xref: /openbmc/linux/drivers/spi/spi-rockchip.c (revision 9dd7c463)
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_SOI_OFFSET				23
111 
112 #define CR0_MTM_OFFSET				0x21
113 
114 /* Bit fields in SER, 2bit */
115 #define SER_MASK					0x3
116 
117 /* Bit fields in BAUDR */
118 #define BAUDR_SCKDV_MIN				2
119 #define BAUDR_SCKDV_MAX				65534
120 
121 /* Bit fields in SR, 6bit */
122 #define SR_MASK						0x3f
123 #define SR_BUSY						(1 << 0)
124 #define SR_TF_FULL					(1 << 1)
125 #define SR_TF_EMPTY					(1 << 2)
126 #define SR_RF_EMPTY					(1 << 3)
127 #define SR_RF_FULL					(1 << 4)
128 #define SR_SLAVE_TX_BUSY				(1 << 5)
129 
130 /* Bit fields in ISR, IMR, ISR, RISR, 5bit */
131 #define INT_MASK					0x1f
132 #define INT_TF_EMPTY				(1 << 0)
133 #define INT_TF_OVERFLOW				(1 << 1)
134 #define INT_RF_UNDERFLOW			(1 << 2)
135 #define INT_RF_OVERFLOW				(1 << 3)
136 #define INT_RF_FULL					(1 << 4)
137 
138 /* Bit fields in ICR, 4bit */
139 #define ICR_MASK					0x0f
140 #define ICR_ALL						(1 << 0)
141 #define ICR_RF_UNDERFLOW			(1 << 1)
142 #define ICR_RF_OVERFLOW				(1 << 2)
143 #define ICR_TF_OVERFLOW				(1 << 3)
144 
145 /* Bit fields in DMACR */
146 #define RF_DMA_EN					(1 << 0)
147 #define TF_DMA_EN					(1 << 1)
148 
149 /* Driver state flags */
150 #define RXDMA					(1 << 0)
151 #define TXDMA					(1 << 1)
152 
153 /* sclk_out: spi master internal logic in rk3x can support 50Mhz */
154 #define MAX_SCLK_OUT				50000000U
155 
156 /*
157  * SPI_CTRLR1 is 16-bits, so we should support lengths of 0xffff + 1. However,
158  * the controller seems to hang when given 0x10000, so stick with this for now.
159  */
160 #define ROCKCHIP_SPI_MAX_TRANLEN		0xffff
161 
162 /* 2 for native cs, 2 for cs-gpio */
163 #define ROCKCHIP_SPI_MAX_CS_NUM			4
164 #define ROCKCHIP_SPI_VER2_TYPE1			0x05EC0002
165 #define ROCKCHIP_SPI_VER2_TYPE2			0x00110002
166 
167 #define ROCKCHIP_AUTOSUSPEND_TIMEOUT		2000
168 
169 struct rockchip_spi {
170 	struct device *dev;
171 
172 	struct clk *spiclk;
173 	struct clk *apb_pclk;
174 
175 	void __iomem *regs;
176 	dma_addr_t dma_addr_rx;
177 	dma_addr_t dma_addr_tx;
178 
179 	const void *tx;
180 	void *rx;
181 	unsigned int tx_left;
182 	unsigned int rx_left;
183 
184 	atomic_t state;
185 
186 	/*depth of the FIFO buffer */
187 	u32 fifo_len;
188 	/* frequency of spiclk */
189 	u32 freq;
190 
191 	u8 n_bytes;
192 	u8 rsd;
193 
194 	bool cs_asserted[ROCKCHIP_SPI_MAX_CS_NUM];
195 
196 	bool slave_abort;
197 };
198 
199 static inline void spi_enable_chip(struct rockchip_spi *rs, bool enable)
200 {
201 	writel_relaxed((enable ? 1U : 0U), rs->regs + ROCKCHIP_SPI_SSIENR);
202 }
203 
204 static inline void wait_for_tx_idle(struct rockchip_spi *rs, bool slave_mode)
205 {
206 	unsigned long timeout = jiffies + msecs_to_jiffies(5);
207 
208 	do {
209 		if (slave_mode) {
210 			if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_SLAVE_TX_BUSY) &&
211 			    !((readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY)))
212 				return;
213 		} else {
214 			if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY))
215 				return;
216 		}
217 	} while (!time_after(jiffies, timeout));
218 
