xref: /openbmc/linux/drivers/spi/spi-sun6i.c (revision ded1ffea)
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.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 #define SUN6I_BURST_CTL_CNT_STC_MASK		GENMASK(23, 0)
87 #define SUN6I_BURST_CTL_CNT_DRM			BIT(28)
88 #define SUN6I_BURST_CTL_CNT_QUAD_EN		BIT(29)
89 
90 #define SUN6I_TXDATA_REG		0x200
91 #define SUN6I_RXDATA_REG		0x300
92 
93 struct sun6i_spi_cfg {
94 	unsigned long		fifo_depth;
95 	bool			has_clk_ctl;
96 	u32			mode_bits;
97 };
98 
99 struct sun6i_spi {
100 	struct spi_master	*master;
101 	void __iomem		*base_addr;
102 	dma_addr_t		dma_addr_rx;
103 	dma_addr_t		dma_addr_tx;
104 	struct clk		*hclk;
105 	struct clk		*mclk;
106 	struct reset_control	*rstc;
107 
108 	struct completion	done;
109 	struct completion	dma_rx_done;
110 
111 	const u8		*tx_buf;
112 	u8			*rx_buf;
113 	int			len;
114 	const struct sun6i_spi_cfg *cfg;
115 };
116 
117 static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
118 {
119 	return readl(sspi->base_addr + reg);
120 }
121 
122 static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
123 {
124 	writel(value, sspi->base_addr + reg);
125 }
126 
127 static inline u32 sun6i_spi_get_rx_fifo_count(struct sun6i_spi *sspi)
128 {
129 	u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
130 
131 	return FIELD_GET(SUN6I_FIFO_STA_RF_CNT_MASK, reg);
132 }
133 
134 static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi)
135 {
136 	u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
137 
138 	return FIELD_GET(SUN6I_FIFO_STA_TF_CNT_MASK, reg);
139 }
140 
141 static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask)
142 {
143 	u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
144 
145 	reg &= ~mask;
146 	sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
147 }
148 
149 static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi)
150 {
151 	u32 len;
152 	u8 byte;
153 
154 	/* See how much data is available */
155 	len = sun6i_spi_get_rx_fifo_count(sspi);
156 
157 	while (len--) {
158 		byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
159 		if (sspi->rx_buf)
160 			*sspi->rx_buf++ = byte;
161 	}
162 }
163 
164 static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi)
165 {
166 	u32 cnt;
167 	int len;
168 	u8 byte;
169 
170 	/* See how much data we can fit */
171 	cnt = sspi->cfg->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi);
172 
173 	len = min((int)cnt, sspi->len);
174 
175 	while (len--) {
176 		byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
177 		writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
178 		sspi->len--;
179 	}
180 }
181 
182 static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
183 {
184 	struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
185 	u32 reg;
186 
187 	reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
188 	reg &= ~SUN6I_TFR_CTL_CS_MASK;
189 	reg |= SUN6I_TFR_CTL_CS(spi_get_chipselect(spi, 0));
190 
191 	if (enable)
192 		reg |= SUN6I_TFR_CTL_CS_LEVEL;
193 	else
194 		reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
195 
196 	sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
197 }
198 
199 static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
200 {
201 	return SUN6I_MAX_XFER_SIZE - 1;
202 }
203 
204 static void sun6i_spi_dma_rx_cb(void *param)
205 {
206 	struct sun6i_spi *sspi = param;
207 
208 	complete(&sspi->dma_rx_done);
209 }
210 
211 static int sun6i_spi_prepare_dma(struct sun6i_spi *sspi,
212 				 struct spi_transfer *tfr)
213 {
214 	struct dma_async_tx_descriptor *rxdesc, *txdesc;
