xref: /openbmc/linux/drivers/spi/spi-rockchip.c (revision 6a143a7c)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
4  * Author: Addy Ke <addy.ke@rock-chips.com>
5  */
6 
7 #include <linux/clk.h>
8 #include <linux/dmaengine.h>
9 #include <linux/interrupt.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/pinctrl/consumer.h>
13 #include <linux/platform_device.h>
14 #include <linux/spi/spi.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/scatterlist.h>
17 
18 #define DRIVER_NAME "rockchip-spi"
19 
20 #define ROCKCHIP_SPI_CLR_BITS(reg, bits) \
21 		writel_relaxed(readl_relaxed(reg) & ~(bits), reg)
22 #define ROCKCHIP_SPI_SET_BITS(reg, bits) \
23 		writel_relaxed(readl_relaxed(reg) | (bits), reg)
24 
25 /* SPI register offsets */
26 #define ROCKCHIP_SPI_CTRLR0			0x0000
27 #define ROCKCHIP_SPI_CTRLR1			0x0004
28 #define ROCKCHIP_SPI_SSIENR			0x0008
29 #define ROCKCHIP_SPI_SER			0x000c
30 #define ROCKCHIP_SPI_BAUDR			0x0010
31 #define ROCKCHIP_SPI_TXFTLR			0x0014
32 #define ROCKCHIP_SPI_RXFTLR			0x0018
33 #define ROCKCHIP_SPI_TXFLR			0x001c
34 #define ROCKCHIP_SPI_RXFLR			0x0020
35 #define ROCKCHIP_SPI_SR				0x0024
36 #define ROCKCHIP_SPI_IPR			0x0028
37 #define ROCKCHIP_SPI_IMR			0x002c
38 #define ROCKCHIP_SPI_ISR			0x0030
39 #define ROCKCHIP_SPI_RISR			0x0034
40 #define ROCKCHIP_SPI_ICR			0x0038
41 #define ROCKCHIP_SPI_DMACR			0x003c
42 #define ROCKCHIP_SPI_DMATDLR			0x0040
43 #define ROCKCHIP_SPI_DMARDLR			0x0044
44 #define ROCKCHIP_SPI_VERSION			0x0048
45 #define ROCKCHIP_SPI_TXDR			0x0400
46 #define ROCKCHIP_SPI_RXDR			0x0800
47 
48 /* Bit fields in CTRLR0 */
49 #define CR0_DFS_OFFSET				0
50 #define CR0_DFS_4BIT				0x0
51 #define CR0_DFS_8BIT				0x1
52 #define CR0_DFS_16BIT				0x2
53 
54 #define CR0_CFS_OFFSET				2
55 
56 #define CR0_SCPH_OFFSET				6
57 
58 #define CR0_SCPOL_OFFSET			7
59 
60 #define CR0_CSM_OFFSET				8
61 #define CR0_CSM_KEEP				0x0
62 /* ss_n be high for half sclk_out cycles */
63 #define CR0_CSM_HALF				0X1
64 /* ss_n be high for one sclk_out cycle */
65 #define CR0_CSM_ONE					0x2
66 
67 /* ss_n to sclk_out delay */
68 #define CR0_SSD_OFFSET				10
69 /*
70  * The period between ss_n active and
71  * sclk_out active is half sclk_out cycles
72  */
73 #define CR0_SSD_HALF				0x0
74 /*
75  * The period between ss_n active and
76  * sclk_out active is one sclk_out cycle
77  */
78 #define CR0_SSD_ONE					0x1
79 
80 #define CR0_EM_OFFSET				11
81 #define CR0_EM_LITTLE				0x0
82 #define CR0_EM_BIG					0x1
83 
84 #define CR0_FBM_OFFSET				12
85 #define CR0_FBM_MSB					0x0
86 #define CR0_FBM_LSB					0x1
87 
88 #define CR0_BHT_OFFSET				13
89 #define CR0_BHT_16BIT				0x0
90 #define CR0_BHT_8BIT				0x1
91 
92 #define CR0_RSD_OFFSET				14
93 #define CR0_RSD_MAX				0x3
94 
95 #define CR0_FRF_OFFSET				16
96 #define CR0_FRF_SPI					0x0
97 #define CR0_FRF_SSP					0x1
98 #define CR0_FRF_MICROWIRE			0x2
99 
100 #define CR0_XFM_OFFSET				18
101 #define CR0_XFM_MASK				(0x03 << SPI_XFM_OFFSET)
102 #define CR0_XFM_TR					0x0
103 #define CR0_XFM_TO					0x1
104 #define CR0_XFM_RO					0x2
105 
106 #define CR0_OPM_OFFSET				20
107 #define CR0_OPM_MASTER				0x0
108 #define CR0_OPM_SLAVE				0x1
109 
110 #define CR0_MTM_OFFSET				0x21
111 
112 /* Bit fields in SER, 2bit */
113 #define SER_MASK					0x3
114 
115 /* Bit fields in BAUDR */
116 #define BAUDR_SCKDV_MIN				2
117 #define BAUDR_SCKDV_MAX				65534
118 
119 /* Bit fields in SR, 5bit */
