1 /*
2  * SPI driver for Nvidia's Tegra20 Serial Flash Controller.
3  *
4  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
5  *
6  * Author: Laxman Dewangan <ldewangan@nvidia.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include <linux/clk.h>
22 #include <linux/completion.h>
23 #include <linux/delay.h>
24 #include <linux/err.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/io.h>
28 #include <linux/kernel.h>
29 #include <linux/kthread.h>
30 #include <linux/module.h>
31 #include <linux/platform_device.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/of.h>
34 #include <linux/of_device.h>
35 #include <linux/spi/spi.h>
36 #include <linux/clk/tegra.h>
37 
38 #define SPI_COMMAND				0x000
39 #define SPI_GO					BIT(30)
40 #define SPI_M_S					BIT(28)
41 #define SPI_ACTIVE_SCLK_MASK			(0x3 << 26)
42 #define SPI_ACTIVE_SCLK_DRIVE_LOW		(0 << 26)
43 #define SPI_ACTIVE_SCLK_DRIVE_HIGH		(1 << 26)
44 #define SPI_ACTIVE_SCLK_PULL_LOW		(2 << 26)
45 #define SPI_ACTIVE_SCLK_PULL_HIGH		(3 << 26)
46 
47 #define SPI_CK_SDA_FALLING			(1 << 21)
48 #define SPI_CK_SDA_RISING			(0 << 21)
49 #define SPI_CK_SDA_MASK				(1 << 21)
50 #define SPI_ACTIVE_SDA				(0x3 << 18)
51 #define SPI_ACTIVE_SDA_DRIVE_LOW		(0 << 18)
52 #define SPI_ACTIVE_SDA_DRIVE_HIGH		(1 << 18)
53 #define SPI_ACTIVE_SDA_PULL_LOW			(2 << 18)
54 #define SPI_ACTIVE_SDA_PULL_HIGH		(3 << 18)
55 
56 #define SPI_CS_POL_INVERT			BIT(16)
57 #define SPI_TX_EN				BIT(15)
58 #define SPI_RX_EN				BIT(14)
59 #define SPI_CS_VAL_HIGH				BIT(13)
60 #define SPI_CS_VAL_LOW				0x0
61 #define SPI_CS_SW				BIT(12)
62 #define SPI_CS_HW				0x0
63 #define SPI_CS_DELAY_MASK			(7 << 9)
64 #define SPI_CS3_EN				BIT(8)
65 #define SPI_CS2_EN				BIT(7)
66 #define SPI_CS1_EN				BIT(6)
67 #define SPI_CS0_EN				BIT(5)
68 
69 #define SPI_CS_MASK			(SPI_CS3_EN | SPI_CS2_EN |	\
70 					SPI_CS1_EN | SPI_CS0_EN)
71 #define SPI_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
72 
73 #define SPI_MODES			(SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK)
74 
75 #define SPI_STATUS			0x004
76 #define SPI_BSY				BIT(31)
77 #define SPI_RDY				BIT(30)
78 #define SPI_TXF_FLUSH			BIT(29)
79 #define SPI_RXF_FLUSH			BIT(28)
80 #define SPI_RX_UNF			BIT(27)
81 #define SPI_TX_OVF			BIT(26)
82 #define SPI_RXF_EMPTY			BIT(25)
83 #define SPI_RXF_FULL			BIT(24)
84 #define SPI_TXF_EMPTY			BIT(23)
85 #define SPI_TXF_FULL			BIT(22)
86 #define SPI_BLK_CNT(count)		(((count) & 0xffff) + 1)
87 
88 #define SPI_FIFO_ERROR			(SPI_RX_UNF | SPI_TX_OVF)
89 #define SPI_FIFO_EMPTY			(SPI_TX_EMPTY | SPI_RX_EMPTY)
90 
91 #define SPI_RX_CMP			0x8
92 #define SPI_DMA_CTL			0x0C
93 #define SPI_DMA_EN			BIT(31)
94 #define SPI_IE_RXC			BIT(27)
95 #define SPI_IE_TXC			BIT(26)
96 #define SPI_PACKED			BIT(20)
97 #define SPI_RX_TRIG_MASK		(0x3 << 18)
98 #define SPI_RX_TRIG_1W			(0x0 << 18)
99 #define SPI_RX_TRIG_4W			(0x1 << 18)
100 #define SPI_TX_TRIG_MASK		(0x3 << 16)
101 #define SPI_TX_TRIG_1W			(0x0 << 16)
102 #define SPI_TX_TRIG_4W			(0x1 << 16)
103 #define SPI_DMA_BLK_COUNT(count)	(((count) - 1) & 0xFFFF);
104 
105 #define SPI_TX_FIFO			0x10
106 #define SPI_RX_FIFO			0x20
107 
108 #define DATA_DIR_TX			(1 << 0)
