xref: /openbmc/linux/drivers/spi/spi-rzv2m-csi.c (revision 829c6524)
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/clk.h>
9 #include <linux/count_zeros.h>
10 #include <linux/interrupt.h>
11 #include <linux/iopoll.h>
12 #include <linux/platform_device.h>
13 #include <linux/reset.h>
14 #include <linux/spi/spi.h>
15 
16 /* Registers */
17 #define CSI_MODE		0x00	/* CSI mode control */
18 #define CSI_CLKSEL		0x04	/* CSI clock select */
19 #define CSI_CNT			0x08	/* CSI control */
20 #define CSI_INT			0x0C	/* CSI interrupt status */
21 #define CSI_IFIFOL		0x10	/* CSI receive FIFO level display */
22 #define CSI_OFIFOL		0x14	/* CSI transmit FIFO level display */
23 #define CSI_IFIFO		0x18	/* CSI receive window */
24 #define CSI_OFIFO		0x1C	/* CSI transmit window */
25 #define CSI_FIFOTRG		0x20	/* CSI FIFO trigger level */
26 
27 /* CSI_MODE */
28 #define CSI_MODE_CSIE		BIT(7)
29 #define CSI_MODE_TRMD		BIT(6)
30 #define CSI_MODE_CCL		BIT(5)
31 #define CSI_MODE_DIR		BIT(4)
32 #define CSI_MODE_CSOT		BIT(0)
33 
34 #define CSI_MODE_SETUP		0x00000040
35 
36 /* CSI_CLKSEL */
37 #define CSI_CLKSEL_CKP		BIT(17)
38 #define CSI_CLKSEL_DAP		BIT(16)
39 #define CSI_CLKSEL_SLAVE	BIT(15)
40 #define CSI_CLKSEL_CKS		GENMASK(14, 1)
41 
42 /* CSI_CNT */
43 #define CSI_CNT_CSIRST		BIT(28)
44 #define CSI_CNT_R_TRGEN		BIT(19)
45 #define CSI_CNT_UNDER_E		BIT(13)
46 #define CSI_CNT_OVERF_E		BIT(12)
47 #define CSI_CNT_TREND_E		BIT(9)
48 #define CSI_CNT_CSIEND_E	BIT(8)
49 #define CSI_CNT_T_TRGR_E	BIT(4)
50 #define CSI_CNT_R_TRGR_E	BIT(0)
51 
52 /* CSI_INT */
53 #define CSI_INT_UNDER		BIT(13)
54 #define CSI_INT_OVERF		BIT(12)
55 #define CSI_INT_TREND		BIT(9)
56 #define CSI_INT_CSIEND		BIT(8)
57 #define CSI_INT_T_TRGR		BIT(4)
58 #define CSI_INT_R_TRGR		BIT(0)
59 
60 /* CSI_FIFOTRG */
61 #define CSI_FIFOTRG_R_TRG       GENMASK(2, 0)
62 
63 #define CSI_FIFO_SIZE_BYTES	32
64 #define CSI_FIFO_HALF_SIZE	16
65 #define CSI_EN_DIS_TIMEOUT_US	100
66 #define CSI_CKS_MAX		0x3FFF
67 
68 #define UNDERRUN_ERROR		BIT(0)
69 #define OVERFLOW_ERROR		BIT(1)
70 #define TX_TIMEOUT_ERROR	BIT(2)
71 #define RX_TIMEOUT_ERROR	BIT(3)
72 
73 #define CSI_MAX_SPI_SCKO	8000000
74 
75 struct rzv2m_csi_priv {
76 	void __iomem *base;
77 	struct clk *csiclk;
78 	struct clk *pclk;
79 	struct device *dev;
80 	struct spi_controller *controller;
81 	const u8 *txbuf;
82 	u8 *rxbuf;
83 	int buffer_len;
84 	int bytes_sent;
85 	int bytes_received;
86 	int bytes_to_transfer;
87 	int words_to_transfer;
88 	unsigned char bytes_per_word;
89 	wait_queue_head_t wait;
90 	u8 errors;
91 	u32 status;
92 };
93 
94 static const unsigned char x_trg[] = {
95 	0, 1, 1, 2, 2, 2, 2, 3,
96 	3, 3, 3, 3, 3, 3, 3, 4,
97 	4, 4, 4, 4, 4, 4, 4, 4,
98 	4, 4, 4, 4, 4, 4, 4, 5
99 };
100 
101 static const unsigned char x_trg_words[] = {
102 	1,  2,  2,  4,  4,  4,  4,  8,
103 	8,  8,  8,  8,  8,  8,  8,  16,
104 	16, 16, 16, 16, 16, 16, 16, 16,
