xref: /openbmc/linux/drivers/spi/spi-sun6i.c (revision 6de298ff)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2012 - 2014 Allwinner Tech
4  * Pan Nan <pannan@allwinnertech.com>
5  *
6  * Copyright (C) 2014 Maxime Ripard
7  * Maxime Ripard <maxime.ripard@free-electrons.com>
8  */
9 
10 #include <linux/bitfield.h>
11 #include <linux/clk.h>
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/interrupt.h>
15 #include <linux/io.h>
16 #include <linux/module.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm_runtime.h>
20 #include <linux/reset.h>
21 #include <linux/dmaengine.h>
22 
23 #include <linux/spi/spi.h>
24 
25 #define SUN6I_AUTOSUSPEND_TIMEOUT	2000
26 
27 #define SUN6I_FIFO_DEPTH		128
28 #define SUN8I_FIFO_DEPTH		64
29 
30 #define SUN6I_GBL_CTL_REG		0x04
31 #define SUN6I_GBL_CTL_BUS_ENABLE		BIT(0)
32 #define SUN6I_GBL_CTL_MASTER			BIT(1)
33 #define SUN6I_GBL_CTL_TP			BIT(7)
34 #define SUN6I_GBL_CTL_RST			BIT(31)
35 
36 #define SUN6I_TFR_CTL_REG		0x08
37 #define SUN6I_TFR_CTL_CPHA			BIT(0)
38 #define SUN6I_TFR_CTL_CPOL			BIT(1)
39 #define SUN6I_TFR_CTL_SPOL			BIT(2)
40 #define SUN6I_TFR_CTL_CS_MASK			0x30
41 #define SUN6I_TFR_CTL_CS(cs)			(((cs) << 4) & SUN6I_TFR_CTL_CS_MASK)
42 #define SUN6I_TFR_CTL_CS_MANUAL			BIT(6)
43 #define SUN6I_TFR_CTL_CS_LEVEL			BIT(7)
44 #define SUN6I_TFR_CTL_DHB			BIT(8)
45 #define SUN6I_TFR_CTL_SDC			BIT(11)
46 #define SUN6I_TFR_CTL_FBS			BIT(12)
47 #define SUN6I_TFR_CTL_SDM			BIT(13)
48 #define SUN6I_TFR_CTL_XCH			BIT(31)
49 
50 #define SUN6I_INT_CTL_REG		0x10
51 #define SUN6I_INT_CTL_RF_RDY			BIT(0)
52 #define SUN6I_INT_CTL_TF_ERQ			BIT(4)
53 #define SUN6I_INT_CTL_RF_OVF			BIT(8)
54 #define SUN6I_INT_CTL_TC			BIT(12)
55 
56 #define SUN6I_INT_STA_REG		0x14
57 
58 #define SUN6I_FIFO_CTL_REG		0x18
59 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_MASK	0xff
60 #define SUN6I_FIFO_CTL_RF_DRQ_EN		BIT(8)
61 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS	0
62 #define SUN6I_FIFO_CTL_RF_RST			BIT(15)
63 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_MASK	0xff
64 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS	16
65 #define SUN6I_FIFO_CTL_TF_DRQ_EN		BIT(24)
66 #define SUN6I_FIFO_CTL_TF_RST			BIT(31)
67 
68 #define SUN6I_FIFO_STA_REG		0x1c
69 #define SUN6I_FIFO_STA_RF_CNT_MASK		GENMASK(7, 0)
70 #define SUN6I_FIFO_STA_TF_CNT_MASK		GENMASK(23, 16)
71 
72 #define SUN6I_CLK_CTL_REG		0x24
73 #define SUN6I_CLK_CTL_CDR2_MASK			0xff
74 #define SUN6I_CLK_CTL_CDR2(div)			(((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0)
75 #define SUN6I_CLK_CTL_CDR1_MASK			0xf
76 #define SUN6I_CLK_CTL_CDR1(div)			(((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8)
77 #define SUN6I_CLK_CTL_DRS			BIT(12)
78 
79 #define SUN6I_MAX_XFER_SIZE		0xffffff
80 
81 #define SUN6I_BURST_CNT_REG		0x30
82 
83 #define SUN6I_XMIT_CNT_REG		0x34
84 
85 #define SUN6I_BURST_CTL_CNT_REG		0x38
86 
87 #define SUN6I_TXDATA_REG		0x200
88 #define SUN6I_RXDATA_REG		0x300
89 
90 struct sun6i_spi_cfg {
91 	unsigned long		fifo_depth;
92 	bool			has_clk_ctl;
93 };
94 
95 struct sun6i_spi {
96 	struct spi_master	*master;
97 	void __iomem		*base_addr;