109 #define DATA_DIR_RX			(1 << 1)
110 
111 #define MAX_CHIP_SELECT			4
112 #define SPI_FIFO_DEPTH			4
113 #define SPI_DMA_TIMEOUT               (msecs_to_jiffies(1000))
114 
115 struct tegra_sflash_data {
116 	struct device				*dev;
117 	struct spi_master			*master;
118 	spinlock_t				lock;
119 
120 	struct clk				*clk;
121 	void __iomem				*base;
122 	unsigned				irq;
123 	u32					spi_max_frequency;
124 	u32					cur_speed;
125 
126 	struct spi_device			*cur_spi;
127 	unsigned				cur_pos;
128 	unsigned				cur_len;
129 	unsigned				bytes_per_word;
130 	unsigned				cur_direction;
131 	unsigned				curr_xfer_words;
132 
133 	unsigned				cur_rx_pos;
134 	unsigned				cur_tx_pos;
135 
136 	u32					tx_status;
137 	u32					rx_status;
138 	u32					status_reg;
139 
140 	u32					def_command_reg;
141 	u32					command_reg;
142 	u32					dma_control_reg;
143 
144 	struct completion			xfer_completion;
145 	struct spi_transfer			*curr_xfer;
146 };
147 
148 static int tegra_sflash_runtime_suspend(struct device *dev);
149 static int tegra_sflash_runtime_resume(struct device *dev);
150 
151 static inline unsigned long tegra_sflash_readl(struct tegra_sflash_data *tsd,
152 		unsigned long reg)
153 {
154 	return readl(tsd->base + reg);
155 }
156 
157 static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd,
158 		unsigned long val, unsigned long reg)
159 {
160 	writel(val, tsd->base + reg);
161 }
162 
163 static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd)
164 {
165 	/* Write 1 to clear status register */
166 	tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, SPI_STATUS);
167 }
168 
169 static unsigned tegra_sflash_calculate_curr_xfer_param(
170 	struct spi_device *spi, struct tegra_sflash_data *tsd,
171 	struct spi_transfer *t)
172 {
173 	unsigned remain_len = t->len - tsd->cur_pos;
174 	unsigned max_word;
175 
176 	tsd->bytes_per_word = (t->bits_per_word - 1) / 8 + 1;
177 	max_word = remain_len / tsd->bytes_per_word;
178 	if (max_word > SPI_FIFO_DEPTH)
179 		max_word = SPI_FIFO_DEPTH;
180 	tsd->curr_xfer_words = max_word;
181 	return max_word;
182 }
183 
184 static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf(
185 	struct tegra_sflash_data *tsd, struct spi_transfer *t)
186 {
187 	unsigned nbytes;
188 	unsigned long status;
189 	unsigned max_n_32bit = tsd->curr_xfer_words;
190 	u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos;
191 
192 	if (max_n_32bit > SPI_FIFO_DEPTH)
193 		max_n_32bit = SPI_FIFO_DEPTH;
194 	nbytes = max_n_32bit * tsd->bytes_per_word;
195 
196 	status = tegra_sflash_readl(tsd, SPI_STATUS);
197 	while (!(status & SPI_TXF_FULL)) {
198 		int i;
199 		unsigned int x = 0;
200 
201 		for (i = 0; nbytes && (i < tsd->bytes_per_word);
202 							i++, nbytes--)
203 				x |= ((*tx_buf++) << i*8);
204 		tegra_sflash_writel(tsd, x, SPI_TX_FIFO);
205 		if (!nbytes)
206 			break;
207 
208 		status = tegra_sflash_readl(tsd, SPI_STATUS);
209 	}
210 	tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word;
211 	return max_n_32bit;
212 }
213 
214 static int tegra_sflash_read_rx_fifo_to_client_rxbuf(
215 		struct tegra_sflash_data *tsd, struct spi_transfer *t)
216 {
217 	unsigned long status;
