summaryrefslogtreecommitdiff
path: root/drivers/spi/atmel_spi.c
blob: 4701b79f161f46b38c1cd39c4580e91248e08740 (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
/*
 * Copyright (C) 2007 Atmel Corporation
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <fdtdec.h>
#include <spi.h>
#include <malloc.h>
#include <wait_bit.h>

#include <asm/io.h>

#include <asm/arch/clk.h>
#include <asm/arch/hardware.h>
#ifdef CONFIG_DM_SPI
#include <asm/arch/at91_spi.h>
#endif
#ifdef CONFIG_DM_GPIO
#include <asm/gpio.h>
#endif

#include "atmel_spi.h"

DECLARE_GLOBAL_DATA_PTR;

#ifndef CONFIG_DM_SPI

static int spi_has_wdrbt(struct atmel_spi_slave *slave)
{
	unsigned int ver;

	ver = spi_readl(slave, VERSION);

	return (ATMEL_SPI_VERSION_REV(ver) >= 0x210);
}

void spi_init()
{

}

struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
			unsigned int max_hz, unsigned int mode)
{
	struct atmel_spi_slave	*as;
	unsigned int		scbr;
	u32			csrx;
	void			*regs;

	if (!spi_cs_is_valid(bus, cs))
		return NULL;

	switch (bus) {
	case 0:
		regs = (void *)ATMEL_BASE_SPI0;
		break;
#ifdef ATMEL_BASE_SPI1
	case 1:
		regs = (void *)ATMEL_BASE_SPI1;
		break;
#endif
#ifdef ATMEL_BASE_SPI2
	case 2:
		regs = (void *)ATMEL_BASE_SPI2;
		break;
#endif
#ifdef ATMEL_BASE_SPI3
	case 3:
		regs = (void *)ATMEL_BASE_SPI3;
		break;
#endif
	default:
		return NULL;
	}


	scbr = (get_spi_clk_rate(bus) + max_hz - 1) / max_hz;
	if (scbr > ATMEL_SPI_CSRx_SCBR_MAX)
		/* Too low max SCK rate */
		return NULL;
	if (scbr < 1)
		scbr = 1;

	csrx = ATMEL_SPI_CSRx_SCBR(scbr);
	csrx |= ATMEL_SPI_CSRx_BITS(ATMEL_SPI_BITS_8);
	if (!(mode & SPI_CPHA))
		csrx |= ATMEL_SPI_CSRx_NCPHA;
	if (mode & SPI_CPOL)
		csrx |= ATMEL_SPI_CSRx_CPOL;

	as = spi_alloc_slave(struct atmel_spi_slave, bus, cs);
	if (!as)
		return NULL;

	as->regs = regs;
	as->mr = ATMEL_SPI_MR_MSTR | ATMEL_SPI_MR_MODFDIS
			| ATMEL_SPI_MR_PCS(~(1 << cs) & 0xf);
	if (spi_has_wdrbt(as))
		as->mr |= ATMEL_SPI_MR_WDRBT;

	spi_writel(as, CSR(cs), csrx);

	return &as->slave;
}

void spi_free_slave(struct spi_slave *slave)
{
	struct atmel_spi_slave *as = to_atmel_spi(slave);

	free(as);
}

int spi_claim_bus(struct spi_slave *slave)
{
	struct atmel_spi_slave *as = to_atmel_spi(slave);

	/* Enable the SPI hardware */
	spi_writel(as, CR, ATMEL_SPI_CR_SPIEN);

	/*
	 * Select the slave. This should set SCK to the correct
	 * initial state, etc.
	 */
	spi_writel(as, MR, as->mr);

	return 0;
}

void spi_release_bus(struct spi_slave *slave)
{
	struct atmel_spi_slave *as = to_atmel_spi(slave);

	/* Disable the SPI hardware */
	spi_writel(as, CR, ATMEL_SPI_CR_SPIDIS);
}

int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
		const void *dout, void *din, unsigned long flags)
{
	struct atmel_spi_slave *as = to_atmel_spi(slave);
	unsigned int	len_tx;
	unsigned int	len_rx;
	unsigned int	len;
	u32		status;
	const u8	*txp = dout;
	u8		*rxp = din;
	u8		value;

	if (bitlen == 0)
		/* Finish any previously submitted transfers */
		goto out;

	/*
	 * TODO: The controller can do non-multiple-of-8 bit
	 * transfers, but this driver currently doesn't support it.
	 *
	 * It's also not clear how such transfers are supposed to be
	 * represented as a stream of bytes...this is a limitation of
	 * the current SPI interface.
	 */
	if (bitlen % 8) {
		/* Errors always terminate an ongoing transfer */
		flags |= SPI_XFER_END;
		goto out;
	}

	len = bitlen / 8;