105 	16, 16, 16, 16, 16, 16, 16, 32
106 };
107 
108 static void rzv2m_csi_reg_write_bit(const struct rzv2m_csi_priv *csi,
109 				    int reg_offs, int bit_mask, u32 value)
110 {
111 	int nr_zeros;
112 	u32 tmp;
113 
114 	nr_zeros = count_trailing_zeros(bit_mask);
115 	value <<= nr_zeros;
116 
117 	tmp = (readl(csi->base + reg_offs) & ~bit_mask) | value;
118 	writel(tmp, csi->base + reg_offs);
119 }
120 
121 static int rzv2m_csi_sw_reset(struct rzv2m_csi_priv *csi, int assert)
122 {
123 	u32 reg;
124 
125 	rzv2m_csi_reg_write_bit(csi, CSI_CNT, CSI_CNT_CSIRST, assert);
126 
127 	if (assert) {
128 		return readl_poll_timeout(csi->base + CSI_MODE, reg,
129 					  !(reg & CSI_MODE_CSOT), 0,
130 					  CSI_EN_DIS_TIMEOUT_US);
131 	}
132 
133 	return 0;
134 }
135 
136 static int rzv2m_csi_start_stop_operation(const struct rzv2m_csi_priv *csi,
137 					  int enable, bool wait)
138 {
139 	u32 reg;
140 
141 	rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_CSIE, enable);
142 
143 	if (!enable && wait)
144 		return readl_poll_timeout(csi->base + CSI_MODE, reg,
145 					  !(reg & CSI_MODE_CSOT), 0,
146 					  CSI_EN_DIS_TIMEOUT_US);
147 
148 	return 0;
149 }
150 
151 static int rzv2m_csi_fill_txfifo(struct rzv2m_csi_priv *csi)
152 {
153 	int i;
154 
155 	if (readl(csi->base + CSI_OFIFOL))
156 		return -EIO;
157 
158 	if (csi->bytes_per_word == 2) {
159 		u16 *buf = (u16 *)csi->txbuf;
160 
161 		for (i = 0; i < csi->words_to_transfer; i++)
162 			writel(buf[i], csi->base + CSI_OFIFO);
163 	} else {
164 		u8 *buf = (u8 *)csi->txbuf;
165 
166 		for (i = 0; i < csi->words_to_transfer; i++)
167 			writel(buf[i], csi->base + CSI_OFIFO);
168 	}
169 
170 	csi->txbuf += csi->bytes_to_transfer;
171 	csi->bytes_sent += csi->bytes_to_transfer;
172 
173 	return 0;
174 }
175 
176 static int rzv2m_csi_read_rxfifo(struct rzv2m_csi_priv *csi)
177 {
178 	int i;
179 
180 	if (readl(csi->base + CSI_IFIFOL) != csi->bytes_to_transfer)
181 		return -EIO;
182 
183 	if (csi->bytes_per_word == 2) {
184 		u16 *buf = (u16 *)csi->rxbuf;
185 
186 		for (i = 0; i < csi->words_to_transfer; i++)
187 			buf[i] = (u16)readl(csi->base + CSI_IFIFO);
188 	} else {
189 		u8 *buf = (u8 *)csi->rxbuf;
190 
191 		for (i = 0; i < csi->words_to_transfer; i++)
192 			buf[i] = (u8)readl(csi->base + CSI_IFIFO);
193 	}
194 
195 	csi->rxbuf += csi->bytes_to_transfer;
196 	csi->bytes_received += csi->bytes_to_transfer;
197 
198 	return 0;
199 }
200 
201 static inline void rzv2m_csi_calc_current_transfer(struct rzv2m_csi_priv *csi)
202 {
203 	int bytes_transferred = max_t(int, csi->bytes_received, csi->bytes_sent);
204 	int bytes_remaining = csi->buffer_len - bytes_transferred;
205 	int to_transfer;
206 
207 	if (csi->txbuf)
208 		/*
209 		 * Leaving a little bit of headroom in the FIFOs makes it very
210 		 * hard to raise an overflow error (which is only possible
211 		 * when IP transmits and receives at the same time).
