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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SPI-Engine SPI controller driver
4  * Copyright 2015 Analog Devices Inc.
5  *  Author: Lars-Peter Clausen <lars@metafoo.de>
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/interrupt.h>
10 #include <linux/io.h>
11 #include <linux/of.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/spi/spi.h>
15 
16 #define SPI_ENGINE_VERSION_MAJOR(x)	((x >> 16) & 0xff)
17 #define SPI_ENGINE_VERSION_MINOR(x)	((x >> 8) & 0xff)
18 #define SPI_ENGINE_VERSION_PATCH(x)	(x & 0xff)
19 
20 #define SPI_ENGINE_REG_VERSION			0x00
21 
22 #define SPI_ENGINE_REG_RESET			0x40
23 
24 #define SPI_ENGINE_REG_INT_ENABLE		0x80
25 #define SPI_ENGINE_REG_INT_PENDING		0x84
26 #define SPI_ENGINE_REG_INT_SOURCE		0x88
27 
28 #define SPI_ENGINE_REG_SYNC_ID			0xc0
29 
30 #define SPI_ENGINE_REG_CMD_FIFO_ROOM		0xd0
31 #define SPI_ENGINE_REG_SDO_FIFO_ROOM		0xd4
32 #define SPI_ENGINE_REG_SDI_FIFO_LEVEL		0xd8
33 
34 #define SPI_ENGINE_REG_CMD_FIFO			0xe0
35 #define SPI_ENGINE_REG_SDO_DATA_FIFO		0xe4
36 #define SPI_ENGINE_REG_SDI_DATA_FIFO		0xe8
37 #define SPI_ENGINE_REG_SDI_DATA_FIFO_PEEK	0xec
38 
39 #define SPI_ENGINE_INT_CMD_ALMOST_EMPTY		BIT(0)
40 #define SPI_ENGINE_INT_SDO_ALMOST_EMPTY		BIT(1)
41 #define SPI_ENGINE_INT_SDI_ALMOST_FULL		BIT(2)
42 #define SPI_ENGINE_INT_SYNC			BIT(3)
43 
44 #define SPI_ENGINE_CONFIG_CPHA			BIT(0)
45 #define SPI_ENGINE_CONFIG_CPOL			BIT(1)
46 #define SPI_ENGINE_CONFIG_3WIRE			BIT(2)
47 
48 #define SPI_ENGINE_INST_TRANSFER		0x0
49 #define SPI_ENGINE_INST_ASSERT			0x1
50 #define SPI_ENGINE_INST_WRITE			0x2
51 #define SPI_ENGINE_INST_MISC			0x3
52 
53 #define SPI_ENGINE_CMD_REG_CLK_DIV		0x0
54 #define SPI_ENGINE_CMD_REG_CONFIG		0x1
55 
56 #define SPI_ENGINE_MISC_SYNC			0x0
57 #define SPI_ENGINE_MISC_SLEEP			0x1
58 
59 #define SPI_ENGINE_TRANSFER_WRITE		0x1
60 #define SPI_ENGINE_TRANSFER_READ		0x2
61 
62 #define SPI_ENGINE_CMD(inst, arg1, arg2) \
63 	(((inst) << 12) | ((arg1) << 8) | (arg2))
64 
65 #define SPI_ENGINE_CMD_TRANSFER(flags, n) \
66 	SPI_ENGINE_CMD(SPI_ENGINE_INST_TRANSFER, (flags), (n))
67 #define SPI_ENGINE_CMD_ASSERT(delay, cs) \
68 	SPI_ENGINE_CMD(SPI_ENGINE_INST_ASSERT, (delay), (cs))
69 #define SPI_ENGINE_CMD_WRITE(reg, val) \
70 	SPI_ENGINE_CMD(SPI_ENGINE_INST_WRITE, (reg), (val))
71 #define SPI_ENGINE_CMD_SLEEP(delay) \
72 	SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SLEEP, (delay))
73 #define SPI_ENGINE_CMD_SYNC(id) \
74 	SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SYNC, (id))
75 
76 struct spi_engine_program {
77 	unsigned int length;
78 	uint16_t instructions[];
79 };
80 
81 struct spi_engine {
82 	struct clk *clk;
83 	struct clk *ref_clk;
84 
85 	spinlock_t lock;
86 
87 	void __iomem *base;
88 
89 	struct spi_message *msg;
90 	struct spi_engine_program *p;
91 	unsigned cmd_length;
92 	const uint16_t *cmd_buf;
93 
94 	struct spi_transfer *tx_xfer;
95 	unsigned int tx_length;
96 	const uint8_t *tx_buf;
97 
98 	struct spi_transfer *rx_xfer;
99 	unsigned int rx_length;
100 	uint8_t *rx_buf;
101 
102 	unsigned int sync_id;
103 	unsigned int completed_id;
104 
105 	unsigned int int_enable;
106 };
107 
spi_engine_program_add_cmd(struct spi_engine_program * p,bool dry,uint16_t cmd)108 static void spi_engine_program_add_cmd(struct spi_engine_program *p,
109 	bool dry, uint16_t cmd)
110 {
111 	if (!dry)
112 		p->instructions[p->length] = cmd;
113 	p->length++;
114 }
115 
spi_engine_get_config(struct spi_device * spi)116 static unsigned int spi_engine_get_config(struct spi_device *spi)
117 {
118 	unsigned int config = 0;
119 
120 	if (spi->mode & SPI_CPOL)
121 		config |= SPI_ENGINE_CONFIG_CPOL;
122 	if (spi->mode & SPI_CPHA)