	/*
	 * The controller can do automatic CS control, but it is
	 * somewhat quirky, and it doesn't really buy us much anyway
	 * in the context of U-Boot.
	 */
	if (flags & SPI_XFER_BEGIN) {
		spi_cs_activate(slave);
		/*
		 * sometimes the RDR is not empty when we get here,
		 * in theory that should not happen, but it DOES happen.
		 * Read it here to be on the safe side.
		 * That also clears the OVRES flag. Required if the
		 * following loop exits due to OVRES!
		 */
		spi_readl(as, RDR);
	}

	for (len_tx = 0, len_rx = 0; len_rx < len; ) {
		status = spi_readl(as, SR);

		if (status & ATMEL_SPI_SR_OVRES)
			return -1;

		if (len_tx < len && (status & ATMEL_SPI_SR_TDRE)) {
			if (txp)
				value = *txp++;
			else
				value = 0;
			spi_writel(as, TDR, value);
			len_tx++;
		}
		if (status & ATMEL_SPI_SR_RDRF) {
			value = spi_readl(as, RDR);
			if (rxp)
				*rxp++ = value;
			len_rx++;
		}
	}

out:
	if (flags & SPI_XFER_END) {
		/*
		 * Wait until the transfer is completely done before
		 * we deactivate CS.
		 */
		do {
			status = spi_readl(as, SR);
		} while (!(status & ATMEL_SPI_SR_TXEMPTY));

		spi_cs_deactivate(slave);
	}

	return 0;
}

#else

#define MAX_CS_COUNT	4

struct atmel_spi_platdata {
	struct at91_spi *regs;
};

struct atmel_spi_priv {
	unsigned int freq;		/* Default frequency */
	unsigned int mode;
	ulong bus_clk_rate;
	struct gpio_desc cs_gpios[MAX_CS_COUNT];
};

static int atmel_spi_claim_bus(struct udevice *dev)
{
	struct udevice *bus = dev_get_parent(dev);
	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
	struct atmel_spi_priv *priv = dev_get_priv(bus);
	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
	struct at91_spi *reg_base = bus_plat->regs;
	u32 cs = slave_plat->cs;
	u32 freq = priv->freq;
	u32 scbr, csrx, mode;

	scbr = (priv->bus_clk_rate + freq - 1) / freq;
	if (scbr > ATMEL_SPI_CSRx_SCBR_MAX)
		return -EINVAL;

	if (scbr < 1)
		scbr = 1;

	csrx = ATMEL_SPI_CSRx_SCBR(scbr);
	csrx |= ATMEL_SPI_CSRx_BITS(ATMEL_SPI_BITS_8);

	if (!(priv->mode & SPI_CPHA))
		csrx |= ATMEL_SPI_CSRx_NCPHA;
	if (priv->mode & SPI_CPOL)
		csrx |= ATMEL_SPI_CSRx_CPOL;

	writel(csrx, &reg_base->csr[cs]);

	mode = ATMEL_SPI_MR_MSTR |
	       ATMEL_SPI_MR_MODFDIS |
	       ATMEL_SPI_MR_WDRBT |
	       ATMEL_SPI_MR_PCS(~(1 << cs));

	writel(mode, &reg_base->mr);

	writel(ATMEL_SPI_CR_SPIEN, &reg_base->cr);

	return 0;
}

static int atmel_spi_release_bus(struct udevice *dev)
{
	struct udevice *bus = dev_get_parent(dev);
	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);

	writel(ATMEL_SPI_CR_SPIDIS, &bus_plat->regs->cr);

	return 0;
}

static void atmel_spi_cs_activate(struct udevice *dev)
{
	struct udevice *bus = dev_get_parent(dev);
	struct atmel_spi_priv *priv = dev_get_priv(bus);
	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
	u32 cs = slave_plat->cs;

	if (!dm_gpio_is_valid(&priv->cs_gpios[cs]))
		return;

	dm_gpio_set_value(&priv->cs_gpios[cs], 0);
}

static void atmel_spi_cs_deactivate(struct udevice *dev)
{
	struct udevice *bus = dev_get_parent(dev);
	struct atmel_spi_priv *priv = dev_get_priv(bus);
	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
	u32 cs = slave_plat->cs;

	if (!dm_gpio_is_valid(&priv->cs_gpios[cs]))
		return;

	dm_gpio_set_value(&priv->cs_gpios[cs], 1);
}

static int atmel_spi_xfer(struct udevice *dev, unsigned int bitlen,
			  const void *dout, void *din, unsigned long flags)
{
	struct udevice *bus = dev_get_parent(dev);
	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
	struct at91_spi *reg_base = bus_plat->regs;

	u32 len_tx, len_rx, len;
	u32 status;
	const u8 *txp = dout;
	u8 *rxp = din;
	u8 value;

	if (bitlen == 0)
		goto out;

