xref: /openbmc/linux/drivers/spi/spi-rzv2m-csi.c (revision 6db6b729)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Renesas RZ/V2M Clocked Serial Interface (CSI) driver
4  *
5  * Copyright (C) 2023 Renesas Electronics Corporation
6  */
7 
8 #include <linux/bits.h>
9 #include <linux/clk.h>
10 #include <linux/count_zeros.h>
11 #include <linux/interrupt.h>
12 #include <linux/iopoll.h>
13 #include <linux/log2.h>
14 #include <linux/platform_device.h>
15 #include <linux/property.h>
16 #include <linux/reset.h>
17 #include <linux/spi/spi.h>
18 #include <linux/units.h>
19 
20 /* Registers */
21 #define CSI_MODE		0x00	/* CSI mode control */
22 #define CSI_CLKSEL		0x04	/* CSI clock select */
23 #define CSI_CNT			0x08	/* CSI control */
24 #define CSI_INT			0x0C	/* CSI interrupt status */
25 #define CSI_IFIFOL		0x10	/* CSI receive FIFO level display */
26 #define CSI_OFIFOL		0x14	/* CSI transmit FIFO level display */
27 #define CSI_IFIFO		0x18	/* CSI receive window */
28 #define CSI_OFIFO		0x1C	/* CSI transmit window */
29 #define CSI_FIFOTRG		0x20	/* CSI FIFO trigger level */
30 
31 /* CSI_MODE */
32 #define CSI_MODE_CSIE		BIT(7)
33 #define CSI_MODE_TRMD		BIT(6)
34 #define CSI_MODE_CCL		BIT(5)
35 #define CSI_MODE_DIR		BIT(4)
36 #define CSI_MODE_CSOT		BIT(0)
37 
38 #define CSI_MODE_SETUP		0x00000040
39 
40 /* CSI_CLKSEL */
41 #define CSI_CLKSEL_CKP		BIT(17)
42 #define CSI_CLKSEL_DAP		BIT(16)
43 #define CSI_CLKSEL_MODE		(CSI_CLKSEL_CKP|CSI_CLKSEL_DAP)
44 #define CSI_CLKSEL_SLAVE	BIT(15)
45 #define CSI_CLKSEL_CKS		GENMASK(14, 1)
46 
47 /* CSI_CNT */
48 #define CSI_CNT_CSIRST		BIT(28)
49 #define CSI_CNT_R_TRGEN		BIT(19)
50 #define CSI_CNT_UNDER_E		BIT(13)
51 #define CSI_CNT_OVERF_E		BIT(12)
52 #define CSI_CNT_TREND_E		BIT(9)
53 #define CSI_CNT_CSIEND_E	BIT(8)
54 #define CSI_CNT_T_TRGR_E	BIT(4)
55 #define CSI_CNT_R_TRGR_E	BIT(0)
56 
57 /* CSI_INT */
58 #define CSI_INT_UNDER		BIT(13)
59 #define CSI_INT_OVERF		BIT(12)
60 #define CSI_INT_TREND		BIT(9)
61 #define CSI_INT_CSIEND		BIT(8)
62 #define CSI_INT_T_TRGR		BIT(4)
63 #define CSI_INT_R_TRGR		BIT(0)
64 
65 /* CSI_FIFOTRG */
66 #define CSI_FIFOTRG_R_TRG       GENMASK(2, 0)
67 
68 #define CSI_FIFO_SIZE_BYTES	32U
69 #define CSI_FIFO_HALF_SIZE	16U
70 #define CSI_EN_DIS_TIMEOUT_US	100
71 /*
72  * Clock "csiclk" gets divided by 2 * CSI_CLKSEL_CKS in order to generate the
73  * serial clock (output from master), with CSI_CLKSEL_CKS ranging from 0x1 (that
74  * means "csiclk" is divided by 2) to 0x3FFF ("csiclk" is divided by 32766).