218 	unsigned int read_words = 0;
219 	u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos;
220 
221 	status = tegra_sflash_readl(tsd, SPI_STATUS);
222 	while (!(status & SPI_RXF_EMPTY)) {
223 		int i;
224 		unsigned long x;
225 
226 		x = tegra_sflash_readl(tsd, SPI_RX_FIFO);
227 		for (i = 0; (i < tsd->bytes_per_word); i++)
228 			*rx_buf++ = (x >> (i*8)) & 0xFF;
229 		read_words++;
230 		status = tegra_sflash_readl(tsd, SPI_STATUS);
231 	}
232 	tsd->cur_rx_pos += read_words * tsd->bytes_per_word;
233 	return 0;
234 }
235 
236 static int tegra_sflash_start_cpu_based_transfer(
237 		struct tegra_sflash_data *tsd, struct spi_transfer *t)
238 {
239 	unsigned long val = 0;
240 	unsigned cur_words;
241 
242 	if (tsd->cur_direction & DATA_DIR_TX)
243 		val |= SPI_IE_TXC;
244 
245 	if (tsd->cur_direction & DATA_DIR_RX)
246 		val |= SPI_IE_RXC;
247 
248 	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
249 	tsd->dma_control_reg = val;
250 
251 	if (tsd->cur_direction & DATA_DIR_TX)
252 		cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t);
253 	else
254 		cur_words = tsd->curr_xfer_words;
255 	val |= SPI_DMA_BLK_COUNT(cur_words);
256 	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
257 	tsd->dma_control_reg = val;
258 	val |= SPI_DMA_EN;
259 	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
260 	return 0;
261 }
262 
263 static int tegra_sflash_start_transfer_one(struct spi_device *spi,
264 		struct spi_transfer *t, bool is_first_of_msg,
265 		bool is_single_xfer)
266 {
267 	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
268 	u32 speed;
269 	unsigned long command;
270 
271 	speed = t->speed_hz;
272 	if (speed != tsd->cur_speed) {
273 		clk_set_rate(tsd->clk, speed);
274 		tsd->cur_speed = speed;
275 	}
276 
277 	tsd->cur_spi = spi;
278 	tsd->cur_pos = 0;
279 	tsd->cur_rx_pos = 0;
280 	tsd->cur_tx_pos = 0;
281 	tsd->curr_xfer = t;
282 	tegra_sflash_calculate_curr_xfer_param(spi, tsd, t);
283 	if (is_first_of_msg) {
284 		command = tsd->def_command_reg;
285 		command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
286 		command |= SPI_CS_VAL_HIGH;
287 
288 		command &= ~SPI_MODES;
289 		if (spi->mode & SPI_CPHA)
290 			command |= SPI_CK_SDA_FALLING;
291 
292 		if (spi->mode & SPI_CPOL)
293 			command |= SPI_ACTIVE_SCLK_DRIVE_HIGH;
294 		else
295 			command |= SPI_ACTIVE_SCLK_DRIVE_LOW;
296 		command |= SPI_CS0_EN << spi->chip_select;
297 	} else {
298 		command = tsd->command_reg;
299 		command &= ~SPI_BIT_LENGTH(~0);
300 		command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
301 		command &= ~(SPI_RX_EN | SPI_TX_EN);
302 	}
303 
304 	tsd->cur_direction = 0;
305 	if (t->rx_buf) {
306 		command |= SPI_RX_EN;
307 		tsd->cur_direction |= DATA_DIR_RX;
308 	}
309 	if (t->tx_buf) {
310 		command |= SPI_TX_EN;
311 		tsd->cur_direction |= DATA_DIR_TX;
312 	}
313 	tegra_sflash_writel(tsd, command, SPI_COMMAND);
314 	tsd->command_reg = command;
315 
316 	return  tegra_sflash_start_cpu_based_transfer(tsd, t);
317 }
318 
319 static int tegra_sflash_setup(struct spi_device *spi)
320 {
321 	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
322 