120 #define SR_MASK						0x1f
121 #define SR_BUSY						(1 << 0)
122 #define SR_TF_FULL					(1 << 1)
123 #define SR_TF_EMPTY					(1 << 2)
124 #define SR_RF_EMPTY					(1 << 3)
125 #define SR_RF_FULL					(1 << 4)
126 
127 /* Bit fields in ISR, IMR, ISR, RISR, 5bit */
128 #define INT_MASK					0x1f
129 #define INT_TF_EMPTY				(1 << 0)
130 #define INT_TF_OVERFLOW				(1 << 1)
131 #define INT_RF_UNDERFLOW			(1 << 2)
132 #define INT_RF_OVERFLOW				(1 << 3)
133 #define INT_RF_FULL					(1 << 4)
134 
135 /* Bit fields in ICR, 4bit */
136 #define ICR_MASK					0x0f
137 #define ICR_ALL						(1 << 0)
138 #define ICR_RF_UNDERFLOW			(1 << 1)
139 #define ICR_RF_OVERFLOW				(1 << 2)
140 #define ICR_TF_OVERFLOW				(1 << 3)
141 
142 /* Bit fields in DMACR */
143 #define RF_DMA_EN					(1 << 0)
144 #define TF_DMA_EN					(1 << 1)
145 
146 /* Driver state flags */
147 #define RXDMA					(1 << 0)
148 #define TXDMA					(1 << 1)
149 
150 /* sclk_out: spi master internal logic in rk3x can support 50Mhz */
151 #define MAX_SCLK_OUT				50000000U
152 
153 /*
154  * SPI_CTRLR1 is 16-bits, so we should support lengths of 0xffff + 1. However,
155  * the controller seems to hang when given 0x10000, so stick with this for now.
156  */
157 #define ROCKCHIP_SPI_MAX_TRANLEN		0xffff
158 
159 #define ROCKCHIP_SPI_MAX_CS_NUM			2
160 #define ROCKCHIP_SPI_VER2_TYPE1			0x05EC0002
161 #define ROCKCHIP_SPI_VER2_TYPE2			0x00110002
162 
163 #define ROCKCHIP_AUTOSUSPEND_TIMEOUT		2000
164 
165 struct rockchip_spi {
166 	struct device *dev;
167 
168 	struct clk *spiclk;
169 	struct clk *apb_pclk;
170 
171 	void __iomem *regs;
172 	dma_addr_t dma_addr_rx;
173 	dma_addr_t dma_addr_tx;
174 
175 	const void *tx;
176 	void *rx;
177 	unsigned int tx_left;
178 	unsigned int rx_left;
179 
180 	atomic_t state;
181 
182 	/*depth of the FIFO buffer */
183 	u32 fifo_len;
184 	/* frequency of spiclk */
185 	u32 freq;
186 
187 	u8 n_bytes;
188 	u8 rsd;
189 
190 	bool cs_asserted[ROCKCHIP_SPI_MAX_CS_NUM];
191 
192 	bool slave_abort;
193 };
194 
195 static inline void spi_enable_chip(struct rockchip_spi *rs, bool enable)
196 {
197 	writel_relaxed((enable ? 1U : 0U), rs->regs + ROCKCHIP_SPI_SSIENR);
198 }
199 
200 static inline void wait_for_idle(struct rockchip_spi *rs)
201 {
202 	unsigned long timeout = jiffies + msecs_to_jiffies(5);
203 
204 	do {
205 		if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY))
206 			return;
207 	} while (!time_after(jiffies, timeout));
208 
209 	dev_warn(rs->dev, "spi controller is in busy state!\n");
210 }
211 
212 static u32 get_fifo_len(struct rockchip_spi *rs)
213 {
214 	u32 ver;
215 
216 	ver = readl_relaxed(rs->regs + ROCKCHIP_SPI_VERSION);
217 
218 	switch (ver) {
219 	case ROCKCHIP_SPI_VER2_TYPE1:
220 	case ROCKCHIP_SPI_VER2_TYPE2:
221 		return 64;
222 	default:
223 		return 32;
224 	}
225 }
226 
227 static void rockchip_spi_set_cs(struct spi_device *spi, bool enable)
228 {
229 	struct spi_controller *ctlr = spi->controller;
230 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
231 	bool cs_asserted = !enable;
232 
233 	/* Return immediately for no-op */
234 	if (cs_asserted == rs->cs_asserted[spi->chip_select])
235 		return;
236 
237 	if (cs_asserted) {
238 		/* Keep things powered as long as CS is asserted */
239 		pm_runtime_get_sync(rs->dev);
240 
241 		ROCKCHIP_SPI_SET_BITS(rs->regs + ROCKCHIP_SPI_SER,
242 				      BIT(spi->chip_select));
243 	} else {
