(master);
}

static int spi100k_read_data(struct spi_master *master, int len)
{
	int dataH,dataL;
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* Always do at least 16 bits */
	if (len <= 8)
		len = 16;

	spi100k_enable_clock(master);
	writew(SPI_CTRL_SEN(0) |
	       SPI_CTRL_WORD_SIZE(len) |
	       SPI_CTRL_RD,
	       spi100k->base + SPI_CTRL);

	while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD);
	udelay(1000);

	dataL = readw(spi100k->base + SPI_RX_LSB);
	dataH = readw(spi100k->base + SPI_RX_MSB);
	spi100k_disable_clock(master);

	return dataL;
}

static void spi100k_open(struct spi_master *master)
{
	/* get control of SPI */
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	writew(SPI_SETUP1_INT_READ_ENABLE |
	       SPI_SETUP1_INT_WRITE_ENABLE |
	       SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);

	/* configure clock and interrupts */
	writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
	       SPI_SETUP2_NEGATIVE_LEVEL |
	       SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
}

static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
{
	if (enable)
		writew(0x05fc, spi100k->base + SPI_CTRL);
	else
		writew(0x05fd, spi100k->base + SPI_CTRL);
}

static unsigned
omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
{
	struct omap1_spi100k    *spi100k;
	struct omap1_spi100k_cs *cs = spi->controller_state;
	unsigned int            count, c;
	int                     word_len;

	spi100k = spi_master_get_devdata(spi->master);
	count = xfer->len;
	c = count;
	word_len = cs->word_len;

	if (word_len <= 8) {
		u8              *rx;
		const u8        *tx;

		rx = xfer->rx_buf;
		tx = xfer->tx_buf;
		do {
			c-=1;
			if (xfer->tx_buf != NULL)
				spi100k_write_data(spi->master, word_len, *tx++);
			if (xfer->rx_buf != NULL)
				*rx++ = spi100k_read_data(spi->master, word_len);
		} while(c);
	} else if (word_len <= 16) {
		u16             *rx;
		const u16       *tx;

		rx = xfer->rx_buf;
		tx = xfer->tx_buf;
		do {
			c-=2;
			if (xfer->tx_buf != NULL)
				spi100k_write_data(spi->master,word_len, *tx++);
			if (xfer->rx_buf != NULL)
				*rx++ = spi100k_read_data(spi->master,word_len);
		} while(c);
	} else if (word_len <= 32) {
		u32             *rx;
		const u32       *tx;

		rx = xfer->rx_buf;
		tx = xfer->tx_buf;
		do {
			c-=4;
			if (xfer->tx_buf != NULL)
				spi100k_write_data(spi->master,word_len, *tx);
			if (xfer->rx_buf != NULL)
				*rx = spi100k_read_data(spi->master,word_len);
		} while(c);
	}
	return count - c;
}

/* called only when no transfer is active to this device */
static int omap1_spi100k_setup_transfer(struct spi_device *spi,
		struct spi_transfer *t)
{
	struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
	struct omap1_spi100k_cs *cs = spi->controller_state;
	u8 word_len = spi->bits_per_word;

	if (t != NULL && t->bits_per_word)
		word_len = t->bits_per_word;
	if (!word_len)
		word_len = 8;

	if (spi->bits_per_word > 32)
		return -EINVAL;
	cs->word_len = word_len;

	/* SPI init before transfer */
	writew(0x3e , spi100k->base + SPI_SETUP1);
	writew(0x00 , spi100k->base + SPI_STATUS);
	writew(0x3e , spi100k->base + SPI_CTRL);

	return 0;
}

/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)

static int omap1_spi100k_setup(struct spi_device *spi)
{
	int                     ret;
	struct omap1_spi100k    *spi100k;
	struct omap1_spi100k_cs *cs = spi->controller_state;

	if (spi->bits_per_word < 4 || spi->bits_per_word > 32) {
		 dev_dbg(&spi->dev, "setup: unsupported %d bit words\n",
			spi->bits_per_word);
		 return -EINVAL;
	}

	spi100k = spi_master_get_devdata(spi->master);

	if (!cs) {
		cs = kzalloc(sizeof *cs, GFP_KERNEL);
		if (!cs)
			return -ENOMEM;
		cs->base = spi100k->base + spi->chip_select * 0x14;
		spi->controller_state = cs;
	}

	spi100k_open(spi->master);

	clk_enable(spi100k->ick);
	clk_enable(spi100k->fck);

	ret = omap1_spi100k_setup_transfer(spi, NULL);

	clk_disable(spi100k->ick);
	clk_disable(spi100k->fck);

	return ret;
}

static void omap1_spi100k_work(struct work_struct *work)
{
	struct omap1_spi100k    *spi100k;
	int status = 0;

	spi100k = container_of(work, struct omap1_spi100k, work);
	spin_lock_irq(&spi100k->lock);

	clk_enable(spi100k->ick);
	clk_enable(spi100k->fck);

