1 // SPDX-License-Identifier: (GPL-2.0)
2 /*
3  * Microchip CoreSPI SPI controller driver
4  *
5  * Copyright (c) 2018-2022 Microchip Technology Inc. and its subsidiaries
6  *
7  * Author: Daire McNamara <daire.mcnamara@microchip.com>
8  * Author: Conor Dooley <conor.dooley@microchip.com>
9  *
10  */
11 
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/io.h>
18 #include <linux/module.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/spi/spi.h>
22 
23 #define MAX_LEN				(0xffff)
24 #define MAX_CS				(8)
25 #define DEFAULT_FRAMESIZE		(8)
26 #define FIFO_DEPTH			(32)
27 #define CLK_GEN_MODE1_MAX		(255)
28 #define CLK_GEN_MODE0_MAX		(15)
29 #define CLK_GEN_MIN			(0)
30 #define MODE_X_MASK_SHIFT		(24)
31 
32 #define CONTROL_ENABLE			BIT(0)
33 #define CONTROL_MASTER			BIT(1)
34 #define CONTROL_RX_DATA_INT		BIT(4)
35 #define CONTROL_TX_DATA_INT		BIT(5)
36 #define CONTROL_RX_OVER_INT		BIT(6)
37 #define CONTROL_TX_UNDER_INT		BIT(7)
38 #define CONTROL_SPO			BIT(24)
39 #define CONTROL_SPH			BIT(25)
40 #define CONTROL_SPS			BIT(26)
41 #define CONTROL_FRAMEURUN		BIT(27)
42 #define CONTROL_CLKMODE			BIT(28)
43 #define CONTROL_BIGFIFO			BIT(29)
44 #define CONTROL_OENOFF			BIT(30)
45 #define CONTROL_RESET			BIT(31)
46 
47 #define CONTROL_MODE_MASK		GENMASK(3, 2)
48 #define  MOTOROLA_MODE			(0)
49 #define CONTROL_FRAMECNT_MASK		GENMASK(23, 8)
50 #define CONTROL_FRAMECNT_SHIFT		(8)
51 
52 #define STATUS_ACTIVE			BIT(14)
53 #define STATUS_SSEL			BIT(13)
54 #define STATUS_FRAMESTART		BIT(12)
55 #define STATUS_TXFIFO_EMPTY_NEXT_READ	BIT(11)
56 #define STATUS_TXFIFO_EMPTY		BIT(10)
57 #define STATUS_TXFIFO_FULL_NEXT_WRITE	BIT(9)
58 #define STATUS_TXFIFO_FULL		BIT(8)
59 #define STATUS_RXFIFO_EMPTY_NEXT_READ	BIT(7)
60 #define STATUS_RXFIFO_EMPTY		BIT(6)
61 #define STATUS_RXFIFO_FULL_NEXT_WRITE	BIT(5)
62 #define STATUS_RXFIFO_FULL		BIT(4)
63 #define STATUS_TX_UNDERRUN		BIT(3)
64 #define STATUS_RX_OVERFLOW		BIT(2)
65 #define STATUS_RXDAT_RXED		BIT(1)
66 #define STATUS_TXDAT_SENT		BIT(0)
67 
68 #define INT_TXDONE			BIT(0)
69 #define INT_RXRDY			BIT(1)
70 #define INT_RX_CHANNEL_OVERFLOW		BIT(2)
71 #define INT_TX_CHANNEL_UNDERRUN		BIT(3)
72 
73 #define INT_ENABLE_MASK (CONTROL_RX_DATA_INT | CONTROL_TX_DATA_INT | \
74 			 CONTROL_RX_OVER_INT | CONTROL_TX_UNDER_INT)
75 
76 #define REG_CONTROL		(0x00)
77 #define REG_FRAME_SIZE		(0x04)
78 #define REG_STATUS		(0x08)
79 #define REG_INT_CLEAR		(0x0c)
80 #define REG_RX_DATA		(0x10)
81 #define REG_TX_DATA		(0x14)
82 #define REG_CLK_GEN		(0x18)
83 #define REG_SLAVE_SELECT	(0x1c)
84 #define  SSEL_MASK		GENMASK(7, 0)
85 #define  SSEL_DIRECT		BIT(8)
86 #define  SSELOUT_SHIFT		9
87 #define  SSELOUT		BIT(SSELOUT_SHIFT)
88 #define REG_MIS			(0x20)
89 #define REG_RIS			(0x24)
90 #define REG_CONTROL2		(0x28)
91 #define REG_COMMAND		(0x2c)
92 #define REG_PKTSIZE		(0x30)
93 #define REG_CMD_SIZE		(0x34)
94 #define REG_HWSTATUS		(0x38)
95 #define REG_STAT8		(0x3c)
96 #define REG_CTRL2		(0x48)
97 #define REG_FRAMESUP		(0x50)