98 	dma_addr_t		dma_addr_rx;
99 	dma_addr_t		dma_addr_tx;
100 	struct clk		*hclk;
101 	struct clk		*mclk;
102 	struct reset_control	*rstc;
103 
104 	struct completion	done;
105 
106 	const u8		*tx_buf;
107 	u8			*rx_buf;
108 	int			len;
109 	const struct sun6i_spi_cfg *cfg;
110 };
111 
112 static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
113 {
114 	return readl(sspi->base_addr + reg);
115 }
116 
117 static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
118 {
119 	writel(value, sspi->base_addr + reg);
120 }
121 
122 static inline u32 sun6i_spi_get_rx_fifo_count(struct sun6i_spi *sspi)
123 {
124 	u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
125 
126 	return FIELD_GET(SUN6I_FIFO_STA_RF_CNT_MASK, reg);
127 }
128 
129 static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi)
130 {
131 	u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
132 
133 	return FIELD_GET(SUN6I_FIFO_STA_TF_CNT_MASK, reg);
134 }
135 
136 static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask)
137 {
138 	u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
139 
140 	reg &= ~mask;
141 	sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
142 }
143 
144 static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi)
145 {
146 	u32 len;
147 	u8 byte;
148 
149 	/* See how much data is available */
150 	len = sun6i_spi_get_rx_fifo_count(sspi);
151 
152 	while (len--) {
153 		byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
154 		if (sspi->rx_buf)
155 			*sspi->rx_buf++ = byte;
156 	}
157 }
158 
159 static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi)
160 {
161 	u32 cnt;
162 	int len;
163 	u8 byte;
164 
165 	/* See how much data we can fit */
166 	cnt = sspi->cfg->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi);
167 
168 	len = min((int)cnt, sspi->len);
169 
170 	while (len--) {
171 		byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
172 		writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
173 		sspi->len--;
174 	}
175 }
176 
177 static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
178 {
179 	struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
180 	u32 reg;
181 
182 	reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
183 	reg &= ~SUN6I_TFR_CTL_CS_MASK;
184 	reg |= SUN6I_TFR_CTL_CS(spi_get_chipselect(spi, 0));
185 
186 	if (enable)
187 		reg |= SUN6I_TFR_CTL_CS_LEVEL;
188 	else
189 		reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
190 
191 	sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
192 }
193 
194 static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
195 {
196 	return SUN6I_MAX_XFER_SIZE - 1;
197 }
198 
199 static int sun6i_spi_prepare_dma(struct sun6i_spi *sspi,
200 				 struct spi_transfer *tfr)
201 {
202 	struct dma_async_tx_descriptor *rxdesc, *txdesc;
203 	struct spi_master *master = sspi->master;
204 
205 	rxdesc = NULL;
206 	if (tfr->rx_buf) {
207 		struct dma_slave_config rxconf = {
208 			.direction = DMA_DEV_TO_MEM,
209 			.src_addr = sspi->dma_addr_rx,
210 			.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
211 			.src_maxburst = 8,
212 		};