244 		ROCKCHIP_SPI_CLR_BITS(rs->regs + ROCKCHIP_SPI_SER,
245 				      BIT(spi->chip_select));
246 
247 		/* Drop reference from when we first asserted CS */
248 		pm_runtime_put(rs->dev);
249 	}
250 
251 	rs->cs_asserted[spi->chip_select] = cs_asserted;
252 }
253 
254 static void rockchip_spi_handle_err(struct spi_controller *ctlr,
255 				    struct spi_message *msg)
256 {
257 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
258 
259 	/* stop running spi transfer
260 	 * this also flushes both rx and tx fifos
261 	 */
262 	spi_enable_chip(rs, false);
263 
264 	/* make sure all interrupts are masked */
265 	writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);
266 
267 	if (atomic_read(&rs->state) & TXDMA)
268 		dmaengine_terminate_async(ctlr->dma_tx);
269 
270 	if (atomic_read(&rs->state) & RXDMA)
271 		dmaengine_terminate_async(ctlr->dma_rx);
272 }
273 
274 static void rockchip_spi_pio_writer(struct rockchip_spi *rs)
275 {
276 	u32 tx_free = rs->fifo_len - readl_relaxed(rs->regs + ROCKCHIP_SPI_TXFLR);
277 	u32 words = min(rs->tx_left, tx_free);
278 
279 	rs->tx_left -= words;
280 	for (; words; words--) {
281 		u32 txw;
282 
283 		if (rs->n_bytes == 1)
284 			txw = *(u8 *)rs->tx;
285 		else
286 			txw = *(u16 *)rs->tx;
287 
288 		writel_relaxed(txw, rs->regs + ROCKCHIP_SPI_TXDR);
289 		rs->tx += rs->n_bytes;
290 	}
291 }
292 
293 static void rockchip_spi_pio_reader(struct rockchip_spi *rs)
294 {
295 	u32 words = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFLR);
296 	u32 rx_left = (rs->rx_left > words) ? rs->rx_left - words : 0;
297 
298 	/* the hardware doesn't allow us to change fifo threshold
299 	 * level while spi is enabled, so instead make sure to leave
300 	 * enough words in the rx fifo to get the last interrupt
301 	 * exactly when all words have been received
302 	 */
303 	if (rx_left) {
304 		u32 ftl = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFTLR) + 1;
305 
306 		if (rx_left < ftl) {
307 			rx_left = ftl;
308 			words = rs->rx_left - rx_left;
309 		}
310 	}
311 
312 	rs->rx_left = rx_left;
313 	for (; words; words--) {
314 		u32 rxw = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXDR);
315 
316 		if (!rs->rx)
317 			continue;
318 
319 		if (rs->n_bytes == 1)
320 			*(u8 *)rs->rx = (u8)rxw;
321 		else
322 			*(u16 *)rs->rx = (u16)rxw;
323 		rs->rx += rs->n_bytes;
324 	}
325 }
326 
327 static irqreturn_t rockchip_spi_isr(int irq, void *dev_id)
328 {
329 	struct spi_controller *ctlr = dev_id;
330 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
331 
332 	if (rs->tx_left)
333 		rockchip_spi_pio_writer(rs);
334 
335 	rockchip_spi_pio_reader(rs);
336 	if (!rs->rx_left) {
337 		spi_enable_chip(rs, false);
338 		writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);
339 		spi_finalize_current_transfer(ctlr);
340 	}
341 
342 	return IRQ_HANDLED;
343 }
344 
345 static int rockchip_spi_prepare_irq(struct rockchip_spi *rs,
346 		struct spi_transfer *xfer)
347 {
348 	rs->tx = xfer->tx_buf;
349 	rs->rx = xfer->rx_buf;
350 	rs->tx_left = rs->tx ? xfer->len / rs->n_bytes : 0;
351 	rs->rx_left = xfer->len / rs->n_bytes;
352 
353 	writel_relaxed(INT_RF_FULL, rs->regs + ROCKCHIP_SPI_IMR);
354 	spi_enable_chip(rs, true);
355 
356 	if (rs->tx_left)
357 		rockchip_spi_pio_writer(rs);
358 
359 	/* 1 means the transfer is in progress */
360 	return 1;
361 }
362 
363 static void rockchip_spi_dma_rxcb(void *data)
364 {