98 
99 struct mchp_corespi {
100 	void __iomem *regs;
101 	struct clk *clk;
102 	const u8 *tx_buf;
103 	u8 *rx_buf;
104 	u32 clk_gen; /* divider for spi output clock generated by the controller */
105 	u32 clk_mode;
106 	int irq;
107 	int tx_len;
108 	int rx_len;
109 	int pending;
110 };
111 
mchp_corespi_read(struct mchp_corespi * spi,unsigned int reg)112 static inline u32 mchp_corespi_read(struct mchp_corespi *spi, unsigned int reg)
113 {
114 	return readl(spi->regs + reg);
115 }
116 
mchp_corespi_write(struct mchp_corespi * spi,unsigned int reg,u32 val)117 static inline void mchp_corespi_write(struct mchp_corespi *spi, unsigned int reg, u32 val)
118 {
119 	writel(val, spi->regs + reg);
120 }
121 
mchp_corespi_enable(struct mchp_corespi * spi)122 static inline void mchp_corespi_enable(struct mchp_corespi *spi)
123 {
124 	u32 control = mchp_corespi_read(spi, REG_CONTROL);
125 
126 	control |= CONTROL_ENABLE;
127 
128 	mchp_corespi_write(spi, REG_CONTROL, control);
129 }
130 
mchp_corespi_disable(struct mchp_corespi * spi)131 static inline void mchp_corespi_disable(struct mchp_corespi *spi)
132 {
133 	u32 control = mchp_corespi_read(spi, REG_CONTROL);
134 
135 	control &= ~CONTROL_ENABLE;
136 
137 	mchp_corespi_write(spi, REG_CONTROL, control);
138 }
139 
mchp_corespi_read_fifo(struct mchp_corespi * spi)140 static inline void mchp_corespi_read_fifo(struct mchp_corespi *spi)
141 {
142 	u8 data;
143 	int fifo_max, i = 0;
144 
145 	fifo_max = min(spi->rx_len, FIFO_DEPTH);
146 
147 	while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_RXFIFO_EMPTY)) {
148 		data = mchp_corespi_read(spi, REG_RX_DATA);
149 
150 		if (spi->rx_buf)
151 			*spi->rx_buf++ = data;
152 		i++;
153 	}
154 	spi->rx_len -= i;
155 	spi->pending -= i;
156 }
157 
mchp_corespi_enable_ints(struct mchp_corespi * spi)158 static void mchp_corespi_enable_ints(struct mchp_corespi *spi)
159 {
160 	u32 control, mask = INT_ENABLE_MASK;
161 
162 	mchp_corespi_disable(spi);
163 
164 	control = mchp_corespi_read(spi, REG_CONTROL);
165 
166 	control |= mask;
167 	mchp_corespi_write(spi, REG_CONTROL, control);
168 
169 	control |= CONTROL_ENABLE;
170 	mchp_corespi_write(spi, REG_CONTROL, control);
171 }
172 
mchp_corespi_disable_ints(struct mchp_corespi * spi)173 static void mchp_corespi_disable_ints(struct mchp_corespi *spi)
174 {
175 	u32 control, mask = INT_ENABLE_MASK;
176 
177 	mchp_corespi_disable(spi);
178 
179 	control = mchp_corespi_read(spi, REG_CONTROL);
180 	control &= ~mask;
181 	mchp_corespi_write(spi, REG_CONTROL, control);
182 
183 	control |= CONTROL_ENABLE;
184 	mchp_corespi_write(spi, REG_CONTROL, control);
185 }
186 
mchp_corespi_set_xfer_size(struct mchp_corespi * spi,int len)187 static inline void mchp_corespi_set_xfer_size(struct mchp_corespi *spi, int len)
188 {
189 	u32 control;
190 	u16 lenpart;
191 
192 	/*
193 	 * Disable the SPI controller. Writes to transfer length have
194 	 * no effect when the controller is enabled.