212 		 */
213 		to_transfer = min_t(int, CSI_FIFO_HALF_SIZE, bytes_remaining);
214 	else
215 		to_transfer = min_t(int, CSI_FIFO_SIZE_BYTES, bytes_remaining);
216 
217 	if (csi->bytes_per_word == 2)
218 		to_transfer >>= 1;
219 
220 	/*
221 	 * We can only choose a trigger level from a predefined set of values.
222 	 * This will pick a value that is the greatest possible integer that's
223 	 * less than or equal to the number of bytes we need to transfer.
224 	 * This may result in multiple smaller transfers.
225 	 */
226 	csi->words_to_transfer = x_trg_words[to_transfer - 1];
227 
228 	if (csi->bytes_per_word == 2)
229 		csi->bytes_to_transfer = csi->words_to_transfer << 1;
230 	else
231 		csi->bytes_to_transfer = csi->words_to_transfer;
232 }
233 
234 static inline void rzv2m_csi_set_rx_fifo_trigger_level(struct rzv2m_csi_priv *csi)
235 {
236 	rzv2m_csi_reg_write_bit(csi, CSI_FIFOTRG, CSI_FIFOTRG_R_TRG,
237 				x_trg[csi->words_to_transfer - 1]);
238 }
239 
240 static inline void rzv2m_csi_enable_rx_trigger(struct rzv2m_csi_priv *csi,
241 					       bool enable)
242 {
243 	rzv2m_csi_reg_write_bit(csi, CSI_CNT, CSI_CNT_R_TRGEN, enable);
244 }
245 
246 static void rzv2m_csi_disable_irqs(const struct rzv2m_csi_priv *csi,
247 				   u32 enable_bits)
248 {
249 	u32 cnt = readl(csi->base + CSI_CNT);
250 
251 	writel(cnt & ~enable_bits, csi->base + CSI_CNT);
252 }
253 
254 static void rzv2m_csi_disable_all_irqs(struct rzv2m_csi_priv *csi)
255 {
256 	rzv2m_csi_disable_irqs(csi, CSI_CNT_R_TRGR_E | CSI_CNT_T_TRGR_E |
257 			       CSI_CNT_CSIEND_E | CSI_CNT_TREND_E |
258 			       CSI_CNT_OVERF_E | CSI_CNT_UNDER_E);
259 }
260 
261 static inline void rzv2m_csi_clear_irqs(struct rzv2m_csi_priv *csi, u32 irqs)
262 {
263 	writel(irqs, csi->base + CSI_INT);
264 }
265 
266 static void rzv2m_csi_clear_all_irqs(struct rzv2m_csi_priv *csi)
267 {
268 	rzv2m_csi_clear_irqs(csi, CSI_INT_UNDER | CSI_INT_OVERF |
269 			     CSI_INT_TREND | CSI_INT_CSIEND |  CSI_INT_T_TRGR |
270 			     CSI_INT_R_TRGR);
271 }
272 
273 static void rzv2m_csi_enable_irqs(struct rzv2m_csi_priv *csi, u32 enable_bits)
274 {
275 	u32 cnt = readl(csi->base + CSI_CNT);