215 	struct spi_master *master = sspi->master;
216 
217 	rxdesc = NULL;
218 	if (tfr->rx_buf) {
219 		struct dma_slave_config rxconf = {
220 			.direction = DMA_DEV_TO_MEM,
221 			.src_addr = sspi->dma_addr_rx,
222 			.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
223 			.src_maxburst = 8,
224 		};
225 
226 		dmaengine_slave_config(master->dma_rx, &rxconf);
227 
228 		rxdesc = dmaengine_prep_slave_sg(master->dma_rx,
229 						 tfr->rx_sg.sgl,
230 						 tfr->rx_sg.nents,
231 						 DMA_DEV_TO_MEM,
232 						 DMA_PREP_INTERRUPT);
233 		if (!rxdesc)
234 			return -EINVAL;
235 		rxdesc->callback_param = sspi;
236 		rxdesc->callback = sun6i_spi_dma_rx_cb;
237 	}
238 
239 	txdesc = NULL;
240 	if (tfr->tx_buf) {
241 		struct dma_slave_config txconf = {
242 			.direction = DMA_MEM_TO_DEV,
243 			.dst_addr = sspi->dma_addr_tx,
244 			.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
245 			.dst_maxburst = 8,
246 		};
247 
248 		dmaengine_slave_config(master->dma_tx, &txconf);
249 
250 		txdesc = dmaengine_prep_slave_sg(master->dma_tx,
251 						 tfr->tx_sg.sgl,
252 						 tfr->tx_sg.nents,
253 						 DMA_MEM_TO_DEV,
254 						 DMA_PREP_INTERRUPT);
255 		if (!txdesc) {
256 			if (rxdesc)
257 				dmaengine_terminate_sync(master->dma_rx);
258 			return -EINVAL;
259 		}
260 	}
261 
262 	if (tfr->rx_buf) {
263 		dmaengine_submit(rxdesc);
264 		dma_async_issue_pending(master->dma_rx);
265 	}
266 
267 	if (tfr->tx_buf) {
268 		dmaengine_submit(txdesc);
269 		dma_async_issue_pending(master->dma_tx);
270 	}
271 
272 	return 0;
273 }
274 
275 static int sun6i_spi_transfer_one(struct spi_master *master,
276 				  struct spi_device *spi,
277 				  struct spi_transfer *tfr)
278 {
279 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
280 	unsigned int div, div_cdr1, div_cdr2, timeout;
281 	unsigned int start, end, tx_time;
282 	unsigned int trig_level;
283 	unsigned int tx_len = 0, rx_len = 0, nbits = 0;
284 	bool use_dma;
285 	int ret = 0;
286 	u32 reg;
287 
288 	if (tfr->len > SUN6I_MAX_XFER_SIZE)
289 		return -EINVAL;
290 
291 	reinit_completion(&sspi->done);
292 	reinit_completion(&sspi->dma_rx_done);
293 	sspi->tx_buf = tfr->tx_buf;
294 	sspi->rx_buf = tfr->rx_buf;
295 	sspi->len = tfr->len;
296 	use_dma = master->can_dma ? master->can_dma(master, spi, tfr) : false;
297 
298 	/* Clear pending interrupts */
299 	sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
300 
301 	/* Reset FIFO */
302 	sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
303 			SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
304 
305 	reg = 0;
306 
307 	if (!use_dma) {
308 		/*
309 		 * Setup FIFO interrupt trigger level
310 		 * Here we choose 3/4 of the full fifo depth, as it's
311 		 * the hardcoded value used in old generation of Allwinner
312 		 * SPI controller. (See spi-sun4i.c)
313 		 */
314 		trig_level = sspi->cfg->fifo_depth / 4 * 3;
315 	} else {
316 		/*
317 		 * Setup FIFO DMA request trigger level
318 		 * We choose 1/2 of the full fifo depth, that value will
319 		 * be used as DMA burst length.
320 		 */
321 		trig_level = sspi->cfg->fifo_depth / 2;
322 
323 		if (tfr->tx_buf)
324 			reg |= SUN6I_FIFO_CTL_TF_DRQ_EN;
325 		if (tfr->rx_buf)
326 			reg |= SUN6I_FIFO_CTL_RF_DRQ_EN;
327 	}
328 
329 	reg |= (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
330 	       (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS);
331 
332 	sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG, reg);
333 
334 	/*
335 	 * Setup the transfer control register: Chip Select,
336 	 * polarities, etc.