213 
214 		dmaengine_slave_config(master->dma_rx, &rxconf);
215 
216 		rxdesc = dmaengine_prep_slave_sg(master->dma_rx,
217 						 tfr->rx_sg.sgl,
218 						 tfr->rx_sg.nents,
219 						 DMA_DEV_TO_MEM,
220 						 DMA_PREP_INTERRUPT);
221 		if (!rxdesc)
222 			return -EINVAL;
223 	}
224 
225 	txdesc = NULL;
226 	if (tfr->tx_buf) {
227 		struct dma_slave_config txconf = {
228 			.direction = DMA_MEM_TO_DEV,
229 			.dst_addr = sspi->dma_addr_tx,
230 			.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
231 			.dst_maxburst = 8,
232 		};
233 
234 		dmaengine_slave_config(master->dma_tx, &txconf);
235 
236 		txdesc = dmaengine_prep_slave_sg(master->dma_tx,
237 						 tfr->tx_sg.sgl,
238 						 tfr->tx_sg.nents,
239 						 DMA_MEM_TO_DEV,
240 						 DMA_PREP_INTERRUPT);
241 		if (!txdesc) {
242 			if (rxdesc)
243 				dmaengine_terminate_sync(master->dma_rx);
244 			return -EINVAL;
245 		}
246 	}
247 
248 	if (tfr->rx_buf) {
249 		dmaengine_submit(rxdesc);
250 		dma_async_issue_pending(master->dma_rx);
251 	}
252 
253 	if (tfr->tx_buf) {
254 		dmaengine_submit(txdesc);
255 		dma_async_issue_pending(master->dma_tx);
256 	}
257 
258 	return 0;
259 }
260 
261 static int sun6i_spi_transfer_one(struct spi_master *master,
262 				  struct spi_device *spi,
263 				  struct spi_transfer *tfr)
264 {
265 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
266 	unsigned int div, div_cdr1, div_cdr2, timeout;
267 	unsigned int start, end, tx_time;
268 	unsigned int trig_level;
269 	unsigned int tx_len = 0, rx_len = 0;
270 	bool use_dma;
271 	int ret = 0;
272 	u32 reg;
273 
274 	if (tfr->len > SUN6I_MAX_XFER_SIZE)
275 		return -EINVAL;
276 
277 	reinit_completion(&sspi->done);
278 	sspi->tx_buf = tfr->tx_buf;
279 	sspi->rx_buf = tfr->rx_buf;
280 	sspi->len = tfr->len;
281 	use_dma = master->can_dma ? master->can_dma(master, spi, tfr) : false;
282 
283 	/* Clear pending interrupts */
284 	sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
285 
286 	/* Reset FIFO */
287 	sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
288 			SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
289 
290 	reg = 0;
291 
292 	if (!use_dma) {
293 		/*
294 		 * Setup FIFO interrupt trigger level
295 		 * Here we choose 3/4 of the full fifo depth, as it's
296 		 * the hardcoded value used in old generation of Allwinner
297 		 * SPI controller. (See spi-sun4i.c)
298 		 */
299 		trig_level = sspi->cfg->fifo_depth / 4 * 3;
300 	} else {
301 		/*
302 		 * Setup FIFO DMA request trigger level
303 		 * We choose 1/2 of the full fifo depth, that value will
304 		 * be used as DMA burst length.
305 		 */
306 		trig_level = sspi->cfg->fifo_depth / 2;
307 
308 		if (tfr->tx_buf)
309 			reg |= SUN6I_FIFO_CTL_TF_DRQ_EN;
310 		if (tfr->rx_buf)
311 			reg |= SUN6I_FIFO_CTL_RF_DRQ_EN;
312 	}
313 
314 	reg |= (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
315 	       (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS);
316 
317 	sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG, reg);
318 
319 	/*
320 	 * Setup the transfer control register: Chip Select,
321 	 * polarities, etc.