75  */
76 #define CSI_CKS_MAX		GENMASK(13, 0)
77 
78 #define UNDERRUN_ERROR		BIT(0)
79 #define OVERFLOW_ERROR		BIT(1)
80 #define TX_TIMEOUT_ERROR	BIT(2)
81 #define RX_TIMEOUT_ERROR	BIT(3)
82 
83 #define CSI_MAX_SPI_SCKO	(8 * HZ_PER_MHZ)
84 
85 struct rzv2m_csi_priv {
86 	void __iomem *base;
87 	struct clk *csiclk;
88 	struct clk *pclk;
89 	struct device *dev;
90 	struct spi_controller *controller;
91 	const void *txbuf;
92 	void *rxbuf;
93 	unsigned int buffer_len;
94 	unsigned int bytes_sent;
95 	unsigned int bytes_received;
96 	unsigned int bytes_to_transfer;
97 	unsigned int words_to_transfer;
98 	unsigned int bytes_per_word;
99 	wait_queue_head_t wait;
100 	u32 errors;
101 	u32 status;
102 };
103 
104 static void rzv2m_csi_reg_write_bit(const struct rzv2m_csi_priv *csi,
105 				    int reg_offs, int bit_mask, u32 value)
106 {
107 	int nr_zeros;
108 	u32 tmp;
109 
110 	nr_zeros = count_trailing_zeros(bit_mask);
111 	value <<= nr_zeros;
112 
113 	tmp = (readl(csi->base + reg_offs) & ~bit_mask) | value;
114 	writel(tmp, csi->base + reg_offs);
115 }
116 
117 static int rzv2m_csi_sw_reset(struct rzv2m_csi_priv *csi, int assert)
118 {
119 	u32 reg;
120 
121 	rzv2m_csi_reg_write_bit(csi, CSI_CNT, CSI_CNT_CSIRST, assert);
122 
123 	if (!assert)
124 		return 0;
125 
126 	return readl_poll_timeout(csi->base + CSI_MODE, reg,
127 				  !(reg & CSI_MODE_CSOT), 0,
128 				  CSI_EN_DIS_TIMEOUT_US);
129 }
130 
131 static int rzv2m_csi_start_stop_operation(const struct rzv2m_csi_priv *csi,
132 					  int enable, bool wait)
133 {
134 	u32 reg;
135 
136 	rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_CSIE, enable);
137 
138 	if (enable || !wait)
139 		return 0;
140 
141 	return readl_poll_timeout(csi->base + CSI_MODE, reg,
142 				  !(reg & CSI_MODE_CSOT), 0,
143 				  CSI_EN_DIS_TIMEOUT_US);
144 }
145 
146 static int rzv2m_csi_fill_txfifo(struct rzv2m_csi_priv *csi)
147 {
148 	unsigned int i;
149 
150 	if (readl(csi->base + CSI_OFIFOL))
151 		return -EIO;
152 
153 	if (csi->bytes_per_word == 2) {
154 		const u16 *buf = csi->txbuf;
155 
156 		for (i = 0; i < csi->words_to_transfer; i++)
157 			writel(buf[i], csi->base + CSI_OFIFO);
158 	} else {
159 		const u8 *buf = csi->txbuf;
160 
161 		for (i = 0; i < csi->words_to_transfer; i++)
162 			writel(buf[i], csi->base + CSI_OFIFO);
163 	}
164 
165 	csi->txbuf += csi->bytes_to_transfer;
166 	csi->bytes_sent += csi->bytes_to_transfer;
167 
168 	return 0;
169 }
170 
171 static int rzv2m_csi_read_rxfifo(struct rzv2m_csi_priv *csi)
172 {
173 	unsigned int i;
174 
175 	if (readl(csi->base + CSI_IFIFOL) != csi->bytes_to_transfer)
176 		return -EIO;
177 
178 	if (csi->bytes_per_word == 2) {
179 		u16 *buf = csi->rxbuf;
180 
181 		for (i = 0; i < csi->words_to_transfer; i++)
182 			buf[i] = (u16)readl(csi->base + CSI_IFIFO);
183 	} else {
184 		u8 *buf = csi->rxbuf;
185 
186 		for (i = 0; i < csi->words_to_transfer; i++)
187 			buf[i] = (u8)readl(csi->base + CSI_IFIFO);
188 	}
189 
190 	csi->rxbuf += csi->bytes_to_transfer;
191 	csi->bytes_received += csi->bytes_to_transfer;
192 
193 	return 0;
194 }
195 
196 static inline void rzv2m_csi_calc_current_transfer(struct rzv2m_csi_priv *csi)
197 {
198 	unsigned int bytes_transferred = max(csi->bytes_received, csi->bytes_sent);
199 	unsigned int bytes_remaining = csi->buffer_len - bytes_transferred;
200 	unsigned int to_transfer;
201 
202 	if (csi->txbuf)
203 		/*
204 		 * Leaving a little bit of headroom in the FIFOs makes it very
205 		 * hard to raise an overflow error (which is only possible
206 		 * when IP transmits and receives at the same time).