123 		config |= SPI_ENGINE_CONFIG_CPHA;
124 	if (spi->mode & SPI_3WIRE)
125 		config |= SPI_ENGINE_CONFIG_3WIRE;
126 
127 	return config;
128 }
129 
spi_engine_get_clk_div(struct spi_engine * spi_engine,struct spi_device * spi,struct spi_transfer * xfer)130 static unsigned int spi_engine_get_clk_div(struct spi_engine *spi_engine,
131 	struct spi_device *spi, struct spi_transfer *xfer)
132 {
133 	unsigned int clk_div;
134 
135 	clk_div = DIV_ROUND_UP(clk_get_rate(spi_engine->ref_clk),
136 		xfer->speed_hz * 2);
137 	if (clk_div > 255)
138 		clk_div = 255;
139 	else if (clk_div > 0)
140 		clk_div -= 1;
141 
142 	return clk_div;
143 }
144 
spi_engine_gen_xfer(struct spi_engine_program * p,bool dry,struct spi_transfer * xfer)145 static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
146 	struct spi_transfer *xfer)
147 {
148 	unsigned int len = xfer->len;
149 
150 	while (len) {
151 		unsigned int n = min(len, 256U);
152 		unsigned int flags = 0;
153 
154 		if (xfer->tx_buf)
155 			flags |= SPI_ENGINE_TRANSFER_WRITE;
156 		if (xfer->rx_buf)
157 			flags |= SPI_ENGINE_TRANSFER_READ;
158 
159 		spi_engine_program_add_cmd(p, dry,
160 			SPI_ENGINE_CMD_TRANSFER(flags, n - 1));
161 		len -= n;
162 	}
163 }
164 
spi_engine_gen_sleep(struct spi_engine_program * p,bool dry,struct spi_engine * spi_engine,unsigned int clk_div,unsigned int delay)165 static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
166 	struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay)
167 {
168 	unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk);
169 	unsigned int t;
170 
171 	if (delay == 0)
172 		return;
173 
174 	t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2);
175 	while (t) {
176 		unsigned int n = min(t, 256U);
177 
178 		spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1));
179 		t -= n;
180 	}
181 }
182 
spi_engine_gen_cs(struct spi_engine_program * p,bool dry,struct spi_device * spi,bool assert)183 static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry,
184 		struct spi_device *spi, bool assert)
185 {
186 	unsigned int mask = 0xff;
187 
188 	if (assert)
189 		mask ^= BIT(spi->chip_select);
190 
191 	spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask));
192 }
193 
spi_engine_compile_message(struct spi_engine * spi_engine,struct spi_message * msg,bool dry,struct spi_engine_program * p)194 static int spi_engine_compile_message(struct spi_engine *spi_engine,
195 	struct spi_message *msg, bool dry, struct spi_engine_program *p)
196 {
197 	struct spi_device *spi = msg->spi;
198 	struct spi_transfer *xfer;
199 	int clk_div, new_clk_div;
200 	bool cs_change = true;
201 
202 	clk_div = -1;
203 
204 	spi_engine_program_add_cmd(p, dry,
205 		SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,
206 			spi_engine_get_config(spi)));
207 
208 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
209 		new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer);
210 		if (new_clk_div != clk_div) {
211 			clk_div = new_clk_div;
212 			spi_engine_program_add_cmd(p, dry,
213 				SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV,
214 					clk_div));
215 		}
216 
217 		if (cs_change)
218 			spi_engine_gen_cs(p, dry, spi, true);
219 
220 		spi_engine_gen_xfer(p, dry, xfer);
221 		spi_engine_gen_sleep(p, dry, spi_engine, clk_div,
222 			xfer->delay_usecs);
223 
224 		cs_change = xfer->cs_change;
225 		if (list_is_last(&xfer->transfer_list, &msg->transfers))
226 			cs_change = !cs_change;
227 
228 		if (cs_change)
229 			spi_engine_gen_cs(p, dry, spi, false);
230 	}
231 
232 	return 0;
233 }
234 
spi_engine_xfer_next(struct spi_engine * spi_engine,struct spi_transfer ** _xfer)235 static void spi_engine_xfer_next(struct spi_engine *spi_engine,
236 	struct spi_transfer **_xfer)