322 	 */
323 	reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
324 
325 	if (spi->mode & SPI_CPOL)
326 		reg |= SUN6I_TFR_CTL_CPOL;
327 	else
328 		reg &= ~SUN6I_TFR_CTL_CPOL;
329 
330 	if (spi->mode & SPI_CPHA)
331 		reg |= SUN6I_TFR_CTL_CPHA;
332 	else
333 		reg &= ~SUN6I_TFR_CTL_CPHA;
334 
335 	if (spi->mode & SPI_LSB_FIRST)
336 		reg |= SUN6I_TFR_CTL_FBS;
337 	else
338 		reg &= ~SUN6I_TFR_CTL_FBS;
339 
340 	/*
341 	 * If it's a TX only transfer, we don't want to fill the RX
342 	 * FIFO with bogus data
343 	 */
344 	if (sspi->rx_buf) {
345 		reg &= ~SUN6I_TFR_CTL_DHB;
346 		rx_len = tfr->len;
347 	} else {
348 		reg |= SUN6I_TFR_CTL_DHB;
349 	}
350 
351 	/* We want to control the chip select manually */
352 	reg |= SUN6I_TFR_CTL_CS_MANUAL;
353 
354 	sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
355 
356 	if (sspi->cfg->has_clk_ctl) {
357 		unsigned int mclk_rate = clk_get_rate(sspi->mclk);
358 
359 		/* Ensure that we have a parent clock fast enough */
360 		if (mclk_rate < (2 * tfr->speed_hz)) {
361 			clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
362 			mclk_rate = clk_get_rate(sspi->mclk);
363 		}
364 
365 		/*
366 		 * Setup clock divider.
367 		 *
368 		 * We have two choices there. Either we can use the clock
369 		 * divide rate 1, which is calculated thanks to this formula:
370 		 * SPI_CLK = MOD_CLK / (2 ^ cdr)
371 		 * Or we can use CDR2, which is calculated with the formula:
372 		 * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
373 		 * Wether we use the former or the latter is set through the
374 		 * DRS bit.
375 		 *
376 		 * First try CDR2, and if we can't reach the expected
377 		 * frequency, fall back to CDR1.
378 		 */
379 		div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz);
380 		div_cdr2 = DIV_ROUND_UP(div_cdr1, 2);
381 		if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
382 			reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS;
383 			tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2);
384 		} else {
385 			div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1));
386 			reg = SUN6I_CLK_CTL_CDR1(div);
387 			tfr->effective_speed_hz = mclk_rate / (1 << div);
388 		}
389 
390 		sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
391 	} else {
392 		clk_set_rate(sspi->mclk, tfr->speed_hz);
393 		tfr->effective_speed_hz = clk_get_rate(sspi->mclk);
394 
395 		/*
396 		 * Configure work mode.
397 		 *
398 		 * There are three work modes depending on the controller clock
399 		 * frequency:
400 		 * - normal sample mode           : CLK <= 24MHz SDM=1 SDC=0
401 		 * - delay half-cycle sample mode : CLK <= 40MHz SDM=0 SDC=0
402 		 * - delay one-cycle sample mode  : CLK >= 80MHz SDM=0 SDC=1
403 		 */
404 		reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
405 		reg &= ~(SUN6I_TFR_CTL_SDM | SUN6I_TFR_CTL_SDC);
406 
407 		if (tfr->effective_speed_hz <= 24000000)
408 			reg |= SUN6I_TFR_CTL_SDM;
409 		else if (tfr->effective_speed_hz >= 80000000)
410 			reg |= SUN6I_TFR_CTL_SDC;
411 
412 		sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
413 	}
414 
415 	/* Finally enable the bus - doing so before might raise SCK to HIGH */
416 	reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG);
417 	reg |= SUN6I_GBL_CTL_BUS_ENABLE;
418 	sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, reg);
419 
420 	/* Setup the transfer now... */
421 	if (sspi->tx_buf)
422 		tx_len = tfr->len;
423 
424 	/* Setup the counters */