337 	 */
338 	reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
339 
340 	if (spi->mode & SPI_CPOL)
341 		reg |= SUN6I_TFR_CTL_CPOL;
342 	else
343 		reg &= ~SUN6I_TFR_CTL_CPOL;
344 
345 	if (spi->mode & SPI_CPHA)
346 		reg |= SUN6I_TFR_CTL_CPHA;
347 	else
348 		reg &= ~SUN6I_TFR_CTL_CPHA;
349 
350 	if (spi->mode & SPI_LSB_FIRST)
351 		reg |= SUN6I_TFR_CTL_FBS;
352 	else
353 		reg &= ~SUN6I_TFR_CTL_FBS;
354 
355 	/*
356 	 * If it's a TX only transfer, we don't want to fill the RX
357 	 * FIFO with bogus data
358 	 */
359 	if (sspi->rx_buf) {
360 		reg &= ~SUN6I_TFR_CTL_DHB;
361 		rx_len = tfr->len;
362 	} else {
363 		reg |= SUN6I_TFR_CTL_DHB;
364 	}
365 
366 	/* We want to control the chip select manually */
367 	reg |= SUN6I_TFR_CTL_CS_MANUAL;
368 
369 	sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
370 
371 	if (sspi->cfg->has_clk_ctl) {
372 		unsigned int mclk_rate = clk_get_rate(sspi->mclk);
373 
374 		/* Ensure that we have a parent clock fast enough */
375 		if (mclk_rate < (2 * tfr->speed_hz)) {
376 			clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
377 			mclk_rate = clk_get_rate(sspi->mclk);
378 		}
379 
380 		/*
381 		 * Setup clock divider.
382 		 *
383 		 * We have two choices there. Either we can use the clock
384 		 * divide rate 1, which is calculated thanks to this formula:
385 		 * SPI_CLK = MOD_CLK / (2 ^ cdr)
386 		 * Or we can use CDR2, which is calculated with the formula:
387 		 * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
388 		 * Wether we use the former or the latter is set through the
389 		 * DRS bit.
390 		 *
391 		 * First try CDR2, and if we can't reach the expected
392 		 * frequency, fall back to CDR1.
393 		 */
394 		div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz);
395 		div_cdr2 = DIV_ROUND_UP(div_cdr1, 2);
396 		if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
397 			reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS;
398 			tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2);
399 		} else {
400 			div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1));
401 			reg = SUN6I_CLK_CTL_CDR1(div);
402 			tfr->effective_speed_hz = mclk_rate / (1 << div);
403 		}
404 
405 		sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
406 	} else {
407 		clk_set_rate(sspi->mclk, tfr->speed_hz);
408 		tfr->effective_speed_hz = clk_get_rate(sspi->mclk);
409 
410 		/*
411 		 * Configure work mode.
412 		 *
413 		 * There are three work modes depending on the controller clock
414 		 * frequency:
415 		 * - normal sample mode           : CLK <= 24MHz SDM=1 SDC=0
416 		 * - delay half-cycle sample mode : CLK <= 40MHz SDM=0 SDC=0
417 		 * - delay one-cycle sample mode  : CLK >= 80MHz SDM=0 SDC=1
418 		 */
419 		reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
420 		reg &= ~(SUN6I_TFR_CTL_SDM | SUN6I_TFR_CTL_SDC);
421 
422 		if (tfr->effective_speed_hz <= 24000000)
423 			reg |= SUN6I_TFR_CTL_SDM;
424 		else if (tfr->effective_speed_hz >= 80000000)
425 			reg |= SUN6I_TFR_CTL_SDC;
426 
427 		sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
428 	}
429 
430 	/* Finally enable the bus - doing so before might raise SCK to HIGH */
431 	reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG);
432 	reg |= SUN6I_GBL_CTL_BUS_ENABLE;
433 	sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, reg);
434 
435 	/* Setup the transfer now... */
436 	if (sspi->tx_buf) {
437 		tx_len = tfr->len;
438 		nbits = tfr->tx_nbits;
439 	} else if (tfr->rx_buf) {
440 		nbits = tfr->rx_nbits;
441 	}
442 
443 	switch (nbits) {
444 	case SPI_NBITS_DUAL:
445 		reg = SUN6I_BURST_CTL_CNT_DRM;
446 		break;
447 	case SPI_NBITS_QUAD:
448 		reg = SUN6I_BURST_CTL_CNT_QUAD_EN;
449 		break;
450 	case SPI_NBITS_SINGLE:
451 	default:
452 		reg = FIELD_PREP(SUN6I_BURST_CTL_CNT_STC_MASK, tx_len);
453 	}
454 
455 	/* Setup the counters */
456 	sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG, reg);
457 	sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, tfr->len);
458 	sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, tx_len);
459 
460 	if (!use_dma) {
461 		/* Fill the TX FIFO */
462 		sun6i_spi_fill_fifo(sspi);
463 	} else {
464 		ret = sun6i_spi_prepare_dma(sspi, tfr);
465 		if (ret) {
466 			dev_warn(&master->dev,
467 				 "%s: prepare DMA failed, ret=%d",
468 				 dev_name(&spi->dev), ret);
469 			return ret;
470 		}
471 	}
472 
473 	/* Enable the interrupts */
474 	reg = SUN6I_INT_CTL_TC;
475 
476 	if (!use_dma) {
477 		if (rx_len > sspi->cfg->fifo_depth)
478 			reg |= SUN6I_INT_CTL_RF_RDY;
479 		if (tx_len > sspi->cfg->fifo_depth)
480 			reg |= SUN6I_INT_CTL_TF_ERQ;
481 	}
482 
483 	sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
484 
485 	/* Start the transfer */
486 	reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
487 	sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
488 
489 	tx_time = spi_controller_xfer_timeout(master, tfr);
490 	start = jiffies;
491 	timeout = wait_for_completion_timeout(&sspi->done,
492 					      msecs_to_jiffies(tx_time));
493 
494 	if (!use_dma) {
495 		sun6i_spi_drain_fifo(sspi);
496 	} else {
497 		if (timeout && rx_len) {
498 			/*
499 			 * Even though RX on the peripheral side has finished
500 			 * RX DMA might still be in flight
501 			 */
502 			timeout = wait_for_completion_timeout(&sspi->dma_rx_done,
503 							      timeout);
504 			if (!timeout)
505 				dev_warn(&master->dev, "RX DMA timeout\n");
506 		}
507 	}
508 
509 	end = jiffies;
510 	if (!timeout) {
511 		dev_warn(&master->dev,
512 			 "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
513 			 dev_name(&spi->dev), tfr->len, tfr->speed_hz,
514 			 jiffies_to_msecs(end - start), tx_time);
515 		ret = -ETIMEDOUT;
516 	}
517 
518 	sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
519 
520 	if (ret && use_dma) {
521 		dmaengine_terminate_sync(master->dma_rx);
522 		dmaengine_terminate_sync(master->dma_tx);
523 	}
524 
525 	return ret;
526 }
527 
528 static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
529 {
530 	struct sun6i_spi *sspi = dev_id;
531 	u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
532 
533 	/* Transfer complete */
534 	if (status & SUN6I_INT_CTL_TC) {
535 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
536 		complete(&sspi->done);
537 		return IRQ_HANDLED;
538 	}
539 
540 	/* Receive FIFO 3/4 full */
541 	if (status & SUN6I_INT_CTL_RF_RDY) {
542 		sun6i_spi_drain_fifo(sspi);
543 		/* Only clear the interrupt _after_ draining the FIFO */
544 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
545 		return IRQ_HANDLED;
546 	}
547 
548 	/* Transmit FIFO 3/4 empty */
549 	if (status & SUN6I_INT_CTL_TF_ERQ) {
550 		sun6i_spi_fill_fifo(sspi);
551 
552 		if (!sspi->len)
553 			/* nothing left to transmit */
554 			sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
555 
556 		/* Only clear the interrupt _after_ re-seeding the FIFO */
557 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
558 
559 		return IRQ_HANDLED;
560 	}
561 
562 	return IRQ_NONE;
563 }
564 
565 static int sun6i_spi_runtime_resume(struct device *dev)
566 {
567 	struct spi_master *master = dev_get_drvdata(dev);
568 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
569 	int ret;
570 
571 	ret = clk_prepare_enable(sspi->hclk);
572 	if (ret) {
573 		dev_err(dev, "Couldn't enable AHB clock\n");
574 		goto out;
575 	}
576 
577 	ret = clk_prepare_enable(sspi->mclk);
578 	if (ret) {
579 		dev_err(dev, "Couldn't enable module clock\n");