207 		 */
208 		to_transfer = min(CSI_FIFO_HALF_SIZE, bytes_remaining);
209 	else
210 		to_transfer = min(CSI_FIFO_SIZE_BYTES, bytes_remaining);
211 
212 	if (csi->bytes_per_word == 2)
213 		to_transfer >>= 1;
214 
215 	/*
216 	 * We can only choose a trigger level from a predefined set of values.
217 	 * This will pick a value that is the greatest possible integer that's
218 	 * less than or equal to the number of bytes we need to transfer.
219 	 * This may result in multiple smaller transfers.
220 	 */
221 	csi->words_to_transfer = rounddown_pow_of_two(to_transfer);
222 
223 	if (csi->bytes_per_word == 2)
224 		csi->bytes_to_transfer = csi->words_to_transfer << 1;
225 	else
226 		csi->bytes_to_transfer = csi->words_to_transfer;
227 }
228 
229 static inline void rzv2m_csi_set_rx_fifo_trigger_level(struct rzv2m_csi_priv *csi)
230 {
231 	rzv2m_csi_reg_write_bit(csi, CSI_FIFOTRG, CSI_FIFOTRG_R_TRG,
232 				ilog2(csi->words_to_transfer));
233 }
234 
235 static inline void rzv2m_csi_enable_rx_trigger(struct rzv2m_csi_priv *csi,
236 					       bool enable)
237 {
238 	rzv2m_csi_reg_write_bit(csi, CSI_CNT, CSI_CNT_R_TRGEN, enable);
239 }
240 
241 static void rzv2m_csi_disable_irqs(const struct rzv2m_csi_priv *csi,
242 				   u32 enable_bits)
243 {
244 	u32 cnt = readl(csi->base + CSI_CNT);
245 
246 	writel(cnt & ~enable_bits, csi->base + CSI_CNT);
247 }
248 
249 static void rzv2m_csi_disable_all_irqs(struct rzv2m_csi_priv *csi)
250 {
251 	rzv2m_csi_disable_irqs(csi, CSI_CNT_R_TRGR_E | CSI_CNT_T_TRGR_E |
252 			       CSI_CNT_CSIEND_E | CSI_CNT_TREND_E |
253 			       CSI_CNT_OVERF_E | CSI_CNT_UNDER_E);
254 }
255 
256 static inline void rzv2m_csi_clear_irqs(struct rzv2m_csi_priv *csi, u32 irqs)
257 {
258 	writel(irqs, csi->base + CSI_INT);
259 }
260 
261 static void rzv2m_csi_clear_all_irqs(struct rzv2m_csi_priv *csi)
262 {
263 	rzv2m_csi_clear_irqs(csi, CSI_INT_UNDER | CSI_INT_OVERF |
264 			     CSI_INT_TREND | CSI_INT_CSIEND |  CSI_INT_T_TRGR |
265 			     CSI_INT_R_TRGR);
266 }
267 
268 static void rzv2m_csi_enable_irqs(struct rzv2m_csi_priv *csi, u32 enable_bits)
269 {
270 	u32 cnt = readl(csi->base + CSI_CNT);
271 
272 	writel(cnt | enable_bits, csi->base + CSI_CNT);
273 }
274 
275 static int rzv2m_csi_wait_for_interrupt(struct rzv2m_csi_priv *csi,
276 					u32 wait_mask, u32 enable_bits)
277 {
278 	int ret;
279 
280 	rzv2m_csi_enable_irqs(csi, enable_bits);
281 
282 	ret = wait_event_timeout(csi->wait,
283 				 ((csi->status & wait_mask) == wait_mask) ||
284 				 csi->errors, HZ);
285 
286 	rzv2m_csi_disable_irqs(csi, enable_bits);
287 
288 	if (csi->errors)
289 		return -EIO;
290 
291 	if (!ret)
292 		return -ETIMEDOUT;
293 
294 	return 0;
295 }
296 
297 static int rzv2m_csi_wait_for_tx_empty(struct rzv2m_csi_priv *csi)
298 {
299 	int ret;
300 
301 	if (readl(csi->base + CSI_OFIFOL) == 0)
302 		return 0;
303 
304 	ret = rzv2m_csi_wait_for_interrupt(csi, CSI_INT_TREND, CSI_CNT_TREND_E);
305 	if (ret == -ETIMEDOUT)
306 		csi->errors |= TX_TIMEOUT_ERROR;
307 
308 	return ret;
309 }
310 
311 static inline int rzv2m_csi_wait_for_rx_ready(struct rzv2m_csi_priv *csi)
312 {
313 	int ret;
314 
315 	if (readl(csi->base + CSI_IFIFOL) == csi->bytes_to_transfer)