425 	sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, tfr->len);
426 	sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, tx_len);
427 	sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG, tx_len);
428 
429 	if (!use_dma) {
430 		/* Fill the TX FIFO */
431 		sun6i_spi_fill_fifo(sspi);
432 	} else {
433 		ret = sun6i_spi_prepare_dma(sspi, tfr);
434 		if (ret) {
435 			dev_warn(&master->dev,
436 				 "%s: prepare DMA failed, ret=%d",
437 				 dev_name(&spi->dev), ret);
438 			return ret;
439 		}
440 	}
441 
442 	/* Enable the interrupts */
443 	reg = SUN6I_INT_CTL_TC;
444 
445 	if (!use_dma) {
446 		if (rx_len > sspi->cfg->fifo_depth)
447 			reg |= SUN6I_INT_CTL_RF_RDY;
448 		if (tx_len > sspi->cfg->fifo_depth)
449 			reg |= SUN6I_INT_CTL_TF_ERQ;
450 	}
451 
452 	sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
453 
454 	/* Start the transfer */
455 	reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
456 	sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
457 
458 	tx_time = spi_controller_xfer_timeout(master, tfr);
459 	start = jiffies;
460 	timeout = wait_for_completion_timeout(&sspi->done,
461 					      msecs_to_jiffies(tx_time));
462 	end = jiffies;
463 	if (!timeout) {
464 		dev_warn(&master->dev,
465 			 "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
466 			 dev_name(&spi->dev), tfr->len, tfr->speed_hz,
467 			 jiffies_to_msecs(end - start), tx_time);
468 		ret = -ETIMEDOUT;
469 	}
470 
471 	sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
472 
473 	if (ret && use_dma) {
474 		dmaengine_terminate_sync(master->dma_rx);
475 		dmaengine_terminate_sync(master->dma_tx);
476 	}
477 
478 	return ret;
479 }
480 
481 static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
482 {
483 	struct sun6i_spi *sspi = dev_id;
484 	u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
485 
486 	/* Transfer complete */
487 	if (status & SUN6I_INT_CTL_TC) {
488 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
489 		sun6i_spi_drain_fifo(sspi);
490 		complete(&sspi->done);
491 		return IRQ_HANDLED;
492 	}
493 
494 	/* Receive FIFO 3/4 full */
495 	if (status & SUN6I_INT_CTL_RF_RDY) {
496 		sun6i_spi_drain_fifo(sspi);
497 		/* Only clear the interrupt _after_ draining the FIFO */
498 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
499 		return IRQ_HANDLED;
500 	}
501 
502 	/* Transmit FIFO 3/4 empty */
503 	if (status & SUN6I_INT_CTL_TF_ERQ) {
504 		sun6i_spi_fill_fifo(sspi);
505 
506 		if (!sspi->len)
507 			/* nothing left to transmit */
508 			sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
509 
510 		/* Only clear the interrupt _after_ re-seeding the FIFO */
511 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
512 
513 		return IRQ_HANDLED;
514 	}
515 
516 	return IRQ_NONE;
517 }
518 
519 static int sun6i_spi_runtime_resume(struct device *dev)
520 {
521 	struct spi_master *master = dev_get_drvdata(dev);
522 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
523 	int ret;
524 
525 	ret = clk_prepare_enable(sspi->hclk);
526 	if (ret) {
527 		dev_err(dev, "Couldn't enable AHB clock\n");
528 		goto out;
529 	}
530 
531 	ret = clk_prepare_enable(sspi->mclk);
532 	if (ret) {
533 		dev_err(dev, "Couldn't enable module clock\n");
534 		goto err;
535 	}
536 
537 	ret = reset_control_deassert(sspi->rstc);
538 	if (ret) {
539 		dev_err(dev, "Couldn't deassert the device from reset\n");
540 		goto err2;
541 	}
542 
543 	sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
544 			SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