219 	dev_warn(rs->dev, "spi controller is in busy state!\n");
220 }
221 
222 static u32 get_fifo_len(struct rockchip_spi *rs)
223 {
224 	u32 ver;
225 
226 	ver = readl_relaxed(rs->regs + ROCKCHIP_SPI_VERSION);
227 
228 	switch (ver) {
229 	case ROCKCHIP_SPI_VER2_TYPE1:
230 	case ROCKCHIP_SPI_VER2_TYPE2:
231 		return 64;
232 	default:
233 		return 32;
234 	}
235 }
236 
237 static void rockchip_spi_set_cs(struct spi_device *spi, bool enable)
238 {
239 	struct spi_controller *ctlr = spi->controller;
240 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
241 	bool cs_asserted = spi->mode & SPI_CS_HIGH ? enable : !enable;
242 
243 	/* Return immediately for no-op */
244 	if (cs_asserted == rs->cs_asserted[spi->chip_select])
245 		return;
246 
247 	if (cs_asserted) {
248 		/* Keep things powered as long as CS is asserted */
249 		pm_runtime_get_sync(rs->dev);
250 
251 		if (spi->cs_gpiod)
252 			ROCKCHIP_SPI_SET_BITS(rs->regs + ROCKCHIP_SPI_SER, 1);
253 		else
254 			ROCKCHIP_SPI_SET_BITS(rs->regs + ROCKCHIP_SPI_SER, BIT(spi->chip_select));
255 	} else {
256 		if (spi->cs_gpiod)
257 			ROCKCHIP_SPI_CLR_BITS(rs->regs + ROCKCHIP_SPI_SER, 1);
258 		else
259 			ROCKCHIP_SPI_CLR_BITS(rs->regs + ROCKCHIP_SPI_SER, BIT(spi->chip_select));
260 
261 		/* Drop reference from when we first asserted CS */
262 		pm_runtime_put(rs->dev);
263 	}
264 
265 	rs->cs_asserted[spi->chip_select] = cs_asserted;
266 }
267 
268 static void rockchip_spi_handle_err(struct spi_controller *ctlr,
269 				    struct spi_message *msg)
270 {
271 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
272 
273 	/* stop running spi transfer
274 	 * this also flushes both rx and tx fifos
275 	 */
276 	spi_enable_chip(rs, false);
277 
278 	/* make sure all interrupts are masked */
279 	writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);
280 
281 	if (atomic_read(&rs->state) & TXDMA)
282 		dmaengine_terminate_async(ctlr->dma_tx);
283 
284 	if (atomic_read(&rs->state) & RXDMA)
285 		dmaengine_terminate_async(ctlr->dma_rx);
286 }
287 
288 static void rockchip_spi_pio_writer(struct rockchip_spi *rs)
289 {
290 	u32 tx_free = rs->fifo_len - readl_relaxed(rs->regs + ROCKCHIP_SPI_TXFLR);
291 	u32 words = min(rs->tx_left, tx_free);
292 
293 	rs->tx_left -= words;
294 	for (; words; words--) {
295 		u32 txw;
296 
297 		if (rs->n_bytes == 1)
298 			txw = *(u8 *)rs->tx;
299 		else
300 			txw = *(u16 *)rs->tx;
301 
302 		writel_relaxed(txw, rs->regs + ROCKCHIP_SPI_TXDR);
303 		rs->tx += rs->n_bytes;
304 	}
305 }
306 
307 static void rockchip_spi_pio_reader(struct rockchip_spi *rs)
308 {
309 	u32 words = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFLR);
310 	u32 rx_left = (rs->rx_left > words) ? rs->rx_left - words : 0;
311 
312 	/* the hardware doesn't allow us to change fifo threshold
313 	 * level while spi is enabled, so instead make sure to leave
314 	 * enough words in the rx fifo to get the last interrupt
315 	 * exactly when all words have been received
316 	 */
317 	if (rx_left) {
318 		u32 ftl = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFTLR) + 1;
319 
320 		if (rx_left < ftl) {
321 			rx_left = ftl;
322 			words = rs->rx_left - rx_left;
323 		}
324 	}
325 
