803d92f8d031666eb814696abc46012248683664
[releases.git] / spi-sun6i.c
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
22 #include <linux/spi/spi.h>
23
24 #define SUN6I_FIFO_DEPTH                128
25 #define SUN8I_FIFO_DEPTH                64
26
27 #define SUN6I_GBL_CTL_REG               0x04
28 #define SUN6I_GBL_CTL_BUS_ENABLE                BIT(0)
29 #define SUN6I_GBL_CTL_MASTER                    BIT(1)
30 #define SUN6I_GBL_CTL_TP                        BIT(7)
31 #define SUN6I_GBL_CTL_RST                       BIT(31)
32
33 #define SUN6I_TFR_CTL_REG               0x08
34 #define SUN6I_TFR_CTL_CPHA                      BIT(0)
35 #define SUN6I_TFR_CTL_CPOL                      BIT(1)
36 #define SUN6I_TFR_CTL_SPOL                      BIT(2)
37 #define SUN6I_TFR_CTL_CS_MASK                   0x30
38 #define SUN6I_TFR_CTL_CS(cs)                    (((cs) << 4) & SUN6I_TFR_CTL_CS_MASK)
39 #define SUN6I_TFR_CTL_CS_MANUAL                 BIT(6)
40 #define SUN6I_TFR_CTL_CS_LEVEL                  BIT(7)
41 #define SUN6I_TFR_CTL_DHB                       BIT(8)
42 #define SUN6I_TFR_CTL_FBS                       BIT(12)
43 #define SUN6I_TFR_CTL_XCH                       BIT(31)
44
45 #define SUN6I_INT_CTL_REG               0x10
46 #define SUN6I_INT_CTL_RF_RDY                    BIT(0)
47 #define SUN6I_INT_CTL_TF_ERQ                    BIT(4)
48 #define SUN6I_INT_CTL_RF_OVF                    BIT(8)
49 #define SUN6I_INT_CTL_TC                        BIT(12)
50
51 #define SUN6I_INT_STA_REG               0x14
52
53 #define SUN6I_FIFO_CTL_REG              0x18
54 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_MASK   0xff
55 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS   0
56 #define SUN6I_FIFO_CTL_RF_RST                   BIT(15)
57 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_MASK   0xff
58 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS   16
59 #define SUN6I_FIFO_CTL_TF_RST                   BIT(31)
60
61 #define SUN6I_FIFO_STA_REG              0x1c
62 #define SUN6I_FIFO_STA_RF_CNT_MASK              GENMASK(7, 0)
63 #define SUN6I_FIFO_STA_TF_CNT_MASK              GENMASK(23, 16)
64
65 #define SUN6I_CLK_CTL_REG               0x24
66 #define SUN6I_CLK_CTL_CDR2_MASK                 0xff
67 #define SUN6I_CLK_CTL_CDR2(div)                 (((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0)
68 #define SUN6I_CLK_CTL_CDR1_MASK                 0xf
69 #define SUN6I_CLK_CTL_CDR1(div)                 (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8)
70 #define SUN6I_CLK_CTL_DRS                       BIT(12)
71
72 #define SUN6I_MAX_XFER_SIZE             0xffffff
73
74 #define SUN6I_BURST_CNT_REG             0x30
75
76 #define SUN6I_XMIT_CNT_REG              0x34
77
78 #define SUN6I_BURST_CTL_CNT_REG         0x38
79
80 #define SUN6I_TXDATA_REG                0x200
81 #define SUN6I_RXDATA_REG                0x300
82
83 struct sun6i_spi {
84         struct spi_master       *master;
85         void __iomem            *base_addr;
86         struct clk              *hclk;
87         struct clk              *mclk;
88         struct reset_control    *rstc;
89
90         struct completion       done;
91
92         const u8                *tx_buf;
93         u8                      *rx_buf;
94         int                     len;
95         unsigned long           fifo_depth;
96 };
97
98 static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
99 {
100         return readl(sspi->base_addr + reg);
101 }
102
103 static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
104 {
105         writel(value, sspi->base_addr + reg);
106 }
107
108 static inline u32 sun6i_spi_get_rx_fifo_count(struct sun6i_spi *sspi)
109 {
110         u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
111
112         return FIELD_GET(SUN6I_FIFO_STA_RF_CNT_MASK, reg);
113 }
114
115 static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi)
116 {
117         u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
118
119         return FIELD_GET(SUN6I_FIFO_STA_TF_CNT_MASK, reg);
120 }
121
122 static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask)
123 {
124         u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
125
126         reg &= ~mask;
127         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
128 }
129
130 static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi)
131 {
132         u32 len;
133         u8 byte;
134
135         /* See how much data is available */
136         len = sun6i_spi_get_rx_fifo_count(sspi);
137
138         while (len--) {
139                 byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
140                 if (sspi->rx_buf)
141                         *sspi->rx_buf++ = byte;
142         }
143 }
144
145 static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi)
146 {
147         u32 cnt;
148         int len;
149         u8 byte;