365 	struct spi_controller *ctlr = data;
366 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
367 	int state = atomic_fetch_andnot(RXDMA, &rs->state);
368 
369 	if (state & TXDMA && !rs->slave_abort)
370 		return;
371 
372 	spi_enable_chip(rs, false);
373 	spi_finalize_current_transfer(ctlr);
374 }
375 
376 static void rockchip_spi_dma_txcb(void *data)
377 {
378 	struct spi_controller *ctlr = data;
379 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
380 	int state = atomic_fetch_andnot(TXDMA, &rs->state);
381 
382 	if (state & RXDMA && !rs->slave_abort)
383 		return;
384 
385 	/* Wait until the FIFO data completely. */
386 	wait_for_idle(rs);
387 
388 	spi_enable_chip(rs, false);
389 	spi_finalize_current_transfer(ctlr);
390 }
391 
392 static u32 rockchip_spi_calc_burst_size(u32 data_len)
393 {
394 	u32 i;
395 
396 	/* burst size: 1, 2, 4, 8 */
397 	for (i = 1; i < 8; i <<= 1) {
398 		if (data_len & i)
399 			break;
400 	}
401 
402 	return i;
403 }
404 
405 static int rockchip_spi_prepare_dma(struct rockchip_spi *rs,
406 		struct spi_controller *ctlr, struct spi_transfer *xfer)
407 {
408 	struct dma_async_tx_descriptor *rxdesc, *txdesc;
409 
410 	atomic_set(&rs->state, 0);
411 
412 	rxdesc = NULL;
413 	if (xfer->rx_buf) {
414 		struct dma_slave_config rxconf = {
415 			.direction = DMA_DEV_TO_MEM,
416 			.src_addr = rs->dma_addr_rx,
417 			.src_addr_width = rs->n_bytes,
418 			.src_maxburst = rockchip_spi_calc_burst_size(xfer->len /
419 								     rs->n_bytes),
420 		};
421 
422 		dmaengine_slave_config(ctlr->dma_rx, &rxconf);
423 
424 		rxdesc = dmaengine_prep_slave_sg(
425 				ctlr->dma_rx,
426 				xfer->rx_sg.sgl, xfer->rx_sg.nents,
427 				DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
428 		if (!rxdesc)
429 			return -EINVAL;
430 
431 		rxdesc->callback = rockchip_spi_dma_rxcb;
432 		rxdesc->callback_param = ctlr;
433 	}
434 
435 	txdesc = NULL;
436 	if (xfer->tx_buf) {
437 		struct dma_slave_config txconf = {
438 			.direction = DMA_MEM_TO_DEV,
439 			.dst_addr = rs->dma_addr_tx,
440 			.dst_addr_width = rs->n_bytes,
441 			.dst_maxburst = rs->fifo_len / 4,
442 		};
443 
444 		dmaengine_slave_config(ctlr->dma_tx, &txconf);
445 
446 		txdesc = dmaengine_prep_slave_sg(
447 				ctlr->dma_tx,
448 				xfer->tx_sg.sgl, xfer->tx_sg.nents,
449 				DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
450 		if (!txdesc) {
451 			if (rxdesc)
452 				dmaengine_terminate_sync(ctlr->dma_rx);
453 			return -EINVAL;
454 		}
455 
456 		txdesc->callback = rockchip_spi_dma_txcb;
457 		txdesc->callback_param = ctlr;
458 	}
459 
460 	/* rx must be started before tx due to spi instinct */
461 	if (rxdesc) {
462 		atomic_or(RXDMA, &rs->state);
463 		dmaengine_submit(rxdesc);
464 		dma_async_issue_pending(ctlr->dma_rx);
465 	}
466 
467 	spi_enable_chip(rs, true);
468 
469 	if (txdesc) {
470 		atomic_or(TXDMA, &rs->state);
471 		dmaengine_submit(txdesc);
472 		dma_async_issue_pending(ctlr->dma_tx);
473 	}
474 
475 	/* 1 means the transfer is in progress */
476 	return 1;
477 }
478 
479 static void rockchip_spi_config(struct rockchip_spi *rs,
480 		struct spi_device *spi, struct spi_transfer *xfer,
481 		bool use_dma, bool slave_mode)
482 {
483 	u32 cr0 = CR0_FRF_SPI  << CR0_FRF_OFFSET
484 	        | CR0_BHT_8BIT << CR0_BHT_OFFSET
485 	        | CR0_SSD_ONE  << CR0_SSD_OFFSET
486 	        | CR0_EM_BIG   << CR0_EM_OFFSET;
487 	u32 cr1;
488 	u32 dmacr = 0;
489 