326 	rs->rx_left = rx_left;
327 	for (; words; words--) {
328 		u32 rxw = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXDR);
329 
330 		if (!rs->rx)
331 			continue;
332 
333 		if (rs->n_bytes == 1)
334 			*(u8 *)rs->rx = (u8)rxw;
335 		else
336 			*(u16 *)rs->rx = (u16)rxw;
337 		rs->rx += rs->n_bytes;
338 	}
339 }
340 
341 static irqreturn_t rockchip_spi_isr(int irq, void *dev_id)
342 {
343 	struct spi_controller *ctlr = dev_id;
344 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
345 
346 	if (rs->tx_left)
347 		rockchip_spi_pio_writer(rs);
348 
349 	rockchip_spi_pio_reader(rs);
350 	if (!rs->rx_left) {
351 		spi_enable_chip(rs, false);
352 		writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);
353 		spi_finalize_current_transfer(ctlr);
354 	}
355 
356 	return IRQ_HANDLED;
357 }
358 
359 static int rockchip_spi_prepare_irq(struct rockchip_spi *rs,
360 		struct spi_transfer *xfer)
361 {
362 	rs->tx = xfer->tx_buf;
363 	rs->rx = xfer->rx_buf;
364 	rs->tx_left = rs->tx ? xfer->len / rs->n_bytes : 0;
365 	rs->rx_left = xfer->len / rs->n_bytes;
366 
367 	writel_relaxed(INT_RF_FULL, rs->regs + ROCKCHIP_SPI_IMR);
368 	spi_enable_chip(rs, true);
369 
370 	if (rs->tx_left)
371 		rockchip_spi_pio_writer(rs);
372 
373 	/* 1 means the transfer is in progress */
374 	return 1;
375 }
376 
377 static void rockchip_spi_dma_rxcb(void *data)
378 {
379 	struct spi_controller *ctlr = data;
380 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
381 	int state = atomic_fetch_andnot(RXDMA, &rs->state);
382 
383 	if (state & TXDMA && !rs->slave_abort)
384 		return;
385 
386 	spi_enable_chip(rs, false);
387 	spi_finalize_current_transfer(ctlr);
388 }
389 
390 static void rockchip_spi_dma_txcb(void *data)
391 {
392 	struct spi_controller *ctlr = data;
393 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
394 	int state = atomic_fetch_andnot(TXDMA, &rs->state);
395 
396 	if (state & RXDMA && !rs->slave_abort)
397 		return;
398 
399 	/* Wait until the FIFO data completely. */
400 	wait_for_tx_idle(rs, ctlr->slave);
401 
402 	spi_enable_chip(rs, false);
403 	spi_finalize_current_transfer(ctlr);
404 }
405 
406 static u32 rockchip_spi_calc_burst_size(u32 data_len)
407 {
408 	u32 i;
409 
410 	/* burst size: 1, 2, 4, 8 */
411 	for (i = 1; i < 8; i <<= 1) {
412 		if (data_len & i)
413 			break;
414 	}
415 
416 	return i;
417 }
418 
419 static int rockchip_spi_prepare_dma(struct rockchip_spi *rs,
420 		struct spi_controller *ctlr, struct spi_transfer *xfer)
421 {
422 	struct dma_async_tx_descriptor *rxdesc, *txdesc;
423 
424 	atomic_set(&rs->state, 0);
425 
426 	rxdesc = NULL;
427 	if (xfer->rx_buf) {
428 		struct dma_slave_config rxconf = {
429 			.direction = DMA_DEV_TO_MEM,
430 			.src_addr = rs->dma_addr_rx,
431 			.src_addr_width = rs->n_bytes,
432 			.src_maxburst = rockchip_spi_calc_burst_size(xfer->len /
433 								     rs->n_bytes),
434 		};
435 
436 		dmaengine_slave_config(ctlr->dma_rx, &rxconf);
437 
438 		rxdesc = dmaengine_prep_slave_sg(
439 				ctlr->dma_rx,
440 				xfer->rx_sg.sgl, xfer->rx_sg.nents,
441 				DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
442 		if (!rxdesc)
443 			return -EINVAL;
444 
