Linux-libre 5.3.12-gnu
[librecmc/linux-libre.git] / drivers / spi / 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/clk.h>
11 #include <linux/delay.h>
12 #include <linux/device.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <linux/module.h>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/reset.h>
20
21 #include <linux/spi/spi.h>
22
23 #define SUN6I_FIFO_DEPTH                128
24 #define SUN8I_FIFO_DEPTH                64
25
26 #define SUN6I_GBL_CTL_REG               0x04
27 #define SUN6I_GBL_CTL_BUS_ENABLE                BIT(0)
28 #define SUN6I_GBL_CTL_MASTER                    BIT(1)
29 #define SUN6I_GBL_CTL_TP                        BIT(7)
30 #define SUN6I_GBL_CTL_RST                       BIT(31)
31
32 #define SUN6I_TFR_CTL_REG               0x08
33 #define SUN6I_TFR_CTL_CPHA                      BIT(0)
34 #define SUN6I_TFR_CTL_CPOL                      BIT(1)
35 #define SUN6I_TFR_CTL_SPOL                      BIT(2)
36 #define SUN6I_TFR_CTL_CS_MASK                   0x30
37 #define SUN6I_TFR_CTL_CS(cs)                    (((cs) << 4) & SUN6I_TFR_CTL_CS_MASK)
38 #define SUN6I_TFR_CTL_CS_MANUAL                 BIT(6)
39 #define SUN6I_TFR_CTL_CS_LEVEL                  BIT(7)
40 #define SUN6I_TFR_CTL_DHB                       BIT(8)
41 #define SUN6I_TFR_CTL_FBS                       BIT(12)
42 #define SUN6I_TFR_CTL_XCH                       BIT(31)
43
44 #define SUN6I_INT_CTL_REG               0x10
45 #define SUN6I_INT_CTL_RF_RDY                    BIT(0)
46 #define SUN6I_INT_CTL_TF_ERQ                    BIT(4)
47 #define SUN6I_INT_CTL_RF_OVF                    BIT(8)
48 #define SUN6I_INT_CTL_TC                        BIT(12)
49
50 #define SUN6I_INT_STA_REG               0x14
51
52 #define SUN6I_FIFO_CTL_REG              0x18
53 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_MASK   0xff
54 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS   0
55 #define SUN6I_FIFO_CTL_RF_RST                   BIT(15)
56 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_MASK   0xff
57 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS   16
58 #define SUN6I_FIFO_CTL_TF_RST                   BIT(31)
59
60 #define SUN6I_FIFO_STA_REG              0x1c
61 #define SUN6I_FIFO_STA_RF_CNT_MASK              0x7f
62 #define SUN6I_FIFO_STA_RF_CNT_BITS              0
63 #define SUN6I_FIFO_STA_TF_CNT_MASK              0x7f
64 #define SUN6I_FIFO_STA_TF_CNT_BITS              16
65
66 #define SUN6I_CLK_CTL_REG               0x24
67 #define SUN6I_CLK_CTL_CDR2_MASK                 0xff
68 #define SUN6I_CLK_CTL_CDR2(div)                 (((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0)
69 #define SUN6I_CLK_CTL_CDR1_MASK                 0xf
70 #define SUN6I_CLK_CTL_CDR1(div)                 (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8)
71 #define SUN6I_CLK_CTL_DRS                       BIT(12)
72
73 #define SUN6I_MAX_XFER_SIZE             0xffffff
74
75 #define SUN6I_BURST_CNT_REG             0x30
76 #define SUN6I_BURST_CNT(cnt)                    ((cnt) & SUN6I_MAX_XFER_SIZE)
77
78 #define SUN6I_XMIT_CNT_REG              0x34
79 #define SUN6I_XMIT_CNT(cnt)                     ((cnt) & SUN6I_MAX_XFER_SIZE)
80
81 #define SUN6I_BURST_CTL_CNT_REG         0x38
82 #define SUN6I_BURST_CTL_CNT_STC(cnt)            ((cnt) & SUN6I_MAX_XFER_SIZE)
83
84 #define SUN6I_TXDATA_REG                0x200
85 #define SUN6I_RXDATA_REG                0x300
86
87 struct sun6i_spi {
88         struct spi_master       *master;
89         void __iomem            *base_addr;
90         struct clk              *hclk;
91         struct clk              *mclk;
92         struct reset_control    *rstc;
93
94         struct completion       done;
95
96         const u8                *tx_buf;
97         u8                      *rx_buf;
98         int                     len;
99         unsigned long           fifo_depth;
100 };
101
102 static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
103 {
104         return readl(sspi->base_addr + reg);
105 }
106
107 static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
108 {
109         writel(value, sspi->base_addr + reg);
110 }
111
112 static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi)
113 {
114         u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
115
116         reg >>= SUN6I_FIFO_STA_TF_CNT_BITS;
117
118         return reg & SUN6I_FIFO_STA_TF_CNT_MASK;
119 }
120
121 static inline void sun6i_spi_enable_interrupt(struct sun6i_spi *sspi, u32 mask)
122 {
123         u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
124
125         reg |= mask;
126         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
127 }
128
129 static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask)
130 {
131         u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
132
133         reg &= ~mask;
134         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
135 }
136
137 static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi, int len)
138 {
139         u32 reg, cnt;
140         u8 byte;
141
142         /* See how much data is available */
143         reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