545 
546 	return 0;
547 
548 err2:
549 	clk_disable_unprepare(sspi->mclk);
550 err:
551 	clk_disable_unprepare(sspi->hclk);
552 out:
553 	return ret;
554 }
555 
556 static int sun6i_spi_runtime_suspend(struct device *dev)
557 {
558 	struct spi_master *master = dev_get_drvdata(dev);
559 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
560 
561 	reset_control_assert(sspi->rstc);
562 	clk_disable_unprepare(sspi->mclk);
563 	clk_disable_unprepare(sspi->hclk);
564 
565 	return 0;
566 }
567 
568 static bool sun6i_spi_can_dma(struct spi_master *master,
569 			      struct spi_device *spi,
570 			      struct spi_transfer *xfer)
571 {
572 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
573 
574 	/*
575 	 * If the number of spi words to transfer is less or equal than
576 	 * the fifo length we can just fill the fifo and wait for a single
577 	 * irq, so don't bother setting up dma
578 	 */
579 	return xfer->len > sspi->cfg->fifo_depth;
580 }
581 
582 static int sun6i_spi_probe(struct platform_device *pdev)
583 {
584 	struct spi_master *master;
585 	struct sun6i_spi *sspi;
586 	struct resource *mem;
587 	int ret = 0, irq;
588 
589 	master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
590 	if (!master) {
591 		dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
592 		return -ENOMEM;
593 	}
594 
595 	platform_set_drvdata(pdev, master);
596 	sspi = spi_master_get_devdata(master);
597 
598 	sspi->base_addr = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
599 	if (IS_ERR(sspi->base_addr)) {
600 		ret = PTR_ERR(sspi->base_addr);
601 		goto err_free_master;
602 	}
603 
604 	irq = platform_get_irq(pdev, 0);
605 	if (irq < 0) {
606 		ret = -ENXIO;
607 		goto err_free_master;
608 	}
609 
610 	ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
611 			       0, "sun6i-spi", sspi);
612 	if (ret) {
613 		dev_err(&pdev->dev, "Cannot request IRQ\n");
614 		goto err_free_master;
615 	}
616 
617 	sspi->master = master;
618 	sspi->cfg = of_device_get_match_data(&pdev->dev);
619 
620 	master->max_speed_hz = 100 * 1000 * 1000;
621 	master->min_speed_hz = 3 * 1000;
622 	master->use_gpio_descriptors = true;
623 	master->set_cs = sun6i_spi_set_cs;
624 	master->transfer_one = sun6i_spi_transfer_one;
625 	master->num_chipselect = 4;
626 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
627 	master->bits_per_word_mask = SPI_BPW_MASK(8);
628 	master->dev.of_node = pdev->dev.of_node;
629 	master->auto_runtime_pm = true;
630 	master->max_transfer_size = sun6i_spi_max_transfer_size;
631 
632 	sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
633 	if (IS_ERR(sspi->hclk)) {
634 		dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
635 		ret = PTR_ERR(sspi->hclk);
636 		goto err_free_master;
637 	}
638 
639 	sspi->mclk = devm_clk_get(&pdev->dev, "mod");
640 	if (IS_ERR(sspi->mclk)) {
641 		dev_err(&pdev->dev, "Unable to acquire module clock\n");
642 		ret = PTR_ERR(sspi->mclk);
643 		goto err_free_master;
644 	}
645 
646 	init_completion(&sspi->done);
647 
648 	sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
649 	if (IS_ERR(sspi->rstc)) {
650 		dev_err(&pdev->dev, "Couldn't get reset controller\n");
651 		ret = PTR_ERR(sspi->rstc);
652 		goto err_free_master;
653 	}
654 
655 	master->dma_tx = dma_request_chan(&pdev->dev, "tx");
656 	if (IS_ERR(master->dma_tx)) {
657 		/* Check tx to see if we need defer probing driver */
658 		if (PTR_ERR(master->dma_tx) == -EPROBE_DEFER) {
659 			ret = -EPROBE_DEFER;