276 
277 	writel(cnt | enable_bits, csi->base + CSI_CNT);
278 }
279 
280 static int rzv2m_csi_wait_for_interrupt(struct rzv2m_csi_priv *csi,
281 					u32 wait_mask, u32 enable_bits)
282 {
283 	int ret;
284 
285 	rzv2m_csi_enable_irqs(csi, enable_bits);
286 
287 	ret = wait_event_timeout(csi->wait,
288 				 ((csi->status & wait_mask) == wait_mask) ||
289 				 csi->errors, HZ);
290 
291 	rzv2m_csi_disable_irqs(csi, enable_bits);
292 
293 	if (csi->errors)
294 		return -EIO;
295 
296 	if (!ret)
297 		return -ETIMEDOUT;
298 
299 	return 0;
300 }
301 
302 static int rzv2m_csi_wait_for_tx_empty(struct rzv2m_csi_priv *csi)
303 {
304 	int ret;
305 
306 	if (readl(csi->base + CSI_OFIFOL) == 0)
307 		return 0;
308 
309 	ret = rzv2m_csi_wait_for_interrupt(csi, CSI_INT_TREND, CSI_CNT_TREND_E);
310 
311 	if (ret == -ETIMEDOUT)
312 		csi->errors |= TX_TIMEOUT_ERROR;
313 
314 	return ret;
315 }
316 
317 static inline int rzv2m_csi_wait_for_rx_ready(struct rzv2m_csi_priv *csi)
318 {
319 	int ret;
320 
321 	if (readl(csi->base + CSI_IFIFOL) == csi->bytes_to_transfer)
322 		return 0;
323 
324 	ret = rzv2m_csi_wait_for_interrupt(csi, CSI_INT_R_TRGR,
325 					   CSI_CNT_R_TRGR_E);
326 
327 	if (ret == -ETIMEDOUT)
328 		csi->errors |= RX_TIMEOUT_ERROR;
329 
330 	return ret;
331 }
332 
333 static irqreturn_t rzv2m_csi_irq_handler(int irq, void *data)
334 {
335 	struct rzv2m_csi_priv *csi = (struct rzv2m_csi_priv *)data;
336 
337 	csi->status = readl(csi->base + CSI_INT);
338 	rzv2m_csi_disable_irqs(csi, csi->status);
339 
340 	if (csi->status & CSI_INT_OVERF)
341 		csi->errors |= OVERFLOW_ERROR;
342 	if (csi->status & CSI_INT_UNDER)
343 		csi->errors |= UNDERRUN_ERROR;
344 
345 	wake_up(&csi->wait);
346 
347 	return IRQ_HANDLED;
348 }
349 
350 static void rzv2m_csi_setup_clock(struct rzv2m_csi_priv *csi, u32 spi_hz)
351 {
352 	unsigned long csiclk_rate = clk_get_rate(csi->csiclk);
353 	unsigned long pclk_rate = clk_get_rate(csi->pclk);
354 	unsigned long csiclk_rate_limit = pclk_rate >> 1;
355 	u32 cks;
356 
357 	/*
358 	 * There is a restriction on the frequency of CSICLK, it has to be <=
359 	 * PCLK / 2.