323 	/* Set speed to the spi max fequency if spi device has not set */
324 	spi->max_speed_hz = spi->max_speed_hz ? : tsd->spi_max_frequency;
325 	return 0;
326 }
327 
328 static int tegra_sflash_transfer_one_message(struct spi_master *master,
329 			struct spi_message *msg)
330 {
331 	bool is_first_msg = true;
332 	int single_xfer;
333 	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
334 	struct spi_transfer *xfer;
335 	struct spi_device *spi = msg->spi;
336 	int ret;
337 
338 	msg->status = 0;
339 	msg->actual_length = 0;
340 	single_xfer = list_is_singular(&msg->transfers);
341 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
342 		INIT_COMPLETION(tsd->xfer_completion);
343 		ret = tegra_sflash_start_transfer_one(spi, xfer,
344 					is_first_msg, single_xfer);
345 		if (ret < 0) {
346 			dev_err(tsd->dev,
347 				"spi can not start transfer, err %d\n", ret);
348 			goto exit;
349 		}
350 		is_first_msg = false;
351 		ret = wait_for_completion_timeout(&tsd->xfer_completion,
352 						SPI_DMA_TIMEOUT);
353 		if (WARN_ON(ret == 0)) {
354 			dev_err(tsd->dev,
355 				"spi trasfer timeout, err %d\n", ret);
356 			ret = -EIO;
357 			goto exit;
358 		}
359 
360 		if (tsd->tx_status ||  tsd->rx_status) {
361 			dev_err(tsd->dev, "Error in Transfer\n");
362 			ret = -EIO;
363 			goto exit;
364 		}
365 		msg->actual_length += xfer->len;
366 		if (xfer->cs_change && xfer->delay_usecs) {
367 			tegra_sflash_writel(tsd, tsd->def_command_reg,
368 					SPI_COMMAND);
369 			udelay(xfer->delay_usecs);
370 		}
371 	}
372 	ret = 0;
373 exit:
374 	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
375 	msg->status = ret;
376 	spi_finalize_current_message(master);
377 	return ret;
378 }
379 
380 static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd)
381 {
382 	struct spi_transfer *t = tsd->curr_xfer;
383 	unsigned long flags;
384 
385 	spin_lock_irqsave(&tsd->lock, flags);
386 	if (tsd->tx_status || tsd->rx_status || (tsd->status_reg & SPI_BSY)) {
387 		dev_err(tsd->dev,
388 			"CpuXfer ERROR bit set 0x%x\n", tsd->status_reg);
389 		dev_err(tsd->dev,
390 			"CpuXfer 0x%08x:0x%08x\n", tsd->command_reg,
391 				tsd->dma_control_reg);
392 		tegra_periph_reset_assert(tsd->clk);
393 		udelay(2);
394 		tegra_periph_reset_deassert(tsd->clk);
395 		complete(&tsd->xfer_completion);
396 		goto exit;
397 	}
398 
399 	if (tsd->cur_direction & DATA_DIR_RX)
400 		tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t);
401 
402 	if (tsd->cur_direction & DATA_DIR_TX)
403 		tsd->cur_pos = tsd->cur_tx_pos;
404 	else
405 		tsd->cur_pos = tsd->cur_rx_pos;
406 
407 	if (tsd->cur_pos == t->len) {
408 		complete(&tsd->xfer_completion);
409 		goto exit;
410 	}
411 
412 	tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t);
413 	tegra_sflash_start_cpu_based_transfer(tsd, t);
414 exit:
415 	spin_unlock_irqrestore(&tsd->lock, flags);
416 	return IRQ_HANDLED;
417 }
418 
419 static irqreturn_t tegra_sflash_isr(int irq, void *context_data)
420 {
421 	struct tegra_sflash_data *tsd = context_data;
422 
423 	tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS);
424 	if (tsd->cur_direction & DATA_DIR_TX)
425 		tsd->tx_status = tsd->status_reg & SPI_TX_OVF;