	/* We only enable one channel at a time -- the one whose message is
	 * at the head of the queue -- although this controller would gladly
	 * arbitrate among multiple channels.  This corresponds to "single
	 * channel" master mode.  As a side effect, we need to manage the
	 * chipselect with the FORCE bit ... CS != channel enable.
	 */
	 while (!list_empty(&spi100k->msg_queue)) {
		struct spi_message              *m;
		struct spi_device               *spi;
		struct spi_transfer             *t = NULL;
		int                             cs_active = 0;
		struct omap1_spi100k_cs         *cs;
		int                             par_override = 0;

		m = container_of(spi100k->msg_queue.next, struct spi_message,
				 queue);

		list_del_init(&m->queue);
		spin_unlock_irq(&spi100k->lock);

		spi = m->spi;
		cs = spi->controller_state;

		list_for_each_entry(t, &m->transfers, transfer_list) {
			if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
				status = -EINVAL;
				break;
			}
			if (par_override || t->speed_hz || t->bits_per_word) {
				par_override = 1;
				status = omap1_spi100k_setup_transfer(spi, t);
				if (status < 0)
					break;
				if (!t->speed_hz && !t->bits_per_word)
					par_override = 0;
			}

			if (!cs_active) {
				omap1_spi100k_force_cs(spi100k, 1);
				cs_active = 1;
			}

			if (t->len) {
				unsigned count;

				count = omap1_spi100k_txrx_pio(spi, t);
				m->actual_length += count;

				if (count != t->len) {
					status = -EIO;
					break;
				}
			}

			if (t->delay_usecs)
				udelay(t->delay_usecs);

			/* ignore the "leave it on after last xfer" hint */

			if (t->cs_change) {
				omap1_spi100k_force_cs(spi100k, 0);
				cs_active = 0;
			}
		}

		/* Restore defaults if they were overriden */
		if (par_override) {
			par_override = 0;
			status = omap1_spi100k_setup_transfer(spi, NULL);
		}

		if (cs_active)
			omap1_spi100k_force_cs(spi100k, 0);

		m->status = status;
		m->complete(m->context);

		spin_lock_irq(&spi100k->lock);
	}

	clk_disable(spi100k->ick);
	clk_disable(spi100k->fck);
	spin_unlock_irq(&spi100k->lock);

	if (status < 0)
		printk(KERN_WARNING "spi transfer failed with %d\n", status);
}

static int omap1_spi100k_transfer(struct spi_device *spi, struct spi_message *m)
{
	struct omap1_spi100k    *spi100k;
	unsigned long           flags;
	struct spi_transfer     *t;

	m->actual_length = 0;
	m->status = -EINPROGRESS;

	spi100k = spi_master_get_devdata(spi->master);

	/* Don't accept new work if we're shutting down */
	if (spi100k->state == SPI_SHUTDOWN)
		return -ESHUTDOWN;

	/* reject invalid messages and transfers */
	if (list_empty(&m->transfers) || !m->complete)
		return -EINVAL;

	list_for_each_entry(t, &m->transfers, transfer_list) {
		const void      *tx_buf = t->tx_buf;
		void            *rx_buf = t->rx_buf;
		unsigned        len = t->len;

		if (t->speed_hz > OMAP1_SPI100K_MAX_FREQ
				|| (len && !(rx_buf || tx_buf))
				|| (t->bits_per_word &&
					(  t->bits_per_word < 4
					|| t->bits_per_word > 32))) {
			dev_dbg(&spi->dev, "transfer: %d Hz, %d %s%s, %d bpw\n",
					t->speed_hz,
					len,
					tx_buf ? "tx" : "",
					rx_buf ? "rx" : "",
					t->bits_per_word);
			return -EINVAL;
		}

		if (t->speed_hz && t->speed_hz < OMAP1_SPI100K_MAX_FREQ/(1<<16)) {
			dev_dbg(&spi->dev, "%d Hz max exceeds %d\n",
					t->speed_hz,
					OMAP1_SPI100K_MAX_FREQ/(1<<16));
			return -EINVAL;
		}