195 	 */
196 	mchp_corespi_disable(spi);
197 
198 	/*
199 	 * The lower 16 bits of the frame count are stored in the control reg
200 	 * for legacy reasons, but the upper 16 written to a different register:
201 	 * FRAMESUP. While both the upper and lower bits can be *READ* from the
202 	 * FRAMESUP register, writing to the lower 16 bits is a NOP
203 	 */
204 	lenpart = len & 0xffff;
205 
206 	control = mchp_corespi_read(spi, REG_CONTROL);
207 	control &= ~CONTROL_FRAMECNT_MASK;
208 	control |= lenpart << CONTROL_FRAMECNT_SHIFT;
209 	mchp_corespi_write(spi, REG_CONTROL, control);
210 
211 	lenpart = len & 0xffff0000;
212 	mchp_corespi_write(spi, REG_FRAMESUP, lenpart);
213 
214 	control |= CONTROL_ENABLE;
215 	mchp_corespi_write(spi, REG_CONTROL, control);
216 }
217 
mchp_corespi_write_fifo(struct mchp_corespi * spi)218 static inline void mchp_corespi_write_fifo(struct mchp_corespi *spi)
219 {
220 	u8 byte;
221 	int fifo_max, i = 0;
222 
223 	fifo_max = min(spi->tx_len, FIFO_DEPTH);
224 	mchp_corespi_set_xfer_size(spi, fifo_max);
225 
226 	while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_TXFIFO_FULL)) {
227 		byte = spi->tx_buf ? *spi->tx_buf++ : 0xaa;
228 		mchp_corespi_write(spi, REG_TX_DATA, byte);
229 		i++;
230 	}
231 
232 	spi->tx_len -= i;
233 	spi->pending += i;
234 }
235 
mchp_corespi_set_framesize(struct mchp_corespi * spi,int bt)236 static inline void mchp_corespi_set_framesize(struct mchp_corespi *spi, int bt)
237 {
238 	u32 control;
239 
240 	/*
241 	 * Disable the SPI controller. Writes to the frame size have
242 	 * no effect when the controller is enabled.
243 	 */
244 	mchp_corespi_disable(spi);
245 
246 	mchp_corespi_write(spi, REG_FRAME_SIZE, bt);
247 
248 	control = mchp_corespi_read(spi, REG_CONTROL);
249 	control |= CONTROL_ENABLE;
250 	mchp_corespi_write(spi, REG_CONTROL, control);
251 }
252 
mchp_corespi_set_cs(struct spi_device * spi,bool disable)253 static void mchp_corespi_set_cs(struct spi_device *spi, bool disable)
254 {
255 	u32 reg;
256 	struct mchp_corespi *corespi = spi_master_get_devdata(spi->master);
257 
258 	reg = mchp_corespi_read(corespi, REG_SLAVE_SELECT);
259 	reg &= ~BIT(spi->chip_select);
260 	reg |= !disable << spi->chip_select;
261 
262 	mchp_corespi_write(corespi, REG_SLAVE_SELECT, reg);
263 }
264 
mchp_corespi_setup(struct spi_device * spi)265 static int mchp_corespi_setup(struct spi_device *spi)
266 {
267 	struct mchp_corespi *corespi = spi_master_get_devdata(spi->master);
268 	u32 reg;
269 
270 	/*
271 	 * Active high slaves need to be specifically set to their inactive
272 	 * states during probe by adding them to the "control group" & thus
273 	 * driving their select line low.
274 	 */
275 	if (spi->mode & SPI_CS_HIGH) {
276 		reg = mchp_corespi_read(corespi, REG_SLAVE_SELECT);
277 		reg |= BIT(spi->chip_select);
278 		mchp_corespi_write(corespi, REG_SLAVE_SELECT, reg);
279 	}
280 	return 0;
281 }
282 
mchp_corespi_init(struct spi_master * master,struct mchp_corespi * spi)283 static void mchp_corespi_init(struct spi_master *master, struct mchp_corespi *spi)
284 {
285 	unsigned long clk_hz;
286 	u32 control = mchp_corespi_read(spi, REG_CONTROL);
287 
288 	control |= CONTROL_MASTER;
289 
290 	control &= ~CONTROL_MODE_MASK;
291 	control |= MOTOROLA_MODE;
292 
293 	mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE);
294 
295 	/* max. possible spi clock rate is the apb clock rate */
296 	clk_hz = clk_get_rate(spi->clk);
297 	master->max_speed_hz = clk_hz;
298 
299 	/*
300 	 * The controller must be configured so that it doesn't remove Chip
301 	 * Select until the entire message has been transferred, even if at
302 	 * some points TX FIFO becomes empty.