445 		rxdesc->callback = rockchip_spi_dma_rxcb;
446 		rxdesc->callback_param = ctlr;
447 	}
448 
449 	txdesc = NULL;
450 	if (xfer->tx_buf) {
451 		struct dma_slave_config txconf = {
452 			.direction = DMA_MEM_TO_DEV,
453 			.dst_addr = rs->dma_addr_tx,
454 			.dst_addr_width = rs->n_bytes,
455 			.dst_maxburst = rs->fifo_len / 4,
456 		};
457 
458 		dmaengine_slave_config(ctlr->dma_tx, &txconf);
459 
460 		txdesc = dmaengine_prep_slave_sg(
461 				ctlr->dma_tx,
462 				xfer->tx_sg.sgl, xfer->tx_sg.nents,
463 				DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
464 		if (!txdesc) {
465 			if (rxdesc)
466 				dmaengine_terminate_sync(ctlr->dma_rx);
467 			return -EINVAL;
468 		}
469 
470 		txdesc->callback = rockchip_spi_dma_txcb;
471 		txdesc->callback_param = ctlr;
472 	}
473 
474 	/* rx must be started before tx due to spi instinct */
475 	if (rxdesc) {
476 		atomic_or(RXDMA, &rs->state);
477 		dmaengine_submit(rxdesc);
478 		dma_async_issue_pending(ctlr->dma_rx);
479 	}
480 
481 	spi_enable_chip(rs, true);
482 
483 	if (txdesc) {
484 		atomic_or(TXDMA, &rs->state);
485 		dmaengine_submit(txdesc);
486 		dma_async_issue_pending(ctlr->dma_tx);
487 	}
488 
489 	/* 1 means the transfer is in progress */
490 	return 1;
491 }
492 
493 static int rockchip_spi_config(struct rockchip_spi *rs,
494 		struct spi_device *spi, struct spi_transfer *xfer,
495 		bool use_dma, bool slave_mode)
496 {
497 	u32 cr0 = CR0_FRF_SPI  << CR0_FRF_OFFSET
498 		| CR0_BHT_8BIT << CR0_BHT_OFFSET
499 		| CR0_SSD_ONE  << CR0_SSD_OFFSET
500 		| CR0_EM_BIG   << CR0_EM_OFFSET;
501 	u32 cr1;
502 	u32 dmacr = 0;
503 
504 	if (slave_mode)
505 		cr0 |= CR0_OPM_SLAVE << CR0_OPM_OFFSET;
506 	rs->slave_abort = false;
507 
508 	cr0 |= rs->rsd << CR0_RSD_OFFSET;
509 	cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET;
510 	if (spi->mode & SPI_LSB_FIRST)
511 		cr0 |= CR0_FBM_LSB << CR0_FBM_OFFSET;
512 	if (spi->mode & SPI_CS_HIGH)
513 		cr0 |= BIT(spi->chip_select) << CR0_SOI_OFFSET;
514 
515 	if (xfer->rx_buf && xfer->tx_buf)
516 		cr0 |= CR0_XFM_TR << CR0_XFM_OFFSET;
517 	else if (xfer->rx_buf)
518 		cr0 |= CR0_XFM_RO << CR0_XFM_OFFSET;
519 	else if (use_dma)
520 		cr0 |= CR0_XFM_TO << CR0_XFM_OFFSET;
521 
522 	switch (xfer->bits_per_word) {
523 	case 4:
524 		cr0 |= CR0_DFS_4BIT << CR0_DFS_OFFSET;
525 		cr1 = xfer->len - 1;
526 		break;
527 	case 8:
528 		cr0 |= CR0_DFS_8BIT << CR0_DFS_OFFSET;
529 		cr1 = xfer->len - 1;
530 		break;
531 	case 16:
532 		cr0 |= CR0_DFS_16BIT << CR0_DFS_OFFSET;
533 		cr1 = xfer->len / 2 - 1;
534 		break;
535 	default:
536 		/* we only whitelist 4, 8 and 16 bit words in
537 		 * ctlr->bits_per_word_mask, so this shouldn't
538 		 * happen
539 		 */
540 		dev_err(rs->dev, "unknown bits per word: %d\n",
541 			xfer->bits_per_word);
542 		return -EINVAL;
543 	}
544 
545 	if (use_dma) {
546 		if (xfer->tx_buf)
547 			dmacr |= TF_DMA_EN;
548 		if (xfer->rx_buf)
549 			dmacr |= RF_DMA_EN;
550 	}
551 
552 	writel_relaxed(cr0, rs->regs + ROCKCHIP_SPI_CTRLR0);
553 	writel_relaxed(cr1, rs->regs + ROCKCHIP_SPI_CTRLR1);
554 
555 	/* unfortunately setting the fifo threshold level to generate an
556 	 * interrupt exactly when the fifo is full doesn't seem to work,