150
151         /* See how much data we can fit */
152         cnt = sspi->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi);
153
154         len = min((int)cnt, sspi->len);
155
156         while (len--) {
157                 byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
158                 writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
159                 sspi->len--;
160         }
161 }
162
163 static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
164 {
165         struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
166         u32 reg;
167
168         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
169         reg &= ~SUN6I_TFR_CTL_CS_MASK;
170         reg |= SUN6I_TFR_CTL_CS(spi->chip_select);
171
172         if (enable)
173                 reg |= SUN6I_TFR_CTL_CS_LEVEL;
174         else
175                 reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
176
177         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
178 }
179
180 static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
181 {
182         return SUN6I_MAX_XFER_SIZE - 1;
183 }
184
185 static int sun6i_spi_transfer_one(struct spi_master *master,
186                                   struct spi_device *spi,
187                                   struct spi_transfer *tfr)
188 {
189         struct sun6i_spi *sspi = spi_master_get_devdata(master);
190         unsigned int mclk_rate, div, div_cdr1, div_cdr2, timeout;
191         unsigned int start, end, tx_time;
192         unsigned int trig_level;
193         unsigned int tx_len = 0, rx_len = 0;
194         int ret = 0;
195         u32 reg;
196
197         if (tfr->len > SUN6I_MAX_XFER_SIZE)
198                 return -EINVAL;
199
200         reinit_completion(&sspi->done);
201         sspi->tx_buf = tfr->tx_buf;
202         sspi->rx_buf = tfr->rx_buf;
203         sspi->len = tfr->len;
204
205         /* Clear pending interrupts */
206         sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
207
208         /* Reset FIFO */
209         sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
210                         SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
211
212         /*
213          * Setup FIFO interrupt trigger level
214          * Here we choose 3/4 of the full fifo depth, as it's the hardcoded
215          * value used in old generation of Allwinner SPI controller.
216          * (See spi-sun4i.c)
217          */
218         trig_level = sspi->fifo_depth / 4 * 3;
219         sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
220                         (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
221                         (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS));
222
223         /*
224          * Setup the transfer control register: Chip Select,
225          * polarities, etc.
226          */
227         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
228
229         if (spi->mode & SPI_CPOL)
230                 reg |= SUN6I_TFR_CTL_CPOL;
231         else
232                 reg &= ~SUN6I_TFR_CTL_CPOL;
233
234         if (spi->mode & SPI_CPHA)
235                 reg |= SUN6I_TFR_CTL_CPHA;
236         else
237                 reg &= ~SUN6I_TFR_CTL_CPHA;
238
239         if (spi->mode & SPI_LSB_FIRST)
240                 reg |= SUN6I_TFR_CTL_FBS;
241         else
242                 reg &= ~SUN6I_TFR_CTL_FBS;
243
244         /*
245          * If it's a TX only transfer, we don't want to fill the RX
246          * FIFO with bogus data
247          */
248         if (sspi->rx_buf) {
249                 reg &= ~SUN6I_TFR_CTL_DHB;
250                 rx_len = tfr->len;
251         } else {
252                 reg |= SUN6I_TFR_CTL_DHB;
253         }
254
255         /* We want to control the chip select manually */
256         reg |= SUN6I_TFR_CTL_CS_MANUAL;
257
258         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
259
260         /* Ensure that we have a parent clock fast enough */
261         mclk_rate = clk_get_rate(sspi->mclk);
262         if (mclk_rate < (2 * tfr->speed_hz)) {
263                 clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
264                 mclk_rate = clk_get_rate(sspi->mclk);
265         }
266
267         /*
268          * Setup clock divider.
269          *
270          * We have two choices there. Either we can use the clock
271          * divide rate 1, which is calculated thanks to this formula:
272          * SPI_CLK = MOD_CLK / (2 ^ cdr)
273          * Or we can use CDR2, which is calculated with the formula:
274          * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
275          * Wether we use the former or the latter is set through the
276          * DRS bit.
277          *
278          * First try CDR2, and if we can't reach the expected
279          * frequency, fall back to CDR1.