303 	 *
304 	 * BIGFIFO mode is also enabled, which sets the fifo depth to 32 frames
305 	 * for the 8 bit transfers that this driver uses.
306 	 */
307 	control = mchp_corespi_read(spi, REG_CONTROL);
308 	control |= CONTROL_SPS | CONTROL_BIGFIFO;
309 
310 	mchp_corespi_write(spi, REG_CONTROL, control);
311 
312 	mchp_corespi_enable_ints(spi);
313 
314 	/*
315 	 * It is required to enable direct mode, otherwise control over the chip
316 	 * select is relinquished to the hardware. SSELOUT is enabled too so we
317 	 * can deal with active high slaves.
318 	 */
319 	mchp_corespi_write(spi, REG_SLAVE_SELECT, SSELOUT | SSEL_DIRECT);
320 
321 	control = mchp_corespi_read(spi, REG_CONTROL);
322 
323 	control &= ~CONTROL_RESET;
324 	control |= CONTROL_ENABLE;
325 
326 	mchp_corespi_write(spi, REG_CONTROL, control);
327 }
328 
mchp_corespi_set_clk_gen(struct mchp_corespi * spi)329 static inline void mchp_corespi_set_clk_gen(struct mchp_corespi *spi)
330 {
331 	u32 control;
332 
333 	mchp_corespi_disable(spi);
334 
335 	control = mchp_corespi_read(spi, REG_CONTROL);
336 	if (spi->clk_mode)
337 		control |= CONTROL_CLKMODE;
338 	else
339 		control &= ~CONTROL_CLKMODE;
340 
341 	mchp_corespi_write(spi, REG_CLK_GEN, spi->clk_gen);
342 	mchp_corespi_write(spi, REG_CONTROL, control);
343 	mchp_corespi_write(spi, REG_CONTROL, control | CONTROL_ENABLE);
344 }
345 
mchp_corespi_set_mode(struct mchp_corespi * spi,unsigned int mode)346 static inline void mchp_corespi_set_mode(struct mchp_corespi *spi, unsigned int mode)
347 {
348 	u32 control, mode_val;
349 
350 	switch (mode & SPI_MODE_X_MASK) {
351 	case SPI_MODE_0:
352 		mode_val = 0;
353 		break;
354 	case SPI_MODE_1:
355 		mode_val = CONTROL_SPH;
356 		break;
357 	case SPI_MODE_2:
358 		mode_val = CONTROL_SPO;
359 		break;
360 	case SPI_MODE_3:
361 		mode_val = CONTROL_SPH | CONTROL_SPO;
362 		break;
363 	}
364 
365 	/*
366 	 * Disable the SPI controller. Writes to the frame size have
367 	 * no effect when the controller is enabled.
368 	 */
369 	mchp_corespi_disable(spi);
370 
371 	control = mchp_corespi_read(spi, REG_CONTROL);
372 	control &= ~(SPI_MODE_X_MASK << MODE_X_MASK_SHIFT);
373 	control |= mode_val;
374 
375 	mchp_corespi_write(spi, REG_CONTROL, control);
376 
377 	control |= CONTROL_ENABLE;
378 	mchp_corespi_write(spi, REG_CONTROL, control);
379 }
380 
mchp_corespi_interrupt(int irq,void * dev_id)381 static irqreturn_t mchp_corespi_interrupt(int irq, void *dev_id)
382 {
383 	struct spi_master *master = dev_id;
384 	struct mchp_corespi *spi = spi_master_get_devdata(master);
385 	u32 intfield = mchp_corespi_read(spi, REG_MIS) & 0xf;
386 	bool finalise = false;
387 
388 	/* Interrupt line may be shared and not for us at all */
389 	if (intfield == 0)
390 		return IRQ_NONE;
391 
392 	if (intfield & INT_TXDONE) {
393 		mchp_corespi_write(spi, REG_INT_CLEAR, INT_TXDONE);
394 
395 		if (spi->rx_len)
396 			mchp_corespi_read_fifo(spi);
397 
398 		if (spi->tx_len)
399 			mchp_corespi_write_fifo(spi);
400 
401 		if (!spi->rx_len)
402 			finalise = true;
403 	}
404 
405 	if (intfield & INT_RXRDY)
406 		mchp_corespi_write(spi, REG_INT_CLEAR, INT_RXRDY);
407 
408 	if (intfield & INT_RX_CHANNEL_OVERFLOW) {
409 		mchp_corespi_write(spi, REG_INT_CLEAR, INT_RX_CHANNEL_OVERFLOW);
410 		finalise = true;
411 		dev_err(&master->dev,
412 			"%s: RX OVERFLOW: rxlen: %d, txlen: %d\n", __func__,