557 	 * so we need the strict inequality here
558 	 */
559 	if ((xfer->len / rs->n_bytes) < rs->fifo_len)
560 		writel_relaxed(xfer->len / rs->n_bytes - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
561 	else
562 		writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
563 
564 	writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_DMATDLR);
565 	writel_relaxed(rockchip_spi_calc_burst_size(xfer->len / rs->n_bytes) - 1,
566 		       rs->regs + ROCKCHIP_SPI_DMARDLR);
567 	writel_relaxed(dmacr, rs->regs + ROCKCHIP_SPI_DMACR);
568 
569 	/* the hardware only supports an even clock divisor, so
570 	 * round divisor = spiclk / speed up to nearest even number
571 	 * so that the resulting speed is <= the requested speed
572 	 */
573 	writel_relaxed(2 * DIV_ROUND_UP(rs->freq, 2 * xfer->speed_hz),
574 			rs->regs + ROCKCHIP_SPI_BAUDR);
575 
576 	return 0;
577 }
578 
579 static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
580 {
581 	return ROCKCHIP_SPI_MAX_TRANLEN;
582 }
583 
584 static int rockchip_spi_slave_abort(struct spi_controller *ctlr)
585 {
586 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
587 
588 	rs->slave_abort = true;
589 	spi_finalize_current_transfer(ctlr);
590 
591 	return 0;
592 }
593 
594 static int rockchip_spi_transfer_one(
595 		struct spi_controller *ctlr,
596 		struct spi_device *spi,
597 		struct spi_transfer *xfer)
598 {
599 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
600 	int ret;
601 	bool use_dma;
602 
603 	/* Zero length transfers won't trigger an interrupt on completion */
604 	if (!xfer->len) {
605 		spi_finalize_current_transfer(ctlr);
606 		return 1;
607 	}
608 
609 	WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) &&
610 		(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY));
611 
612 	if (!xfer->tx_buf && !xfer->rx_buf) {
613 		dev_err(rs->dev, "No buffer for transfer\n");
614 		return -EINVAL;
615 	}
616 
617 	if (xfer->len > ROCKCHIP_SPI_MAX_TRANLEN) {
618 		dev_err(rs->dev, "Transfer is too long (%d)\n", xfer->len);
619 		return -EINVAL;
620 	}
621 
622 	rs->n_bytes = xfer->bits_per_word <= 8 ? 1 : 2;
623 
624 	use_dma = ctlr->can_dma ? ctlr->can_dma(ctlr, spi, xfer) : false;
625 
626 	ret = rockchip_spi_config(rs, spi, xfer, use_dma, ctlr->slave);
627 	if (ret)
628 		return ret;
629 
630 	if (use_dma)
631 		return rockchip_spi_prepare_dma(rs, ctlr, xfer);
632 
633 	return rockchip_spi_prepare_irq(rs, xfer);
634 }
635 
636 static bool rockchip_spi_can_dma(struct spi_controller *ctlr,
637 				 struct spi_device *spi,
638 				 struct spi_transfer *xfer)
639 {
640 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
641 	unsigned int bytes_per_word = xfer->bits_per_word <= 8 ? 1 : 2;
642 
643 	/* if the numbor of spi words to transfer is less than the fifo
644 	 * length we can just fill the fifo and wait for a single irq,
645 	 * so don't bother setting up dma
646 	 */
647 	return xfer->len / bytes_per_word >= rs->fifo_len;
648 }
649 
650 static int rockchip_spi_probe(struct platform_device *pdev)
651 {
652 	int ret;
653 	struct rockchip_spi *rs;
654 	struct spi_controller *ctlr;
655 	struct resource *mem;
656 	struct device_node *np = pdev->dev.of_node;