280          */
281         div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz);
282         div_cdr2 = DIV_ROUND_UP(div_cdr1, 2);
283         if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
284                 reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS;
285                 tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2);
286         } else {
287                 div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1));
288                 reg = SUN6I_CLK_CTL_CDR1(div);
289                 tfr->effective_speed_hz = mclk_rate / (1 << div);
290         }
291
292         sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
293         /* Finally enable the bus - doing so before might raise SCK to HIGH */
294         reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG);
295         reg |= SUN6I_GBL_CTL_BUS_ENABLE;
296         sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, reg);
297
298         /* Setup the transfer now... */
299         if (sspi->tx_buf)
300                 tx_len = tfr->len;
301
302         /* Setup the counters */
303         sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, tfr->len);
304         sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, tx_len);
305         sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG, tx_len);
306
307         /* Fill the TX FIFO */
308         sun6i_spi_fill_fifo(sspi);
309
310         /* Enable the interrupts */
311         reg = SUN6I_INT_CTL_TC;
312
313         if (rx_len > sspi->fifo_depth)
314                 reg |= SUN6I_INT_CTL_RF_RDY;
315         if (tx_len > sspi->fifo_depth)
316                 reg |= SUN6I_INT_CTL_TF_ERQ;
317
318         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
319
320         /* Start the transfer */
321         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
322         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
323
324         tx_time = max(tfr->len * 8 * 2 / (tfr->speed_hz / 1000), 100U);
325         start = jiffies;
326         timeout = wait_for_completion_timeout(&sspi->done,
327                                               msecs_to_jiffies(tx_time));
328         end = jiffies;
329         if (!timeout) {
330                 dev_warn(&master->dev,
331                          "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
332                          dev_name(&spi->dev), tfr->len, tfr->speed_hz,
333                          jiffies_to_msecs(end - start), tx_time);
334                 ret = -ETIMEDOUT;
335         }
336
337         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
338
339         return ret;
340 }
341
342 static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
343 {
344         struct sun6i_spi *sspi = dev_id;
345         u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
346
347         /* Transfer complete */
348         if (status & SUN6I_INT_CTL_TC) {
349                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
350                 sun6i_spi_drain_fifo(sspi);
351                 complete(&sspi->done);
352                 return IRQ_HANDLED;
353         }
354
355         /* Receive FIFO 3/4 full */
356         if (status & SUN6I_INT_CTL_RF_RDY) {
357                 sun6i_spi_drain_fifo(sspi);
358                 /* Only clear the interrupt _after_ draining the FIFO */
359                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
360                 return IRQ_HANDLED;
361         }
362
363         /* Transmit FIFO 3/4 empty */
364         if (status & SUN6I_INT_CTL_TF_ERQ) {
365                 sun6i_spi_fill_fifo(sspi);
366
367                 if (!sspi->len)
368                         /* nothing left to transmit */
369                         sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
370
371                 /* Only clear the interrupt _after_ re-seeding the FIFO */
372                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
373
374                 return IRQ_HANDLED;
375         }
376
377         return IRQ_NONE;
378 }
379
380 static int sun6i_spi_runtime_resume(struct device *dev)
381 {
382         struct spi_master *master = dev_get_drvdata(dev);
383         struct sun6i_spi *sspi = spi_master_get_devdata(master);
384         int ret;
385
386         ret = clk_prepare_enable(sspi->hclk);
387         if (ret) {
388                 dev_err(dev, "Couldn't enable AHB clock\n");
389                 goto out;
390         }
391
392         ret = clk_prepare_enable(sspi->mclk);
393         if (ret) {
394                 dev_err(dev, "Couldn't enable module clock\n");
395                 goto err;
396         }
397
398         ret = reset_control_deassert(sspi->rstc);
399         if (ret) {
400                 dev_err(dev, "Couldn't deassert the device from reset\n");
401                 goto err2;
402         }
403
404         sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
405                         SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
406
407         return 0;
408
409 err2:
410         clk_disable_unprepare(sspi->mclk);
411 err:
412         clk_disable_unprepare(sspi->hclk);
413 out:
414         return ret;
415 }
416
417 static int sun6i_spi_runtime_suspend(struct device *dev)
418 {