316 		return 0;
317 
318 	ret = rzv2m_csi_wait_for_interrupt(csi, CSI_INT_R_TRGR,
319 					   CSI_CNT_R_TRGR_E);
320 	if (ret == -ETIMEDOUT)
321 		csi->errors |= RX_TIMEOUT_ERROR;
322 
323 	return ret;
324 }
325 
326 static irqreturn_t rzv2m_csi_irq_handler(int irq, void *data)
327 {
328 	struct rzv2m_csi_priv *csi = data;
329 
330 	csi->status = readl(csi->base + CSI_INT);
331 	rzv2m_csi_disable_irqs(csi, csi->status);
332 
333 	if (csi->status & CSI_INT_OVERF)
334 		csi->errors |= OVERFLOW_ERROR;
335 	if (csi->status & CSI_INT_UNDER)
336 		csi->errors |= UNDERRUN_ERROR;
337 
338 	wake_up(&csi->wait);
339 
340 	return IRQ_HANDLED;
341 }
342 
343 static void rzv2m_csi_setup_clock(struct rzv2m_csi_priv *csi, u32 spi_hz)
344 {
345 	unsigned long csiclk_rate = clk_get_rate(csi->csiclk);
346 	unsigned long pclk_rate = clk_get_rate(csi->pclk);
347 	unsigned long csiclk_rate_limit = pclk_rate >> 1;
348 	u32 cks;
349 
350 	/*
351 	 * There is a restriction on the frequency of CSICLK, it has to be <=
352 	 * PCLK / 2.
353 	 */
354 	if (csiclk_rate > csiclk_rate_limit) {
355 		clk_set_rate(csi->csiclk, csiclk_rate >> 1);
356 		csiclk_rate = clk_get_rate(csi->csiclk);
357 	} else if ((csiclk_rate << 1) <= csiclk_rate_limit) {
358 		clk_set_rate(csi->csiclk, csiclk_rate << 1);
359 		csiclk_rate = clk_get_rate(csi->csiclk);
360 	}
361 
362 	spi_hz = spi_hz > CSI_MAX_SPI_SCKO ? CSI_MAX_SPI_SCKO : spi_hz;
363 
364 	cks = DIV_ROUND_UP(csiclk_rate, spi_hz << 1);
365 	if (cks > CSI_CKS_MAX)
366 		cks = CSI_CKS_MAX;
367 
368 	dev_dbg(csi->dev, "SPI clk rate is %ldHz\n", csiclk_rate / (cks << 1));
369 
370 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_CKS, cks);
371 }
372 
373 static void rzv2m_csi_setup_operating_mode(struct rzv2m_csi_priv *csi,
374 					   struct spi_transfer *t)
375 {
376 	if (t->rx_buf && !t->tx_buf)
377 		/* Reception-only mode */
378 		rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_TRMD, 0);
379 	else
380 		/* Send and receive mode */
381 		rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_TRMD, 1);
382 
383 	csi->bytes_per_word = t->bits_per_word / 8;
384 	rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_CCL,
385 				csi->bytes_per_word == 2);
386 }
387 
388 static int rzv2m_csi_setup(struct spi_device *spi)
389 {
390 	struct rzv2m_csi_priv *csi = spi_controller_get_devdata(spi->controller);
391 	int ret;
392 
393 	rzv2m_csi_sw_reset(csi, 0);
394 
395 	writel(CSI_MODE_SETUP, csi->base + CSI_MODE);
396 
397 	/* Setup clock polarity and phase timing */
398 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_MODE,
399 				~spi->mode & SPI_MODE_X_MASK);
400 
401 	/* Setup serial data order */
402 	rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_DIR,
403 				!!(spi->mode & SPI_LSB_FIRST));
404 
405 	/* Set the operation mode as master */
406 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_SLAVE, 0);
407 
408 	/* Give the IP a SW reset */
409 	ret = rzv2m_csi_sw_reset(csi, 1);
410 	if (ret)
411 		return ret;
412 	rzv2m_csi_sw_reset(csi, 0);
413 
414 	/*
415 	 * We need to enable the communication so that the clock will settle
416 	 * for the right polarity before enabling the CS.