580 		goto err;
581 	}
582 
583 	ret = reset_control_deassert(sspi->rstc);
584 	if (ret) {
585 		dev_err(dev, "Couldn't deassert the device from reset\n");
586 		goto err2;
587 	}
588 
589 	sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
590 			SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
591 
592 	return 0;
593 
594 err2:
595 	clk_disable_unprepare(sspi->mclk);
596 err:
597 	clk_disable_unprepare(sspi->hclk);
598 out:
599 	return ret;
600 }
601 
602 static int sun6i_spi_runtime_suspend(struct device *dev)
603 {
604 	struct spi_master *master = dev_get_drvdata(dev);
605 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
606 
607 	reset_control_assert(sspi->rstc);
608 	clk_disable_unprepare(sspi->mclk);
609 	clk_disable_unprepare(sspi->hclk);
610 
611 	return 0;
612 }
613 
614 static bool sun6i_spi_can_dma(struct spi_master *master,
615 			      struct spi_device *spi,
616 			      struct spi_transfer *xfer)
617 {
618 	struct sun6i_spi *sspi = spi_master_get_devdata(master);
619 
620 	/*
621 	 * If the number of spi words to transfer is less or equal than
622 	 * the fifo length we can just fill the fifo and wait for a single
623 	 * irq, so don't bother setting up dma
624 	 */
625 	return xfer->len > sspi->cfg->fifo_depth;
626 }
627 
628 static int sun6i_spi_probe(struct platform_device *pdev)
629 {
630 	struct spi_master *master;
631 	struct sun6i_spi *sspi;
632 	struct resource *mem;
633 	int ret = 0, irq;
634 
635 	master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
636 	if (!master) {
637 		dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
638 		return -ENOMEM;
639 	}
640 
641 	platform_set_drvdata(pdev, master);
642 	sspi = spi_master_get_devdata(master);
643 
644 	sspi->base_addr = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
645 	if (IS_ERR(sspi->base_addr)) {
646 		ret = PTR_ERR(sspi->base_addr);
647 		goto err_free_master;
648 	}
649 
650 	irq = platform_get_irq(pdev, 0);
651 	if (irq < 0) {
652 		ret = -ENXIO;
653 		goto err_free_master;
654 	}
655 
656 	ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
657 			       0, "sun6i-spi", sspi);
658 	if (ret) {
659 		dev_err(&pdev->dev, "Cannot request IRQ\n");
660 		goto err_free_master;
661 	}
662 
663 	sspi->master = master;
664 	sspi->cfg = of_device_get_match_data(&pdev->dev);
665 
666 	master->max_speed_hz = 100 * 1000 * 1000;
667 	master->min_speed_hz = 3 * 1000;
668 	master->use_gpio_descriptors = true;
669 	master->set_cs = sun6i_spi_set_cs;
670 	master->transfer_one = sun6i_spi_transfer_one;
671 	master->num_chipselect = 4;
672 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST |
673 			    sspi->cfg->mode_bits;
674 	master->bits_per_word_mask = SPI_BPW_MASK(8);
675 	master->dev.of_node = pdev->dev.of_node;
676 	master->auto_runtime_pm = true;
677 	master->max_transfer_size = sun6i_spi_max_transfer_size;
678 
679 	sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
680 	if (IS_ERR(sspi->hclk)) {
681 		dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
682 		ret = PTR_ERR(sspi->hclk);
683 		goto err_free_master;
684 	}
685 
686 	sspi->mclk = devm_clk_get(&pdev->dev, "mod");
687 	if (IS_ERR(sspi->mclk)) {
688 		dev_err(&pdev->dev, "Unable to acquire module clock\n");
689 		ret = PTR_ERR(sspi->mclk);
690 		goto err_free_master;
691 	}
692 
693 	init_completion(&sspi->done);
694 	init_completion(&sspi->dma_rx_done);
695 
696 	sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
697 	if (IS_ERR(sspi->rstc)) {
698 		dev_err(&pdev->dev, "Couldn't get reset controller\n");
699 		ret = PTR_ERR(sspi->rstc);
700 		goto err_free_master;
701 	}
702 
703 	master->dma_tx = dma_request_chan(&pdev->dev, "tx");
704 	if (IS_ERR(master->dma_tx)) {