144         reg &= SUN6I_FIFO_STA_RF_CNT_MASK;
145         cnt = reg >> SUN6I_FIFO_STA_RF_CNT_BITS;
146
147         if (len > cnt)
148                 len = cnt;
149
150         while (len--) {
151                 byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
152                 if (sspi->rx_buf)
153                         *sspi->rx_buf++ = byte;
154         }
155 }
156
157 static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi, int len)
158 {
159         u32 cnt;
160         u8 byte;
161
162         /* See how much data we can fit */
163         cnt = sspi->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi);
164
165         len = min3(len, (int)cnt, sspi->len);
166
167         while (len--) {
168                 byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
169                 writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
170                 sspi->len--;
171         }
172 }
173
174 static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
175 {
176         struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
177         u32 reg;
178
179         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
180         reg &= ~SUN6I_TFR_CTL_CS_MASK;
181         reg |= SUN6I_TFR_CTL_CS(spi->chip_select);
182
183         if (enable)
184                 reg |= SUN6I_TFR_CTL_CS_LEVEL;
185         else
186                 reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
187
188         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
189 }
190
191 static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
192 {
193         return SUN6I_MAX_XFER_SIZE - 1;
194 }
195
196 static int sun6i_spi_transfer_one(struct spi_master *master,
197                                   struct spi_device *spi,
198                                   struct spi_transfer *tfr)
199 {
200         struct sun6i_spi *sspi = spi_master_get_devdata(master);
201         unsigned int mclk_rate, div, timeout;
202         unsigned int start, end, tx_time;
203         unsigned int trig_level;
204         unsigned int tx_len = 0;
205         int ret = 0;
206         u32 reg;
207
208         if (tfr->len > SUN6I_MAX_XFER_SIZE)
209                 return -EINVAL;
210
211         reinit_completion(&sspi->done);
212         sspi->tx_buf = tfr->tx_buf;
213         sspi->rx_buf = tfr->rx_buf;
214         sspi->len = tfr->len;
215
216         /* Clear pending interrupts */
217         sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
218
219         /* Reset FIFO */
220         sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
221                         SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
222
223         /*
224          * Setup FIFO interrupt trigger level
225          * Here we choose 3/4 of the full fifo depth, as it's the hardcoded
226          * value used in old generation of Allwinner SPI controller.
227          * (See spi-sun4i.c)
228          */
229         trig_level = sspi->fifo_depth / 4 * 3;
230         sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
231                         (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
232                         (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS));
233
234         /*
235          * Setup the transfer control register: Chip Select,
236          * polarities, etc.
237          */
238         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
239
240         if (spi->mode & SPI_CPOL)
241                 reg |= SUN6I_TFR_CTL_CPOL;
242         else
243                 reg &= ~SUN6I_TFR_CTL_CPOL;
244
245         if (spi->mode & SPI_CPHA)
246                 reg |= SUN6I_TFR_CTL_CPHA;
247         else
248                 reg &= ~SUN6I_TFR_CTL_CPHA;
249
250         if (spi->mode & SPI_LSB_FIRST)
251                 reg |= SUN6I_TFR_CTL_FBS;
252         else
253                 reg &= ~SUN6I_TFR_CTL_FBS;
254
255         /*
256          * If it's a TX only transfer, we don't want to fill the RX
257          * FIFO with bogus data
258          */
259         if (sspi->rx_buf)
260                 reg &= ~SUN6I_TFR_CTL_DHB;
261         else
262                 reg |= SUN6I_TFR_CTL_DHB;
263
264         /* We want to control the chip select manually */
265         reg |= SUN6I_TFR_CTL_CS_MANUAL;
266
267         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
268
269         /* Ensure that we have a parent clock fast enough */
270         mclk_rate = clk_get_rate(sspi->mclk);
271         if (mclk_rate < (2 * tfr->speed_hz)) {
272                 clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
273                 mclk_rate = clk_get_rate(sspi->mclk);
274         }
275
276         /*
277          * Setup clock divider.
278          *
279          * We have two choices there. Either we can use the clock
280          * divide rate 1, which is calculated thanks to this formula:
281          * SPI_CLK = MOD_CLK / (2 ^ cdr)
282          * Or we can use CDR2, which is calculated with the formula:
283          * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
284          * Wether we use the former or the latter is set through the
285          * DRS bit.