	}

	spin_lock_irqsave(&spi100k->lock, flags);
	list_add_tail(&m->queue, &spi100k->msg_queue);
	queue_work(omap1_spi100k_wq, &spi100k->work);
	spin_unlock_irqrestore(&spi100k->lock, flags);

	return 0;
}

static int omap1_spi100k_reset(struct omap1_spi100k *spi100k)
{
	return 0;
}

static int omap1_spi100k_probe(struct platform_device *pdev)
{
	struct spi_master       *master;
	struct omap1_spi100k    *spi100k;
	int                     status = 0;

	if (!pdev->id)
		return -EINVAL;

	master = spi_alloc_master(&pdev->dev, sizeof *spi100k);
	if (master == NULL) {
		dev_dbg(&pdev->dev, "master allocation failed\n");
		return -ENOMEM;
	}

	if (pdev->id != -1)
	       master->bus_num = pdev->id;

	master->setup = omap1_spi100k_setup;
	master->transfer = omap1_spi100k_transfer;
	master->cleanup = NULL;
	master->num_chipselect = 2;
	master->mode_bits = MODEBITS;

	dev_set_drvdata(&pdev->dev, master);

	spi100k = spi_master_get_devdata(master);
	spi100k->master = master;

	/*
	 * The memory region base address is taken as the platform_data.
	 * You should allocate this with ioremap() before initializing
	 * the SPI.
	 */
	spi100k->base = (void __iomem *) pdev->dev.platform_data;

	INIT_WORK(&spi100k->work, omap1_spi100k_work);

	spin_lock_init(&spi100k->lock);
	INIT_LIST_HEAD(&spi100k->msg_queue);
	spi100k->ick = clk_get(&pdev->dev, "ick");
	if (IS_ERR(spi100k->ick)) {
		dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
		status = PTR_ERR(spi100k->ick);
		goto err1;
	}

	spi100k->fck = clk_get(&pdev->dev, "fck");
	if (IS_ERR(spi100k->fck)) {
		dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
		status = PTR_ERR(spi100k->fck);
		goto err2;
	}

	if (omap1_spi100k_reset(spi100k) < 0)
		goto err3;

	status = spi_register_master(master);
	if (status < 0)
		goto err3;

	spi100k->state = SPI_RUNNING;

	return status;

err3:
	clk_put(spi100k->fck);
err2:
	clk_put(spi100k->ick);
err1:
	spi_master_put(master);
	return status;
}

static int omap1_spi100k_remove(struct platform_device *pdev)
{
	struct spi_master       *master;
	struct omap1_spi100k    *spi100k;
	struct resource         *r;
	unsigned		limit = 500;
	unsigned long		flags;
	int			status = 0;

	master = dev_get_drvdata(&pdev->dev);
	spi100k = spi_master_get_devdata(master);

	spin_lock_irqsave(&spi100k->lock, flags);

	spi100k->state = SPI_SHUTDOWN;
	while (!list_empty(&spi100k->msg_queue) && limit--) {
		spin_unlock_irqrestore(&spi100k->lock, flags);
		msleep(10);
		spin_lock_irqsave(&spi100k->lock, flags);
	}

	if (!list_empty(&spi100k->msg_queue))
		status = -EBUSY;

	spin_unlock_irqrestore(&spi100k->lock, flags);

	if (status != 0)
		return status;

	clk_put(spi100k->fck);
	clk_put(spi100k->ick);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	spi_unregister_master(master);

	return 0;
}

static struct platform_driver omap1_spi100k_driver = {
	.driver = {
		.name		= "omap1_spi100k",
		.owner		= THIS_MODULE,
	},
	.remove		= omap1_spi100k_remove,
};


static int __init omap1_spi100k_init(void)
{
	omap1_spi100k_wq = create_singlethread_workqueue(
			omap1_spi100k_driver.driver.name);

	if (omap1_spi100k_wq == NULL)
		return -1;

	return platform_driver_probe(&omap1_spi100k_driver, omap1_spi100k_probe);
}

static void __exit omap1_spi100k_exit(void)
{
	platform_driver_unregister(&omap1_spi100k_driver);

	destroy_workqueue(omap1_spi100k_wq);
}

module_init(omap1_spi100k_init);
module_exit(omap1_spi100k_exit);

MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
MODULE_LICENSE("GPL");

OpenPOWER on IntegriCloud