237 {
238 	struct spi_message *msg = spi_engine->msg;
239 	struct spi_transfer *xfer = *_xfer;
240 
241 	if (!xfer) {
242 		xfer = list_first_entry(&msg->transfers,
243 			struct spi_transfer, transfer_list);
244 	} else if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
245 		xfer = NULL;
246 	} else {
247 		xfer = list_next_entry(xfer, transfer_list);
248 	}
249 
250 	*_xfer = xfer;
251 }
252 
spi_engine_tx_next(struct spi_engine * spi_engine)253 static void spi_engine_tx_next(struct spi_engine *spi_engine)
254 {
255 	struct spi_transfer *xfer = spi_engine->tx_xfer;
256 
257 	do {
258 		spi_engine_xfer_next(spi_engine, &xfer);
259 	} while (xfer && !xfer->tx_buf);
260 
261 	spi_engine->tx_xfer = xfer;
262 	if (xfer) {
263 		spi_engine->tx_length = xfer->len;
264 		spi_engine->tx_buf = xfer->tx_buf;
265 	} else {
266 		spi_engine->tx_buf = NULL;
267 	}
268 }
269 
spi_engine_rx_next(struct spi_engine * spi_engine)270 static void spi_engine_rx_next(struct spi_engine *spi_engine)
271 {
272 	struct spi_transfer *xfer = spi_engine->rx_xfer;
273 
274 	do {
275 		spi_engine_xfer_next(spi_engine, &xfer);
276 	} while (xfer && !xfer->rx_buf);
277 
278 	spi_engine->rx_xfer = xfer;
279 	if (xfer) {
280 		spi_engine->rx_length = xfer->len;
281 		spi_engine->rx_buf = xfer->rx_buf;
282 	} else {
283 		spi_engine->rx_buf = NULL;
284 	}
285 }
286 
spi_engine_write_cmd_fifo(struct spi_engine * spi_engine)287 static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine)
288 {
289 	void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO;
290 	unsigned int n, m, i;
291 	const uint16_t *buf;
292 
293 	n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM);
294 	while (n && spi_engine->cmd_length) {
295 		m = min(n, spi_engine->cmd_length);
296 		buf = spi_engine->cmd_buf;
297 		for (i = 0; i < m; i++)
298 			writel_relaxed(buf[i], addr);
299 		spi_engine->cmd_buf += m;
300 		spi_engine->cmd_length -= m;
301 		n -= m;
302 	}
303 
304 	return spi_engine->cmd_length != 0;
305 }
306 
spi_engine_write_tx_fifo(struct spi_engine * spi_engine)307 static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine)
308 {
309 	void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;
310 	unsigned int n, m, i;
311 	const uint8_t *buf;
312 
313 	n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);
314 	while (n && spi_engine->tx_length) {
315 		m = min(n, spi_engine->tx_length);
316 		buf = spi_engine->tx_buf;
317 		for (i = 0; i < m; i++)
318 			writel_relaxed(buf[i], addr);
319 		spi_engine->tx_buf += m;
320 		spi_engine->tx_length -= m;
321 		n -= m;
322 		if (spi_engine->tx_length == 0)
323 			spi_engine_tx_next(spi_engine);
324 	}
325 
326 	return spi_engine->tx_length != 0;
327 }
328 
spi_engine_read_rx_fifo(struct spi_engine * spi_engine)329 static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine)
330 {
331 	void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;
332 	unsigned int n, m, i;
333 	uint8_t *buf;
334 
335 	n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);
336 	while (n && spi_engine->rx_length) {
337 		m = min(n, spi_engine->rx_length);
338 		buf = spi_engine->rx_buf;
339 		for (i = 0; i < m; i++)
340 			buf[i] = readl_relaxed(addr);
341 		spi_engine->rx_buf += m;
342 		spi_engine->rx_length -= m;
343 		n -= m;
344 		if (spi_engine->rx_length == 0)
345 			spi_engine_rx_next(spi_engine);
346 	}
347 
348 	return spi_engine->rx_length != 0;
349 }
350 
spi_engine_irq(int irq,void * devid)351 static irqreturn_t spi_engine_irq(int irq, void *devid)
352 {
353 	struct spi_master *master = devid;
354 	struct spi_engine *spi_engine = spi_master_get_devdata(master);
355 	unsigned int disable_int = 0;
356 	unsigned int pending;
357 