657 	u32 rsd_nsecs;
658 	bool slave_mode;
659 
660 	slave_mode = of_property_read_bool(np, "spi-slave");
661 
662 	if (slave_mode)
663 		ctlr = spi_alloc_slave(&pdev->dev,
664 				sizeof(struct rockchip_spi));
665 	else
666 		ctlr = spi_alloc_master(&pdev->dev,
667 				sizeof(struct rockchip_spi));
668 
669 	if (!ctlr)
670 		return -ENOMEM;
671 
672 	platform_set_drvdata(pdev, ctlr);
673 
674 	rs = spi_controller_get_devdata(ctlr);
675 	ctlr->slave = slave_mode;
676 
677 	/* Get basic io resource and map it */
678 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
679 	rs->regs = devm_ioremap_resource(&pdev->dev, mem);
680 	if (IS_ERR(rs->regs)) {
681 		ret =  PTR_ERR(rs->regs);
682 		goto err_put_ctlr;
683 	}
684 
685 	rs->apb_pclk = devm_clk_get(&pdev->dev, "apb_pclk");
686 	if (IS_ERR(rs->apb_pclk)) {
687 		dev_err(&pdev->dev, "Failed to get apb_pclk\n");
688 		ret = PTR_ERR(rs->apb_pclk);
689 		goto err_put_ctlr;
690 	}
691 
692 	rs->spiclk = devm_clk_get(&pdev->dev, "spiclk");
693 	if (IS_ERR(rs->spiclk)) {
694 		dev_err(&pdev->dev, "Failed to get spi_pclk\n");
695 		ret = PTR_ERR(rs->spiclk);
696 		goto err_put_ctlr;
697 	}
698 
699 	ret = clk_prepare_enable(rs->apb_pclk);
700 	if (ret < 0) {
701 		dev_err(&pdev->dev, "Failed to enable apb_pclk\n");
702 		goto err_put_ctlr;
703 	}
704 
705 	ret = clk_prepare_enable(rs->spiclk);
706 	if (ret < 0) {
707 		dev_err(&pdev->dev, "Failed to enable spi_clk\n");
708 		goto err_disable_apbclk;
709 	}
710 
711 	spi_enable_chip(rs, false);
712 
713 	ret = platform_get_irq(pdev, 0);
714 	if (ret < 0)
715 		goto err_disable_spiclk;
716 
717 	ret = devm_request_threaded_irq(&pdev->dev, ret, rockchip_spi_isr, NULL,
718 			IRQF_ONESHOT, dev_name(&pdev->dev), ctlr);
719 	if (ret)
720 		goto err_disable_spiclk;
721 
722 	rs->dev = &pdev->dev;
723 	rs->freq = clk_get_rate(rs->spiclk);
724 
725 	if (!of_property_read_u32(pdev->dev.of_node, "rx-sample-delay-ns",
726 				  &rsd_nsecs)) {
727 		/* rx sample delay is expressed in parent clock cycles (max 3) */
728 		u32 rsd = DIV_ROUND_CLOSEST(rsd_nsecs * (rs->freq >> 8),
729 				1000000000 >> 8);
730 		if (!rsd) {
731 			dev_warn(rs->dev, "%u Hz are too slow to express %u ns delay\n",
732 					rs->freq, rsd_nsecs);
733 		} else if (rsd > CR0_RSD_MAX) {
734 			rsd = CR0_RSD_MAX;
735 			dev_warn(rs->dev, "%u Hz are too fast to express %u ns delay, clamping at %u ns\n",
736 					rs->freq, rsd_nsecs,
737 					CR0_RSD_MAX * 1000000000U / rs->freq);
738 		}
739 		rs->rsd = rsd;
740 	}
741 
742 	rs->fifo_len = get_fifo_len(rs);
743 	if (!rs->fifo_len) {
744 		dev_err(&pdev->dev, "Failed to get fifo length\n");
745 		ret = -EINVAL;
746 		goto err_disable_spiclk;
747 	}
748 
749 	pm_runtime_set_autosuspend_delay(&pdev->dev, ROCKCHIP_AUTOSUSPEND_TIMEOUT);
750 	pm_runtime_use_autosuspend(&pdev->dev);
751 	pm_runtime_set_active(&pdev->dev);
752 	pm_runtime_enable(&pdev->dev);
753 
754 	ctlr->auto_runtime_pm = true;
755 	ctlr->bus_num = pdev->id;
756 	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_LSB_FIRST;
757 	if (slave_mode) {
758 		ctlr->mode_bits |= SPI_NO_CS;
759 		ctlr->slave_abort = rockchip_spi_slave_abort;
760 	} else {