426 
427 	if (tsd->cur_direction & DATA_DIR_RX)
428 		tsd->rx_status = tsd->status_reg & SPI_RX_UNF;
429 	tegra_sflash_clear_status(tsd);
430 
431 	return handle_cpu_based_xfer(tsd);
432 }
433 
434 static void tegra_sflash_parse_dt(struct tegra_sflash_data *tsd)
435 {
436 	struct device_node *np = tsd->dev->of_node;
437 
438 	if (of_property_read_u32(np, "spi-max-frequency",
439 					&tsd->spi_max_frequency))
440 		tsd->spi_max_frequency = 25000000; /* 25MHz */
441 }
442 
443 static struct of_device_id tegra_sflash_of_match[] = {
444 	{ .compatible = "nvidia,tegra20-sflash", },
445 	{}
446 };
447 MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);
448 
449 static int tegra_sflash_probe(struct platform_device *pdev)
450 {
451 	struct spi_master	*master;
452 	struct tegra_sflash_data	*tsd;
453 	struct resource		*r;
454 	int ret;
455 	const struct of_device_id *match;
456 
457 	match = of_match_device(tegra_sflash_of_match, &pdev->dev);
458 	if (!match) {
459 		dev_err(&pdev->dev, "Error: No device match found\n");
460 		return -ENODEV;
461 	}
462 
463 	master = spi_alloc_master(&pdev->dev, sizeof(*tsd));
464 	if (!master) {
465 		dev_err(&pdev->dev, "master allocation failed\n");
466 		return -ENOMEM;
467 	}
468 
469 	/* the spi->mode bits understood by this driver: */
470 	master->mode_bits = SPI_CPOL | SPI_CPHA;
471 	master->setup = tegra_sflash_setup;
472 	master->transfer_one_message = tegra_sflash_transfer_one_message;
473 	master->auto_runtime_pm = true;
474 	master->num_chipselect = MAX_CHIP_SELECT;
475 	master->bus_num = -1;
476 
477 	platform_set_drvdata(pdev, master);
478 	tsd = spi_master_get_devdata(master);
479 	tsd->master = master;
480 	tsd->dev = &pdev->dev;
481 	spin_lock_init(&tsd->lock);
482 
483 	tegra_sflash_parse_dt(tsd);
484 
485 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
486 	tsd->base = devm_ioremap_resource(&pdev->dev, r);
487 	if (IS_ERR(tsd->base)) {
488 		ret = PTR_ERR(tsd->base);
489 		goto exit_free_master;
490 	}
491 
492 	tsd->irq = platform_get_irq(pdev, 0);
493 	ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
494 			dev_name(&pdev->dev), tsd);
495 	if (ret < 0) {
496 		dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
497 					tsd->irq);
498 		goto exit_free_master;
499 	}
500 
501 	tsd->clk = devm_clk_get(&pdev->dev, NULL);
502 	if (IS_ERR(tsd->clk)) {
503 		dev_err(&pdev->dev, "can not get clock\n");
504 		ret = PTR_ERR(tsd->clk);
505 		goto exit_free_irq;
506 	}
507 
508 	init_completion(&tsd->xfer_completion);
509 	pm_runtime_enable(&pdev->dev);
510 	if (!pm_runtime_enabled(&pdev->dev)) {
511 		ret = tegra_sflash_runtime_resume(&pdev->dev);
512 		if (ret)
513 			goto exit_pm_disable;
514 	}
515 
516 	ret = pm_runtime_get_sync(&pdev->dev);
517 	if (ret < 0) {
518 		dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
519 		goto exit_pm_disable;
520 	}
521 
522 	/* Reset controller */
523 	tegra_periph_reset_assert(tsd->clk);
524 	udelay(2);
525 	tegra_periph_reset_deassert(tsd->clk);
526 
527 	tsd->def_command_reg  = SPI_M_S | SPI_CS_SW;
528 	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
529 	pm_runtime_put(&pdev->dev);
530 