490 	if (slave_mode)
491 		cr0 |= CR0_OPM_SLAVE << CR0_OPM_OFFSET;
492 	rs->slave_abort = false;
493 
494 	cr0 |= rs->rsd << CR0_RSD_OFFSET;
495 	cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET;
496 	if (spi->mode & SPI_LSB_FIRST)
497 		cr0 |= CR0_FBM_LSB << CR0_FBM_OFFSET;
498 
499 	if (xfer->rx_buf && xfer->tx_buf)
500 		cr0 |= CR0_XFM_TR << CR0_XFM_OFFSET;
501 	else if (xfer->rx_buf)
502 		cr0 |= CR0_XFM_RO << CR0_XFM_OFFSET;
503 	else if (use_dma)
504 		cr0 |= CR0_XFM_TO << CR0_XFM_OFFSET;
505 
506 	switch (xfer->bits_per_word) {
507 	case 4:
508 		cr0 |= CR0_DFS_4BIT << CR0_DFS_OFFSET;
509 		cr1 = xfer->len - 1;
510 		break;
511 	case 8:
512 		cr0 |= CR0_DFS_8BIT << CR0_DFS_OFFSET;
513 		cr1 = xfer->len - 1;
514 		break;
515 	case 16:
516 		cr0 |= CR0_DFS_16BIT << CR0_DFS_OFFSET;
517 		cr1 = xfer->len / 2 - 1;
518 		break;
519 	default:
520 		/* we only whitelist 4, 8 and 16 bit words in
521 		 * ctlr->bits_per_word_mask, so this shouldn't
522 		 * happen
523 		 */
524 		unreachable();
525 	}
526 
527 	if (use_dma) {
528 		if (xfer->tx_buf)
529 			dmacr |= TF_DMA_EN;
530 		if (xfer->rx_buf)
531 			dmacr |= RF_DMA_EN;
532 	}
533 
534 	writel_relaxed(cr0, rs->regs + ROCKCHIP_SPI_CTRLR0);
535 	writel_relaxed(cr1, rs->regs + ROCKCHIP_SPI_CTRLR1);
536 
537 	/* unfortunately setting the fifo threshold level to generate an
538 	 * interrupt exactly when the fifo is full doesn't seem to work,
539 	 * so we need the strict inequality here
540 	 */
541 	if (xfer->len < rs->fifo_len)
542 		writel_relaxed(xfer->len - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
543 	else
544 		writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
545 
546 	writel_relaxed(rs->fifo_len / 2, rs->regs + ROCKCHIP_SPI_DMATDLR);
547 	writel_relaxed(rockchip_spi_calc_burst_size(xfer->len / rs->n_bytes) - 1,
548 		       rs->regs + ROCKCHIP_SPI_DMARDLR);
549 	writel_relaxed(dmacr, rs->regs + ROCKCHIP_SPI_DMACR);
550 
551 	/* the hardware only supports an even clock divisor, so
552 	 * round divisor = spiclk / speed up to nearest even number
553 	 * so that the resulting speed is <= the requested speed
554 	 */
555 	writel_relaxed(2 * DIV_ROUND_UP(rs->freq, 2 * xfer->speed_hz),
556 			rs->regs + ROCKCHIP_SPI_BAUDR);
557 }
558 
559 static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
560 {
561 	return ROCKCHIP_SPI_MAX_TRANLEN;
562 }
563 
564 static int rockchip_spi_slave_abort(struct spi_controller *ctlr)
565 {
566 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
567 
568 	rs->slave_abort = true;
569 	spi_finalize_current_transfer(ctlr);
570 
571 	return 0;
572 }
573 
574 static int rockchip_spi_transfer_one(
575 		struct spi_controller *ctlr,
576 		struct spi_device *spi,
577 		struct spi_transfer *xfer)
578 {
579 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
580 	bool use_dma;
581 
582 	WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) &&
583 		(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY));
584 
585 	if (!xfer->tx_buf && !xfer->rx_buf) {
586 		dev_err(rs->dev, "No buffer for transfer\n");
587 		return -EINVAL;
588 	}
589 
590 	if (xfer->len > ROCKCHIP_SPI_MAX_TRANLEN) {
591 		dev_err(rs->dev, "Transfer is too long (%d)\n", xfer->len);
592 		return -EINVAL;
593 	}
594 
595 	rs->n_bytes = xfer->bits_per_word <= 8 ? 1 : 2;
596 
597 	use_dma = ctlr->can_dma ? ctlr->can_dma(ctlr, spi, xfer) : false;
598 