360 	 */
361 	if (csiclk_rate > csiclk_rate_limit) {
362 		clk_set_rate(csi->csiclk, csiclk_rate >> 1);
363 		csiclk_rate = clk_get_rate(csi->csiclk);
364 	} else if ((csiclk_rate << 1) <= csiclk_rate_limit) {
365 		clk_set_rate(csi->csiclk, csiclk_rate << 1);
366 		csiclk_rate = clk_get_rate(csi->csiclk);
367 	}
368 
369 	spi_hz = spi_hz > CSI_MAX_SPI_SCKO ? CSI_MAX_SPI_SCKO : spi_hz;
370 
371 	cks = DIV_ROUND_UP(csiclk_rate, spi_hz << 1);
372 	if (cks > CSI_CKS_MAX)
373 		cks = CSI_CKS_MAX;
374 
375 	dev_dbg(csi->dev, "SPI clk rate is %ldHz\n", csiclk_rate / (cks << 1));
376 
377 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_CKS, cks);
378 }
379 
380 static void rzv2m_csi_setup_operating_mode(struct rzv2m_csi_priv *csi,
381 					   struct spi_transfer *t)
382 {
383 	if (t->rx_buf && !t->tx_buf)
384 		/* Reception-only mode */
385 		rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_TRMD, 0);
386 	else
387 		/* Send and receive mode */
388 		rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_TRMD, 1);
389 
390 	csi->bytes_per_word = t->bits_per_word / 8;
391 	rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_CCL,
392 				csi->bytes_per_word == 2);
393 }
394 
395 static int rzv2m_csi_setup(struct spi_device *spi)
396 {
397 	struct rzv2m_csi_priv *csi = spi_controller_get_devdata(spi->controller);
398 	int ret;
399 
400 	rzv2m_csi_sw_reset(csi, 0);
401 
402 	writel(CSI_MODE_SETUP, csi->base + CSI_MODE);
403 
404 	/* Setup clock polarity and phase timing */
405 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_CKP,
406 				!(spi->mode & SPI_CPOL));
407 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_DAP,
408 				!(spi->mode & SPI_CPHA));
409 
410 	/* Setup serial data order */
411 	rzv2m_csi_reg_write_bit(csi, CSI_MODE, CSI_MODE_DIR,
412 				!!(spi->mode & SPI_LSB_FIRST));
413 
414 	/* Set the operation mode as master */
415 	rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_SLAVE, 0);
416 
417 	/* Give the IP a SW reset */
418 	ret = rzv2m_csi_sw_reset(csi, 1);
419 	if (ret)
420 		return ret;
421 	rzv2m_csi_sw_reset(csi, 0);
422 
423 	/*
424 	 * We need to enable the communication so that the clock will settle
425 	 * for the right polarity before enabling the CS.
426 	 */
427 	rzv2m_csi_start_stop_operation(csi, 1, false);
428 	udelay(10);
429 	rzv2m_csi_start_stop_operation(csi, 0, false);
430 
431 	return 0;
432 }
433 
434 static int rzv2m_csi_pio_transfer(struct rzv2m_csi_priv *csi)
435 {
436 	bool tx_completed = csi->txbuf ? false : true;
437 	bool rx_completed = csi->rxbuf ? false : true;
438 	int ret = 0;
439 
440 	/* Make sure the TX FIFO is empty */
441 	writel(0, csi->base + CSI_OFIFOL);
442 
443 	csi->bytes_sent = 0;
444 	csi->bytes_received = 0;
445 	csi->errors = 0;
446 
447 	rzv2m_csi_disable_all_irqs(csi);
448 	rzv2m_csi_clear_all_irqs(csi);
449 	rzv2m_csi_enable_rx_trigger(csi, true);
450 
451 	while (!tx_completed || !rx_completed) {
452 		/*
453 		 * Decide how many words we are going to transfer during
454 		 * this cycle (for both TX and RX), then set the RX FIFO trigger
455 		 * level accordingly. No need to set a trigger level for the
456 		 * TX FIFO, as this IP comes with an interrupt that fires when
457 		 * the TX FIFO is empty.