286          *
287          * First try CDR2, and if we can't reach the expected
288          * frequency, fall back to CDR1.
289          */
290         div = mclk_rate / (2 * tfr->speed_hz);
291         if (div <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
292                 if (div > 0)
293                         div--;
294
295                 reg = SUN6I_CLK_CTL_CDR2(div) | SUN6I_CLK_CTL_DRS;
296         } else {
297                 div = ilog2(mclk_rate) - ilog2(tfr->speed_hz);
298                 reg = SUN6I_CLK_CTL_CDR1(div);
299         }
300
301         sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
302
303         /* Setup the transfer now... */
304         if (sspi->tx_buf)
305                 tx_len = tfr->len;
306
307         /* Setup the counters */
308         sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, SUN6I_BURST_CNT(tfr->len));
309         sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, SUN6I_XMIT_CNT(tx_len));
310         sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG,
311                         SUN6I_BURST_CTL_CNT_STC(tx_len));
312
313         /* Fill the TX FIFO */
314         sun6i_spi_fill_fifo(sspi, sspi->fifo_depth);
315
316         /* Enable the interrupts */
317         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, SUN6I_INT_CTL_TC);
318         sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TC |
319                                          SUN6I_INT_CTL_RF_RDY);
320         if (tx_len > sspi->fifo_depth)
321                 sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
322
323         /* Start the transfer */
324         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
325         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
326
327         tx_time = max(tfr->len * 8 * 2 / (tfr->speed_hz / 1000), 100U);
328         start = jiffies;
329         timeout = wait_for_completion_timeout(&sspi->done,
330                                               msecs_to_jiffies(tx_time));
331         end = jiffies;
332         if (!timeout) {
333                 dev_warn(&master->dev,
334                          "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
335                          dev_name(&spi->dev), tfr->len, tfr->speed_hz,
336                          jiffies_to_msecs(end - start), tx_time);
337                 ret = -ETIMEDOUT;
338                 goto out;
339         }
340
341 out:
342         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
343
344         return ret;
345 }
346
347 static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
348 {
349         struct sun6i_spi *sspi = dev_id;
350         u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
351
352         /* Transfer complete */
353         if (status & SUN6I_INT_CTL_TC) {
354                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
355                 sun6i_spi_drain_fifo(sspi, sspi->fifo_depth);
356                 complete(&sspi->done);
357                 return IRQ_HANDLED;
358         }
359
360         /* Receive FIFO 3/4 full */
361         if (status & SUN6I_INT_CTL_RF_RDY) {
362                 sun6i_spi_drain_fifo(sspi, SUN6I_FIFO_DEPTH);
363                 /* Only clear the interrupt _after_ draining the FIFO */
364                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
365                 return IRQ_HANDLED;
366         }
367
368         /* Transmit FIFO 3/4 empty */
369         if (status & SUN6I_INT_CTL_TF_ERQ) {
370                 sun6i_spi_fill_fifo(sspi, SUN6I_FIFO_DEPTH);
371
372                 if (!sspi->len)
373                         /* nothing left to transmit */
374                         sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
375
376                 /* Only clear the interrupt _after_ re-seeding the FIFO */
377                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
378
379                 return IRQ_HANDLED;
380         }
381
382         return IRQ_NONE;
383 }
384
385 static int sun6i_spi_runtime_resume(struct device *dev)
386 {
387         struct spi_master *master = dev_get_drvdata(dev);
388         struct sun6i_spi *sspi = spi_master_get_devdata(master);
389         int ret;
390
391         ret = clk_prepare_enable(sspi->hclk);
392         if (ret) {
393                 dev_err(dev, "Couldn't enable AHB clock\n");
394                 goto out;
395         }
396
397         ret = clk_prepare_enable(sspi->mclk);
398         if (ret) {
399                 dev_err(dev, "Couldn't enable module clock\n");
400                 goto err;
401         }
402
403         ret = reset_control_deassert(sspi->rstc);
404         if (ret) {
405                 dev_err(dev, "Couldn't deassert the device from reset\n");
406                 goto err2;
407         }
408
409         sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
410                         SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
411
412         return 0;
413
414 err2:
415         clk_disable_unprepare(sspi->mclk);
416 err:
417         clk_disable_unprepare(sspi->hclk);
418 out:
419         return ret;
420 }
421
422 static int sun6i_spi_runtime_suspend(struct device *dev)
423 {
424         struct spi_master *master = dev_get_drvdata(dev);
425         struct sun6i_spi *sspi = spi_master_get_devdata(master);