599 	rockchip_spi_config(rs, spi, xfer, use_dma, ctlr->slave);
600 
601 	if (use_dma)
602 		return rockchip_spi_prepare_dma(rs, ctlr, xfer);
603 
604 	return rockchip_spi_prepare_irq(rs, xfer);
605 }
606 
607 static bool rockchip_spi_can_dma(struct spi_controller *ctlr,
608 				 struct spi_device *spi,
609 				 struct spi_transfer *xfer)
610 {
611 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
612 	unsigned int bytes_per_word = xfer->bits_per_word <= 8 ? 1 : 2;
613 
614 	/* if the numbor of spi words to transfer is less than the fifo
615 	 * length we can just fill the fifo and wait for a single irq,
616 	 * so don't bother setting up dma
617 	 */
618 	return xfer->len / bytes_per_word >= rs->fifo_len;
619 }
620 
621 static int rockchip_spi_probe(struct platform_device *pdev)
622 {
623 	int ret;
624 	struct rockchip_spi *rs;
625 	struct spi_controller *ctlr;
626 	struct resource *mem;
627 	struct device_node *np = pdev->dev.of_node;
628 	u32 rsd_nsecs;
629 	bool slave_mode;
630 
631 	slave_mode = of_property_read_bool(np, "spi-slave");
632 
633 	if (slave_mode)
634 		ctlr = spi_alloc_slave(&pdev->dev,
635 				sizeof(struct rockchip_spi));
636 	else
637 		ctlr = spi_alloc_master(&pdev->dev,
638 				sizeof(struct rockchip_spi));
639 
640 	if (!ctlr)
641 		return -ENOMEM;
642 
643 	platform_set_drvdata(pdev, ctlr);
644 
645 	rs = spi_controller_get_devdata(ctlr);
646 	ctlr->slave = slave_mode;
647 
648 	/* Get basic io resource and map it */
649 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
650 	rs->regs = devm_ioremap_resource(&pdev->dev, mem);
651 	if (IS_ERR(rs->regs)) {
652 		ret =  PTR_ERR(rs->regs);
653 		goto err_put_ctlr;
654 	}
655 
656 	rs->apb_pclk = devm_clk_get(&pdev->dev, "apb_pclk");
657 	if (IS_ERR(rs->apb_pclk)) {
658 		dev_err(&pdev->dev, "Failed to get apb_pclk\n");
659 		ret = PTR_ERR(rs->apb_pclk);
660 		goto err_put_ctlr;
661 	}
662 
663 	rs->spiclk = devm_clk_get(&pdev->dev, "spiclk");
664 	if (IS_ERR(rs->spiclk)) {
665 		dev_err(&pdev->dev, "Failed to get spi_pclk\n");
666 		ret = PTR_ERR(rs->spiclk);
667 		goto err_put_ctlr;
668 	}
669 
670 	ret = clk_prepare_enable(rs->apb_pclk);
671 	if (ret < 0) {
672 		dev_err(&pdev->dev, "Failed to enable apb_pclk\n");
673 		goto err_put_ctlr;
674 	}
675 
676 	ret = clk_prepare_enable(rs->spiclk);
677 	if (ret < 0) {
678 		dev_err(&pdev->dev, "Failed to enable spi_clk\n");
679 		goto err_disable_apbclk;
680 	}
681 
682 	spi_enable_chip(rs, false);
683 
684 	ret = platform_get_irq(pdev, 0);
685 	if (ret < 0)
686 		goto err_disable_spiclk;
687 
688 	ret = devm_request_threaded_irq(&pdev->dev, ret, rockchip_spi_isr, NULL,
689 			IRQF_ONESHOT, dev_name(&pdev->dev), ctlr);
690 	if (ret)
691 		goto err_disable_spiclk;
692 
693 	rs->dev = &pdev->dev;
694 	rs->freq = clk_get_rate(rs->spiclk);
695 
696 	if (!of_property_read_u32(pdev->dev.of_node, "rx-sample-delay-ns",
697 				  &rsd_nsecs)) {
698 		/* rx sample delay is expressed in parent clock cycles (max 3) */
699 		u32 rsd = DIV_ROUND_CLOSEST(rsd_nsecs * (rs->freq >> 8),
700 				1000000000 >> 8);
701 		if (!rsd) {
702 			dev_warn(rs->dev, "%u Hz are too slow to express %u ns delay\n",
703 					rs->freq, rsd_nsecs);
704 		} else if (rsd > CR0_RSD_MAX) {
705 			rsd = CR0_RSD_MAX;
706 			dev_warn(rs->dev, "%u Hz are too fast to express %u ns delay, clamping at %u ns\n",
707 					rs->freq, rsd_nsecs,
708 					CR0_RSD_MAX * 1000000000U / rs->freq);
709 		}