358 	pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
359 
360 	if (pending & SPI_ENGINE_INT_SYNC) {
361 		writel_relaxed(SPI_ENGINE_INT_SYNC,
362 			spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
363 		spi_engine->completed_id = readl_relaxed(
364 			spi_engine->base + SPI_ENGINE_REG_SYNC_ID);
365 	}
366 
367 	spin_lock(&spi_engine->lock);
368 
369 	if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) {
370 		if (!spi_engine_write_cmd_fifo(spi_engine))
371 			disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
372 	}
373 
374 	if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) {
375 		if (!spi_engine_write_tx_fifo(spi_engine))
376 			disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
377 	}
378 
379 	if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) {
380 		if (!spi_engine_read_rx_fifo(spi_engine))
381 			disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
382 	}
383 
384 	if (pending & SPI_ENGINE_INT_SYNC) {
385 		if (spi_engine->msg &&
386 		    spi_engine->completed_id == spi_engine->sync_id) {
387 			struct spi_message *msg = spi_engine->msg;
388 
389 			kfree(spi_engine->p);
390 			msg->status = 0;
391 			msg->actual_length = msg->frame_length;
392 			spi_engine->msg = NULL;
393 			spi_finalize_current_message(master);
394 			disable_int |= SPI_ENGINE_INT_SYNC;
395 		}
396 	}
397 
398 	if (disable_int) {
399 		spi_engine->int_enable &= ~disable_int;
400 		writel_relaxed(spi_engine->int_enable,
401 			spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
402 	}
403 
404 	spin_unlock(&spi_engine->lock);
405 
406 	return IRQ_HANDLED;
407 }
408 
spi_engine_transfer_one_message(struct spi_master * master,struct spi_message * msg)409 static int spi_engine_transfer_one_message(struct spi_master *master,
410 	struct spi_message *msg)
411 {
412 	struct spi_engine_program p_dry, *p;
413 	struct spi_engine *spi_engine = spi_master_get_devdata(master);
414 	unsigned int int_enable = 0;
415 	unsigned long flags;
416 	size_t size;
417 
418 	p_dry.length = 0;
419 	spi_engine_compile_message(spi_engine, msg, true, &p_dry);
420 
421 	size = sizeof(*p->instructions) * (p_dry.length + 1);
422 	p = kzalloc(sizeof(*p) + size, GFP_KERNEL);
423 	if (!p)
424 		return -ENOMEM;
425 	spi_engine_compile_message(spi_engine, msg, false, p);
426 
427 	spin_lock_irqsave(&spi_engine->lock, flags);
428 	spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff;
429 	spi_engine_program_add_cmd(p, false,
430 		SPI_ENGINE_CMD_SYNC(spi_engine->sync_id));
431 
432 	spi_engine->msg = msg;
433 	spi_engine->p = p;
434 
435 	spi_engine->cmd_buf = p->instructions;
436 	spi_engine->cmd_length = p->length;
437 	if (spi_engine_write_cmd_fifo(spi_engine))
438 		int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
439 
440 	spi_engine_tx_next(spi_engine);
441 	if (spi_engine_write_tx_fifo(spi_engine))
442 		int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
443 
444 	spi_engine_rx_next(spi_engine);
445 	if (spi_engine->rx_length != 0)
446 		int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
447 
448 	int_enable |= SPI_ENGINE_INT_SYNC;
449 
450 	writel_relaxed(int_enable,
451 		spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
452 	spi_engine->int_enable = int_enable;
453 	spin_unlock_irqrestore(&spi_engine->lock, flags);
454 
455 	return 0;
456 }
457 
spi_engine_probe(struct platform_device * pdev)458 static int spi_engine_probe(struct platform_device *pdev)
459 {
460 	struct spi_engine *spi_engine;
461 	struct spi_master *master;
462 	unsigned int version;
463 	int irq;
464 	int ret;
465 
466 	irq = platform_get_irq(pdev, 0);
467 	if (irq <= 0)
468 		return -ENXIO;
469 
470 	spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL);
471 	if (!spi_engine)