413 			spi->rx_len, spi->tx_len);
414 	}
415 
416 	if (intfield & INT_TX_CHANNEL_UNDERRUN) {
417 		mchp_corespi_write(spi, REG_INT_CLEAR, INT_TX_CHANNEL_UNDERRUN);
418 		finalise = true;
419 		dev_err(&master->dev,
420 			"%s: TX UNDERFLOW: rxlen: %d, txlen: %d\n", __func__,
421 			spi->rx_len, spi->tx_len);
422 	}
423 
424 	if (finalise)
425 		spi_finalize_current_transfer(master);
426 
427 	return IRQ_HANDLED;
428 }
429 
mchp_corespi_calculate_clkgen(struct mchp_corespi * spi,unsigned long target_hz)430 static int mchp_corespi_calculate_clkgen(struct mchp_corespi *spi,
431 					 unsigned long target_hz)
432 {
433 	unsigned long clk_hz, spi_hz, clk_gen;
434 
435 	clk_hz = clk_get_rate(spi->clk);
436 	if (!clk_hz)
437 		return -EINVAL;
438 	spi_hz = min(target_hz, clk_hz);
439 
440 	/*
441 	 * There are two possible clock modes for the controller generated
442 	 * clock's division ratio:
443 	 * CLK_MODE = 0: 1 / (2^(CLK_GEN + 1)) where CLK_GEN = 0 to 15.
444 	 * CLK_MODE = 1: 1 / (2 * CLK_GEN + 1) where CLK_GEN = 0 to 255.
445 	 * First try mode 1, fall back to 0 and if we have tried both modes and
446 	 * we /still/ can't get a good setting, we then throw the toys out of
447 	 * the pram and give up
448 	 * clk_gen is the register name for the clock divider on MPFS.
449 	 */
450 	clk_gen = DIV_ROUND_UP(clk_hz, 2 * spi_hz) - 1;
451 	if (clk_gen > CLK_GEN_MODE1_MAX || clk_gen <= CLK_GEN_MIN) {
452 		clk_gen = DIV_ROUND_UP(clk_hz, spi_hz);
453 		clk_gen = fls(clk_gen) - 1;
454 
455 		if (clk_gen > CLK_GEN_MODE0_MAX)
456 			return -EINVAL;
457 
458 		spi->clk_mode = 0;
459 	} else {
460 		spi->clk_mode = 1;
461 	}
462 
463 	spi->clk_gen = clk_gen;
464 	return 0;
465 }
466 
mchp_corespi_transfer_one(struct spi_master * master,struct spi_device * spi_dev,struct spi_transfer * xfer)467 static int mchp_corespi_transfer_one(struct spi_master *master,
468 				     struct spi_device *spi_dev,
469 				     struct spi_transfer *xfer)
470 {
471 	struct mchp_corespi *spi = spi_master_get_devdata(master);
472 	int ret;
473 
474 	ret = mchp_corespi_calculate_clkgen(spi, (unsigned long)xfer->speed_hz);
475 	if (ret) {
476 		dev_err(&master->dev, "failed to set clk_gen for target %u Hz\n", xfer->speed_hz);
477 		return ret;
478 	}
479 
480 	mchp_corespi_set_clk_gen(spi);
481 
482 	spi->tx_buf = xfer->tx_buf;
483 	spi->rx_buf = xfer->rx_buf;
484 	spi->tx_len = xfer->len;
485 	spi->rx_len = xfer->len;
486 	spi->pending = 0;
487 
488 	mchp_corespi_set_xfer_size(spi, (spi->tx_len > FIFO_DEPTH)
489 				   ? FIFO_DEPTH : spi->tx_len);
490 
491 	if (spi->tx_len)
492 		mchp_corespi_write_fifo(spi);
493 	return 1;
494 }
495 
mchp_corespi_prepare_message(struct spi_master * master,struct spi_message * msg)496 static int mchp_corespi_prepare_message(struct spi_master *master,
497 					struct spi_message *msg)
498 {
499 	struct spi_device *spi_dev = msg->spi;
500 	struct mchp_corespi *spi = spi_master_get_devdata(master);
501 
502 	mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE);
503 	mchp_corespi_set_mode(spi, spi_dev->mode);
504 
505 	return 0;
506 }
507 
mchp_corespi_probe(struct platform_device * pdev)508 static int mchp_corespi_probe(struct platform_device *pdev)
509 {
510 	struct spi_master *master;
511 	struct mchp_corespi *spi;
512 	struct resource *res;
513 	u32 num_cs;
514 	int ret = 0;
515 