531 	master->dev.of_node = pdev->dev.of_node;
532 	ret = spi_register_master(master);
533 	if (ret < 0) {
534 		dev_err(&pdev->dev, "can not register to master err %d\n", ret);
535 		goto exit_pm_disable;
536 	}
537 	return ret;
538 
539 exit_pm_disable:
540 	pm_runtime_disable(&pdev->dev);
541 	if (!pm_runtime_status_suspended(&pdev->dev))
542 		tegra_sflash_runtime_suspend(&pdev->dev);
543 exit_free_irq:
544 	free_irq(tsd->irq, tsd);
545 exit_free_master:
546 	spi_master_put(master);
547 	return ret;
548 }
549 
550 static int tegra_sflash_remove(struct platform_device *pdev)
551 {
552 	struct spi_master *master = platform_get_drvdata(pdev);
553 	struct tegra_sflash_data	*tsd = spi_master_get_devdata(master);
554 
555 	free_irq(tsd->irq, tsd);
556 	spi_unregister_master(master);
557 
558 	pm_runtime_disable(&pdev->dev);
559 	if (!pm_runtime_status_suspended(&pdev->dev))
560 		tegra_sflash_runtime_suspend(&pdev->dev);
561 
562 	return 0;
563 }
564 
565 #ifdef CONFIG_PM_SLEEP
566 static int tegra_sflash_suspend(struct device *dev)
567 {
568 	struct spi_master *master = dev_get_drvdata(dev);
569 
570 	return spi_master_suspend(master);
571 }
572 
573 static int tegra_sflash_resume(struct device *dev)
574 {
575 	struct spi_master *master = dev_get_drvdata(dev);
576 	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
577 	int ret;
578 
579 	ret = pm_runtime_get_sync(dev);
580 	if (ret < 0) {
581 		dev_err(dev, "pm runtime failed, e = %d\n", ret);
582 		return ret;
583 	}
584 	tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
585 	pm_runtime_put(dev);
586 
587 	return spi_master_resume(master);
588 }
589 #endif
590 
591 static int tegra_sflash_runtime_suspend(struct device *dev)
592 {
593 	struct spi_master *master = dev_get_drvdata(dev);
594 	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
595 
596 	/* Flush all write which are in PPSB queue by reading back */
597 	tegra_sflash_readl(tsd, SPI_COMMAND);
598 
599 	clk_disable_unprepare(tsd->clk);
600 	return 0;
601 }
602 
603 static int tegra_sflash_runtime_resume(struct device *dev)
604 {
605 	struct spi_master *master = dev_get_drvdata(dev);
606 	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
607 	int ret;
608 
609 	ret = clk_prepare_enable(tsd->clk);
610 	if (ret < 0) {
611 		dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
612 		return ret;
613 	}
614 	return 0;
615 }
616 
617 static const struct dev_pm_ops slink_pm_ops = {
618 	SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
619 		tegra_sflash_runtime_resume, NULL)
620 	SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
621 };
622 static struct platform_driver tegra_sflash_driver = {
623 	.driver = {
624 		.name		= "spi-tegra-sflash",
625 		.owner		= THIS_MODULE,
626 		.pm		= &slink_pm_ops,
627 		.of_match_table	= tegra_sflash_of_match,
628 	},
629 	.probe =	tegra_sflash_probe,
630 	.remove =	tegra_sflash_remove,
631 };
632 module_platform_driver(tegra_sflash_driver);
633 
634 MODULE_ALIAS("platform:spi-tegra-sflash");
635 MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
636 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
637 MODULE_LICENSE("GPL v2");
638