761 		ctlr->flags = SPI_MASTER_GPIO_SS;
762 		ctlr->max_native_cs = ROCKCHIP_SPI_MAX_CS_NUM;
763 		/*
764 		 * rk spi0 has two native cs, spi1..5 one cs only
765 		 * if num-cs is missing in the dts, default to 1
766 		 */
767 		if (of_property_read_u16(np, "num-cs", &ctlr->num_chipselect))
768 			ctlr->num_chipselect = 1;
769 		ctlr->use_gpio_descriptors = true;
770 	}
771 	ctlr->dev.of_node = pdev->dev.of_node;
772 	ctlr->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8) | SPI_BPW_MASK(4);
773 	ctlr->min_speed_hz = rs->freq / BAUDR_SCKDV_MAX;
774 	ctlr->max_speed_hz = min(rs->freq / BAUDR_SCKDV_MIN, MAX_SCLK_OUT);
775 
776 	ctlr->set_cs = rockchip_spi_set_cs;
777 	ctlr->transfer_one = rockchip_spi_transfer_one;
778 	ctlr->max_transfer_size = rockchip_spi_max_transfer_size;
779 	ctlr->handle_err = rockchip_spi_handle_err;
780 
781 	ctlr->dma_tx = dma_request_chan(rs->dev, "tx");
782 	if (IS_ERR(ctlr->dma_tx)) {
783 		/* Check tx to see if we need defer probing driver */
784 		if (PTR_ERR(ctlr->dma_tx) == -EPROBE_DEFER) {
785 			ret = -EPROBE_DEFER;
786 			goto err_disable_pm_runtime;
787 		}
788 		dev_warn(rs->dev, "Failed to request TX DMA channel\n");
789 		ctlr->dma_tx = NULL;
790 	}
791 
792 	ctlr->dma_rx = dma_request_chan(rs->dev, "rx");
793 	if (IS_ERR(ctlr->dma_rx)) {
794 		if (PTR_ERR(ctlr->dma_rx) == -EPROBE_DEFER) {
795 			ret = -EPROBE_DEFER;
796 			goto err_free_dma_tx;
797 		}
798 		dev_warn(rs->dev, "Failed to request RX DMA channel\n");
799 		ctlr->dma_rx = NULL;
800 	}
801 
802 	if (ctlr->dma_tx && ctlr->dma_rx) {
803 		rs->dma_addr_tx = mem->start + ROCKCHIP_SPI_TXDR;
804 		rs->dma_addr_rx = mem->start + ROCKCHIP_SPI_RXDR;
805 		ctlr->can_dma = rockchip_spi_can_dma;
806 	}
807 
808 	switch (readl_relaxed(rs->regs + ROCKCHIP_SPI_VERSION)) {
809 	case ROCKCHIP_SPI_VER2_TYPE2:
810 		ctlr->mode_bits |= SPI_CS_HIGH;
811 		break;
812 	default:
813 		break;
814 	}
815 
816 	ret = devm_spi_register_controller(&pdev->dev, ctlr);
817 	if (ret < 0) {
818 		dev_err(&pdev->dev, "Failed to register controller\n");
819 		goto err_free_dma_rx;
820 	}
821 
822 	return 0;
823 
824 err_free_dma_rx:
825 	if (ctlr->dma_rx)
826 		dma_release_channel(ctlr->dma_rx);
827 err_free_dma_tx:
828 	if (ctlr->dma_tx)
829 		dma_release_channel(ctlr->dma_tx);
830 err_disable_pm_runtime:
831 	pm_runtime_disable(&pdev->dev);
832 err_disable_spiclk:
833 	clk_disable_unprepare(rs->spiclk);
834 err_disable_apbclk:
835 	clk_disable_unprepare(rs->apb_pclk);
836 err_put_ctlr:
837 	spi_controller_put(ctlr);
838 
839 	return ret;
840 }
841 
842 static int rockchip_spi_remove(struct platform_device *pdev)
843 {
844 	struct spi_controller *ctlr = spi_controller_get(platform_get_drvdata(pdev));
845 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
846 
847 	pm_runtime_get_sync(&pdev->dev);
848 
849 	clk_disable_unprepare(rs->spiclk);
850 	clk_disable_unprepare(rs->apb_pclk);
851 
852 	pm_runtime_put_noidle(&pdev->dev);
853 	pm_runtime_disable(&pdev->dev);
854 	pm_runtime_set_suspended(&pdev->dev);
855 
856 	if (ctlr->dma_tx)
857 		dma_release_channel(ctlr->dma_tx);
858 	if (ctlr->dma_rx)
859 		dma_release_channel(ctlr->dma_rx);
860 
861 	spi_controller_put(ctlr);