705 		/* Check tx to see if we need defer probing driver */
706 		if (PTR_ERR(master->dma_tx) == -EPROBE_DEFER) {
707 			ret = -EPROBE_DEFER;
708 			goto err_free_master;
709 		}
710 		dev_warn(&pdev->dev, "Failed to request TX DMA channel\n");
711 		master->dma_tx = NULL;
712 	}
713 
714 	master->dma_rx = dma_request_chan(&pdev->dev, "rx");
715 	if (IS_ERR(master->dma_rx)) {
716 		if (PTR_ERR(master->dma_rx) == -EPROBE_DEFER) {
717 			ret = -EPROBE_DEFER;
718 			goto err_free_dma_tx;
719 		}
720 		dev_warn(&pdev->dev, "Failed to request RX DMA channel\n");
721 		master->dma_rx = NULL;
722 	}
723 
724 	if (master->dma_tx && master->dma_rx) {
725 		sspi->dma_addr_tx = mem->start + SUN6I_TXDATA_REG;
726 		sspi->dma_addr_rx = mem->start + SUN6I_RXDATA_REG;
727 		master->can_dma = sun6i_spi_can_dma;
728 	}
729 
730 	/*
731 	 * This wake-up/shutdown pattern is to be able to have the
732 	 * device woken up, even if runtime_pm is disabled
733 	 */
734 	ret = sun6i_spi_runtime_resume(&pdev->dev);
735 	if (ret) {
736 		dev_err(&pdev->dev, "Couldn't resume the device\n");
737 		goto err_free_dma_rx;
738 	}
739 
740 	pm_runtime_set_autosuspend_delay(&pdev->dev, SUN6I_AUTOSUSPEND_TIMEOUT);
741 	pm_runtime_use_autosuspend(&pdev->dev);
742 	pm_runtime_set_active(&pdev->dev);
743 	pm_runtime_enable(&pdev->dev);
744 
745 	ret = devm_spi_register_master(&pdev->dev, master);
746 	if (ret) {
747 		dev_err(&pdev->dev, "cannot register SPI master\n");
748 		goto err_pm_disable;
749 	}
750 
751 	return 0;
752 
753 err_pm_disable:
754 	pm_runtime_disable(&pdev->dev);
755 	sun6i_spi_runtime_suspend(&pdev->dev);
756 err_free_dma_rx:
757 	if (master->dma_rx)
758 		dma_release_channel(master->dma_rx);
759 err_free_dma_tx:
760 	if (master->dma_tx)
761 		dma_release_channel(master->dma_tx);
762 err_free_master:
763 	spi_master_put(master);
764 	return ret;
765 }
766 
767 static void sun6i_spi_remove(struct platform_device *pdev)
768 {
769 	struct spi_master *master = platform_get_drvdata(pdev);
770 
771 	pm_runtime_force_suspend(&pdev->dev);
772 
773 	if (master->dma_tx)
774 		dma_release_channel(master->dma_tx);
775 	if (master->dma_rx)
776 		dma_release_channel(master->dma_rx);
777 }
778 
779 static const struct sun6i_spi_cfg sun6i_a31_spi_cfg = {
780 	.fifo_depth	= SUN6I_FIFO_DEPTH,
781 	.has_clk_ctl	= true,
782 };
783 
784 static const struct sun6i_spi_cfg sun8i_h3_spi_cfg = {
785 	.fifo_depth	= SUN8I_FIFO_DEPTH,
786 	.has_clk_ctl	= true,
787 };
788 
789 static const struct sun6i_spi_cfg sun50i_r329_spi_cfg = {
790 	.fifo_depth	= SUN8I_FIFO_DEPTH,
791 	.mode_bits	= SPI_RX_DUAL | SPI_TX_DUAL | SPI_RX_QUAD | SPI_TX_QUAD,
792 };
793 
794 static const struct of_device_id sun6i_spi_match[] = {
795 	{ .compatible = "allwinner,sun6i-a31-spi", .data = &sun6i_a31_spi_cfg },
796 	{ .compatible = "allwinner,sun8i-h3-spi",  .data = &sun8i_h3_spi_cfg },
797 	{
798 		.compatible = "allwinner,sun50i-r329-spi",
799 		.data = &sun50i_r329_spi_cfg
800 	},
801 	{}
802 };
803 MODULE_DEVICE_TABLE(of, sun6i_spi_match);
804 
805 static const struct dev_pm_ops sun6i_spi_pm_ops = {
806 	.runtime_resume		= sun6i_spi_runtime_resume,
807 	.runtime_suspend	= sun6i_spi_runtime_suspend,
808 };
809 
810 static struct platform_driver sun6i_spi_driver = {
811 	.probe	= sun6i_spi_probe,
812 	.remove_new = sun6i_spi_remove,
813 	.driver	= {
814 		.name		= "sun6i-spi",
815 		.of_match_table	= sun6i_spi_match,
816 		.pm		= &sun6i_spi_pm_ops,
817 	},
818 };
819 module_platform_driver(sun6i_spi_driver);
820 
821 MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
822 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
823 MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
824 MODULE_LICENSE("GPL");
825