472 		return -ENOMEM;
473 
474 	master = spi_alloc_master(&pdev->dev, 0);
475 	if (!master)
476 		return -ENOMEM;
477 
478 	spi_master_set_devdata(master, spi_engine);
479 
480 	spin_lock_init(&spi_engine->lock);
481 
482 	spi_engine->base = devm_platform_ioremap_resource(pdev, 0);
483 	if (IS_ERR(spi_engine->base)) {
484 		ret = PTR_ERR(spi_engine->base);
485 		goto err_put_master;
486 	}
487 
488 	version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
489 	if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
490 		dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
491 			SPI_ENGINE_VERSION_MAJOR(version),
492 			SPI_ENGINE_VERSION_MINOR(version),
493 			SPI_ENGINE_VERSION_PATCH(version));
494 		ret = -ENODEV;
495 		goto err_put_master;
496 	}
497 
498 	spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
499 	if (IS_ERR(spi_engine->clk)) {
500 		ret = PTR_ERR(spi_engine->clk);
501 		goto err_put_master;
502 	}
503 
504 	spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk");
505 	if (IS_ERR(spi_engine->ref_clk)) {
506 		ret = PTR_ERR(spi_engine->ref_clk);
507 		goto err_put_master;
508 	}
509 
510 	ret = clk_prepare_enable(spi_engine->clk);
511 	if (ret)
512 		goto err_put_master;
513 
514 	ret = clk_prepare_enable(spi_engine->ref_clk);
515 	if (ret)
516 		goto err_clk_disable;
517 
518 	writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET);
519 	writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
520 	writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
521 
522 	ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master);
523 	if (ret)
524 		goto err_ref_clk_disable;
525 
526 	master->dev.of_node = pdev->dev.of_node;
527 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
528 	master->bits_per_word_mask = SPI_BPW_MASK(8);
529 	master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
530 	master->transfer_one_message = spi_engine_transfer_one_message;
531 	master->num_chipselect = 8;
532 
533 	ret = spi_register_master(master);
534 	if (ret)
535 		goto err_free_irq;
536 
537 	platform_set_drvdata(pdev, master);
538 
539 	return 0;
540 err_free_irq:
541 	free_irq(irq, master);
542 err_ref_clk_disable:
543 	clk_disable_unprepare(spi_engine->ref_clk);
544 err_clk_disable:
545 	clk_disable_unprepare(spi_engine->clk);
546 err_put_master:
547 	spi_master_put(master);
548 	return ret;
549 }
550 
spi_engine_remove(struct platform_device * pdev)551 static int spi_engine_remove(struct platform_device *pdev)
552 {
553 	struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
554 	struct spi_engine *spi_engine = spi_master_get_devdata(master);
555 	int irq = platform_get_irq(pdev, 0);
556 
557 	spi_unregister_master(master);
558 
559 	free_irq(irq, master);
560 
561 	spi_master_put(master);
562 
563 	writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
564 	writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
565 	writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET);
566 
567 	clk_disable_unprepare(spi_engine->ref_clk);
568 	clk_disable_unprepare(spi_engine->clk);
569 
570 	return 0;
571 }
572 
573 static const struct of_device_id spi_engine_match_table[] = {
574 	{ .compatible = "adi,axi-spi-engine-1.00.a" },
575 	{ },
576 };
577 MODULE_DEVICE_TABLE(of, spi_engine_match_table);
578 
579 static struct platform_driver spi_engine_driver = {
580 	.probe = spi_engine_probe,
581 	.remove = spi_engine_remove,
582 	.driver = {
583 		.name = "spi-engine",
584 		.of_match_table = spi_engine_match_table,
585 	},
586 };
587 module_platform_driver(spi_engine_driver);
588 
589 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
590 MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver");
591 MODULE_LICENSE("GPL");
592