458 		 */
459 		rzv2m_csi_calc_current_transfer(csi);
460 		rzv2m_csi_set_rx_fifo_trigger_level(csi);
461 
462 		rzv2m_csi_enable_irqs(csi, CSI_INT_OVERF | CSI_INT_UNDER);
463 
464 		/* Make sure the RX FIFO is empty */
465 		writel(0, csi->base + CSI_IFIFOL);
466 
467 		writel(readl(csi->base + CSI_INT), csi->base + CSI_INT);
468 		csi->status = 0;
469 
470 		rzv2m_csi_start_stop_operation(csi, 1, false);
471 
472 		/* TX */
473 		if (csi->txbuf) {
474 			ret = rzv2m_csi_fill_txfifo(csi);
475 			if (ret)
476 				break;
477 
478 			ret = rzv2m_csi_wait_for_tx_empty(csi);
479 			if (ret)
480 				break;
481 
482 			if (csi->bytes_sent == csi->buffer_len)
483 				tx_completed = true;
484 		}
485 
486 		/*
487 		 * Make sure the RX FIFO contains the desired number of words.
488 		 * We then either flush its content, or we copy it onto
489 		 * csi->rxbuf.
490 		 */
491 		ret = rzv2m_csi_wait_for_rx_ready(csi);
492 		if (ret)
493 			break;
494 
495 		/* RX */
496 		if (csi->rxbuf) {
497 			rzv2m_csi_start_stop_operation(csi, 0, false);
498 
499 			ret = rzv2m_csi_read_rxfifo(csi);
500 			if (ret)
501 				break;
502 
503 			if (csi->bytes_received == csi->buffer_len)
504 				rx_completed = true;
505 		}
506 
507 		ret = rzv2m_csi_start_stop_operation(csi, 0, true);
508 		if (ret)
509 			goto pio_quit;
510 
511 		if (csi->errors) {
512 			ret = -EIO;
513 			goto pio_quit;
514 		}
515 	}
516 
517 	rzv2m_csi_start_stop_operation(csi, 0, true);
518 
519 pio_quit:
520 	rzv2m_csi_disable_all_irqs(csi);
521 	rzv2m_csi_enable_rx_trigger(csi, false);
522 	rzv2m_csi_clear_all_irqs(csi);
523 
524 	return ret;
525 }
526 
527 static int rzv2m_csi_transfer_one(struct spi_controller *controller,
528 				  struct spi_device *spi,
529 				  struct spi_transfer *transfer)
530 {
531 	struct rzv2m_csi_priv *csi = spi_controller_get_devdata(controller);
532 	struct device *dev = csi->dev;
533 	int ret;
534 
535 	csi->txbuf = transfer->tx_buf;
536 	csi->rxbuf = transfer->rx_buf;
537 	csi->buffer_len = transfer->len;
538 
539 	rzv2m_csi_setup_operating_mode(csi, transfer);
540 
541 	rzv2m_csi_setup_clock(csi, transfer->speed_hz);
542 
543 	ret = rzv2m_csi_pio_transfer(csi);
544 	if (ret) {
545 		if (csi->errors & UNDERRUN_ERROR)
546 			dev_err(dev, "Underrun error\n");
547 		if (csi->errors & OVERFLOW_ERROR)
548 			dev_err(dev, "Overflow error\n");
549 		if (csi->errors & TX_TIMEOUT_ERROR)
550 			dev_err(dev, "TX timeout error\n");
551 		if (csi->errors & RX_TIMEOUT_ERROR)
552 			dev_err(dev, "RX timeout error\n");
553 	}
554 
555 	return ret;
556 }
557 
558 static int rzv2m_csi_probe(struct platform_device *pdev)
559 {
560 	struct spi_controller *controller;
561 	struct device *dev = &pdev->dev;
562 	struct rzv2m_csi_priv *csi;
563 	struct reset_control *rstc;
564 	int irq;
565 	int ret;
566 
567 	controller = devm_spi_alloc_master(dev, sizeof(*csi));
568 	if (!controller)
569 		return -ENOMEM;
570 
571 	csi = spi_controller_get_devdata(controller);