862 
863 	return 0;
864 }
865 
866 #ifdef CONFIG_PM_SLEEP
867 static int rockchip_spi_suspend(struct device *dev)
868 {
869 	int ret;
870 	struct spi_controller *ctlr = dev_get_drvdata(dev);
871 
872 	ret = spi_controller_suspend(ctlr);
873 	if (ret < 0)
874 		return ret;
875 
876 	ret = pm_runtime_force_suspend(dev);
877 	if (ret < 0)
878 		return ret;
879 
880 	pinctrl_pm_select_sleep_state(dev);
881 
882 	return 0;
883 }
884 
885 static int rockchip_spi_resume(struct device *dev)
886 {
887 	int ret;
888 	struct spi_controller *ctlr = dev_get_drvdata(dev);
889 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
890 
891 	pinctrl_pm_select_default_state(dev);
892 
893 	ret = pm_runtime_force_resume(dev);
894 	if (ret < 0)
895 		return ret;
896 
897 	ret = spi_controller_resume(ctlr);
898 	if (ret < 0) {
899 		clk_disable_unprepare(rs->spiclk);
900 		clk_disable_unprepare(rs->apb_pclk);
901 	}
902 
903 	return 0;
904 }
905 #endif /* CONFIG_PM_SLEEP */
906 
907 #ifdef CONFIG_PM
908 static int rockchip_spi_runtime_suspend(struct device *dev)
909 {
910 	struct spi_controller *ctlr = dev_get_drvdata(dev);
911 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
912 
913 	clk_disable_unprepare(rs->spiclk);
914 	clk_disable_unprepare(rs->apb_pclk);
915 
916 	return 0;
917 }
918 
919 static int rockchip_spi_runtime_resume(struct device *dev)
920 {
921 	int ret;
922 	struct spi_controller *ctlr = dev_get_drvdata(dev);
923 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
924 
925 	ret = clk_prepare_enable(rs->apb_pclk);
926 	if (ret < 0)
927 		return ret;
928 
929 	ret = clk_prepare_enable(rs->spiclk);
930 	if (ret < 0)
931 		clk_disable_unprepare(rs->apb_pclk);
932 
933 	return 0;
934 }
935 #endif /* CONFIG_PM */
936 
937 static const struct dev_pm_ops rockchip_spi_pm = {
938 	SET_SYSTEM_SLEEP_PM_OPS(rockchip_spi_suspend, rockchip_spi_resume)
939 	SET_RUNTIME_PM_OPS(rockchip_spi_runtime_suspend,
940 			   rockchip_spi_runtime_resume, NULL)
941 };
942 
943 static const struct of_device_id rockchip_spi_dt_match[] = {
944 	{ .compatible = "rockchip,px30-spi", },
945 	{ .compatible = "rockchip,rk3036-spi", },
946 	{ .compatible = "rockchip,rk3066-spi", },
947 	{ .compatible = "rockchip,rk3188-spi", },
948 	{ .compatible = "rockchip,rk3228-spi", },
949 	{ .compatible = "rockchip,rk3288-spi", },
950 	{ .compatible = "rockchip,rk3308-spi", },
951 	{ .compatible = "rockchip,rk3328-spi", },
952 	{ .compatible = "rockchip,rk3368-spi", },
953 	{ .compatible = "rockchip,rk3399-spi", },
954 	{ .compatible = "rockchip,rv1108-spi", },
955 	{ .compatible = "rockchip,rv1126-spi", },
956 	{ },
957 };
958 MODULE_DEVICE_TABLE(of, rockchip_spi_dt_match);
959 
960 static struct platform_driver rockchip_spi_driver = {
961 	.driver = {
962 		.name	= DRIVER_NAME,
963 		.pm = &rockchip_spi_pm,
964 		.of_match_table = of_match_ptr(rockchip_spi_dt_match),
965 	},
966 	.probe = rockchip_spi_probe,
967 	.remove = rockchip_spi_remove,
968 };
969 
970 module_platform_driver(rockchip_spi_driver);
971 
972 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
973 MODULE_DESCRIPTION("ROCKCHIP SPI Controller Driver");
974 MODULE_LICENSE("GPL v2");
975