417 	 */
418 	rzv2m_csi_start_stop_operation(csi, 1, false);
419 	udelay(10);
420 	rzv2m_csi_start_stop_operation(csi, 0, false);
421 
422 	return 0;
423 }
424 
425 static int rzv2m_csi_pio_transfer(struct rzv2m_csi_priv *csi)
426 {
427 	bool tx_completed = !csi->txbuf;
428 	bool rx_completed = !csi->rxbuf;
429 	int ret = 0;
430 
431 	/* Make sure the TX FIFO is empty */
432 	writel(0, csi->base + CSI_OFIFOL);
433 
434 	csi->bytes_sent = 0;
435 	csi->bytes_received = 0;
436 	csi->errors = 0;
437 
438 	rzv2m_csi_disable_all_irqs(csi);
439 	rzv2m_csi_clear_all_irqs(csi);
440 	rzv2m_csi_enable_rx_trigger(csi, true);
441 
442 	while (!tx_completed || !rx_completed) {
443 		/*
444 		 * Decide how many words we are going to transfer during
445 		 * this cycle (for both TX and RX), then set the RX FIFO trigger
446 		 * level accordingly. No need to set a trigger level for the
447 		 * TX FIFO, as this IP comes with an interrupt that fires when
448 		 * the TX FIFO is empty.
449 		 */
450 		rzv2m_csi_calc_current_transfer(csi);
451 		rzv2m_csi_set_rx_fifo_trigger_level(csi);
452 
453 		rzv2m_csi_enable_irqs(csi, CSI_INT_OVERF | CSI_INT_UNDER);
454 
455 		/* Make sure the RX FIFO is empty */
456 		writel(0, csi->base + CSI_IFIFOL);
457 
458 		writel(readl(csi->base + CSI_INT), csi->base + CSI_INT);
459 		csi->status = 0;
460 
461 		rzv2m_csi_start_stop_operation(csi, 1, false);
462 
463 		/* TX */
464 		if (csi->txbuf) {
465 			ret = rzv2m_csi_fill_txfifo(csi);
466 			if (ret)
467 				break;
468 
469 			ret = rzv2m_csi_wait_for_tx_empty(csi);
470 			if (ret)
471 				break;
472 
473 			if (csi->bytes_sent == csi->buffer_len)
474 				tx_completed = true;
475 		}
476 
477 		/*
478 		 * Make sure the RX FIFO contains the desired number of words.
479 		 * We then either flush its content, or we copy it onto
480 		 * csi->rxbuf.
481 		 */
482 		ret = rzv2m_csi_wait_for_rx_ready(csi);
483 		if (ret)
484 			break;
485 
486 		/* RX */
487 		if (csi->rxbuf) {
488 			rzv2m_csi_start_stop_operation(csi, 0, false);
489 
490 			ret = rzv2m_csi_read_rxfifo(csi);
491 			if (ret)
492 				break;
493 
494 			if (csi->bytes_received == csi->buffer_len)
495 				rx_completed = true;
496 		}
497 
498 		ret = rzv2m_csi_start_stop_operation(csi, 0, true);
499 		if (ret)
500 			goto pio_quit;
501 
502 		if (csi->errors) {
503 			ret = -EIO;
504 			goto pio_quit;
505 		}
506 	}
507 
508 	rzv2m_csi_start_stop_operation(csi, 0, true);
509 
510 pio_quit:
511 	rzv2m_csi_disable_all_irqs(csi);
512 	rzv2m_csi_enable_rx_trigger(csi, false);
513 	rzv2m_csi_clear_all_irqs(csi);
514 
515 	return ret;
516 }
517 
518 static int rzv2m_csi_transfer_one(struct spi_controller *controller,
519 				  struct spi_device *spi,
520 				  struct spi_transfer *transfer)
521 {
522 	struct rzv2m_csi_priv *csi = spi_controller_get_devdata(controller);
523 	struct device *dev = csi->dev;
524 	int ret;
525 
526 	csi->txbuf = transfer->tx_buf;
527 	csi->rxbuf = transfer->rx_buf;
528 	csi->buffer_len = transfer->len;
529 
530 	rzv2m_csi_setup_operating_mode(csi, transfer);
531 
532 	rzv2m_csi_setup_clock(csi, transfer->speed_hz);
533 
534 	ret = rzv2m_csi_pio_transfer(csi);
535 	if (ret) {
536 		if (csi->errors & UNDERRUN_ERROR)
537 			dev_err(dev, "Underrun error\n");
538 		if (csi->errors & OVERFLOW_ERROR)
539 			dev_err(dev, "Overflow error\n");
540 		if (csi->errors & TX_TIMEOUT_ERROR)
541 			dev_err(dev, "TX timeout error\n");
542 		if (csi->errors & RX_TIMEOUT_ERROR)