572 	platform_set_drvdata(pdev, csi);
573 
574 	csi->dev = dev;
575 	csi->controller = controller;
576 
577 	csi->base = devm_platform_ioremap_resource(pdev, 0);
578 	if (IS_ERR(csi->base))
579 		return PTR_ERR(csi->base);
580 
581 	irq = platform_get_irq(pdev, 0);
582 	if (irq < 0)
583 		return irq;
584 
585 	csi->csiclk = devm_clk_get(dev, "csiclk");
586 	if (IS_ERR(csi->csiclk))
587 		return dev_err_probe(dev, PTR_ERR(csi->csiclk),
588 				     "could not get csiclk\n");
589 
590 	csi->pclk = devm_clk_get(dev, "pclk");
591 	if (IS_ERR(csi->pclk))
592 		return dev_err_probe(dev, PTR_ERR(csi->pclk),
593 				     "could not get pclk\n");
594 
595 	rstc = devm_reset_control_get_shared(dev, NULL);
596 	if (IS_ERR(rstc))
597 		return dev_err_probe(dev, PTR_ERR(rstc), "Missing reset ctrl\n");
598 
599 	init_waitqueue_head(&csi->wait);
600 
601 	controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
602 	controller->dev.of_node = pdev->dev.of_node;
603 	controller->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8);
604 	controller->setup = rzv2m_csi_setup;
605 	controller->transfer_one = rzv2m_csi_transfer_one;
606 	controller->use_gpio_descriptors = true;
607 
608 	ret = devm_request_irq(dev, irq, rzv2m_csi_irq_handler, 0,
609 			       dev_name(dev), csi);
610 	if (ret)
611 		return dev_err_probe(dev, ret, "cannot request IRQ\n");
612 
613 	/*
614 	 * The reset also affects other HW that is not under the control
615 	 * of Linux. Therefore, all we can do is make sure the reset is
616 	 * deasserted.
617 	 */
618 	reset_control_deassert(rstc);
619 
620 	/* Make sure the IP is in SW reset state */
621 	ret = rzv2m_csi_sw_reset(csi, 1);
622 	if (ret)
623 		return ret;
624 
625 	ret = clk_prepare_enable(csi->csiclk);
626 	if (ret)
627 		return dev_err_probe(dev, ret, "could not enable csiclk\n");
628 
629 	ret = spi_register_controller(controller);
630 	if (ret) {
631 		clk_disable_unprepare(csi->csiclk);
632 		return dev_err_probe(dev, ret, "register controller failed\n");
633 	}
634 
635 	return 0;
636 }
637 
638 static int rzv2m_csi_remove(struct platform_device *pdev)
639 {
640 	struct rzv2m_csi_priv *csi = platform_get_drvdata(pdev);
641 
642 	spi_unregister_controller(csi->controller);
643 	rzv2m_csi_sw_reset(csi, 1);
644 	clk_disable_unprepare(csi->csiclk);
645 
646 	return 0;
647 }
648 
649 static const struct of_device_id rzv2m_csi_match[] = {
650 	{ .compatible = "renesas,rzv2m-csi" },
651 	{ /* sentinel */ }
652 };
653 MODULE_DEVICE_TABLE(of, rzv2m_csi_match);
654 
655 static struct platform_driver rzv2m_csi_drv = {
656 	.probe = rzv2m_csi_probe,
657 	.remove = rzv2m_csi_remove,
658 	.driver = {
659 		.name = "rzv2m_csi",
660 		.of_match_table = rzv2m_csi_match,
661 	},
662 };
663 module_platform_driver(rzv2m_csi_drv);
664 
665 MODULE_LICENSE("GPL");
666 MODULE_AUTHOR("Fabrizio Castro <castro.fabrizio.jz@renesas.com>");
667 MODULE_DESCRIPTION("Clocked Serial Interface Driver");
668