710 		rs->rsd = rsd;
711 	}
712 
713 	rs->fifo_len = get_fifo_len(rs);
714 	if (!rs->fifo_len) {
715 		dev_err(&pdev->dev, "Failed to get fifo length\n");
716 		ret = -EINVAL;
717 		goto err_disable_spiclk;
718 	}
719 
720 	pm_runtime_set_autosuspend_delay(&pdev->dev, ROCKCHIP_AUTOSUSPEND_TIMEOUT);
721 	pm_runtime_use_autosuspend(&pdev->dev);
722 	pm_runtime_set_active(&pdev->dev);
723 	pm_runtime_enable(&pdev->dev);
724 
725 	ctlr->auto_runtime_pm = true;
726 	ctlr->bus_num = pdev->id;
727 	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_LSB_FIRST;
728 	if (slave_mode) {
729 		ctlr->mode_bits |= SPI_NO_CS;
730 		ctlr->slave_abort = rockchip_spi_slave_abort;
731 	} else {
732 		ctlr->flags = SPI_MASTER_GPIO_SS;
733 		ctlr->max_native_cs = ROCKCHIP_SPI_MAX_CS_NUM;
734 		/*
735 		 * rk spi0 has two native cs, spi1..5 one cs only
736 		 * if num-cs is missing in the dts, default to 1
737 		 */
738 		if (of_property_read_u16(np, "num-cs", &ctlr->num_chipselect))
739 			ctlr->num_chipselect = 1;
740 		ctlr->use_gpio_descriptors = true;
741 	}
742 	ctlr->dev.of_node = pdev->dev.of_node;
743 	ctlr->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8) | SPI_BPW_MASK(4);
744 	ctlr->min_speed_hz = rs->freq / BAUDR_SCKDV_MAX;
745 	ctlr->max_speed_hz = min(rs->freq / BAUDR_SCKDV_MIN, MAX_SCLK_OUT);
746 
747 	ctlr->set_cs = rockchip_spi_set_cs;
748 	ctlr->transfer_one = rockchip_spi_transfer_one;
749 	ctlr->max_transfer_size = rockchip_spi_max_transfer_size;
750 	ctlr->handle_err = rockchip_spi_handle_err;
751 
752 	ctlr->dma_tx = dma_request_chan(rs->dev, "tx");
753 	if (IS_ERR(ctlr->dma_tx)) {
754 		/* Check tx to see if we need defer probing driver */
755 		if (PTR_ERR(ctlr->dma_tx) == -EPROBE_DEFER) {
756 			ret = -EPROBE_DEFER;
757 			goto err_disable_pm_runtime;
758 		}
759 		dev_warn(rs->dev, "Failed to request TX DMA channel\n");
760 		ctlr->dma_tx = NULL;
761 	}
762 
763 	ctlr->dma_rx = dma_request_chan(rs->dev, "rx");
764 	if (IS_ERR(ctlr->dma_rx)) {
765 		if (PTR_ERR(ctlr->dma_rx) == -EPROBE_DEFER) {
766 			ret = -EPROBE_DEFER;
767 			goto err_free_dma_tx;
768 		}
769 		dev_warn(rs->dev, "Failed to request RX DMA channel\n");
770 		ctlr->dma_rx = NULL;
771 	}
772 
773 	if (ctlr->dma_tx && ctlr->dma_rx) {
774 		rs->dma_addr_tx = mem->start + ROCKCHIP_SPI_TXDR;
775 		rs->dma_addr_rx = mem->start + ROCKCHIP_SPI_RXDR;
776 		ctlr->can_dma = rockchip_spi_can_dma;
777 	}
778 
779 	ret = devm_spi_register_controller(&pdev->dev, ctlr);
780 	if (ret < 0) {
781 		dev_err(&pdev->dev, "Failed to register controller\n");
782 		goto err_free_dma_rx;
783 	}
784 
785 	return 0;
786 
787 err_free_dma_rx:
788 	if (ctlr->dma_rx)
789 		dma_release_channel(ctlr->dma_rx);
790 err_free_dma_tx:
791 	if (ctlr->dma_tx)
792 		dma_release_channel(ctlr->dma_tx);
793 err_disable_pm_runtime:
794 	pm_runtime_disable(&pdev->dev);
795 err_disable_spiclk:
796 	clk_disable_unprepare(rs->spiclk);
797 err_disable_apbclk:
798 	clk_disable_unprepare(rs->apb_pclk);
799 err_put_ctlr:
800 	spi_controller_put(ctlr);
801 
802 	return ret;
803 }
804 
805 static int rockchip_spi_remove(struct platform_device *pdev)
806 {
807 	struct spi_controller *ctlr = spi_controller_get(platform_get_drvdata(pdev));
808 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
809 
810 	pm_runtime_get_sync(&pdev->dev);
811 
812 	clk_disable_unprepare(rs->spiclk);
813 	clk_disable_unprepare(rs->apb_pclk);
814 