419         struct spi_master *master = dev_get_drvdata(dev);
420         struct sun6i_spi *sspi = spi_master_get_devdata(master);
421
422         reset_control_assert(sspi->rstc);
423         clk_disable_unprepare(sspi->mclk);
424         clk_disable_unprepare(sspi->hclk);
425
426         return 0;
427 }
428
429 static int sun6i_spi_probe(struct platform_device *pdev)
430 {
431         struct spi_master *master;
432         struct sun6i_spi *sspi;
433         int ret = 0, irq;
434
435         master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
436         if (!master) {
437                 dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
438                 return -ENOMEM;
439         }
440
441         platform_set_drvdata(pdev, master);
442         sspi = spi_master_get_devdata(master);
443
444         sspi->base_addr = devm_platform_ioremap_resource(pdev, 0);
445         if (IS_ERR(sspi->base_addr)) {
446                 ret = PTR_ERR(sspi->base_addr);
447                 goto err_free_master;
448         }
449
450         irq = platform_get_irq(pdev, 0);
451         if (irq < 0) {
452                 ret = -ENXIO;
453                 goto err_free_master;
454         }
455
456         ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
457                                0, "sun6i-spi", sspi);
458         if (ret) {
459                 dev_err(&pdev->dev, "Cannot request IRQ\n");
460                 goto err_free_master;
461         }
462
463         sspi->master = master;
464         sspi->fifo_depth = (unsigned long)of_device_get_match_data(&pdev->dev);
465
466         master->max_speed_hz = 100 * 1000 * 1000;
467         master->min_speed_hz = 3 * 1000;
468         master->use_gpio_descriptors = true;
469         master->set_cs = sun6i_spi_set_cs;
470         master->transfer_one = sun6i_spi_transfer_one;
471         master->num_chipselect = 4;
472         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
473         master->bits_per_word_mask = SPI_BPW_MASK(8);
474         master->dev.of_node = pdev->dev.of_node;
475         master->auto_runtime_pm = true;
476         master->max_transfer_size = sun6i_spi_max_transfer_size;
477
478         sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
479         if (IS_ERR(sspi->hclk)) {
480                 dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
481                 ret = PTR_ERR(sspi->hclk);
482                 goto err_free_master;
483         }
484
485         sspi->mclk = devm_clk_get(&pdev->dev, "mod");
486         if (IS_ERR(sspi->mclk)) {
487                 dev_err(&pdev->dev, "Unable to acquire module clock\n");
488                 ret = PTR_ERR(sspi->mclk);
489                 goto err_free_master;
490         }
491
492         init_completion(&sspi->done);
493
494         sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
495         if (IS_ERR(sspi->rstc)) {
496                 dev_err(&pdev->dev, "Couldn't get reset controller\n");
497                 ret = PTR_ERR(sspi->rstc);
498                 goto err_free_master;
499         }
500
501         /*
502          * This wake-up/shutdown pattern is to be able to have the
503          * device woken up, even if runtime_pm is disabled
504          */
505         ret = sun6i_spi_runtime_resume(&pdev->dev);
506         if (ret) {
507                 dev_err(&pdev->dev, "Couldn't resume the device\n");
508                 goto err_free_master;
509         }
510
511         pm_runtime_set_active(&pdev->dev);
512         pm_runtime_enable(&pdev->dev);
513         pm_runtime_idle(&pdev->dev);
514
515         ret = devm_spi_register_master(&pdev->dev, master);
516         if (ret) {
517                 dev_err(&pdev->dev, "cannot register SPI master\n");
518                 goto err_pm_disable;
519         }
520
521         return 0;
522
523 err_pm_disable:
524         pm_runtime_disable(&pdev->dev);
525         sun6i_spi_runtime_suspend(&pdev->dev);
526 err_free_master:
527         spi_master_put(master);
528         return ret;
529 }
530
531 static int sun6i_spi_remove(struct platform_device *pdev)
532 {
533         pm_runtime_force_suspend(&pdev->dev);
534
535         return 0;
536 }
537
538 static const struct of_device_id sun6i_spi_match[] = {
539         { .compatible = "allwinner,sun6i-a31-spi", .data = (void *)SUN6I_FIFO_DEPTH },
540         { .compatible = "allwinner,sun8i-h3-spi",  .data = (void *)SUN8I_FIFO_DEPTH },
541         {}
542 };
543 MODULE_DEVICE_TABLE(of, sun6i_spi_match);
544
545 static const struct dev_pm_ops sun6i_spi_pm_ops = {
546         .runtime_resume         = sun6i_spi_runtime_resume,
547         .runtime_suspend        = sun6i_spi_runtime_suspend,
548 };
549
550 static struct platform_driver sun6i_spi_driver = {
551         .probe  = sun6i_spi_probe,
552         .remove = sun6i_spi_remove,
553         .driver = {
554                 .name           = "sun6i-spi",
555                 .of_match_table = sun6i_spi_match,
556                 .pm             = &sun6i_spi_pm_ops,
557         },
558 };
559 module_platform_driver(sun6i_spi_driver);
560
561 MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
562 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
563 MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
564 MODULE_LICENSE("GPL");