660 			goto err_free_master;
661 		}
662 		dev_warn(&pdev->dev, "Failed to request TX DMA channel\n");
663 		master->dma_tx = NULL;
664 	}
665 
666 	master->dma_rx = dma_request_chan(&pdev->dev, "rx");
667 	if (IS_ERR(master->dma_rx)) {
668 		if (PTR_ERR(master->dma_rx) == -EPROBE_DEFER) {
669 			ret = -EPROBE_DEFER;
670 			goto err_free_dma_tx;
671 		}
672 		dev_warn(&pdev->dev, "Failed to request RX DMA channel\n");
673 		master->dma_rx = NULL;
674 	}
675 
676 	if (master->dma_tx && master->dma_rx) {
677 		sspi->dma_addr_tx = mem->start + SUN6I_TXDATA_REG;
678 		sspi->dma_addr_rx = mem->start + SUN6I_RXDATA_REG;
679 		master->can_dma = sun6i_spi_can_dma;
680 	}
681 
682 	/*
683 	 * This wake-up/shutdown pattern is to be able to have the
684 	 * device woken up, even if runtime_pm is disabled
685 	 */
686 	ret = sun6i_spi_runtime_resume(&pdev->dev);
687 	if (ret) {
688 		dev_err(&pdev->dev, "Couldn't resume the device\n");
689 		goto err_free_dma_rx;
690 	}
691 
692 	pm_runtime_set_autosuspend_delay(&pdev->dev, SUN6I_AUTOSUSPEND_TIMEOUT);
693 	pm_runtime_use_autosuspend(&pdev->dev);
694 	pm_runtime_set_active(&pdev->dev);
695 	pm_runtime_enable(&pdev->dev);
696 
697 	ret = devm_spi_register_master(&pdev->dev, master);
698 	if (ret) {
699 		dev_err(&pdev->dev, "cannot register SPI master\n");
700 		goto err_pm_disable;
701 	}
702 
703 	return 0;
704 
705 err_pm_disable:
706 	pm_runtime_disable(&pdev->dev);
707 	sun6i_spi_runtime_suspend(&pdev->dev);
708 err_free_dma_rx:
709 	if (master->dma_rx)
710 		dma_release_channel(master->dma_rx);
711 err_free_dma_tx:
712 	if (master->dma_tx)
713 		dma_release_channel(master->dma_tx);
714 err_free_master:
715 	spi_master_put(master);
716 	return ret;
717 }
718 
719 static void sun6i_spi_remove(struct platform_device *pdev)
720 {
721 	struct spi_master *master = platform_get_drvdata(pdev);
722 
723 	pm_runtime_force_suspend(&pdev->dev);
724 
725 	if (master->dma_tx)
726 		dma_release_channel(master->dma_tx);
727 	if (master->dma_rx)
728 		dma_release_channel(master->dma_rx);
729 }
730 
731 static const struct sun6i_spi_cfg sun6i_a31_spi_cfg = {
732 	.fifo_depth	= SUN6I_FIFO_DEPTH,
733 	.has_clk_ctl	= true,
734 };
735 
736 static const struct sun6i_spi_cfg sun8i_h3_spi_cfg = {
737 	.fifo_depth	= SUN8I_FIFO_DEPTH,
738 	.has_clk_ctl	= true,
739 };
740 
741 static const struct sun6i_spi_cfg sun50i_r329_spi_cfg = {
742 	.fifo_depth	= SUN8I_FIFO_DEPTH,
743 };
744 
745 static const struct of_device_id sun6i_spi_match[] = {
746 	{ .compatible = "allwinner,sun6i-a31-spi", .data = &sun6i_a31_spi_cfg },
747 	{ .compatible = "allwinner,sun8i-h3-spi",  .data = &sun8i_h3_spi_cfg },
748 	{
749 		.compatible = "allwinner,sun50i-r329-spi",
750 		.data = &sun50i_r329_spi_cfg
751 	},
752 	{}
753 };
754 MODULE_DEVICE_TABLE(of, sun6i_spi_match);
755 
756 static const struct dev_pm_ops sun6i_spi_pm_ops = {
757 	.runtime_resume		= sun6i_spi_runtime_resume,
758 	.runtime_suspend	= sun6i_spi_runtime_suspend,
759 };
760 
761 static struct platform_driver sun6i_spi_driver = {
762 	.probe	= sun6i_spi_probe,
763 	.remove_new = sun6i_spi_remove,
764 	.driver	= {
765 		.name		= "sun6i-spi",
766 		.of_match_table	= sun6i_spi_match,
767 		.pm		= &sun6i_spi_pm_ops,
768 	},
769 };
770 module_platform_driver(sun6i_spi_driver);
771 
772 MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
773 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
774 MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
775 MODULE_LICENSE("GPL");
776