815 	pm_runtime_put_noidle(&pdev->dev);
816 	pm_runtime_disable(&pdev->dev);
817 	pm_runtime_set_suspended(&pdev->dev);
818 
819 	if (ctlr->dma_tx)
820 		dma_release_channel(ctlr->dma_tx);
821 	if (ctlr->dma_rx)
822 		dma_release_channel(ctlr->dma_rx);
823 
824 	spi_controller_put(ctlr);
825 
826 	return 0;
827 }
828 
829 #ifdef CONFIG_PM_SLEEP
830 static int rockchip_spi_suspend(struct device *dev)
831 {
832 	int ret;
833 	struct spi_controller *ctlr = dev_get_drvdata(dev);
834 
835 	ret = spi_controller_suspend(ctlr);
836 	if (ret < 0)
837 		return ret;
838 
839 	ret = pm_runtime_force_suspend(dev);
840 	if (ret < 0)
841 		return ret;
842 
843 	pinctrl_pm_select_sleep_state(dev);
844 
845 	return 0;
846 }
847 
848 static int rockchip_spi_resume(struct device *dev)
849 {
850 	int ret;
851 	struct spi_controller *ctlr = dev_get_drvdata(dev);
852 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
853 
854 	pinctrl_pm_select_default_state(dev);
855 
856 	ret = pm_runtime_force_resume(dev);
857 	if (ret < 0)
858 		return ret;
859 
860 	ret = spi_controller_resume(ctlr);
861 	if (ret < 0) {
862 		clk_disable_unprepare(rs->spiclk);
863 		clk_disable_unprepare(rs->apb_pclk);
864 	}
865 
866 	return 0;
867 }
868 #endif /* CONFIG_PM_SLEEP */
869 
870 #ifdef CONFIG_PM
871 static int rockchip_spi_runtime_suspend(struct device *dev)
872 {
873 	struct spi_controller *ctlr = dev_get_drvdata(dev);
874 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
875 
876 	clk_disable_unprepare(rs->spiclk);
877 	clk_disable_unprepare(rs->apb_pclk);
878 
879 	return 0;
880 }
881 
882 static int rockchip_spi_runtime_resume(struct device *dev)
883 {
884 	int ret;
885 	struct spi_controller *ctlr = dev_get_drvdata(dev);
886 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
887 
888 	ret = clk_prepare_enable(rs->apb_pclk);
889 	if (ret < 0)
890 		return ret;
891 
892 	ret = clk_prepare_enable(rs->spiclk);
893 	if (ret < 0)
894 		clk_disable_unprepare(rs->apb_pclk);
895 
896 	return 0;
897 }
898 #endif /* CONFIG_PM */
899 
900 static const struct dev_pm_ops rockchip_spi_pm = {
901 	SET_SYSTEM_SLEEP_PM_OPS(rockchip_spi_suspend, rockchip_spi_resume)
902 	SET_RUNTIME_PM_OPS(rockchip_spi_runtime_suspend,
903 			   rockchip_spi_runtime_resume, NULL)
904 };
905 
906 static const struct of_device_id rockchip_spi_dt_match[] = {
907 	{ .compatible = "rockchip,px30-spi", },
908 	{ .compatible = "rockchip,rk3036-spi", },
909 	{ .compatible = "rockchip,rk3066-spi", },
910 	{ .compatible = "rockchip,rk3188-spi", },
911 	{ .compatible = "rockchip,rk3228-spi", },
912 	{ .compatible = "rockchip,rk3288-spi", },
913 	{ .compatible = "rockchip,rk3308-spi", },
914 	{ .compatible = "rockchip,rk3328-spi", },
915 	{ .compatible = "rockchip,rk3368-spi", },
916 	{ .compatible = "rockchip,rk3399-spi", },
917 	{ .compatible = "rockchip,rv1108-spi", },
918 	{ },
919 };
920 MODULE_DEVICE_TABLE(of, rockchip_spi_dt_match);
921 
922 static struct platform_driver rockchip_spi_driver = {
923 	.driver = {
924 		.name	= DRIVER_NAME,
925 		.pm = &rockchip_spi_pm,
926 		.of_match_table = of_match_ptr(rockchip_spi_dt_match),
927 	},
928 	.probe = rockchip_spi_probe,
929 	.remove = rockchip_spi_remove,
930 };
931 
932 module_platform_driver(rockchip_spi_driver);
933 
934 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
935 MODULE_DESCRIPTION("ROCKCHIP SPI Controller Driver");
936 MODULE_LICENSE("GPL v2");
937