426
427         reset_control_assert(sspi->rstc);
428         clk_disable_unprepare(sspi->mclk);
429         clk_disable_unprepare(sspi->hclk);
430
431         return 0;
432 }
433
434 static int sun6i_spi_probe(struct platform_device *pdev)
435 {
436         struct spi_master *master;
437         struct sun6i_spi *sspi;
438         struct resource *res;
439         int ret = 0, irq;
440
441         master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
442         if (!master) {
443                 dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
444                 return -ENOMEM;
445         }
446
447         platform_set_drvdata(pdev, master);
448         sspi = spi_master_get_devdata(master);
449
450         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
451         sspi->base_addr = devm_ioremap_resource(&pdev->dev, res);
452         if (IS_ERR(sspi->base_addr)) {
453                 ret = PTR_ERR(sspi->base_addr);
454                 goto err_free_master;
455         }
456
457         irq = platform_get_irq(pdev, 0);
458         if (irq < 0) {
459                 dev_err(&pdev->dev, "No spi IRQ specified\n");
460                 ret = -ENXIO;
461                 goto err_free_master;
462         }
463
464         ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
465                                0, "sun6i-spi", sspi);
466         if (ret) {
467                 dev_err(&pdev->dev, "Cannot request IRQ\n");
468                 goto err_free_master;
469         }
470
471         sspi->master = master;
472         sspi->fifo_depth = (unsigned long)of_device_get_match_data(&pdev->dev);
473
474         master->max_speed_hz = 100 * 1000 * 1000;
475         master->min_speed_hz = 3 * 1000;
476         master->set_cs = sun6i_spi_set_cs;
477         master->transfer_one = sun6i_spi_transfer_one;
478         master->num_chipselect = 4;
479         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
480         master->bits_per_word_mask = SPI_BPW_MASK(8);
481         master->dev.of_node = pdev->dev.of_node;
482         master->auto_runtime_pm = true;
483         master->max_transfer_size = sun6i_spi_max_transfer_size;
484
485         sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
486         if (IS_ERR(sspi->hclk)) {
487                 dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
488                 ret = PTR_ERR(sspi->hclk);
489                 goto err_free_master;
490         }
491
492         sspi->mclk = devm_clk_get(&pdev->dev, "mod");
493         if (IS_ERR(sspi->mclk)) {
494                 dev_err(&pdev->dev, "Unable to acquire module clock\n");
495                 ret = PTR_ERR(sspi->mclk);
496                 goto err_free_master;
497         }
498
499         init_completion(&sspi->done);
500
501         sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
502         if (IS_ERR(sspi->rstc)) {
503                 dev_err(&pdev->dev, "Couldn't get reset controller\n");
504                 ret = PTR_ERR(sspi->rstc);
505                 goto err_free_master;
506         }
507
508         /*
509          * This wake-up/shutdown pattern is to be able to have the
510          * device woken up, even if runtime_pm is disabled
511          */
512         ret = sun6i_spi_runtime_resume(&pdev->dev);
513         if (ret) {
514                 dev_err(&pdev->dev, "Couldn't resume the device\n");
515                 goto err_free_master;
516         }
517
518         pm_runtime_set_active(&pdev->dev);
519         pm_runtime_enable(&pdev->dev);
520         pm_runtime_idle(&pdev->dev);
521
522         ret = devm_spi_register_master(&pdev->dev, master);
523         if (ret) {
524                 dev_err(&pdev->dev, "cannot register SPI master\n");
525                 goto err_pm_disable;
526         }
527
528         return 0;
529
530 err_pm_disable:
531         pm_runtime_disable(&pdev->dev);
532         sun6i_spi_runtime_suspend(&pdev->dev);
533 err_free_master:
534         spi_master_put(master);
535         return ret;
536 }
537
538 static int sun6i_spi_remove(struct platform_device *pdev)
539 {
540         pm_runtime_force_suspend(&pdev->dev);
541
542         return 0;
543 }
544
545 static const struct of_device_id sun6i_spi_match[] = {
546         { .compatible = "allwinner,sun6i-a31-spi", .data = (void *)SUN6I_FIFO_DEPTH },
547         { .compatible = "allwinner,sun8i-h3-spi",  .data = (void *)SUN8I_FIFO_DEPTH },
548         {}
549 };
550 MODULE_DEVICE_TABLE(of, sun6i_spi_match);
551
552 static const struct dev_pm_ops sun6i_spi_pm_ops = {
553         .runtime_resume         = sun6i_spi_runtime_resume,
554         .runtime_suspend        = sun6i_spi_runtime_suspend,
555 };
556
557 static struct platform_driver sun6i_spi_driver = {
558         .probe  = sun6i_spi_probe,
559         .remove = sun6i_spi_remove,
560         .driver = {
561                 .name           = "sun6i-spi",
562                 .of_match_table = sun6i_spi_match,
563                 .pm             = &sun6i_spi_pm_ops,
564         },
565 };
566 module_platform_driver(sun6i_spi_driver);
567
568 MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
569 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
570 MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
571 MODULE_LICENSE("GPL");