516 	master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi));
517 	if (!master)
518 		return dev_err_probe(&pdev->dev, -ENOMEM,
519 				     "unable to allocate master for SPI controller\n");
520 
521 	platform_set_drvdata(pdev, master);
522 
523 	if (of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs))
524 		num_cs = MAX_CS;
525 
526 	master->num_chipselect = num_cs;
527 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
528 	master->setup = mchp_corespi_setup;
529 	master->bits_per_word_mask = SPI_BPW_MASK(8);
530 	master->transfer_one = mchp_corespi_transfer_one;
531 	master->prepare_message = mchp_corespi_prepare_message;
532 	master->set_cs = mchp_corespi_set_cs;
533 	master->dev.of_node = pdev->dev.of_node;
534 
535 	spi = spi_master_get_devdata(master);
536 
537 	spi->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
538 	if (IS_ERR(spi->regs))
539 		return PTR_ERR(spi->regs);
540 
541 	spi->irq = platform_get_irq(pdev, 0);
542 	if (spi->irq <= 0)
543 		return dev_err_probe(&pdev->dev, -ENXIO,
544 				     "invalid IRQ %d for SPI controller\n",
545 				     spi->irq);
546 
547 	ret = devm_request_irq(&pdev->dev, spi->irq, mchp_corespi_interrupt,
548 			       IRQF_SHARED, dev_name(&pdev->dev), master);
549 	if (ret)
550 		return dev_err_probe(&pdev->dev, ret,
551 				     "could not request irq\n");
552 
553 	spi->clk = devm_clk_get(&pdev->dev, NULL);
554 	if (IS_ERR(spi->clk))
555 		return dev_err_probe(&pdev->dev, PTR_ERR(spi->clk),
556 				     "could not get clk\n");
557 
558 	ret = clk_prepare_enable(spi->clk);
559 	if (ret)
560 		return dev_err_probe(&pdev->dev, ret,
561 				     "failed to enable clock\n");
562 
563 	mchp_corespi_init(master, spi);
564 
565 	ret = devm_spi_register_master(&pdev->dev, master);
566 	if (ret) {
567 		mchp_corespi_disable(spi);
568 		clk_disable_unprepare(spi->clk);
569 		return dev_err_probe(&pdev->dev, ret,
570 				     "unable to register master for SPI controller\n");
571 	}
572 
573 	dev_info(&pdev->dev, "Registered SPI controller %d\n", master->bus_num);
574 
575 	return 0;
576 }
577 
mchp_corespi_remove(struct platform_device * pdev)578 static int mchp_corespi_remove(struct platform_device *pdev)
579 {
580 	struct spi_master *master  = platform_get_drvdata(pdev);
581 	struct mchp_corespi *spi = spi_master_get_devdata(master);
582 
583 	mchp_corespi_disable_ints(spi);
584 	clk_disable_unprepare(spi->clk);
585 	mchp_corespi_disable(spi);
586 
587 	return 0;
588 }
589 
590 #define MICROCHIP_SPI_PM_OPS (NULL)
591 
592 /*
593  * Platform driver data structure
594  */
595 
596 #if defined(CONFIG_OF)
597 static const struct of_device_id mchp_corespi_dt_ids[] = {
598 	{ .compatible = "microchip,mpfs-spi" },
599 	{ /* sentinel */ }
600 };
601 MODULE_DEVICE_TABLE(of, mchp_corespi_dt_ids);
602 #endif
603 
604 static struct platform_driver mchp_corespi_driver = {
605 	.probe = mchp_corespi_probe,
606 	.driver = {
607 		.name = "microchip-corespi",
608 		.pm = MICROCHIP_SPI_PM_OPS,
609 		.of_match_table = of_match_ptr(mchp_corespi_dt_ids),
610 	},
611 	.remove = mchp_corespi_remove,
612 };
613 module_platform_driver(mchp_corespi_driver);
614 MODULE_DESCRIPTION("Microchip coreSPI SPI controller driver");
615 MODULE_AUTHOR("Daire McNamara <daire.mcnamara@microchip.com>");
616 MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
617 MODULE_LICENSE("GPL");
618