	/*
	 * The controller can do non-multiple-of-8 bit
	 * transfers, but this driver currently doesn't support it.
	 *
	 * It's also not clear how such transfers are supposed to be
	 * represented as a stream of bytes...this is a limitation of
	 * the current SPI interface.
	 */
	if (bitlen % 8) {
		/* Errors always terminate an ongoing transfer */
		flags |= SPI_XFER_END;
		goto out;
	}

	len = bitlen / 8;

	/*
	 * The controller can do automatic CS control, but it is
	 * somewhat quirky, and it doesn't really buy us much anyway
	 * in the context of U-Boot.
	 */
	if (flags & SPI_XFER_BEGIN) {
		atmel_spi_cs_activate(dev);

		/*
		 * sometimes the RDR is not empty when we get here,
		 * in theory that should not happen, but it DOES happen.
		 * Read it here to be on the safe side.
		 * That also clears the OVRES flag. Required if the
		 * following loop exits due to OVRES!
		 */
		readl(&reg_base->rdr);
	}

	for (len_tx = 0, len_rx = 0; len_rx < len; ) {
		status = readl(&reg_base->sr);

		if (status & ATMEL_SPI_SR_OVRES)
			return -1;

		if ((len_tx < len) && (status & ATMEL_SPI_SR_TDRE)) {
			if (txp)
				value = *txp++;
			else
				value = 0;
			writel(value, &reg_base->tdr);
			len_tx++;
		}

		if (status & ATMEL_SPI_SR_RDRF) {
			value = readl(&reg_base->rdr);
			if (rxp)
				*rxp++ = value;
			len_rx++;
		}
	}

out:
	if (flags & SPI_XFER_END) {
		/*
		 * Wait until the transfer is completely done before
		 * we deactivate CS.
		 */
		wait_for_bit(__func__, &reg_base->sr,
			     ATMEL_SPI_SR_TXEMPTY, true, 1000, false);

		atmel_spi_cs_deactivate(dev);
	}

	return 0;
}

static int atmel_spi_set_speed(struct udevice *bus, uint speed)
{
	struct atmel_spi_priv *priv = dev_get_priv(bus);

	priv->freq = speed;

	return 0;
}

static int atmel_spi_set_mode(struct udevice *bus, uint mode)
{
	struct atmel_spi_priv *priv = dev_get_priv(bus);

	priv->mode = mode;

	return 0;
}

static const struct dm_spi_ops atmel_spi_ops = {
	.claim_bus	= atmel_spi_claim_bus,
	.release_bus	= atmel_spi_release_bus,
	.xfer		= atmel_spi_xfer,
	.set_speed	= atmel_spi_set_speed,
	.set_mode	= atmel_spi_set_mode,
	/*
	 * cs_info is not needed, since we require all chip selects to be
	 * in the device tree explicitly
	 */
};

static int atmel_spi_enable_clk(struct udevice *bus)
{
	struct atmel_spi_priv *priv = dev_get_priv(bus);
	struct clk clk;
	ulong clk_rate;
	int ret;

	ret = clk_get_by_index(bus, 0, &clk);
	if (ret)
		return -EINVAL;

	ret = clk_enable(&clk);
	if (ret)
		return ret;

	clk_rate = clk_get_rate(&clk);
	if (!clk_rate)
		return -EINVAL;

	priv->bus_clk_rate = clk_rate;

	clk_free(&clk);

	return 0;
}

static int atmel_spi_probe(struct udevice *bus)
{
	struct atmel_spi_platdata *bus_plat = dev_get_platdata(bus);
	struct atmel_spi_priv *priv = dev_get_priv(bus);
	int i, ret;

	ret = atmel_spi_enable_clk(bus);
	if (ret)
		return ret;

	bus_plat->regs = (struct at91_spi *)dev_get_addr(bus);

	ret = gpio_request_list_by_name(bus, "cs-gpios", priv->cs_gpios,
					ARRAY_SIZE(priv->cs_gpios), 0);
	if (ret < 0) {
		error("Can't get %s gpios! Error: %d", bus->name, ret);
		return ret;
	}

	for(i = 0; i < ARRAY_SIZE(priv->cs_gpios); i++) {
		if (!dm_gpio_is_valid(&priv->cs_gpios[i]))
			continue;

		dm_gpio_set_dir_flags(&priv->cs_gpios[i],
				      GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
	}

	writel(ATMEL_SPI_CR_SWRST, &bus_plat->regs->cr);

	return 0;
}

static const struct udevice_id atmel_spi_ids[] = {
	{ .compatible = "atmel,at91rm9200-spi" },
	{ }
};

U_BOOT_DRIVER(atmel_spi) = {
	.name	= "atmel_spi",
	.id	= UCLASS_SPI,
	.of_match = atmel_spi_ids,
	.ops	= &atmel_spi_ops,
	.platdata_auto_alloc_size = sizeof(struct atmel_spi_platdata),
	.priv_auto_alloc_size = sizeof(struct atmel_spi_priv),
	.probe	= atmel_spi_probe,
};
#endif