543 			dev_err(dev, "RX timeout error\n");
544 	}
545 
546 	return ret;
547 }
548 
549 static int rzv2m_csi_probe(struct platform_device *pdev)
550 {
551 	struct spi_controller *controller;
552 	struct device *dev = &pdev->dev;
553 	struct rzv2m_csi_priv *csi;
554 	struct reset_control *rstc;
555 	int irq;
556 	int ret;
557 
558 	controller = devm_spi_alloc_host(dev, sizeof(*csi));
559 	if (!controller)
560 		return -ENOMEM;
561 
562 	csi = spi_controller_get_devdata(controller);
563 	platform_set_drvdata(pdev, csi);
564 
565 	csi->dev = dev;
566 	csi->controller = controller;
567 
568 	csi->base = devm_platform_ioremap_resource(pdev, 0);
569 	if (IS_ERR(csi->base))
570 		return PTR_ERR(csi->base);
571 
572 	irq = platform_get_irq(pdev, 0);
573 	if (irq < 0)
574 		return irq;
575 
576 	csi->csiclk = devm_clk_get(dev, "csiclk");
577 	if (IS_ERR(csi->csiclk))
578 		return dev_err_probe(dev, PTR_ERR(csi->csiclk),
579 				     "could not get csiclk\n");
580 
581 	csi->pclk = devm_clk_get(dev, "pclk");
582 	if (IS_ERR(csi->pclk))
583 		return dev_err_probe(dev, PTR_ERR(csi->pclk),
584 				     "could not get pclk\n");
585 
586 	rstc = devm_reset_control_get_shared(dev, NULL);
587 	if (IS_ERR(rstc))
588 		return dev_err_probe(dev, PTR_ERR(rstc), "Missing reset ctrl\n");
589 
590 	init_waitqueue_head(&csi->wait);
591 
592 	controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
593 	controller->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8);
594 	controller->setup = rzv2m_csi_setup;
595 	controller->transfer_one = rzv2m_csi_transfer_one;
596 	controller->use_gpio_descriptors = true;
597 
598 	device_set_node(&controller->dev, dev_fwnode(dev));
599 
600 	ret = devm_request_irq(dev, irq, rzv2m_csi_irq_handler, 0,
601 			       dev_name(dev), csi);
602 	if (ret)
603 		return dev_err_probe(dev, ret, "cannot request IRQ\n");
604 
605 	/*
606 	 * The reset also affects other HW that is not under the control
607 	 * of Linux. Therefore, all we can do is make sure the reset is
608 	 * deasserted.
609 	 */
610 	reset_control_deassert(rstc);
611 
612 	/* Make sure the IP is in SW reset state */
613 	ret = rzv2m_csi_sw_reset(csi, 1);
614 	if (ret)
615 		return ret;
616 
617 	ret = clk_prepare_enable(csi->csiclk);
618 	if (ret)
619 		return dev_err_probe(dev, ret, "could not enable csiclk\n");
620 
621 	ret = spi_register_controller(controller);
622 	if (ret) {
623 		clk_disable_unprepare(csi->csiclk);
624 		return dev_err_probe(dev, ret, "register controller failed\n");
625 	}
626 
627 	return 0;
628 }
629 
630 static void rzv2m_csi_remove(struct platform_device *pdev)
631 {
632 	struct rzv2m_csi_priv *csi = platform_get_drvdata(pdev);
633 
634 	spi_unregister_controller(csi->controller);
635 	rzv2m_csi_sw_reset(csi, 1);
636 	clk_disable_unprepare(csi->csiclk);
637 }
638 
639 static const struct of_device_id rzv2m_csi_match[] = {
640 	{ .compatible = "renesas,rzv2m-csi" },
641 	{ /* sentinel */ }
642 };
643 MODULE_DEVICE_TABLE(of, rzv2m_csi_match);
644 
645 static struct platform_driver rzv2m_csi_drv = {
646 	.probe = rzv2m_csi_probe,
647 	.remove_new = rzv2m_csi_remove,
648 	.driver = {
649 		.name = "rzv2m_csi",
650 		.of_match_table = rzv2m_csi_match,
651 	},
652 };
653 module_platform_driver(rzv2m_csi_drv);
654 
655 MODULE_LICENSE("GPL");
656 MODULE_AUTHOR("Fabrizio Castro <castro.fabrizio.jz@renesas.com>");
657 MODULE_DESCRIPTION("Clocked Serial Interface Driver");
658